JP6892191B2 - Power system - Google Patents

Description

The present disclosure relates to a grid-connected electric power system, and more particularly to an electric power system that controls an adjustment target electric power to a target electric power.

In recent years, power generation systems using renewable energy have become widespread. One example is a photovoltaic power generation system that uses sunlight. The photovoltaic power generation system is equipped with a solar cell and a power conditioner. The solar cell generates DC power, and the power conditioner converts this DC power into AC power. The converted AC power is supplied to the power system. Photovoltaic power generation systems range from small-scale ones for general households to large-scale ones such as mega solar systems.

Large-scale photovoltaic power generation systems are equipped with multiple power conditioners, each of which is connected to an electric power system. For example, the photovoltaic power generation system disclosed in Patent Document 1 includes a plurality of solar cells, a plurality of power conditioners, and a monitoring and control system. The monitoring and control system monitors and controls the plurality of power conditioners. Specifically, the monitoring and control system monitors input / output power, input / output voltage, input / output current, etc. of a plurality of power conditioners, and controls such as changing the output voltage.

Japanese Unexamined Patent Publication No. 2012-205322

Since the above-mentioned monitoring and control system monitors and controls each power conditioner, the processing load inevitably increases as the number of power conditioners to be monitored and controlled increases. The high load problem of such a monitoring and control system is not limited to the photovoltaic power generation system, but also in other power generation systems in which a plurality of power devices (such as a power conditioner and a control device for controlling output power) are monitored by the monitoring and control system. Also occurs.

The electric power system according to the present disclosure was created in view of the above circumstances. Therefore, the purpose is to provide a power system capable of setting the adjustment target power to a target value while reducing the processing load of the device that manages a plurality of power devices.

The electric power system provided by the first aspect of the present invention is an electric power system connected to an electric power system, and includes a plurality of electric power devices and a centralized management device for managing the plurality of electric power devices. The centralized management device has an individual output of each of the plurality of power devices based on the detection means for detecting the power to be adjusted and the power to be adjusted and the target power so that the power to be adjusted becomes the target power. An index calculating means for calculating an index for controlling electric power and a transmitting means for transmitting the index to the plurality of electric power devices are provided, and each of the plurality of electric power devices receives the index. The means, the target power calculation means for calculating the individual target power of each power device based on the optimization problem using the index, and the individual output power of each power device so as to be the individual target power. The index calculation means includes a control means for controlling, a calculation means for performing an operation using the adjustment target power and the target power, the adjustment target power detected by the detection means, and the calculation. A change in the adjustment target power and a change in the calculation result by using a storage means for sequentially storing the calculation result calculated by the means, a plurality of the adjustment target powers stored in the storage means, and the plurality of the calculation results. Based on the above, the first determination means for determining whether or not the calculation result of the calculation means tends to diverge, and when the calculation result of the calculation means tends to diverge, a predetermined alternative value is used as the index, while When the calculation result does not tend to diverge, the determination means using the calculation result as the index is provided, and the first determination means has a change in the power to be adjusted smaller than a predetermined threshold value. If it is determined that the calculation result tends to diverge when the calculation result is decreasing or increasing, and the determining means is determined to have a diverging tendency by the first determining means, the above-mentioned before the determination. It is characterized in that any one of the plurality of calculation results stored in the storage means is used as the alternative value.

In a preferred embodiment of the power system, the index calculation means further includes a second determination means for determining that the calculation result tends to diverge when the calculation result is outside the divergence determination range, and the determination is made. When the means is determined by the second determination means to have a divergence tendency, when the calculation result is less than the lower limit value of the divergence determination range, the lower limit value is used as the alternative value, and the calculation result is the said. When it is larger than the upper limit value of the divergence determination range, the upper limit value is used as the alternative value.

In a preferred embodiment of the power system, the plurality of power devices include n photovoltaic power conditioners (n is a positive integer) to which power is input from the solar cell, and the index calculation means. Calculates a suppression index as the index for each photovoltaic power conditioner, and the transmission means transmits the suppression index to each photovoltaic power conditioner.

In a preferred embodiment of the power system, each of the n photovoltaic power conditioners is set with a weight relating to output control of each photovoltaic power conditioner, and the weight is used as the suppression index. Is a value that sets the individual target power calculated by each photovoltaic power conditioner to 0 when is the predetermined suppression index limit, and the upper limit value of the divergence determination range is set based on the suppression index limit. ..

In a preferred embodiment of the power system, the plurality of power devices comprises m storage battery power conditioners (m is a positive integer) that receive power from the storage battery or output power to the storage battery. The index calculation means calculates a charge / discharge index as the index for each storage battery power conditioner, and the transmission means transmits the charge / discharge index to each storage battery power conditioner.

In a preferred embodiment of the power system, each of the m storage battery power conditioners is set with a weight relating to output control of each storage battery power conditioner, and the weight is a charge / discharge index. When the absolute value is the predetermined charge / discharge index limit, the individual target power calculated by each storage battery power conditioner is set to a power value that can be output to the maximum from each storage battery power conditioner, and the divergence determination range. Is set based on the charge / discharge index limit.

According to the power system of the present disclosure, in the centralized management device, an index for controlling the individual output power of each of the plurality of power conditioners is calculated so that the power to be adjusted becomes the target power. Then, each of the plurality of power conditioners calculated the individual target power of each power conditioner based on the optimization problem using the index, so that the individual output power becomes the individual target power. As a result, the centralized management device only calculates the index without calculating the individual target power for each of the plurality of power conditioners. Therefore, the processing load of the centralized management device can be reduced. Then, each of the plurality of power conditioners controls the individual output power based on the index. As a result, the power to be adjusted can be set as the target power. Further, if the power to be adjusted does not reach the target power, the index may diverge. At this time, the centralized management device determines that the index tends to diverge and uses a predetermined alternative value as the index, so that the divergence of the index can be prevented.

It is a figure which shows the whole structure of the solar power generation system which concerns on 1st Embodiment. It is a figure which shows the functional structure about the interconnection point power suppression control of the photovoltaic power generation system which concerns on 1st Embodiment. It is a figure which shows the model of the power conditioner assumed in the simulation. It is a figure which shows the step response of the power control system of the power conditioner assumed in the simulation. It is a figure which shows the verification result (case 1) by the simulation which concerns on 1st Embodiment. It is a figure which shows the verification result (case 2) by the simulation which concerns on 1st Embodiment. It is a figure which shows the verification result (case 3) by the simulation which concerns on 1st Embodiment. It is a figure which shows the verification result (case 4) by the simulation which concerns on 1st Embodiment. It is a figure which shows the verification result (case 5) by the simulation which concerns on 1st Embodiment. It is a figure which shows the verification result (case 6) by the simulation which concerns on 1st Embodiment. It is a figure which shows the verification result (case 7) by the simulation which concerns on 1st Embodiment. It is a figure which shows the whole structure of the solar power generation system which concerns on 2nd Embodiment. It is a figure which shows the functional structure about the interconnection point power suppression control of the photovoltaic power generation system which concerns on 2nd Embodiment. It is a figure which shows the verification result (case 1) by the simulation which concerns on 2nd Embodiment. It is a figure which shows the verification result (case 2) by the simulation which concerns on 2nd Embodiment. It is a figure which shows the verification result (case 3) by the simulation which concerns on 2nd Embodiment. It is a figure which shows the whole structure of the solar power generation system which concerns on 3rd Embodiment. It is a figure which shows the functional structure about the interconnection point power suppression control of the photovoltaic power generation system which concerns on 3rd Embodiment. It is a figure which shows the functional structure about the peak cut control of the solar power generation system which concerns on 4th Embodiment. It is a figure which shows the functional structure about the reverse power flow avoidance control of the solar power generation system which concerns on 5th Embodiment. It is a figure which shows the whole structure of the solar power generation system which concerns on 6th Embodiment. It is a figure which shows the functional structure about the system total output suppression control of the solar power generation system which concerns on 6th Embodiment. It is a figure which shows the whole structure of the solar power generation system which concerns on 7th Embodiment. It is a figure which shows the functional structure about the system total output suppression control of the solar power generation system which concerns on 7th Embodiment. It is a figure which shows the functional structure about the schedule control of the solar power generation system which concerns on 8th Embodiment. It is a figure for demonstrating the solar power generation system which concerns on 9th Embodiment. It is a figure which shows the relationship between the suppression index and individual output power. It is a figure which shows the relationship between the charge / discharge index and individual output power. It is a figure which shows the centralized management apparatus which concerns on the modification of 9th Embodiment.

Hereinafter, an embodiment of the electric power system of the present disclosure will be described as an example when applied to a photovoltaic power generation system interconnected to an electric power system. In the following description, when the electric power at the interconnection point is positive, it is assumed that the electric power is output from the photovoltaic power generation system to the electric power system (reverse power flow). On the other hand, when the electric power at the interconnection point is a negative value, it is assumed that the electric power is output from the electric power system to the photovoltaic power generation system.

1 and 2 are diagrams for explaining the photovoltaic power generation system PVS1 according to the first embodiment. FIG. 1 shows the overall configuration of the photovoltaic power generation system PVS1. FIG. 2 shows the functional configuration of the control system that controls the electric power at the interconnection point with the electric power system A in the photovoltaic power generation system PVS1 shown in FIG.

As shown in FIG. 1, the photovoltaic power generation system PVS1 includes a plurality of solar cells SP _i (i = 1,2, ..., n; n is a positive integer), a plurality of power conditioners PCS _i , and a plurality of power conditioners PCS i. It also has a centralized management device MC1. The photovoltaic power generation system PVS1 is a grid-connected reverse power flow system.

Each of the plurality of solar cells SP _i converts solar energy into electrical energy. Each solar cell SP _i is configured to include a plurality of solar cell panels connected in series or in parallel. The solar cell panel is, for example, a solar cell panel in which a plurality of solar cells made of a semiconductor such as silicon are connected and protected with a resin or tempered glass so that they can be used outdoors. The solar cell SP _i outputs the generated power (DC power) to the power conditioner PCS _i. The maximum amount of power that can be generated by the solar cell SP _i is defined as the power generation amount P _i ^SP _{of the solar cell SP i} .

Each of the plurality of power conditioners PCS _{i converts the power generated by the solar cell SP i} (DC power) into AC power. Then, the converted AC power is output to the power system A. Each power conditioner PCS _i includes an inverter circuit, a transformer, a control circuit, and the like. The inverter circuit converts the DC power input from the solar cell SP _i into AC power synchronized with the power system A. The transformer boosts (or steps down) the AC voltage output from the inverter circuit. The control circuit controls an inverter circuit and the like. Further, the power conditioner PCS _i is not limited to the one configured as described above.

When the effective power output from the power conditioner PCS _i P _i ^out, the reactive power and Q _i ^out, the complex power of P _i ^out + jQ _i ^out from the power conditioner PCS _i is outputted. Therefore, the complex power of _{Σ i} P _i ^out + j _{Σ i} Q _i ^out is output to the interconnection point between the plurality of power conditioners PCS _{i and the power system A.} That is, the power at the interconnection point (hereinafter referred to as "interconnection point power") is the sum of the output powers of _{each power conditioner PCS i.} In the present embodiment, the output control of the ^negative _{power Q i} out, which is mainly used for suppressing the voltage fluctuation at the interconnection point, is not particularly considered. That is, the interconnection point power is the sum _{of the active power Pi} ^{out at} _{the interconnection point (Σ i Pi} ^out ). The interconnection point power is P (t).

When the number of photovoltaic power generation systems PVS1 connected to the power system A increases, the supply of power to the power system A becomes excessive compared to the demand. In order to eliminate this oversupply condition, it is conceivable that each photovoltaic power generation system PVS1 is instructed by the electric power company to suppress the output power. Therefore, the photovoltaic power generation system PVS1 according to the present embodiment suppresses the output power in accordance with the output suppression command from the electric power company.

In the present embodiment, the photovoltaic power generation system PVS1 is instructed as an output suppression command from the electric power company so that the interconnection point power P (t) does not exceed a predetermined value. The photovoltaic power generation system PVS1 controls the interconnection point power P (t) in accordance with this output suppression command. ^{Specifically, the photovoltaic power generation system PVS1 is instructed as an output command value P C} , which is an upper limit value of the interconnection point power P (t), as an output suppression command from the electric power company. Photovoltaic systems PVS1, like interconnection point power P (t) is the output command value P ^C of commanded from the power company, the output power of each power conditioner PCS _i (hereinafter, referred to as "individual output power" .) Control _{P i} ^out. Therefore, the interconnection point power P (t) is set as the adjustment target power, and the output command value P ^C is set as the target value of the interconnection point power P (t). The photovoltaic power generation system PVS1 suppresses the individual output power P _i ^out of each power conditioner PCS _i when the interconnection point power P (t) exceeds the output command value P ^C. For this reason, the control performed by the solar power generation system PVS1 is referred to as "interconnection point power suppression control".

In the interconnection point power suppression control, each power conditioner PCS _i receives the suppression index pr from the centralized management device MC1, and based on the received suppression index pr, _{the target of the individual output power P i} ^out (hereinafter, "individual"). "Target power".) Calculate _{P i} ^ref. Suppression indicator pr is information for linking point power P (t) to the output command value P ^C, which is information for calculating the individual target power P _i ^ref. Each power conditioner PCS _i controls the individual output power P _i ^out based on the calculated individual target power P _i ^ref. Therefore, as shown in FIG. 2, each power conditioner PCS _i includes a receiving unit 11, a target power calculation unit 12, and an output control unit 13.

The receiving unit 11 receives the suppression index pr transmitted from the centralized management device MC1. The receiving unit 11 receives the suppression index pr from the centralized management device MC1 by, for example, wireless communication. Note that wired communication may be used instead of wireless communication.

Target power calculation unit 12, based on the suppression indicators pr the receiving unit 11 has received, and calculates the individual target power P _i ^ref of the apparatus (power conditioner PCS _i). Specifically, the target power calculation unit 12, by solving a constrained optimization problem represented by the following equation (8), to calculate an individual target power P _i ^ref. In the equation (8), P _i ^lmt represents the rated output (output limit) of each power conditioner PCS _{i , and w i} represents the weight of the power conditioner PCS _i regarding the suppression of active power. Weight w _i for this active power suppression is stored in the target power calculation unit 12. Further, the weight w _i regarding the active power suppression can be manually set by the user. Alternatively, each power conditioner PCS _i may be automatically set according to the conditions (temperature, climate, amount of ineffective power, etc.) of the power conditioner PCS _i. The details of the following equation (8) will be described later.

The output control unit 13 controls the inverter circuit to control the individual output power P _i ^out . The output control unit 13 sets the individual output power P _i ^out _{to the individual target power P i} ^ref calculated by the target power calculation unit 12.

The centralized management device MC1 centrally manages a plurality of power conditioners PCS _i . The centralized management device MC1 transmits and receives various information to and from each power conditioner PCS _{i by, for example, wireless communication.} Note that wired communication may be used instead of wireless communication. The centralized management device MC1 monitors the interconnection point power P (t) in the interconnection point power suppression control. In addition, the output command value P ^C commanded by the electric power company is acquired. Then, the central control device MC1 calculates the suppression indicators pr for interconnection point power P (t) to the output command value P ^C, and transmits to each of the power conditioner PCS _i. Therefore, as shown in FIG. 2, the centralized management device MC1 includes an output command value acquisition unit 21, an interconnection point power detection unit 22, an index calculation unit 23, and a transmission unit 24.

Output command value obtaining unit 21 obtains the output command value P ^C of commanded from the power company. For example, to obtain the output command value P ^C from the power company through wireless communication. ^{Further, even if the administrator manually inputs the output command value P C} commanded by the electric power company to a predetermined computer and the output command value acquisition unit 21 acquires the output command value P ^{C from the computer.} Good. Alternatively, it relays the other communication device may be configured to acquire the output command value P ^C of commanded from the power company. Output command value acquiring unit 21 outputs the output command value P ^C acquired in the index calculation unit 23.

The output command value acquisition unit 21 notifies the index calculation unit 23 that there is no command when there is no output suppression command from the electric power company. "When there is no output suppression command from the electric power company" is when the output of the photovoltaic power generation system PVS1 can be output to the maximum _{without suppressing the output of the solar cell SP i.} For example, when each power conditioner PCS _i operates at the maximum power point by the maximum power point tracking control, the maximum output can be achieved. In the present embodiment, the output command value acquiring unit 21, when there is no command for output suppression from power company, as an output command value P ^C, outputs a numeric -1 to the index calculation unit 23. The method is not limited as long as it can be transmitted to the index calculation unit 23 that there is no command. For example, the output command value acquisition unit 21 may acquire flag information indicating the presence or absence of an output suppression command from an electric power company or the like and transmit this to the index calculation unit 23. The flag information is, for example, "0" when there is no output suppression command, and "1" when there is an output suppression command. Note that if there is a command for output suppression (when the flag information is "1"), to obtain the output command value P ^C together with the flag information.

In the present embodiment, illustrating a case where the output command value obtaining unit 21 obtains the output command value P ^C as an example, but is not limited thereto. Specifically, it is also possible to obtain information of an output inhibition rate [%] instead of the output command value P ^C. At this time, the output command value acquisition unit 21 sets the acquired output suppression rate [%] and the rated output of the entire photovoltaic power generation system PVS1 (that is, the total rated output of _{each power conditioner PCS i ) Σ i} P _i ^lmt . The output command value P ^C is calculated based on. For example, the output command value acquiring unit 21, when obtaining a 20% command as output inhibition rate, 80% of the rated output Σ _i P _i ^lmt photovoltaic systems PVS1 (= 100-20) the output command value calculated as P ^C. Output command value acquiring unit 21 outputs the calculated output command value P ^C in the index calculation unit 23.

The interconnection point power detection unit 22 detects the interconnection point power P (t). Then, the detected interconnection point power P (t) is output to the index calculation unit 23. The interconnection point power detection unit 22 may be configured as a detection device different from the centralized management device MC1. In this case, the detection device (interconnection point power detection unit 22) transmits the detection value of the interconnection point power P (t) to the centralized management device MC1 by wireless communication or wired communication.

Index calculating unit 23 calculates the suppression indicators pr for interconnection point power P (t) to the output command value P ^C. The index calculation unit 23 calculates the suppression index pr based on the following equations (9) and (10), where the Lagrange multiplier is λ, the gradient coefficient is ε, and the time is t. However, the index calculation unit 23 as an output command value P ^C, when it is entered the numerical value -1 to indicate that there is no command output suppression from power company, the Lagrange multiplier λ is set to "0". That is, the suppression index pr is calculated as "0". In the following equation (9), since the individual output power P _i ^out and the output command value P ^C are values that change with time t, the individual output power is P _i ^out (t) and the output command value, respectively. Is ^{described as PC} (t). Details of the following equations (9) and (10) will be described later.

The transmission unit 24 transmits the suppression index pr calculated by the index calculation unit 23 to each power conditioner PCS _i .

Next, the interconnection point power suppression control photovoltaic system PVS1 performed, and why the expression (8) is used for calculation of individual target power P _i ^ref by the power conditioner PCS _i, suppression by the central control device MC1 The reason why the above equation (9) and the above equation (10) are used for the calculation of the index pr will be described.

The photovoltaic power generation system PVS1 is configured to achieve the following three goals in the interconnection point power suppression control. The first goal (goal 1-1) is that "each power conditioner PCS _i calculates the individual target power in a distributed manner". The second goal (Goal 1-2) is to "match the output power (coupling point power) at the interconnection point of the photovoltaic power generation system PVS1 with the output command value from the electric power company." The third goal (goal 1-3) is "to enable the output suppression amount to be adjusted for each _{power conditioner PCS i".} The output suppression amount is the difference between the maximum power value that can be output _{by the power conditioner PCS i and the individual output power P i} ^out. The maximum power value that can be the output, when the power generation amount P _i ^SP> rated output P _i ^lmt solar cell SP _i is the rated output P _i ^lmt power conditioner PCS _i. On the other hand, when the power generation amount P _i ^SP _{of the solar cell SP i} ≤ the rated output P _i ^lmt , the power generation amount P _i ^SP of the solar cell SP _i.

First, the central control device MC1 is, consider the constrained optimization problem when intensive determining the single target power P _i ^ref. Then, the following equation (11) is obtained. Here, as described above, P _i ^ref represents the individual target power of each power conditioner PCS _{i , P i} ^lmt represents the rated output (output limit) of each power conditioner PCS ^{i, and P C} represents the rated output (output limit) of _{each power conditioner PCS i.} , Indicates the output command value commanded by the electric power company. Incidentally, the individual target power P _i ^ref which is the optimal solution of the following equation (11) and (P _i ^{ref) *.} In the following equations (11), the equation (11a) is the minimization of the output suppression amount of the _{individual output power P i} ^out _{, the equation (11b) is the constraint by the rated output P i} ^lmt , and the equation (11c) is the interconnection point. it represents respectively to match the power P (t) to the output command value P ^C.

This shows the case where the centralized management device MC1 obtains the _{individual target power (P i} ^ref ) ^{* from the above equation (11).} Therefore, in the case of the above equation (11), since each power conditioner PCS _i does not calculate the individual target power (P _i ^ref ) ^* in a distributed manner, the target 1-1 is not achieved.

Next, consider a constrained optimization problem when each power conditioner PCS _i obtains an individual target power P _i ^{ref in a distributed manner.} Then, the following equation (12) is obtained.

However, the individual target power is the optimum solution of equation (12) is the power conditioner PCS _i is the individual target power P _i ^ref obtained dispersion, the above-mentioned (11c) below are not considered. Thus, unable to achieve the target 1-2 to match the interconnection point power P (t) to the output command value P ^C from the power company.

Therefore, consider achieving Goal 1-2 by the following method. That is, each power conditioner PCS _i calculates the _{individual target power P i} ^ref in a distributed manner based on the suppression index pr received from the centralized management device MC1. As a result, Goal 1-2 is achieved. The constrained optimization problem when each power conditioner PCS _{i obtains the individual target power P i} ^ref in a distributed manner using the suppression index pr can be expressed by the above equation (8). _{The individual target power P i} ^ref , which is the optimum solution of the above equation (8), is set to (P _i ^ref ) ^♭ .

Here, when the optimum solution (P _i ^ref ) ^* _{obtained by the above equation (11) and the optimum solution (P i} ^ref ) ^♭ obtained by the above equation (8) match, the interconnection point power P ( t) it is possible to match the output command value P ^C from the power company. That is, even when each power conditioner PCS _i solves the optimization problem in a distributed manner, the target 1-2 can be achieved. Therefore, paying attention to the optimality of the steady state, consider the suppression index pr such that _{(P i} ^ref ) ^* = (P _i ^ref ) ^♭. Therefore, the KKT (Karush-Kuhn-Tucker) conditions of the above equations (11) and (8) are considered. As a result, the following equation (13) can be obtained from the KKT condition of the above equation (11), and the following equation (14) can be obtained from the KKT condition of the above equation (8). In addition, μ is a predetermined Lagrange multiplier.

From the above equations (13) and (14), by setting pr = λ (the above equation (10)), the two optimal solutions (P _i ^ref ) ^* and (P _i ^ref ) ^♭ match. I understand. Therefore, the centralized management device MC1 calculates the Lagrange multiplier λ and _{presents (transmits) the calculated Lagrange multiplier λ to each power conditioner PCS i} as the suppression index pr, so that each power conditioner PCS _i is described above. The individual target power (P _i ^ref ) ^♭ can be calculated from Eq. (8). As a result, even when each power conditioner PCS _i obtains the individual target power P _i ^ref in a distributed manner, the interconnection point power P (t) and the output command value P ^C from the power company are matched. be able to. That is, the goal 1-2 can be achieved.

Subsequently, a method of calculating the Lagrange multiplier λ by the centralized management device MC1 will be described. To the central control device MC1 seeks Lagrangian multiplier lambda, _{firstly, h 1, i = -P i} ref, and ^{_{h 2, i = P i ref}} -P i lmt, collectively inequality constraints of the power conditioner PCS _i Let h _{j, i} (j = 1, 2, i = 1, ..., N). Then, consider the following equation (15), which is the dual problem of the above equation (11).

Here, assuming that the optimum solution (P _i ^ref ) ^♭ obtained by each power conditioner PCS _i is determined, the following equation (16) is obtained, which is a form of the maximization problem for the Lagrange multiplier λ. When the gradient method is applied to the following equation (16), the following equation (17) is obtained. Note that ε represents the gradient coefficient and τ represents the time variable.

In the above equation (17), (P _i ^ref ) ^♭ is replaced with the individual output power P _i ^out of each corresponding power conditioner PCS _i. Further, the centralized management device MC1 does not individually observe the individual output power P _i ^out _{of each power conditioner PCS i} , but observes the interconnection point power P (t) = Σ _i P _i ^out . Further, it is assumed that the sequential output command value P ^{C is acquired from the electric power company.} Then, the above equation (9) is obtained. Therefore, the centralized management device MC1 can calculate the Lagrange multiplier λ based on the interconnection point power P (t) and the output command value P ^{C from the electric power company.} Then, the Lagrange multiplier λ calculated based on the above equation (10) is used as the suppression index pr.

From the above, in the present embodiment, the power conditioner PCS _i, when calculating the individual target power P _i ^ref, and using an optimization problem shown in equation (8). Further, the centralized management device MC1 uses the above equation (9) and the above equation (10) to calculate the suppression index pr.

Next, in the photovoltaic power generation system PVS1 configured as described above, it was verified by simulation that the above three goals were achieved and the system was operating properly.

In the simulation, a photovoltaic power generation system PVS1 having _{10 power conditioners PCS i} (i = 1 to 10; PCS _{1 to PCS 10) was assumed.}

The model of the power system A (interconnection point voltage) is the following equation (18). In the following equation (18), R = R _L × _L, a _{X = X L × L, R} L is the resistance component per unit length of the distribution line, X _L is the reactance component per unit length of the distribution lines , L represents the length of the distribution line, and V ₁ represents the upper system voltage. In this simulation, the upper system voltage V ₁ is 6600 [V], the resistance component _RL per unit length of the wiring line is 0.220 [Ω / km], and the reactance component X _{L per unit length of the distribution line.} Was 0.276 [Ω / km], and the length L of the distribution line was 5 [km].

The power conditioner PCS _i is assumed to be the model shown in FIG. 3, and PI control is performed in order to control the _{individual output power P i} ^out to the individual target power P _i ^ref. The current control system of the power conditioner PCS _i is designed to respond much faster than the effective / invalid power control system. Here, it is assumed that an appropriate control system has been designed in advance, and it is realized by a first-order lag system of ^{K = 1, T = 10 -4.} The power control system, which is the upper control system of the current control system, assumes a time constant such that the step response converges within 1 [s], and K _PP = K _PQ = 1.0 × 10 ^-7 , K _IP = K _IQ = 1.2 × 10 ^-3 . K _PP represents the proportional gain of active power, K _PQ represents the proportional gain of ineffective power, K _IP represents the integrated gain of active power, and K _IQ represents the integrated gain of ineffective power. FIG. 4 shows the step response of the effective / invalid power control system.

FIGS. 5 to 11 show the results when the simulation was performed under a plurality of conditions using the solar power generation system PVS1 of the model shown above. When the power generation amount P _i ^SP of the connected solar cell SP _i is larger than the rated output P _i ^lmt , each power conditioner PCS _i is suppressed to the rated output P _i ^lmt _{of the power conditioner PCS i.} And.

As case 1, a simulation was performed in which _{10 power conditioners PCS 1 to} PCS 10 all had the same conditions. Let the simulation be simulation 1-1. In simulation 1-1, _{all 10 power conditioners PCS 1 to} PCS 10 have a rated output P _i ^lmt of 500 [kW], a weight w _i related to active power suppression of 1.0, and a power generation amount of the _{solar cell SP i.} P _i ^SP has to be 600 [kW]. Further, the output command value P ^C from the electric power company is assumed to be 3000 [kW] when there is no command when 0 ≦ t <60 [s] and when 60 ≦ t [s]. When "there is no command of the output command value P ^C ", the numerical value -1 indicating that there is no command is used as the ^{output command value P C as described above.} Other, gradient coefficients epsilon 0.025, and each sampling time and update the central control device MC1 individual target power update and the power conditioner PCS _i suppression indicators pr is performed to carry out P _i ^ref and 1 [s] .. Further, it _{is assumed that all the power conditioners PCS i} are operated at a power factor of 1 (reactive power target value = 0 [kvar]). FIG. 5 shows the simulation results in simulation 1-1.

FIGS. 5 (a) to 5 (e) show the amount of power generated by the solar cell SP _{i of each power conditioner PCS i P i} ^SP (dashed line), rated output P _i ^lmt (solid line), and individual target power P _i ^ref ( (Dashed line) and individual output power P _i ^out (solid line) are shown. 5 (a) is, for the power conditioner PCS _1, PCS _2, FIG. 5 (b), the power conditioner PCS _3, PCS _4, FIG. 5 (c), the power conditioner PCS _5, PCS ₆ 5 (d) shows the power conditioners PCS ₇ and ₈ and FIG. 5 (e) shows the power conditioners PCS ₉ and PCS ₁₀ . Incidentally, in FIG. 5 (a) ~ (e) , for convenience of understanding, been described in slightly shifted upward to separate target power P _i ^ref (dashed line). FIG. 5 (f) shows the individual output powers P ₁ ^{out to} P ₁₀ ^out _{of the power conditioners PCS 1 to} PC ₁₀ in one graph. FIG. 5 (g) illustrates the interconnection point power P (t) output command value from the (solid line) and electric power company P ^C (dashed line). Incidentally, in FIG. 5 (g), the convenience of understanding, if there is no command output command value P ^C, outputs command the sum of the rated output P ₁ ^lmt ~P ₁₀ ^lmt of PCS ₁ ~PCS ₁₀ of the power conditioner It is described as the value P ^C. FIG. 5H shows the Lagrange multiplier λ calculated by the index calculation unit 23. Then, FIG. 5 (i) shows the suppression index pr calculated by the index calculation unit 23.

The following can be confirmed from FIG. That is, in the period from the start of the simulation to the issuance of the output suppression command (0 ≦ t <60 [s]), as shown in FIGS. 5A to 5E, each of the power conditioners PCS _{1 to PCS 10} is individually used. The output power P ₁ ^{out to} P ₁₀ ^out increases according to the power generation amount P ₁ ^{SP to} P ₁₀ ^SP _{of the solar cell SP i} until it reaches 500 [kW] of the individual target powers P ₁ ^{ref to} P ₁₀ ^ref. There is. Then, when the individual target powers P ₁ ^{ref to} P ₁₀ ^ref reach 500 [kW], the individual output powers P ₁ ^{out to} P ₁₀ ^out thereafter reach 500 [kW] of the individual target powers P ₁ ^{ref to} P ₁₀ ^ref. ] Can be confirmed to be controlled. Moreover, the post command output command value ^{P C (60 ≦ t [s} ]), as shown in FIG. 5 (h) and FIG. 5 (i), be the Lagrange multiplier λ and inhibition index pr is updated You can check. Each power conditioner PCS ₁ ~PCS _10, based on the update of the suppression indicators pr, as shown in FIG. 5 (a) ~ (e) , by changing the individual target power P ₁ ^ref ~P ₁₀ ^ref There is. Therefore, it can be confirmed that the individual output powers P ₁ ^{out to} P ₁₀ ^out are suppressed and follow the individual target powers P ₁ ^{ref to} P ₁₀ ^ref. Thus, as shown in FIG. 5 (g), the suppressed linking point power P (t) is, it can be confirmed that they match the output command value P ^C in the steady state.

As case 2, the _{weights w 5} and w ₆ related to the active power suppression set in the power conditioners PCS ₅ and PCS _{6 out of the 10 power conditioners PCS 1 to} PCS 10 are the other power conditioners PCS _1. The cases different from those of ~ _{PCS 4} and PCS _{7 ~ PCS 10 were simulated.} Let the simulation be simulation 1-2. _{In simulation 1-2, the weight w i} for the active power suppression of the two power conditioners PCS ₅ and PCS ₆ was set to 2.0. Other conditions are the same as in Simulation 1-1. FIG. 6 shows the simulation results in simulation 1-2. Note that FIGS. 6 (a) to 6 (i) are diagrams corresponding to FIGS. 5 (a) to 5 (i) in the simulation 1-1, respectively.

The following can be confirmed from FIG. That is, as shown in FIG. 6 (a) ~ FIG 6 (e), compared with the simulation 1-1 shown in FIG. 5, the power conditioner PCS ₅ changed weights w _i relating active power suppression, the output of the PCS ₆ It can be confirmed that the suppression amount is half of the output suppression amount of the other power conditioners PCS _{1 to PCS 4} and PCS _{7 to PCS 10.} At this time, as shown in FIGS. 6 (h) and 6 (i), the Lagrange multiplier λ and the suppression index pr calculated by the centralized management device MC1 are also the values in the above simulation 1-1 (FIGS. 5 (h) and 5). It can also be confirmed that it is different from (i)). Therefore, by adjusting the weights w _i relating active power suppression, it is possible to have a difference in output suppression quantity. Further, as shown in FIG. 6, the output suppression amount of the other power conditioners PCS _{1 to PCS 4} and PCS _{7 to PCS 10 is measured by the reduction of the output suppression amount of the power conditioners PCS 5} and PCS _{6 in} the above simulation 1. by greater than -1, as shown in FIG. 6 (g), interconnection point power P (t) is, it can be confirmed that they match the output command value P ^C in the steady state. Therefore, it can be said that the photovoltaic power generation system PVS1 is operating appropriately in consideration _{of the weight w i} regarding the active power suppression set in the _{power conditioner PCS i.}

As case 3, a simulation was performed in which the _{weights w 5} and w ₆ related to the active power suppression of two power conditioners PCS ₅ and PCS _{6 out of 10 power conditioners PCS 1 to PCS 10 were changed in the middle.} .. Let the simulation be simulation 1-3. _{In simulation 1-3, the weights w 5} and w ₆ related to the active power suppression of the two power conditioners PCS ₅ and PCS _{6 are set to w 5} = w ₆ = 1.0 at the start time (0 [s]). After the lapse of 120 [s], the change was made to _{w 5} = w _{6 = 2.0.} That is, in 60 ≦ t <120 [s] , while the weight w ₁ to w ₁₀ about the effective suppression of power each power conditioner PCS ₁ ~PCS ₁₀ as described above simulation 1-1 are all 1.0, 120 In ≦ t [s], the _{weights w 5} and w ₆ related to the active power suppression of the _{power conditioners PCS 5} and PCS ₆ were changed to 2.0 as in the above simulation 1-2. Other conditions are the same as in Simulation 1-1. FIG. 7 shows the simulation results in Simulation 1-3. Note that FIGS. 7 (a) to 7 (i) are diagrams corresponding to FIGS. 5 (a) to 5 (i) in the simulation 1-1, respectively.

The following can be confirmed from FIG. 7. _{That is, before changing the weights w 5} and w ₆ related to the active power suppression of the power conditioners PCS ₅ and PC ₆ to 2.0 (60 ≦ t <120 [s]), the same result as the above simulation 1-1 is obtained. _{Yes, after changing the weights w 5} and w ₆ related to the active power suppression of the power conditioners PCS ₅ and PC ₆ to 2.0 (120 ≦ t [s]), the same result as the above simulation 1-2 is obtained. It can be confirmed that Therefore, even in this way adjust the weights w _i relating active power suppression in the middle (change), continuously, it is possible to match the interconnection point power P (t) to the output command value P ^C.

In case 4, the power generation of the solar cell SP _{i is performed} for each of the two power conditioners (PCS ₁ and PCS ₂ , PCS ₃ and PCS ₄ , PCS ₅ and PCS ₆ , PCS ₇ and PCS ₈ , PCS ₉ and PCS _10). The case where the quantity P _i ^SP was different was simulated. Let the simulation be simulation 1-4. In Simulation 1-4, of the solar cell SP _i of each of the two power conditioners (PCS ₁ and PCS ₂ , PCS ₃ and PCS ₄ , PCS ₅ and PCS ₆ , PCS ₇ and PCS ₈ , PCS ₉ and PCS _10). Power generation amount P _i ^SP , P ₁ ^SP , P ₂ ^SP = 600 [kW], P ₃ ^SP , P ₄ ^SP = 500 [kW], P ₅ ^SP , P ₆ ^SP = 400 [kW], P ₇ ^{SP, respectively.} , P ₈ ^SP = 300 [kW], P ₉ ^SP , P ₁₀ ^SP = 200 [kW]. Other conditions are the same as in Simulation 1-1. FIG. 8 shows the simulation results in Simulation 1-4. 8 (a) to 8 (i) are diagrams corresponding to FIGS. 5 (a) to 5 (i) in the simulation 1-1, respectively.

The following can be confirmed from FIG. That is, as shown in FIG. 8 (a) ~ (e) , if the individual target power P _i ^ref is power generation amount P _i ^SP or more solar cells SP _i, it can be confirmed that not performing the output suppression. Further, as shown in FIG. 8 (f), if the same power conditioner PCS ₁ ~PCS ₁₀ rated output P _i ^lmt power generation amount P _i ^SP solar cell SP _i different, the amount of power generated by solar cell SP _i P _i ^SP with less power conditioner PCS ₇ ~PCS ₁₀ it can be confirmed that that has not been output suppression. Furthermore, as shown in FIG. 8 (g), the suppressed linking point power P (t) is, it can be confirmed that they match the output command value P ^C in the steady state. Therefore, it can be said that the photovoltaic power generation system PVS1 is operating appropriately in consideration of the power generation amount P _i ^SP _{of the solar cell SP i.}

As a case 5, every two of the power conditioner (PCS ₁ and PCS _2, PCS ₃ and PCS _4, PCS ₅ and PCS _6, PCS ₇ and PCS _8, PCS ₉ and PCS _10), the rated output P _i ^lmt Different cases were simulated. Let the simulation be simulation 1-5. In the simulation 1-5, the rated output P _i ^lmt every two of the power conditioner (PCS ₁ and PCS _2, PCS ₃ and PCS _4, PCS ₅ and PCS _6, PCS ₇ and PCS _8, PCS ₉ and PCS ₁₀₎ P ₁ ^lmt , P ₂ ^lmt = 500 [kW], P ₃ ^lmt , P ₄ ^lmt = 400 [kW], P ₅ ^lmt , P ₆ ^lmt = 300 [kW], P ₇ ^lmt , P ₈ ^lmt = 200 [kW], P ₉ ^lmt , P ₁₀ ^lmt = 100 [kW]. Further, as the output command value P ^C from the power company, 0 ≦ t <60 [s ] no directive in, and 60 ≦ t [s] in 2000 [kW], the power generation amount P _i ^SP solar cell SP _i The rated output P _i ^lmt +100 [kW] was set for each. Other conditions are the same as in Simulation 1-1. FIG. 9 shows the simulation results in Simulation 1-5. Note that FIGS. 9 (a) to 9 (i) are diagrams corresponding to FIGS. 5 (a) to 5 (i) in the simulation 1-1, respectively.

The following can be confirmed from FIG. That is, as shown in FIG. 9 (f), the case where the rated output P _i ^lmt is different, the output suppression amount can be confirmed to be equal in each of the power conditioner PCS ₁ ~PCS _10. Further, the interconnection point power P (t) is suppressed as shown in FIG. 9 (g), the can be confirmed that matches the output command value P ^C in the steady state. Therefore, it can be said that the photovoltaic power generation system PVS1 is operating appropriately in consideration of the rated output P _i ^lmt _{of the power conditioner PCS i.}

As case 6, a case where the sampling time was lengthened was simulated. Let the simulation be simulation 1-6. In simulation 1-6, the sampling time was set to 60 [s] = 1 [min]. Further, the slope coefficient ε and 0.0005, as the output command value P ^C from the power company, 0 ≦ t <5 [min ] no instruction in, and a 5 ≦ t [min] In 3000 [kW]. Other conditions are the same as in Simulation 1-1. FIG. 10 shows the simulation results in Simulation 1-6. Note that FIGS. 10 (a) to 10 (i) are diagrams corresponding to FIGS. 5 (a) to 5 (i) in the simulation 1-1, respectively.

The following can be confirmed from FIG. That is, as shown in FIG. 10 (g), when longer the sampling time, although the time to interconnection point power P (t) follows the output command value P ^C is longer than the above-described simulation 1-1 , is suppressed linking point power P (t) is, it can be confirmed that they match the output command value P ^C in the steady state.

In case 7, a simulation was performed in which the sampling time was made longer than the sampling time in case 6. Let the simulation be simulation 1-7. In simulation 1-7, the sampling time was set to 180 [s] = 3 [min]. Further, the slope coefficient ε and 0.0003, as the output command value P ^C from the power company, 0 ≦ t <5 [min ] no instruction in, and a 5 ≦ t [min] In 3000 [kW]. Other conditions are the same as in Simulation 1-1. FIG. 11 shows the simulation results in Simulation 1-7. 11 (a) to 11 (i) are diagrams corresponding to FIGS. 5 (a) to 5 (i) in the simulation 1-1, respectively.

The following can be confirmed from FIG. That is, as shown in FIG. 11 (g), in the case where the sampling time was longer than the simulation 1-6 also are interconnection point power P (t) is suppressed, one to the output command value P ^C in a steady state You can confirm that you are doing it.

The following can be confirmed by comparing FIGS. 5 to 11 in addition to the results for each of FIGS. 5 to 11. That is, as shown in each figure (h) and (i), the Lagrange multiplier λ and suppression indicator pr is the power conditioner PCS ₁ ~PCS _10, power generation of the solar cell SP _i P _i ^SP, the rated output P _i ^lmt, weight w _i relating active power suppression, and, on the basis of such an output command value P ^C, it can be confirmed that different values are calculated. Further, as shown in each figure (a) ~ (e), in accordance with the updating of the suppression indicators pr, it can be confirmed that the individual target power P _i ^ref is updated. The power conditioner PCS ₁ ~PCS _10, in response to the individual target power P _i ^ref, and controls the individual output power P _i ^out. Thus, as shown in (g) is each figure, it can be confirmed that by matching linking point power P (t) to the output command value P ^C. From the above, it can be said that the suppression index pr calculated by the centralized management device MC1 using the above equations (9) and (10) is an appropriate value.

From the results of the above simulations 1-1 to 1-7, in the photovoltaic power generation system PVS1, each power conditioner PCS _i distributes the individual target power P based on the suppression index pr received from the centralized management device MC1. _i ^ref is calculated. Therefore, the above goal 1-1 has been achieved. Further, the interconnection point power P (t) is suppressed, coincides with the output command value P ^C. Therefore, the above target 1-2 has been achieved. Then, the individual output power P _i ^out changes for _{each power conditioner PCS i} according to various conditions. That is, the output suppression amount changes for each _{power conditioner PCS i according to various conditions.} Therefore, the above goals 1-3 have been achieved. From the above, it can be seen that the photovoltaic power generation system PVS1 has achieved the above three goals.

As described above, in the photovoltaic power generation system PVS1 according to the first embodiment, the central control device MC1 is outputted from the command value P ^C and detected interconnection point power P (t) from the power company, the ( The suppression index pr is calculated using the equation 9) and the above equation (10), and this is transmitted to _{each power conditioner PCS i.} Further, each power conditioner PCS _{i calculates the individual target power P i} ^ref by solving the optimization problem of the above equation (8) in a distributed manner based on the received suppression index pr, and then obtains the individual output power. The P _i ^out is controlled to the individual target power P _i ^ref. As a result, the centralized management device MC1 can perform only the simple calculations shown in the above equations (9) and (10). Therefore, in the photovoltaic power generation system PVS1, the processing load of the centralized management device MC1 can be reduced. Further, even when each power conditioner PCS _{i calculates the individual target power P i} ^ref in a distributed manner based on the suppression index pr and controls the individual output power P _i ^out , the interconnection point power P (t). ) it can be matched to the output command value P ^C from the power company.

The case where the photovoltaic power generation system PVS1 according to the first embodiment is composed of a plurality of power conditioners PCS _{i to which the solar cell SP i} is connected has been described as an example. However, in the case of such a photovoltaic power generation system PVS1, the influence on the output due to the weather change is large. Therefore, in order to suppress output fluctuations due to weather fluctuations and the like, there is a photovoltaic power generation system in which a power conditioner connected to a solar cell and a power conditioner connected to a storage battery are installed side by side. This case will be described below as a second embodiment.

12 and 13 are diagrams for explaining the photovoltaic power generation system PVS2 according to the second embodiment. FIG. 12 is a diagram showing the overall configuration of the photovoltaic power generation system PVS2. FIG. 13 is a diagram showing a functional configuration of a control system that controls electric power at an interconnection point with the electric power system A in the photovoltaic power generation system PVS2 shown in FIG. The same or similar to the photovoltaic power generation system PVS1 according to the first embodiment is designated by the same reference numerals and the description thereof will be omitted.

As shown in FIG. 12, the photovoltaic power generation system PVS2 includes a plurality of solar cells SP _i (i = 1, 2, ..., N; n is a positive integer), a plurality of power conditioners PCS _PVi , and a plurality of power conditioners PCS PVi. It is composed of a plurality of storage batteries B _k (k = 1, 2, ..., M; m is a positive integer), a plurality of power conditioners PCS _Bk , and a centralized management device MC2. The photovoltaic power generation system PVS2 is a grid-connected reverse power flow system.

Each of the plurality of power conditioner PCS _PVi is configured in the same manner as the power conditioner PCS _{i of the first embodiment.} That is, each power conditioner PCS _PVi converts the power (DC power) generated by the solar cell SP _i into AC power, and outputs the converted AC power to the power system A.

Each of the plurality of storage batteries B _k is a battery that can store electric power by repeatedly charging. The storage battery B _k is, for example, a secondary battery such as a lithium ion battery, a nickel hydrogen battery, a nickel cadmium battery, or a lead storage battery. Further, a capacitor such as an electric double layer capacitor may be used. Battery B _k is to discharge accumulated power and supplies DC power to the power conditioner PCS _Bk.

Each plurality is the power conditioner PCS _Bk, is intended for converting the DC power supplied from battery B _k to AC power. Further, each power conditioner PCS _Bk converts AC power input from the power system A and each power conditioner PCS _PVi into DC power and supplies it _{to the storage battery B k.} That is, the storage battery B _k is charged. Each power conditioner PCS _Bk is controlling the charging and discharging of the battery B _k. Thus, functions as a discharge circuit to discharge the charging circuit and the battery B _k to charge the battery B _k.

_Assuming that the active power output from each power conditioner PCS _{PVi is P PVi} ^out and the ineffective power is Q _PVi ^out , the complex power of P _PVi ^out + jQ _PVi ^out is output from each power conditioner PCS _PVi. Further, assuming that the active power output from each power conditioner PCS _{Bk is P Bk} ^out and the ineffective power is Q _Bk ^out , the complex power of P _Bk ^out + jQ _Bk ^out is output from each power conditioner PCS _Bk. Therefore, at the interconnection point between the power conditioners PCS _PVi and PCS _Bk and the power system A, (Σ _i P _PVi ^out + Σ _k P _Bk ^out ) + j (Σ _i Q _PVi ^out + Σ _k Q _Bk ^out ) Complex power is output. That is, the interconnection point power is the sum of the output powers of the _{power conditioners PCS PVi} and PCS _{Bk. Also in this embodiment, the output control of the ineffective powers Q PVi} ^out and Q _Bk ^out , which are mainly used for suppressing voltage fluctuations at the interconnection point, is not particularly considered. That is, the interconnection point power is the sum _{of the active powers P PVi} ^out and P _Bk ^{out at} _{the interconnection point (Σ i} P _PVi ^out + Σ _k P _Bk ^out ).

In the present embodiment, the photovoltaic power generation system PVS2 is instructed by the electric power company so that the interconnection point power P (t) does not exceed a predetermined value. The photovoltaic power generation system PVS2 controls the interconnection point power P (t) according to this instruction. Specifically, photovoltaic systems PVS2 as an instruction from the power company is commanded the output command value P ^C. Photovoltaic systems PVS2, like interconnection point power P (t) is the output command value P ^C of commanded from the power company, the power conditioner PCS _PVi, PCS _Bk individual output power P _PVi ^out, P Control _Bk ^out. Therefore, the interconnection point power P (t) is set as the adjustment target power, and the output command value P ^C is set as the target value of the interconnection point power P (t). Photovoltaic systems PVS2, when interconnection point power P (t) exceeds the output command value P ^C, suppresses the power conditioner PCS _PVi, individual output power P _PVi ^out of PCS _Bk, the P _Bk ^out .. For this reason, the photovoltaic power generation system PVS2 also performs interconnection point power suppression control.

In the interconnection point power suppression control, each power conditioner PCS _{PVi receives the suppression index pr PV} from the centralized management device MC2, and calculates the individual target power P _PVi ^ref based on the received suppression index pr _PV. Suppression indicator pr _PV is information for linking point power P (t) to the output command value P ^C, which is information for calculating the individual target power P _PVi ^ref. Each power conditioner PCS _PVi controls the individual output power P _PVi ^out based on the calculated individual target power P _PVi ^ref. Therefore, as shown in FIG. 13, each power conditioner PCS _PVi includes a receiving unit 11, a target power calculation unit 12', and an output control unit 13.

_{The target power calculation unit 12'calculates} the individual target power P _PVi ^ref of the own device (power conditioner PCS _{PVi) based on the suppression index pr PV} received by the reception unit 11. _{Specifically, the target power calculation unit 12'calculates} ^{the individual target power P PVi ref} by solving the constrained optimization problem shown in the following equation (19). _{Therefore, the target power calculation unit 12'is} different from the target power calculation unit 12 according to the first embodiment in the calculation formula of the optimization problem for calculating the ^{individual target power P PVi ref.} In the equation (19), w _PVi represents the weight related to the active power suppression of the power conditioner PCS _{PVi, and is a design value.} Further, P _φi indicates a design parameter (hereinafter referred to as “priority parameter”) indicating whether or not to give priority to suppressing the individual output power P _PVi ^out of the power conditioner PCS _{PVi, which is a design value.} .. When the priority parameter P _φi is reduced, _{the charge amount of the storage battery B k} is reduced, and the individual output power P _PVi ^out is likely to be suppressed. On the other hand, when the priority parameter P _φi is increased, the charge amount of the _{storage battery B k} is increased, and it becomes difficult to suppress the _{individual output power P PVi} ^out. Therefore, it can be said that the priority parameter P _φi is a design parameter indicating whether or not to prioritize the charging of the storage battery B _k. In addition, this priority parameter P _.phi.i, the output limit according to the rated output of the power conditioner PCS _PVi separately, considered as pseudo output limits of the individual output power P _PVi ^out of the power conditioner PCS _PVi is set Be done. Therefore, the priority parameter _Pφi can be said to be a pseudo effective output limit. The weight w _PVi and the priority parameter _Pφi can be set by the user. Details of the following equation (19) will be described later.

In the interconnection point power suppression control, each power conditioner PCS _{Bk receives the charge / discharge index pr B} from the centralized management device MC2, and calculates the individual target power P _Bk ^ref based on the received charge / discharge index pr _B. .. The charge / discharge index pr _B is information for setting the interconnection point power P (t) to the output command value P ^C , and is information for calculating the _{individual target power P Bk} ^ref. It is also information for determining how much the storage battery B _{k is to be charged or discharged.} Each power conditioner PCS _Bk controls the individual output power P _Bk ^out based on the calculated individual target power P _Bk ^ref. Therefore, as shown in FIG. 13, each power conditioner PCS _Bk includes a receiving unit 31, a target power calculation unit 32, and an output control unit 33.

The receiving unit 31 is configured in the same manner as the receiving unit 11 according to the first embodiment, and receives the charge / discharge index pr _B transmitted from the centralized management device MC2.

The target power calculation unit 32 calculates the individual target power P _Bk ^ref of the own device (power conditioner PCS _{Bk ) based on the charge / discharge index pr B received by the reception unit 31.} Specifically, the target power calculation unit 32 calculates the individual target power P _Bk ^ref by solving the optimization problem shown in the following equation (20). In the equation (20), P _Bk ^lmt represents the rated output (output limit) of each power conditioner PCS _Bk. w _Bk represents the weight regarding the active power of the power conditioner PCS _Bk. The weight w _Bk can be set by the user. Further, α _k and β _k represent adjustment parameters that can be adjusted according to the remaining amount of the storage battery B _k. The details of the following equation (20) will be described later.

The output control unit 33 is configured in the same manner as the output control unit 13 according to the first embodiment. The output control unit 33 controls _{the discharge and charge of the storage battery B k to set} the individual output power P _Bk ^out _{to the individual target power P Bk} ^ref calculated by the target power calculation unit 32. Specifically, when the individual target power P _Bk ^ref calculated by the target power calculation unit 32 is a positive value, _{the power (DC power) stored in the storage battery B k} is converted into AC power and used in the power system A. Supply. That is, the power conditioner PCS _{Bk is made} to function as a discharge circuit. On the other hand, when the individual target power P _Bk ^ref is a negative value, at least a part of the AC power output from the _{power conditioner PCS PVi} is converted into DC power and supplied _{to the storage battery B k.} That is, the power conditioner PCS _{Bk is made} to function as a charging circuit.

The centralized management device MC2 centrally manages a plurality of power conditioners PCS _PVi and PCS _Bk . As shown in FIG. 13, the centralized management device MC2 is compared with the centralized management device MC1 according to the first embodiment, in which the index calculation unit 23 is replaced by the index calculation unit 43 and the transmission unit 24 is replaced by the transmission unit 44. It differs in that it is. The central control device MC2, at interconnection node power suppression control, calculates a suppression index pr _PV and charge-discharge indicator pr _B for interconnection point power P (t) to the output command value P ^C, suppression index pr _{PV Is} transmitted to the power conditioner PCS PVi, and the charge / discharge index pr _B is transmitted to the power conditioner PCS _Bk.

Index calculating unit 43 calculates the suppression indicators pr _PV and charge-discharge indicator pr _B for interconnection point power P (t) to the output command value P ^C. _{The index calculation unit 43 calculates the suppression index pr PV} and the charge / discharge index pr _B based on the following equations (21) and (22), where the Lagrange multiplier is λ, the gradient coefficient is ε, and the time is t. However, the index calculation unit 43 as the output command value P ^C from the output command value acquiring unit 21, when it is entered the numerical value -1 to indicate that there is no command output suppression from power company, the Lagrange multiplier λ " 0 ”. That is, both the suppression index pr _PV and the charge / discharge index pr _B are calculated as “0”. In the following equation (21), since the individual output powers P _PVi ^out , P _Bk ^out and the output command value P ^C are values that change with respect to time t, the individual output powers are respectively P _PVi ^out (t). describes a P _Bk ^out (t) and the output command value and P ^C (t). Details of the following equation (21) and the following equation (22) will be described later.

The transmission unit 44 transmits the suppression index pr _PV calculated by the index calculation unit 43 to the power conditioner PCS _PVi, and transmits the charge / discharge index pr _B calculated by the index calculation unit 43 to the power conditioner PCS _Bk .

Next, the reason why the above equation (19) is used to calculate the individual target power P _PVi ^ref _{by the power conditioner PCS PVi} in the interconnection point power suppression control performed by the photovoltaic power generation system PVS2, and the _{individual by the power conditioner PCS Bk} . The reason why the above equation (20) is used to calculate the target power P _Bk ^ref , and the above equations (21) and (22) _{are used to calculate the suppression index pr PV} and the charge / discharge index pr _{B by the centralized control device MC2.} The reason why it is used will be explained.

The photovoltaic power generation system PVS2 is configured to achieve the following five goals in the interconnection point power suppression control. The first goal (Goal 2-1) is that "each power conditioner PCS _PVi and PCS _Bk calculate individual target power in a distributed manner". The second goal (Goal 2-2) is to "do not suppress the output power of _{the power conditioner PCS PVi connected to the solar cell as much as possible".} The third goal (goal 2-3) is that "the storage battery is charged when the interconnection point power is larger than the output command value, and discharged when the interconnection point power is insufficient". The fourth goal (goal 2-4) is to "match the output power (coupling point power) at the interconnection point of the photovoltaic power generation system PVS2 with the output command value from the electric power company." The fifth goal (2-5) is to "enable the output suppression amount to be adjusted for each _{power conditioner PCS PVi} and PCS _Bk".

First, consider a constrained optimization problem when the centralized management device MC2 centrally _{obtains individual target powers P PVi} ^ref and P _Bk ^ref. Then, the following equation (23) is obtained. Here, as described above, P _PVi ^ref and P _Bk ^ref represent the individual target powers of the respective power conditioners PCS _PVi and PCS _{Bk , respectively, and P PVi} ^lmt and P _Bk ^lmt represent the individual target powers of the respective power conditioners PCS _{PVi, respectively.} , PCS _Bk 's rated output (output limit), P _φi represents the priority parameter. _{The individual target powers P PVi} ^ref and P _Bk ^ref, which are the optimum solutions of the following equation (23), are set to _{(P PVi} ^ref ) ^* and (P _Bk ^ref ) ^* , respectively. In the following equation (23), the equation (23a) is the minimization of the output suppression amount of the individual output power P _PVi ^out _{of each power conditioner PCS PVi} and the output amount of the individual output power P _Bk ^out of _{each power conditioner PCS Bk.} Equation (23b) is the constraint by the rated output P _PVi ^lmt _{of each power conditioner PCS PVi} , and equation (23c) is the constraint by the rated output P _Bk ^lmt _{of each power conditioner PCS Bk} , equation (23d). the remaining constraints of the storage batteries B _k, (23e) expression to match interconnection point power P (t) to the output command value P ^C, represents respectively.

This shows the case where the centralized control device MC2 obtains the _{individual target powers (P PVi} ^ref ) ^* and (P _Bk ^ref ) ^{* from the above equation (23).} Therefore, in the case of the above equation (23), since the power conditioners PCS _PVi and PCS _Bk do not calculate the individual target powers (P _PVi ^ref ) ^* and (P _Bk ^ref ) ^{* in a distributed manner, the target 2-1} Has not been achieved.

Next, consider a constrained optimization problem when each power conditioner PCS _PVi obtains an individual target power P _PVi ^{ref in a distributed manner.} Then, the following equation (24) is obtained.

Similarly, consider a constrained optimization problem when each power conditioner PCS _Bk finds the individual target power P _Bk ^{ref in a distributed manner.} Then, the following equation (25) is obtained.

However, the individual target power, which is the optimum solution of the above equation (24), is the individual target power P _PVi ^ref _{distributed by each power conditioner PCS PVi} , but the above equation (23e) is not taken into consideration. Similarly, the individual target power that is the optimum solution of the above equation (25) is the individual target power P _Bk ^ref _{distributed by each power conditioner PCS Bk} , but the above equation (23e) is not taken into consideration. .. Thus, unable to achieve the target 2-4 to match the interconnection point power P (t) to the output command value P ^C from the power company.

Therefore, next, let us consider achieving the goal 2-4 by the method. That is, each power conditioner PCS _PVi calculates the individual target power P _PVi ^ref _{in a distributed manner based on the suppression index pr PV} received from the centralized management device MC2, and each power conditioner PCS _Bk is the centralized management device MC2. Based on the charge / discharge index pr _B received from, the individual target power P _Bk ^ref is calculated in a distributed manner. As a result, Goal 2-4 is achieved. The constrained optimization problem when each power conditioner PCS _PVi obtains the individual target power P _PVi ^ref in a distributed manner using the suppression index pr _PV can be expressed by the above equation (19). _{The individual target power P PVi} ^ref , which is the optimum solution of the above equation (19), is set to (P _PVi ^ref ) ^♭ . Similarly, the constrained optimization problem when each power conditioner PCS _Bk obtains the individual target power P _Bk ^ref in a distributed manner using the charge / discharge index pr _B can be expressed by the above equation (20). .. _{The individual target power P Bk} ^ref , which is the optimum solution of the above equation (20), is set to (P _Bk ^ref ) ^♭ .

Here, the optimum solution (P _PVi ^ref ) ^* _{obtained by the above equation (23) and the optimum solution (P PVi} ^ref ) ^♭ obtained by the above equation (19) match, and according to the above equation (23). When the obtained optimum solution (P _Bk ^ref ) ^* _{and the optimum solution (P Bk} ^ref ) ^♭ obtained by the above equation (20) match, the interconnection point power P (t) is output from the electric power company. Can be matched to the value P ^C. That is, even when the power conditioners PCS _PVi and PCS _Bk solve the optimization problem in a distributed manner, the goals 2-4 can be achieved. Therefore, paying attention to the optimality of the steady state, the suppression index pr _PV in which _{(P PVi} ^ref ) ^* = (P _PVi ^ref ) ^♭ and the charge / discharge in which _{(P Bk} ^ref ) ^* = (P _Bk ^ref ) ^♭ Consider the index pr _B. Therefore, the KKT conditions of the above equation (23), the above equation (19), and the above equation (20) are considered. As a result, the following equation (26) is obtained from the KKT condition of the above equation (23), the following equation (27) is obtained from the KKT condition of the above equation (19), and the following equation (20) is obtained from the KKT condition of the above equation (20). 28) Equation is obtained. Note that μ and ν are predetermined Lagrange multipliers.

From the above equations (26), (27), and (28 _{), by setting pr PV} = pr _B = λ (the above equation (22)), (P _PVi ^ref ) ^* and (P) It can be seen that _PVi ^ref ) ^♭ and (P _Bk ^ref ) ^* and (P _Bk ^ref ) ^{♭ match.} Therefore, the centralized management device MC2 calculates the Lagrange multiplier λ and _{presents (transmits) the calculated Lagrange multiplier λ as the suppression index pr PV} to each power conditioner PCS _PVi , so that each power conditioner PCS _PVi has its own _{The individual target power (PPVi} ^ref ) ^♭ can be calculated from the above equation (19). Similarly, the centralized management device MC2 presents (transmits) the calculated Lagrange multiplier λ as the charge / discharge index pr _B to each power conditioner PCS _Bk , so that each power conditioner PCS _Bk has the above (20). The individual target power (P _Bk ^ref ) ^♭ can be calculated from the formula. As a result, even if each power conditioner PCS _PVi and PCS _Bk obtain the individual target powers P _PVi ^ref and P _Bk ^ref in a distributed manner, the interconnection point power P (t) and the output command from the power company The value P ^C can be matched. That is, the goal 2-4 can be achieved.

Next, a method of calculating the Lagrange multiplier λ by the centralized management device MC2 will be described. In order to obtain the Lagrange multiplier λ, first, h ¹ _{1, i} = −P _PVi ^ref , h ¹ _{2, i} = P _PVi ^ref −P _PVi ^lmt, and the inequality constraints of each power conditioner PCS _PVi ^{are collectively h 1} _{Let x, i} ≤ 0 (x = 1, 2, i = 1, ..., N). Similarly, h ² _{1, k} = −P _Bk ^lmt −P _Bk ^ref , h ² _{2, k} = P _Bk ^ref −P _Bk ^lmt , h ² _{3, k} = α _k −P _Bk ^ref , h ² _{4 , k} = P _Bk ^ref −β _k, and the inequality constraints of each power conditioner PCS _Bk ^{are summarized as h 2} _{y, k} ≦ 0 (y = 1,2,3,4, k = 1, ···, m ). Then, consider the following equation (29), which is the dual problem of the above equation (23).

Here, assuming that the optimum solution (P _PVi ^ref ) ^♭ , (P _Bk ^ref ) ^♭ obtained by each power conditioner PCS _PVi and PCS _Bk is determined, the following equation (30) is obtained, and the maximum for the Lagrange multiplier λ is obtained. It becomes a form of the conversion problem. When the gradient method is applied to the following equation (30), the following equation (31) is obtained. Note that ε represents the gradient coefficient and τ represents the time variable.

In the above equation (31), (P _PVi ^ref ) ^♭ is replaced with the individual output power P _PVi ^out of the corresponding power conditioner PCS _PVi , and (P _Bk ^ref ) ^♭ is replaced with the individual output power P of the corresponding power conditioner PCS _{Bk. Replace} with ^{Bk out.} Further, the centralized management device MC2 does not individually observe the individual output powers P _PVi ^out and P _Bk ^out _{of each power conditioner PCS PVi} and PCS _Bk , and the interconnection point power P (t) = Σ _i P _PVi ^out + Σ. Observe _k P _Bk ^out. Further, it is assumed that the sequential output command value P ^{C is acquired from the electric power company.} Then, the above equation (21) is obtained. Thus, the central control device MC2, based on the interconnection point power P (t) and the output command value P ^C from the power company may calculate the Lagrange multiplier lambda. Then, the Lagrange multiplier λ calculated based on the above equation (22) is used as the suppression index pr _PV and the charge / discharge index pr _B.

From the above, in the present embodiment, each power conditioner PCS _PVi uses the optimization problem shown in the above equation (19) when calculating the individual target power P _PVi ^ref. Further, each power conditioner PCS _Bk uses the optimization problem shown in the above equation (20) when calculating the individual target power P _Bk ^ref. Then, the centralized management device MC2 uses the above equations (21) and (22) when calculating the _{suppression index pr PV} and the charge / discharge index pr _B.

Next, in the photovoltaic power generation system PVS2 configured as described above, it was verified by simulation that the above five goals were achieved and the system was operating properly.

In the simulation, 5 power conditioner PCS _PVi to which the solar cell SP _i was connected (i = 1 to 5; PCS _{PV1 to} PCS PV5 _{) and 5} power conditioner PCS _Bk to which the storage battery B _{k was connected (i = 1 to 5; PCS PV1 to PCS PV5).} A photovoltaic power generation system PVS2 having k = 1 to 5; PCS _{B1 to PCS B5) was assumed.}

Further, in this simulation, the model of the storage battery B _{k is, d / dt (x k)} = - K k P Bk out, was s _k = x _k. Here, s _k denotes the charged electrical energy of the storage battery B _k, K _K represents the characteristic of the battery B _{k. Further, the adjustment parameters α k} and β _k that can be adjusted according to the remaining amount of the storage battery B _k are set as shown in Table 1. In Table 1, SOC _k indicates the charge rate (State Of Charge) [%] of each storage battery B _{k , the charge power amount [kWh] is Sk} , and the maximum capacity [kWh] of the storage battery B _{k is S. As k} ^max , it is calculated by _{SOC k} = (S _k / S _k ^{max) × 100.}

The priority parameter (pseudo effective output limit) P _{φi of each power conditioner PCS PVi} , which is a parameter related to the optimization problem, was set to 1000 [kW]. In addition, the model of the power system A (interconnection point voltage) (see equation (18) above) and the models of the power conditioners PCS PVi and PCS _Bk (see FIGS. 3 and 4) _{relate to the first embodiment.} It was the same as the one at the time of simulation.

14 to 16 show the results when the simulation was performed under a plurality of conditions using the solar power generation system PVS2 of the model shown above.

Case 1, all five of the power conditioner PCS _PV1 ~PCS _PV5 the same conditions, a case where all five of the power conditioner PCS _B1 ~PCS _B5 are the same conditions was simulated. Let the simulation be simulation 2-1. In the simulation 2-1, all five of the power conditioner PCS _PV1 ~PCS _PV5 is rated output P _PVi ^lmt is 500 [kW], the weights w _PVi about active power suppression 1.0, the amount of power generated by solar cell SP _i P _i ^SP has to be 600 [kW]. In addition, all five power conditioners PCS _{B1 to PCS B5} have a rated output P _PVi ^lmt of 500 [kW] and a weight w _PVi related to active power suppression of 1.0. It is assumed that the maximum capacities S ₁ ^{max to} S ₅ ^max of the storage batteries B _{1 to} B ₅ are all 500 [kWh]. Then, the output command value P ^C from the electric power company is assumed to be 1500 [kW] when there is no command when 0 ≦ t <60 [s] and when 60 ≦ t [s]. When "there is no command of the output command value P ^C ", the numerical value -1 indicating that there is no command is used as the ^{output command value P C as described above.} In addition, the gradient coefficient ε is 0.05, the suppression index pr _PV and charge / discharge index pr _B performed by the centralized control device MC2 are updated, and the individual target powers P _PVi ^ref and P _Bk ^ref _{performed by each power conditioner PCS PVi} and PCS _Bk. Each sampling time with the update of was set to 1 [s]. Further, it _{was assumed that all the power conditioners PCS PVi} and PCS _Bk were operated at a power factor of 1 (reactive power target value = 0 [kvar]). FIG. 14 shows the simulation results in simulation 2-1.

FIG. 14 (a) shows a power generation amount P _i ^SP solar cell SP _i. FIG. 14B shows the individual target power P _PVi ^ref of each power conditioner PCS _PVi. FIG. 14C shows the individual output power P _PVi ^out of each power conditioner PCS _PVi. FIG. 14 (d) shows the linking point power P (t) output command value from the (solid line) and electric power company P ^C (dashed line). _{FIG. 14E} shows the individual target power P ^{Bk ref} of each power conditioner PCS _Bk. FIG. 14 (f) shows the individual output power P _Bk ^out of _{each power conditioner PCS Bk.} FIG. 14 (g) shows the suppression index pr _PV and the charge / discharge index pr _B calculated by the index calculation unit 43.

The following can be confirmed from FIG. That is, as shown in FIG. 14 (b) and FIG. 14 (c), the even after the command output command value ^{P C (60 ≦ t [s} ]), the individual target power P _PV1 ^ref ~P _PV5 ^ref It remains at 500 [kW], and it can be confirmed that _{the individual output powers P PV1} ^{out to} P _PV5 ^{out are not suppressed.} Further, as shown in FIGS. 14 (e) and 14 (f), the individual output powers P _B1 ^{out to} P _B5 ^{out of} _{each power conditioner PCS Bk} transition from 0 [kW] to negative (minus). It can be confirmed that there is. This indicates that electric power is input to the power conditioner PCS _Bk, and the electric power input to each power conditioner PCS _Bk is used to charge the storage battery B _k. Further, as shown in FIG. 14 (d), the interconnection point power P (t) can also be confirmed that it matches the output command value P ^C. Thus, solar systems PVS2, when the output command value P ^C from the power company is commanded not suppress individual output power P _PVi ^out of the power conditioner PCS _PVi, is used to charge the battery B _k Can be confirmed.

Case 2, the five power conditioner PCS _B1 ~PCS maximum capacity of the storage battery B _5, which is connected to one of the power conditioner PCS _B5 of _B5 S ₅ ^max other power conditioner PCS _B1 ~PCS _B4 A case different from that of the connected storage batteries B _{1 to} B _{4 was simulated.} Let the simulation be simulation 2-2. In the simulation 2-2 was the maximum capacity S ₅ ^max storage battery B ₅ connected to a single power conditioner PCS _B5 and 3 [kWh]. Other conditions were the same as in Simulation 2-1. FIG. 15 shows the simulation results in simulation 2-2. In FIG. 15, FIGS. 15 (a) to 15 (g) are views corresponding to FIGS. 14 (a) to 14 (g) in the simulation 2-1.

The following can be confirmed from FIG. That is, as shown in FIG. 15 (a) ~ (c) , similarly to the simulation 2-1, even after a command output command value ^{P C (60 ≦ t [s} ]), the individual target power P _It can be confirmed that ^{PV1 ref to} P _PV5 ^{ref are not suppressed.} Further, as shown in FIGS. 15 (e) and 15 (f), the individual output powers P _B1 ^{out to} P _B5 ^out _{of the power conditioners PCS B1 to PCS B5} change from 0 [kW] to negative (minus). It can be confirmed that the transition has occurred. Therefore, similarly to the simulation 2-1 above, each of the power conditioners PCS _{B1 to PCS B5} charges _{the storage battery B k} using the input electric power. Further, as shown in FIGS. 15 (e) and 15 (f), when 110 ≦ t [s], the individual output power P _B5 ^out _{of the power conditioner PCS B5} becomes 0 (zero), and the other power conditioners PCS _B1 individual output power P _B1 ^out ~P _B4 ^out of ～PCS _B4 is further decreased (the input power is increasing). This is because the maximum capacity S ₅ ^max of the storage battery B ₅ is 3 [kWh], which is _{lower than that of the other storage batteries B 1 to} B ₄ , so that t = 110 [s], and the storage battery B ₅ is the other storage battery B ₁ to B 1 to. before the B ₄ represents that the charging is completed. Thus, since the charging of the battery B ₅ is completed, it stops the input power to the power conditioner PCS _B5, represents that it stops charging. Then, the power due to distribute conditioner PCS _B5 minute power which has been input to the other of the power conditioner PCS _B1 ~PCS _B4, other power conditioner PCS _B1 ~PCS _B4 individual output power P _B1 ^out to P _B4 ^out is further reduced (power input is increasing). Furthermore, as shown in FIG. 15 (d), the with the charge stop the battery B _5, and temporarily linking point power P (t) becomes greater than the output command value P ^C. However, in the steady state, interconnection point power P (t) can also be confirmed that it matches the output command value P ^C. Therefore, it can be said that the photovoltaic power generation system PVS2 operates appropriately in consideration of the performance of _{each storage battery B k.}

Case 3, the weight w _B5 is set to the other of the power conditioner PCS _B1 ~PCS _B4 relates active power is set to one of the power conditioner PCS _B5 of five power conditioner PCS _B1 ~PCS _B5 A different case was simulated. Let the simulation be simulation 2-3. In simulation 2-3, the _{weight w B5} regarding the active power of the _{one power conditioner PCS B5} was set to 2.0. That is, it means that the charge amount is halved as compared with that of other power conditioners PCS _{B1 to PCS B4.} Other conditions were the same as in Simulation 2-1. FIG. 16 shows the simulation results in Simulation 2-3. In FIG. 16, FIGS. 16 (a) to 16 (g) are views corresponding to FIGS. 14 (a) to 14 (g) in the simulation 2-1.

The following can be confirmed from FIG. That is, as shown in FIG. 16 (a) ~ (c) , similarly to the simulation 2-1, even after a command output command value ^{P C (60 ≦ t [s} ]), the individual target power P _It can be confirmed that ^{PV1 ref to} P _PV5 ^{ref are not suppressed.} Further, from FIG. 15 (e) and FIG. 15 (f), the individual output power P _B1 ^out ~P _B5 ^out of the power conditioner PCS _B1 ~PCS _B5 has a transition from 0 [kW] negative (minus) Can be confirmed. Therefore, similarly to the simulation 2-1 above, each of the power conditioners PCS _{B1 to PCS B5} charges _{the storage battery B k} using the input electric power. Further, as shown in FIGS. 16 (e) and 16 (f), the charge amount ( _{input power to the power conditioner PCS B5} ) of the power conditioner PCS _{B5 having different weights w B5} regarding the active power is the other power. It can be confirmed that the _{conditioners are half of PCS B1 to PCS B4.} Then, as shown in FIG. 16 (d), the interconnection point power P (t) can also be confirmed that it matches the output command value P ^C in the steady state. Therefore, it can be said that the photovoltaic power generation system PVS2 is operating appropriately in consideration _{of the weight w Bk} regarding the active power set in the _{power conditioner PCS Bk.}

The following can be confirmed by comparing FIGS. 14 to 16 in addition to the results for each of FIGS. 14 to 16. That is, as shown in each figure (g), suppression indicators pr _PV and charge-discharge index pr _B is, in each power conditioner _{PCS PV1 ~PCS PV5, PCS B1 ~PCS} B5, power generation amount P of the solar cell SP _i Different values are calculated based on _i ^SP , performance of storage battery B _k , rated output P _PVi ^lmt , P _Bk ^lmt _{, weight w PVi} related to active power suppression, _{weight w Bk} related to active power, and output command value P ^C. It can be confirmed that Then, as shown in (b) and (e) of each figure, the individual target powers P _PVi ^ref and P _Bk ^ref are updated _{according to the update of the suppression index pr PV} and the charge / discharge index pr _B. You can check it. Each power conditioner _{PCS PV1 ~PCS PV5, PCS B1 ~PCS} B5 , the individual target power P _PVi ^ref, depending on the P _Bk ^ref, and controls the individual output power P _PVi ^out, P _Bk ^out. Therefore, as shown in each figure (d), it can be confirmed that the interconnection point power P (t) coincides with the output command value P ^C. _{From the above, it can be said that the suppression index pr PV} and the charge / discharge index pr _B calculated by the centralized control device MC2 using the above equations (21) and (22) are appropriate values.

From the results of the above simulations 2-1 to 2-3, in the photovoltaic power generation system PVS2, each power conditioner PCS _PVi is distributed and individually targeted power based on the _{suppression index pr PV} received from the centralized management device MC2. The _PVi ^ref is calculated. Further, each power conditioner PCS _Bk calculates the individual target power P _Bk ^ref in a distributed manner based on the charge / discharge index pr _{B received from the centralized management device MC2.} Therefore, the above target 2-1 has been achieved. Each power conditioner PCS _PVi are individually output power P _PVi ^out not suppress as much as possible, the amount of interconnection point power P (t) exceeds the output command value P ^C, the power conditioner PCS enter to _Bk, it is available to charge the battery B _k. Therefore, the above-mentioned Goal 2-2 and the above-mentioned Goal 2-3 have been achieved. Furthermore, interconnection point power P (t) coincides with the output command value P ^C. Therefore, the above goals 2-4 have been achieved. Then, the individual output powers P _PVi ^out and P _Bk ^out are changed for each power conditioner PCS _PVi and PCS _{Bk according to various conditions.} That is, the output suppression amount changes for each of the power conditioners PCS _PVi and PCS _{Bk according to various conditions.} Therefore, the above target 2-5 has been achieved. From the above, it can be seen that the photovoltaic power generation system PVS2 has achieved the above five goals.

As described above, in the photovoltaic power generation system PVS2 according to the second embodiment, the central control device MC2 is suppressed index pr from the output command value P ^C and detected interconnection point power P from the power company (t) Calculate _PV and charge / discharge index pr _B. Then, the suppression index pr _PV is transmitted to each power conditioner PCS _PVi , and the charge / discharge index pr _B is transmitted to each power conditioner PCS _Bk. Further, each power conditioner PCS _PVi calculates the _{individual target power P PVi} ^ref by solving the optimization problem of the above equation (19) in a distributed manner based on the received suppression index pr _PV. Then, the individual output power P _PVi ^out is controlled by the individual target power P _PVi ^ref. Further, each power conditioner PCS _Bk calculates the _{individual target power P Bk} ^ref by solving the optimization problem of the above equation (20) in a distributed manner based on the received charge / discharge index pr _B. Then, the individual output power P _Bk ^out is controlled to the individual target power P _Bk ^ref. As a result, the centralized management device MC2 can perform only the simple calculations shown in the above equations (21) and (22). Therefore, in the photovoltaic power generation system PVS2, the processing load of the centralized management device MC2 can be reduced. In addition, each power conditioner PCS _PVi and PCS _Bk calculate the individual target power P _PVi ^ref and P _Bk ^ref in a distributed manner based on the suppression index pr _PV and the charge / discharge index pr _B , respectively, and the individual output power P _PVi ^out , Even _{when controlling P Bk} ^out , the interconnection point power P (t) can be matched with ^{the output command value P C from the power company.}

In the first embodiment, the weight w _i related to active power suppression is taken into consideration, and in the second embodiment, the weight w _PVi related to active power suppression and the weight w _Bk related to active power are taken into consideration. However, it is not limited to this. For example, in the first embodiment, if it is not necessary to consider the target 1-3 "enable the output suppression amount to be adjusted for each _{power conditioner PCS i} ", it is set for each _{power conditioner PCS i. The weights w i} related to the above active power suppression may all have the same value (for example, “1”). Similarly, in the second embodiment, unless it is necessary to consider the target 2-5 "to enable the output suppression amount to be adjusted for each _{power conditioner PCS PVi} and PCS _{Bk", the power conditioner PCS PVi,} may be weight w _PVi and active power of all the same value of the weight w _Bk relates about the effective power restriction set for each PCS _Bk (e.g. "1").

In the second embodiment, the case where the target power calculation unit _{12'calculates} the individual target power P ^{PVi ref} _{using the priority parameter P φi} as in the above equation (19) has been described as an example. _{The rated output P PVi} ^lmt may be used as in the above equation (8) in the first embodiment. In this case, whether to prioritize the suppression of the individual output power P _PVi ^out or the charge / discharge of the _{storage battery B k (individual output power P Bk} ^out ) is the weight related to the active power suppression w The weight related to _PVi and the active power. It can be adjusted with _{w Bk.}

In the second embodiment, the optimization problem solved by the target power calculation unit 12'is not limited to the above equation (19). For example, the following equation (19') may be used instead of the above equation (19). The following equation (19') has an additional output current constraint of _{each power conditioner PCS PVi} shown in the following equation (19c') as compared with the above equation (19). In the following (19 ') equation, Q _PVi the reactive power of the power conditioner PCS _PVi, S _PVi ^d is printable maximum apparent power of the power conditioner PCS _PVi, V ₀ is the interconnection at the time of design The reference voltage of the point, V _PVi , indicates the voltage of the interconnection point in each power conditioner PCS _PVi. Further, in the following equation (19') _{, instead of the output current constraint of each power conditioner PCS PVi} shown in the following equation (19c'), the rated capacity constraint of the _{power conditioner PCS PVi} shown in the following equation (19d') is applied. You may use it.

In the second embodiment, the optimization problem solved by the target power calculation unit 32 is not limited to the above equation (20). For example, the following equation (20') may be used instead of the above equation (20). _{In the following equation (20'), a weight w SOCk} corresponding to the SOC of the _{storage battery B k} is added in the evaluation function shown in the following (20a') as compared with the above equation (20). This weight w _SOCk is calculated by the following equation (32). The In (32), A _SOC's w _SOCK offset, K _SOC is the weight w _SOCK gain, s is the weight w _SOCK ON / OFF switch (e.g., 1 When on, the off-0), SOC _k Indicates the SOC of the current storage battery B _k , and SOC _d indicates the reference SOC. _{Further, the C rate constraint of the storage battery B k} shown in the following equation (20c') _{and the output current constraint of each power conditioner PCS Bk} shown in the following equation (20e') are added to the constraints. The C rate is a relative ratio of the charging time or the time of the discharge current to the total capacitance of the storage battery B _k, obtained by the 1C when to charge or discharge the total capacitance of the storage battery B _k at 1 hour is there. In the present embodiment, the C rate on the charging side is set to the charging rate C _rate ^M , the C rate on the discharging side is set to the discharging rate C _rate ^P, and predetermined values (for example, both 0.3C) are set in advance. .. In the following equation (20'), P _SMk ^lmt is the charge rated output of the _{storage battery B k obtained by −C rate} ^M × WH _S ^lmt (WH _S ^lmt is the rated output capacity of the storage battery B _{k ), and P SPk} ^lmt is The discharge rated output of the storage battery B _k obtained by C _rate ^P × WH _S ^lmt _{, Q Bk} is the invalid power of each power conditioner PCS _{Bk , and S Bk} ^d is the maximum apparent power that can be output by each power conditioner PCS _Bk. V _Bk indicates the voltage at the interconnection point in each power conditioner PCS _Bk. Further, in the charge rated output _PSMk ^lmt of the storage battery B _k , the storage battery charge amount correction according to the SOC shown in the following equation (33) is taken into consideration, with the correction start SOC as SOC _{C and the SOC charge limit threshold value as cMAX.} .. The storage battery charge amount correction is performed as usual until the correction start SOC, and the output is linearly corrected so that the output becomes 0 at the SOC upper limit from the correction start SOC to the SOC upper limit. There is. Further, in the following equation (20') _{, instead of the output current constraint of each power conditioner PCS Bk} shown in the following (20e'), the rated capacity constraint of _{each power conditioner PCS Bk} shown in the following equation (20f') is set. You may use it.

In the photovoltaic power generation system according to another embodiment described below, when the target power calculation unit _{12'calculates} ^{the individual target power P PVi ref} , the above formula (19) or the above formula (19') Any of these optimization problems may be used. Similarly, the target power calculation unit 32 may use either the optimization problem of the above equation (20) or the above equation (20') when calculating the _{individual target power P Bk} ^ref.

In the second embodiment, _{the solar power generation system PVS2 in which a plurality of power conditioners PCS PVi} and PCS _Bk are connected to the interconnection point has been described as an example, but a power load may be further connected. The electric power load consumes the supplied electric power, and is, for example, a factory or a general household. Such other embodiments will be described below with reference to FIGS. 17-20. In the following description, the same or similar components as those in the first embodiment and the second embodiment will be designated by the same reference numerals and the description thereof will be omitted.

17 and 18 show the photovoltaic power generation system PVS3 according to the third embodiment. FIG. 17 shows the overall configuration of the photovoltaic power generation system PVS3. FIG. 18 shows the functional configuration of the control system that controls the electric power at the interconnection point in the photovoltaic power generation system PVS3 shown in FIG. The photovoltaic power generation system PVS3 includes a plurality of power conditioner PCS _PVi and a plurality of power conditioner PCS _Bk , but in FIG. 18, only the first one is shown. As shown in FIGS. 17 and 18, the photovoltaic power generation system PVS3 is different from the photovoltaic power generation system PVS2 according to the second embodiment in that a power load L is added. The power load L is connected to the interconnection point, and power is supplied from _{the power system A, each power conditioner PCS PVi} , and each power conditioner PCS _Bk. In the present embodiment, it is assumed that the total ΣP _PVi ^out of the individual output power P _PVi ^out (power generation amount P _i ^SP of the solar cell SP _{i ) of each power conditioner PCS PVi} exceeds the power consumption of the power load L. .. Then, it is assumed that part or all of the surplus power not consumed by the power load L is reverse power flow to the power system A. Excess power is the difference between the individual output power P _PVi ^out of total .SIGMA.P _PVi ^out and the power consumption.

In such a solar power generation system PVS3, when to reverse power flow surplus power, it is necessary to prevent this excess power does not exceed the output command value P ^C from the power company. In the photovoltaic power generation system PVS3, the surplus power flowing backward can be regarded as the interconnection point power P (t) detected by the interconnection point power detection unit 22. Therefore, the photovoltaic power generation system PVS3 performs _{the interconnection point power suppression control using the suppression index pr PV} and the charge / discharge index pr _B as in the second embodiment, thereby performing the interconnection point power P (t). is the target power (output command value P ^C) a.

According to the solar power generation system PVS3 according to the present embodiment, the central control device MC3, based on the output command value P ^C and linking point power P from the power company (t), suppression indicators pr _PV and charge-discharge index The pr _B is calculated. At this time, the centralized management device MC3 calculates the _{suppression index pr PV} and the charge / discharge index pr _B using the above equations (21) and (22). Then, each power conditioner PCS _PVi calculates the _{individual target power P PVi} ^ref in a distributed manner based on the suppression index pr _PV. Further, each power conditioner PCS _Bk calculates the _{individual target power P Bk} ^ref in a distributed manner based on the charge / discharge index pr _B. As a result, the processing load of the centralized management device MC3 can be reduced. Furthermore, interconnection point power P (t), i.e., it is possible to control the surplus power to be backward flow to the power grid A to the output command value P ^C. Therefore, the surplus power to be backward flow to the electric power system A can not exceed the output command value P ^C from the power company.

In the third embodiment, the case where the power load L is added to the photovoltaic power generation system PVS2 according to the second embodiment has been described as an example, but the power is supplied to the photovoltaic power generation system PVS1 according to the first embodiment. Even when the load L is added, the interconnection point power suppression control can be performed by using the suppression index pr. Again, while the linking point power P (t) to the target power (output command value P ^C), it is possible to reduce the processing load of the central control device MC1.

FIG. 19 shows the photovoltaic power generation system PVS4 according to the fourth embodiment. The photovoltaic power generation system PVS4 includes a plurality of power conditioners PCS _PVi and PCS _Bk , but in FIG. 19, only the first unit is shown as in FIG. Further, the overall configuration of the photovoltaic power generation system PVS4 is substantially the same as that of the photovoltaic power generation system PVS3 (see FIG. 17) according to the third embodiment. In the above-described third embodiment, the individual output power P _PVi ^out of the power conditioner PCS _PVi (power generation amount P _i ^SP solar cell SP _i) is assumed to be greater than than the power consumption of the power load L, In the fourth embodiment, it is assumed that the total ΣP _PVi ^out of the individual output power P _PVi ^out (power generation amount P _i ^SP of the solar cell SP _{i ) of each power conditioner PCS PVi} is less than the power consumption of the power load L. To do. That is, it is assumed that a part or all of the insufficient power that is insufficient in the power generation amount P _i ^SP of the solar cell SP _{i is supplied from the power system A.} Insufficient power is the difference between the individual output power P _PVi ^out of total .SIGMA.P _PVi ^out and the power consumption.

In such a photovoltaic power generation system PVS4, in order to supply the insufficient power from the power system A, it is necessary to buy (purchase) power from the power company. Then, the electricity bill is paid to the electric power company for the amount of electricity purchased. Electricity charges include basic charges and pay-as-you-go charges. The basic charge is determined by the maximum value (peak value) of, for example, the amount of electricity used every 30 minutes recorded by the electricity meter provided at the interconnection point. Specifically, when the peak value of power consumption is high, the basic charge is high, and when the peak value of power consumption is low, the basic charge is low. Therefore, in the photovoltaic power generation system PVS4 according to the fourth embodiment, the power conditioners PCS _PVi and PCS _{Bk are distributedly controlled by using the suppression index pr PV} and the charge / discharge index pr _B to control the power system A from the power system A. Suppress the peak value of the supplied power (purchased power). This is called "peak cut control". The purchased power is the magnitude of the power supplied from the power system A to the photovoltaic power generation system PVS4, that is, the power obtained (purchased) from the photovoltaic power system A by the photovoltaic power generation system PVS4. As described above, the interconnection point power P (t) has a positive value when it is output from the photovoltaic power generation system PVS4 to the power system A (in the case of reverse power flow). Therefore, when the power system A inputs the power to the photovoltaic power generation system PVS4, the interconnection point power P (t) becomes a negative value. In the case of peak cut control for controlling the power purchase power, the target value is set as a negative value, and the interconnection point power P (t) is controlled so as not to fall below the target value.

The photovoltaic power generation system PVS4 controls the individual output power P _PVi ^out _{of each power conditioner PCS PVi in} the peak cut control, and outputs all the power generated by the solar cell SP _i. In addition, the individual output power P _Bk ^out of each power conditioner PCS _Bk is controlled, and the power stored in the _{storage battery B k is discharged as needed.} In this way, by supplementing a part of the power consumption of the power load L with the power _{generated by the solar cell SP i} and the power _{stored in the storage battery B k} , the increase in the purchased power is suppressed. .. In order to perform this peak cut control, as shown in FIG. 19, the centralized management device MC4 differs from the centralized management device MC2 according to the second embodiment in the following points. That is, the centralized management device MC4 includes a peak cut setting unit 45 instead of the output command value acquisition unit 21, and also includes an index calculation unit 43'instead of the index calculation unit 43.

The peak cut setting unit 45 makes various settings for peak cut control. In the present embodiment, the peak cut setting unit 45 sets the peak cut target power P _cut with the upper limit value as a negative value based on the upper limit value of the power purchase power. This peak cut target power P _cut is a target value of the interconnection point power P (t) and is a negative value. The peak cut target power P _cut is arbitrarily set by the user. The peak cut setting unit 45 outputs the set peak cut target power P _cut to the index calculation unit 43'.

Index calculating unit 43 'uses the second compared to the index calculation unit 43 according to the embodiment, the peak-cut target power P _cut inputted from the peak cut setting unit 45 instead of the output command value P ^C, The suppression index pr _PV and the charge / discharge index pr _B are calculated. That is, in the present embodiment, the index calculation unit 43'calculates the suppression index pr _PV and the charge / discharge index pr _{B for} setting the interconnection point power P (t) to the peak cut target power P _cut. In this case, index calculating section 43 'uses the peak cut target power P _cut instead of the above (21) the output command value in the equation P ^C (t), calculates the Lagrange multiplier lambda. Then, the Lagrange multiplier λ calculated by the above equation (22) is calculated as the charge / discharge index pr _B. Note that the suppression indicators pr _PV, electric power generated by the solar cell SP _i from the power conditioner PCS _PVi is so is output every fixed value "0" is used. Therefore, it can be said that the index calculation unit 43'calculates _{only the charge / discharge index pr B.} The index calculation unit 43'transmits the calculated suppression index pr _PV to each power conditioner PCS _PVi via the transmission unit 44. Further, the calculated charge / discharge index pr _B is transmitted to each power conditioner PCS _Bk via the transmission unit 44.

In the photovoltaic power generation system PVS4 configured in this way, the centralized management device MC4 monitors the interconnection point power P (t) detected by the interconnection point power detection unit 22. Then, when the interconnection point power P (t) becomes _{equal to or less than the peak cut target power P cut} , the index calculation unit 43'suppresses the interconnection point power P (t) to be the peak cut target power P _cut. The index pr _PV (= 0) and the charge / discharge index pr _B are calculated. Each power conditioner PCS _{PVi calculates the individual target power P PVi} ^ref based on the optimization problem using the _{suppression index pr PV} calculated by the centralized management device MC4, and the individual output power P _PVi ^out is the individual target power. It is controlled to be P _PVi ^ref. Further, each power conditioner PCS _{Bk calculates the individual target power P Bk} ^ref based on the optimization problem using the _{charge / discharge index pr B} calculated by the centralized management device MC4, and sets the individual output power P _Bk ^out . Control to individual target power P _Bk ^ref. As a result, when the interconnection point power P (t) is equal to or less than the _{peak cut target power P cut} , all the power generated by _{the solar cell SP i} is output, and the power stored in the _{storage battery B k is discharged.} Will be done. As a result, the interconnection point power P (t) rises, and the interconnection point power P (t) becomes the peak cut target power P _cut . Therefore, the photovoltaic power generation system PVS4 suppresses the peak value by suppressing the interconnection point power P (t) from _{becoming equal to or less than the peak cut target power P cut.}

When the interconnection point power P (t) is equal to or less than the _{set peak cut target power P cut} , the centralized management device MC4 controls the _{peak cut target power P cut.} Therefore, depending on the detection interval of the interconnection point power P (t) and the calculation interval of the suppression index pr _PV and the charge / discharge index pr _B , the peak cut target power P _cut or less is instantaneously obtained. Therefore, when setting the upper limit value of the purchased power, it is preferable to set a value smaller than the upper limit value desired by the user by a predetermined amount. As a result, the peak cut target power P _cut is set to a value larger than the actual target value, so that even if the interconnection point power P (t) drops instantaneously, it will be less than or equal to the _{peak cut target power P cut.} It can be suppressed.

From the above, according to the solar power generation system PVS4 according to the present embodiment, as the target power of the interconnection point power P (t), peak cut set by the peak cut setting unit 45 instead of the output command value P ^C Even when the target power P _cut is used, the interconnection point power P (t) can be set to the target power (peak cut target power P _cut ). Further, the processing load of the centralized management device MC4 can be reduced by _{obtaining the} individual target powers P ^{PVi ref} and P _Bk ^ref in a distributed manner by each power conditioner PCS _PVi and PCS _Bk.

In the fourth embodiment, since the discharge of _{the storage battery B k} is prioritized during the peak cut control, the electric power stored in the _{storage battery B k is reduced.} Therefore, when a predetermined charging condition is satisfied, a part of the electric power supplied from the electric power system A may be used to charge _{the storage battery B k.} Examples of such a charging condition include a case where the interconnection point power P (t) is _{larger than the peak cut target power P cut} by a threshold value or more. By doing so, the storage battery B _k can be charged in preparation for the next peak cut control.

In such charge control of the storage battery B _k , the presence / absence of charging and the charging speed may be changed at predetermined time zones. For example, the charging mode can be set for each predetermined time zone. Then, the charging of the storage battery B _k is controlled according to the charging mode. Such charging modes include, for example, a non-charging mode, a normal charging mode, and a low-speed charging mode. The no-charge mode is a mode in which charging is not performed. The normal charging mode is a mode for charging at a predetermined charging speed (normal speed). The low-speed charging mode is a mode for charging at a predetermined speed (low speed) slower than the normal speed. The charging mode is not limited to these. The user can set the charging mode by the user interface of the centralized management device MC4 or the like, and the peak cut setting unit 45 sets the charging mode according to the operation instruction of the user. The above-mentioned predetermined time zone is a predetermined period in which one day is divided into a plurality of times. For example, when the day is divided into a plurality of time zones, it can be set for each of 24 time zones, and is divided into every 30 minutes. In the case, it can be set for each of 48 time zones. In addition, it may be divided into time zones such as morning, noon, evening, evening, and midnight. Further, a predetermined time zone may be provided not on a daily basis but on a weekly basis.

Specifically, the centralized management device MC4 transmits the charging mode setting information set by the peak cut setting unit 45 to each of the power conditioner PCS _Bk via the transmission unit 44. Then, each power conditioner PCS _{Bk that receives the power conditioner PCS Bk via the receiving unit 31 uses the charging rate C rate} ^M associated with the set charging mode to store the storage battery B shown in the above equation (20c'). Change the C rate constraint of _{k (charge rated output PSMk} ^lmt ). For example, the charge rate C _rate ^M for the normal charge mode is set to 0.3, the charge rate C _rate ^M for the low speed charge mode is set to 0.1, and the charge rate C _rate ^M for the no charge mode is set to 0. .. Then, each power conditioner PCS _{Bk obtains an individual target power P Bk} ^ref based on the optimization problem shown in the above equation (20'), and thus whether or not the _{storage battery B k} is charged according to the setting of the charging mode. And the charging speed can be changed. The charging speed may be changed so _{that the storage battery B k} is fully charged in the time zone in which the low-speed charging mode is continuously set. For example, when the "low-speed charging mode" is continuously set from midnight to 6:00 am, the charging speed is set so _{that the storage battery B k is fully charged over 6 hours.} Specifically, the charge rate C _rate ^{M is set} to 1/6 (≈0.167). However, it is desirable not to exceed the normal speed. By doing so, it is possible to appropriately _{change whether or not the storage battery B k} is charged and the charging speed according to the charging mode. Therefore, when the power unit price of the above-mentioned pay-as-you-go rate (of power purchase) changes depending on the time zone, for example, the power purchase is increased during the time when the power unit price is low, and the power purchase is performed during the time when the power unit price is high. The power can be reduced.

In the fourth embodiment, the case where a plurality of power conditioners PCS _{PVi to which the solar cell SP i} is connected is provided as an example has been described, but these may not be provided. That is, it may be composed of a plurality of power conditioner PCS _{Bk to which the storage battery B k} is connected, the power load L, and the centralized management device MC4.

FIG. 20 shows the photovoltaic power generation system PVS5 according to the fifth embodiment. The photovoltaic power generation system PVS5 includes a plurality of power conditioners PCS _PVi and PCS _Bk , but in FIG. 20, only the first unit is shown as in FIG. Further, the overall configuration of the photovoltaic power generation system PVS5 is substantially the same as that of the photovoltaic power generation system PVS3 (see FIG. 17) according to the third embodiment. In the third embodiment, it was possible to reverse power flow, but in the fifth embodiment, reverse power flow is prohibited.

In the photovoltaic power generation system PVS5 in which reverse power flow is prohibited, it is necessary to provide an RPR (reverse power relay) 51 at the interconnection point to the power system A. This RPR51 is a kind of relay. When the RPR51 detects that reverse power flow has occurred in the power system A from the photovoltaic power generation system PVS5, the RPR51 shuts off the photovoltaic power generation system PVS5 from the power system A. Once blocked, it takes time to recover because it is necessary to call a specialized contractor. For example, when the power load L is low due to a factory suspension day or the like, the power consumption of the power load L decreases. Therefore, when the weather is fine on the day when the factory is closed, the power generation amount P _i ^SP _{of the solar cell SP i} may exceed the power consumption of the power load L, and at this time, reverse power flow occurs. Therefore, in the photovoltaic power generation system PVS5 according to the fifth embodiment, the power conditioners PCS _PVi and PCS _{Bk are distributedly controlled by using the suppression index pr PV} and the charge / discharge index pr _B to generate reverse power flow. Suppress. This is called "reverse power flow avoidance control". When the interconnection point power P (t) is a positive value, reverse power flow is generated. Therefore, in order to suppress the occurrence of reverse power flow, the interconnection point power P (t) is a positive value. The negative value should be maintained so that it does not become.

The photovoltaic power generation system PVS5 suppresses the individual output power P _PVi ^out _{of each power conditioner PCS PVi in reverse power flow avoidance control.} Further, to charge the battery B _k controls the individual output power P _Bk ^out of the power conditioner PCS _Bk. In this way, electric power is constantly supplied from the electric power system A to the photovoltaic power generation system PVS5. Therefore, the interconnection point power P (t) is maintained at a negative value so that it does not become a positive value. As a result, the occurrence of reverse power flow is suppressed. In order to perform this reverse power flow avoidance control, as shown in FIG. 20, the centralized management device MC5 differs from the centralized management device MC2 according to the second embodiment in the following points. That is, the centralized management device MC5 includes a reverse power flow avoidance setting unit 46 instead of the output command value acquisition unit 21, and also includes an index calculation unit 43 ”instead of the index calculation unit 43.

The reverse power flow avoidance setting unit 46 makes various settings for reverse power flow avoidance control. In the present embodiment, the reverse power flow avoidance setting unit 46 sets the reverse power flow avoidance target power P _RPR for suppressing the occurrence of reverse power flow. This reverse power flow avoidance target power P _RPR is a target value of the interconnection point power P (t) and is a negative value. The reverse power flow avoidance target power P _RPR is arbitrarily set by the user. The reverse power flow avoidance setting unit 46 outputs the set reverse power flow avoidance target power P _RPR to the index calculation unit 43 ”.

The index calculation unit 43 ”calculates the suppression index pr _PV and the charge / discharge index pr _{B for} setting the interconnection point power P (t) to the reverse power flow avoidance target power P _RPR . That is, in the present embodiment, the index calculator 43 ', as compared with the index calculation unit 43 according to the second embodiment, by using the backward flow around the target power P _RPR inputted from the reverse flow prevention settings unit 46 instead of the output command value P ^C , Suppression index pr _PV and charge / discharge index pr _B are calculated. Specifically, the index calculator 43 ", the above (21) using the backward flow around the target power P _RPR instead of the output command value P ^C (t) in the equation to calculate the Lagrange multiplier lambda. Then, the The calculated Lagrange multiplier λ is calculated as the suppression index pr _PV and the charge / discharge index pr _{B according} to the equation (22). The index calculation unit 43 ” _{powers the calculated suppression index pr PV} via the transmission unit 44. Send to PCS _PVi. Further, the calculated charge / discharge index pr _B is transmitted to the power conditioner PCS _Bk via the transmission unit 44.

In the photovoltaic power generation system PVS5 configured in this way, the centralized management device MC5 monitors the interconnection point power P (t) detected by the interconnection point power detection unit 22. Then, when the interconnection point power P (t) becomes _{equal to or higher than the reverse power flow avoidance target power P RPR} , the index calculation unit 43 ”sets the interconnection point power P (t) to the reverse power flow avoidance target power P _RPR. to the calculated suppression indicators pr _PV and charge-discharge indicator pr _B. each power conditioner PCS _PVi, based on the optimization problem using suppression index pr _PV to the central control device MC5 has been calculated, the individual target power P _PVi ^{The ref} is calculated and the individual output power P _PVi ^out is controlled to the individual target power P _PVi ^ref . Each power conditioner PCS _Bk is optimized using the _{charge / discharge index pr B} calculated by the centralized management device MC5. Based on the problem, the individual target power P _Bk ^ref is calculated, and the individual output power P _Bk ^out is controlled to the individual target power P _Bk ^ref . By these, the interconnection point power P (t) is changed to the reverse power flow avoidance target power P. _{The RPR} is controlled to suppress the generation of reverse power flow, that is, the operation of the RPR 51 by the reverse power flow is suppressed.

When the set value of the reverse power flow avoidance target power _PRPR is 0 (or close to 0), it depends on the detection interval of the interconnection point power P (t) and the calculation interval of the suppression index pr _PV and the charge / discharge index pr _B. When the interconnection point power P (t) rises instantaneously, the interconnection point power P (t) becomes a positive value, and reverse power flow may occur. Therefore, it is preferable that the set reverse power flow avoidance target power P _RPR is set to a value smaller than 0 by a predetermined amount. As a result, the reverse power flow avoidance target power P _RPR becomes smaller than 0, so that even if the interconnection point power P (t) rises instantaneously, it can be suppressed from exceeding 0. Therefore, it is possible to suppress the occurrence of reverse power flow.

From the above, according to the solar power generation system PVS5 according to the present embodiment, as the target power of the interconnection point power P (t), the inverse of the reverse flow prevention settings unit 46 sets, instead of the output command value P ^C Even when the power flow avoidance target power _{PR PR} is used, the interconnection point power P (t) can be set to the target power (reverse power flow avoidance target power _{PR PR} ). Further, the processing load of the centralized management device MC4 can be reduced by _{obtaining the} individual target powers P ^{PVi ref} and P _Bk ^ref in a distributed manner by each power conditioner PCS _PVi and PCS _Bk.

In the fifth embodiment, since _{charging of the storage battery B k} is prioritized during reverse power flow avoidance control, electric power is stored in the storage battery B _{k. Therefore, the storage battery B k} may be discharged when a predetermined discharge condition is satisfied. Examples of such a discharge condition include a case where the interconnection point power P (t) is _{smaller than the reverse power flow avoidance target power P RPR} by a threshold value or more. _{By doing so, the storage battery B k} can be discharged in preparation for the next reverse power flow avoidance control.

In such discharge control of the storage battery B _k , whether or not to discharge may be changed at each predetermined time zone. For example, the discharge mode can be set for each of the predetermined time zones. Then, whether or not to discharge the _{storage battery B k} is controlled according to the discharge mode. Such a discharge mode includes, for example, a discharge mode and a discharge non-discharge mode. The discharge-existing mode is a mode in which discharge is performed. The no-discharge mode is a mode in which no discharge is performed. The discharge mode is not limited to these. The user can set the discharge mode by the user interface of the centralized management device MC5 or the like, and the reverse power flow avoidance setting unit 46 sets the discharge mode according to the operation instruction of the user. The predetermined time zone at this time may be the same as or different from the predetermined time zone in the peak cut control.

Specifically, the centralized management device MC5 transmits the discharge mode setting information set by the reverse power flow avoidance setting unit 46 to each of the power conditioner PCS _Bk via the transmission unit 44. Then, each power conditioner PCS _{Bk that receives the power conditioner PCS Bk via the receiving unit 31 uses the discharge rate C rate} ^P associated with the set discharge mode to store the storage battery B shown in the above equation (20c'). Change the C rate constraint of _{k (discharge rated output P SPk} ^lmt ). For example, 0.3 is the discharge rate C _rate ^P to the discharge chromatic mode, the discharge rate C _rate ^P to the discharge-free mode is set to 0, respectively. Then, whether the power conditioner PCS _Bk is the (20 ') on the basis of the optimization problem shown in equation by obtaining the individual target power P _Bk ^ref, discharging the storage battery B _k in accordance with the setting of the discharge mode Can be changed. By doing so, it is possible to appropriately change whether or not to discharge the _{storage battery B k according to the discharge mode.} Therefore, it is possible to store the electric power without discharging the storage battery B _{k as needed.}

In the fifth embodiment, the case where a plurality of power conditioners PCS _{Bk to which the storage battery B k} is connected is provided as an example has been described, but these may not be provided. That is, it may be composed of a plurality of power conditioners PCS _{PVi to which the solar cell SP i} is connected, a power load L, and a centralized management device MC5. In this case, when the photovoltaic power generation system PVS5 performs reverse power flow avoidance control, the reverse power flow for which the interconnection point power P (t) is set is only suppressed by suppressing the individual output power P _PVi ^out _{from the power conditioner PCS PVi.} The avoidance target power _{PR PR} is set.

In the third to fifth embodiments, the photovoltaic power generation systems PVS3, PVS4, and PVS5 in which the interconnection point power suppression control, the peak cut control, and the reverse power flow avoidance control are individually implemented have been described. It is also possible to combine various controls. In this case, the centralized management device may appropriately switch which control is performed. For example, it may be switched according to the user's operation, the situation (positive / negative of interconnection point power P (t) (whether or not reverse power flow is in progress), reverse power flow is prohibited, or power of power load L. It may be switched automatically according to the consumption history, working days, etc.).

In the first to fifth embodiments, the interconnection point power P (t) which interconnection point power detector 22 detects the target power (output command value P ^C, peak shaving target power P _cut or, , The case of controlling to the reverse power flow avoidance target power _PRPR ) has been described, but the present invention is not limited to this. For example, instead of the interconnection point power P (t) detected by the interconnection point power detection unit 22, the centralized management device receives individual output powers P _i ^out _{from each of the power conditioners PCS i} , PCS _PVi , and PCS _Bk , respectively. P _PVi ^out, the P _Bk ^out to obtain the individual output power P _i ^out, obtained, P _PVi ^out, the sum of P _Bk ^out (hereinafter, referred to as "system total output".) is controlled to be the target power May be good. Such other embodiments will be described below with reference to FIGS. 21-25.

21 and 22 show the photovoltaic power generation system PVS6 according to the sixth embodiment. FIG. 21 shows the overall configuration of the photovoltaic power generation system PVS6. FIG. 22 shows the functional configuration of the control system that controls the total system output in the photovoltaic power generation system PVS6 shown in FIG. The photovoltaic power generation system PVS6 includes a plurality of power conditioners PCS _PVi and PCS _Bk , but in FIG. 22, only the first unit is shown as in FIG.

The photovoltaic power generation system PVS6 according to the sixth embodiment does not detect the interconnection point power P (t), and is the sum of all the individual output powers P _PVi ^out and P _Bk ^out _{of each power conditioner PCS PVi} and PCS _Bk. (System total output P _total (t)) is calculated, and control is performed so that the system total output P _total (t) becomes the output command value P ^C instructed by the electric power company. That is, in the present embodiment, the _total system output P total (t) is set as the adjustment target power, and the output command value P ^C is set as the target power of the _total system output P total (t). In this embodiment, the control performed by the photovoltaic power generation system PVS6 is referred to as "system total output suppression control".

As shown in FIGS. 21 and 22, the photovoltaic power generation system PVS6 differs from the photovoltaic power generation system PVS2 according to the second embodiment in the following points. That is, the centralized management device MC6 is not provided with the interconnection point power detection unit 22, and has a configuration for obtaining individual output powers P _PVi ^out and P _Bk ^out _{from the respective power conditioners PCS PVi} and PCS _{Bk, respectively.} There is. Specifically, each power conditioner PCS _PVi further includes an output power detection unit 14 and a transmission unit 15, and each power conditioner PCS _Bk further includes an output power detection unit 34 and a transmission unit 35, respectively. ing. Further, the centralized management device MC6 includes a receiving unit 61, a total output calculation unit 62, and an index calculation unit 63 instead of the interconnection point power detection unit 22 and the index calculation unit 43.

The output power detection unit 14 is provided in each power conditioner PCS _PVi , and detects the individual output power P _PVi ^{out of the own device.} The output power detection unit 34 is provided in each power conditioner PCS _Bk , and detects the individual output power P _Bk ^{out of the own device.}

The transmission unit 15 transmits the individual output power P _PVi ^out detected by the output power detection unit 14 to the centralized management device MC6. The transmission unit 35 transmits the individual output power P _Bk ^out detected by the output power detection unit 34 to the centralized management device MC6.

The receiving unit 61 receives the individual output powers P _PVi ^out and P _Bk ^out _{transmitted from the respective power conditioners PCS PVi} and PCS _Bk .

The total output calculation unit 62 calculates the system total output P _total (t), _{which is the sum of the individual output powers P PVi} ^out and P _Bk ^{out received by the reception unit 61.} In the present embodiment, the total output calculation unit 62 calculates the _total system output P total (t) by _{adding all the input individual output powers P PVi} ^out and P _Bk ^out.

Index calculating unit 63, the total output calculation section 62 calculates the systems total output P _total (t), calculates the suppression indicators pr _PV and charge-discharge indicator pr _B to the output command value P ^C. At this time, the index calculation unit 63 calculates the Lagrange multiplier λ by using the _{system total output P total} (t) instead of the interconnection point power P (t) in the above equation (21). Then, the calculated Lagrange multiplier λ is calculated as the suppression index pr _PV and the charge / discharge index pr _B by the above equation (22). The calculated suppression index pr _PV is transmitted to each power conditioner PCS _PVi via the transmission unit 44. Further, the calculated charge / discharge index pr _B is transmitted to each power conditioner PCS _Bk via the transmission unit 44, respectively.

_{According to the photovoltaic power generation system PVS6 according to the present embodiment, the total} system output P total (t) is used instead of the interconnection point power P (t) in the second embodiment as the power to be adjusted. also, it is possible to total system output P _total (t) to the target power (output command value P ^C). Further, since each power conditioner PCS _PVi and PCS _Bk obtain the individual target powers P _PVi ^ref and P _Bk ^ref in a distributed manner, the processing load of the centralized management device MC6 can be reduced.

In the above-described sixth embodiment, with respect to solar power generation system PVS2 according to the second embodiment, a case has been described for controlling the output command value P ^C total system output P _total (t) as an example, the first The same may be applied to the photovoltaic power generation system PVS1 according to the embodiment. That is, in the photovoltaic power generation system PVS1 according to the first embodiment, even when controlling system total output P _total (t) to the output command value P ^C in place of interconnection point power P (t), the suppression indicators pr It can be used to control the total output of the system. Again, while the system total output P _total (t) to the target power (output command value P ^C), it is possible to reduce the processing load of the central control device.

In the sixth embodiment, _{the solar power generation system PVS6 in which the power conditioners PCS PVi} and PCS _Bk are connected to the interconnection point has been described as an example, but similarly to the third to fifth embodiments, further , The power load L may be provided.

23 and 24 show the photovoltaic power generation system PVS7 according to the seventh embodiment. FIG. 23 shows the overall configuration of the photovoltaic power generation system PVS7. FIG. 24 shows the functional configuration of the control system that controls the total system output in the photovoltaic power generation system PVS7 shown in FIG. 23. The photovoltaic power generation system PVS7 includes a plurality of power conditioners PCS _PVi and PCS _Bk , but in FIG. 24, only the first unit is shown as in FIG.

As shown in FIGS. 23 and 24, the photovoltaic power generation system PVS7 is further different from the photovoltaic power generation system PVS6 according to the sixth embodiment in that the power load L is connected to the interconnection point. different. Even in such a case, the system total output suppression control using the suppression index pr _PV and the charge / discharge index pr _{B is performed based on the calculated system total output P total (t) as in the sixth embodiment.} be able to. Therefore, similarly to the sixth embodiment, the processing load of the centralized management device MC7 can be reduced while setting the _total system output P total (t) to the output command value P ^C.

In the seventh embodiment, the case where the power load L is added to the photovoltaic power generation system PVS6 according to the sixth embodiment has been described as an example, but the power load L has been described with respect to the photovoltaic power generation system PVS1. Add a, and, even in the solar power generation system that controls the output command value P ^C total system output P _total (t) instead of interconnection point power P (t), by using the suppression indicators pr, system Total output suppression control can be performed. Again, with the total system output P _total (t) to the target power (output command value P ^C), it is possible to reduce the processing load of the central control device.

FIG. 25 shows the photovoltaic power generation system PVS8 according to the eighth embodiment. The photovoltaic power generation system PVS8 includes a plurality of power conditioners PCS _PVi and PCS _Bk , but in FIG. 25, only the first unit is shown as in FIG. Further, the overall configuration of the photovoltaic power generation system PVS8 is substantially the same as that of the photovoltaic power generation system PVS7 according to the seventh embodiment. Photovoltaic system PVS8 according to the eighth embodiment, the plurality power conditioner PCS _PVi, the PCS _Bk, the plurality power conditioner PCS _PVi first power conditioner group G _PV and a plurality of a set of a case in which divided into two groups of the second power conditioner group G _B is the set of the power conditioner PCS _Bk will be described as an example.

Photovoltaic system PVS8 according to the eighth embodiment, in the above-described first power conditioner group G _PV and the second power conditioner group G _B, respectively set the target power, the first power conditioner group G _PV the total output power and the total output power of the second power conditioner group G _B in is controlled to respectively become the target power. This control is called "schedule control". The total output power of the first power conditioner group G _PV is the sum .SIGMA.P _PVi ^out individual output power P _PVi ^out of the power conditioner PCS _PVi, hereinafter referred to as the first group the total output P _GPV. The total output power of the second power conditioner group G _B is the sum .SIGMA.P _Bk ^out of individual output power P _Bk ^out of the power conditioner PCS _Bk, hereinafter referred to as the second group the total output P _GB.

As shown in FIG. 25, the photovoltaic power generation system PVS8 differs from the photovoltaic power generation system PVS7 according to the seventh embodiment in the following points in order to control the schedule. That is, in the centralized management device MC8, the schedule setting unit 64 is used instead of the output command value acquisition unit 21, the total output calculation unit 62'is used instead of the total output calculation unit 62, and the index calculation unit is used instead of the index calculation unit 63. It has a part 63'.

The schedule setting unit 64 makes various settings for schedule control. In the present embodiment, the schedule setting unit 64 has the _{target power P TPV of} the first group, which is the target value of the _{total output P GPV} of the first group, and the target power P of the second group, which is the target value of the _{total output P GB of the second group.} Set _TB. The first group target power P _TPV and the second group target power P _TB can be set for each of the predetermined time zones. These setting values are arbitrarily set by the user. The schedule setting unit 64 outputs various set values to the index calculation unit 63'.

The total output calculation unit _{62'calculates the} total output P GPV of the first group and the total output P _GB of the second group, respectively. Specifically, the total output calculation unit _62'adds the individual output power P _PVi ^out of the power conditioner PCS PVi received by the reception unit 61, and calculates the first group total output P _GPV. Further, the total output calculation unit _62'adds the individual output power P _Bk ^out of the power conditioner PCS Bk received by the reception unit 61, and calculates the second group total output P _GB.

_{The index calculation unit 63'calculates} the suppression index pr _PV for converting the first group total output P GPV calculated by the total output calculation unit _{62'to the first group target power P TPV} input from the schedule setting unit 64. To do. At this time, the index calculation unit 63'calculates the suppression index pr _PV using the following equation (34). In the following equation (34), λ _PV indicates the Lagrange multiplier for a plurality of power conditioner PCS _{PVi , and ε PV} indicates the gradient coefficient for a plurality of power conditioner PCS _PVi. Further, since the first group total output P _GPV and the first group target power P _TPV are values that change with time t, the first group total output is P _GPV (t) and the first group target power is P, respectively. It is described as _{TPV (t).} Thus, the index calculation unit 63 ', in the above-mentioned (9), the first group the total output P _GPV (t) instead of interconnection point power P (t), instead of the output command value P ^C (t) The Lagrange multiplier λ _PV is calculated using the first group target power P _{TPV (t).} Then, the calculated Lagrange multiplier λ _PV is used as the suppression index pr _PV . The index calculation unit 63'transmits the calculated suppression index pr _PV to each power conditioner PCS _PVi via the transmission unit 44.

The index calculation unit 63'sets a charge / discharge index pr _B for _{converting the total output P GB} of the second group calculated by the total output calculation unit 62'to the _{target power P TB} of the second group input from the schedule setting unit 64. calculate. At this time, the index calculation unit 63'calculates the charge / discharge index pr _B using the following equation (35). In the following equation (35), λ _B indicates a Lagrange multiplier for a plurality of power conditioner PCS _{Bk , and ε B} indicates a gradient coefficient for a plurality of power conditioner PCS _Bk. Further, since the total output of the second group P _GB and the target power P _TB of the second group are values that change with time t, the total output of the second group is P _GB (t) and the target power of the second group is P, respectively. It is described as _{TB (t).} Thus, the index calculation unit 63 ', in the above-mentioned (9), a second group total output P _GB (t) instead of interconnection point power P (t), instead of the output command value P ^C (t) The Lagrange multiplier λ _B is calculated using the second group target power P _{TB (t).} Then, the calculated Lagrange multiplier λ _B is used as the charge / discharge index pr _B. The index calculation unit 63'transmits the calculated charge / discharge index pr _B to each power conditioner PCS _Bk via the transmission unit 44.

In the photovoltaic power generation system PVS8 configured in this way, the centralized management device MC8 obtains the individual output power P _PVi ^out _{from each power conditioner PCS PVi} and calculates the first group total output P _GPV. The first group total output P _GPV was calculated such that the first group target power P _TPV, using the above equation (34), calculates the suppression indicators pr _PV. The calculated suppression index pr _PV is transmitted to each power conditioner PCS _PVi. Each power conditioner PCS _PVi calculates the individual target power P _PVi ^ref by using the received suppression index pr _PV , and controls so that the individual output power P _PVi ^out becomes the individual target power P _PVi ^ref. Further, the centralized management device MC8 obtains the individual output power P _Bk ^out _{from the power conditioner PCS Bk,} and calculates the total output P _{GB of the second group. Then, the charge / discharge index pr B} is calculated using the above equation (35) so that the calculated total output P _GB of the second group _{becomes the target power P TB of the second group.} The calculated charge / discharge index pr _B is transmitted to each power conditioner PCS _Bk. Each power conditioner PCS _Bk calculates an individual target power P _Bk ^ref using the received charge / discharge index pr _B , and controls so that the individual output power P _Bk ^out becomes the individual target power P _Bk ^ref. As a result, the total output P _GPV of the first group _{becomes the target power P TPV of} the first group, and the total output P _GB of the second group becomes the _{target power P TB of the second group.}

From the above, according to the solar power generation system PVS8 according to this embodiment, and target power (first group target power P _TPV to the first power conditioner group G _PV and the second power for each conditioner group G _B No. Group 2 target power P _TB ) can be set to set the 1st group total output P _GPV to the 1st group target power P _TPV and the 2nd group total output P _GB to the 2nd group target power P _TB. it can. Further, since the power conditioners PCS _PVi and PCS _{Bk calculate the individual target powers P PVi} ^ref and P _Bk ^ref in a distributed manner based on the suppression index pr _PV and the charge / discharge index pr _B , respectively, the centralized management device MC8 The processing load can be reduced.

In the above-described eighth embodiment, if you set the target power (first group target power P _TPV and the second group target power P _TB) to the first power conditioner group each G _PV and second power conditioner group G _B Has been described as an example, but only one of them may be used.

In the above-described eighth embodiment, a plurality of power conditioners PCS _PVi, PCS _Bk a first power conditioner group is a set of a plurality of power conditioners PCS _PVi G _PV and a plurality of power conditioners PCS _Bk it is a set of but a case in which divided into two groups with the second power conditioner group G _B is described as an example, but is not limited thereto. For example, the first power conditioner group G _PV further divided into a plurality of groups, may be set the target power for each the group. The same applies to the second power conditioner group G _B. Further, the target power may be set for each group by grouping so that one group includes both one or more power conditioner PCS _PVi and one or more power conditioner PCS _Bk. .. _{In this case, the suppression index pr PV} and the charge / discharge index pr _B may be calculated for each group using the above equations (21) and (22).

In the seventh and eighth embodiments, the photovoltaic power generation systems PVS7 and PVS8 in which the total system output suppression control and the schedule control are individually implemented have been described, but these can be combined. In this case, the centralized management device may appropriately switch which control is performed. For example, it may be switched according to the user's operation, or the situation (whether the suppression instruction is received from the electric power company, the first group target power _PTPV or the second group target power _PTB is set, etc.). It may be switched automatically according to.

In the seventh and eighth embodiments, the centralized management devices MC7 and MC8 are provided with a configuration in which the individual output powers P _PVi ^out and P _Bk ^out _{are obtained from the respective power conditioners PCS PVi} and PCS _Bk. Although described as an example, a configuration may be added in which the power consumption of the power load L is obtained from the power load L. When the power consumption of the power load L is available in this way, the sum of the individual output powers P _PVi ^out and P _Bk ^out _{obtained from each power conditioner PCS PVi} and PCS _Bk and the power consumption obtained from the power load L is calculated. By calculating, the interconnection point power P (t) can be estimated. Therefore, even if the interconnection point power detection unit 22 is not provided, the interconnection point power suppression control, peak cut control, and reverse power flow avoidance control described in the third to fifth embodiments can be performed. it can.

In each of the third to fifth embodiments, the case where the interconnection point power suppression control, the peak cut control, and the reverse power flow avoidance control are performed based on the interconnection point power P (t) will be described as an example. In the seventh and eighth embodiments, the system total output suppression control and the schedule control are based on _{the system total output P total} (t), the first group total output P _GPV, and the second group total output P _{GB, respectively.} Each of these cases has been described as an example, but the present invention is not limited to this. It is provided with both means for detecting the interconnection point power P (t) (interconnection point power detection unit 22) and means for obtaining individual output powers P _PVi ^out and P _Bk ^out _{from the power conditioners PCS PVi} and PCS _{Bk, respectively.} In addition, interconnection point power suppression control, peak cut control, reverse power flow avoidance control, system total output suppression control, and schedule control may be controlled in combination.

In the first embodiment to eighth embodiment, a case has been described to match the adjusted power to the target power, solar radiation and SOC _k of the storage battery B _k, the power consumption of the power load L, various target power value For physical reasons such as, it may not be possible to match the adjusted power with the target power. In this case, the centralized management device keeps increasing or decreasing the indexes (suppression index and charge / discharge index) in order to match the adjusted power with the target power. As a result, the indicators may diverge. For example, the interconnection point power suppression control according to the second embodiment, such as when or when the output command value P ^C is less amount of solar radiation is greater than the output the maximum possible power of the photovoltaic system PVS2, Photovoltaic system PVS2 despite the output power to the maximum interconnection point power P (t) is to be less than the output command value P ^C. At this time, the central control device MC2 raises the linking point power P (t), in an attempt to match the output command value P ^C, reduces the suppression indicators pr _PV and charge-discharge indicator pr _B. However, since the solar power system PVS2 can not rise any more linking point power P (t), the state in which interconnection point power P (t) falls below the output command value P ^C is maintained. Therefore, the centralized control device MC2 further reduces _{the suppression index pr PV} and the charge / discharge index pr _B. This is repeated, and the suppression index pr _PV and the charge / discharge index pr _B diverge. As a result, even if the values of the suppression index pr _PV and the charge / discharge index pr _B overflow or the amount of solar radiation returns, it takes time until _{the suppression index pr PV} and the charge / discharge index pr _{B, which have continued to decrease, return to appropriate values.} It takes. Therefore, the ninth solar power generation system prevents the index from diverging when the adjusted power is below (exceeded) the target power in a situation where the adjusted power cannot be increased (decreased) any more. An embodiment will be described below.

FIG. 26 is a diagram for explaining the photovoltaic power generation system PVS9 according to the ninth embodiment. The photovoltaic power generation system PVS9 includes a centralized management device MC9 and a plurality of power conditioners PCS _PVi and PCS _Bk . Note that FIG. 26 shows the configuration of the centralized management device MC9, and the description of a plurality of power conditioners PCS _PVi and PCS _Bk is omitted. Further, the overall configuration of the photovoltaic power generation system PVS9 is substantially the same as, for example, the photovoltaic power generation systems PVS2 to PVS8.

As shown in FIG. 26, the centralized management device MC9 includes a target power setting unit 91, an adjustment target power detection unit 92, an index calculation unit 93, and a transmission unit 94.

The target power setting unit 91 sets a target value of the power to be adjusted. For example, when the photovoltaic power generation system PVS9 performs interconnection point power suppression control or system total output suppression control, the target value is the output command value P ^C. At this time, the target power setting unit 91 corresponds to the output command value acquisition unit 21. When the photovoltaic power generation system PVS9 performs peak cut control, the target value is the peak cut target power P _cut . At this time, the target power setting unit 91 corresponds to the peak cut setting unit 45. Alternatively, when the photovoltaic power generation system PVS9 performs reverse power flow avoidance control, the target value is reverse power flow avoidance target power P _RPR . At this time, the target power setting unit 91 corresponds to the reverse power flow avoidance setting unit 46. In addition, when the photovoltaic power generation system PVS9 performs schedule control, the target value is a target value in schedule control. At this time, the target power setting unit 91 corresponds to the schedule setting unit 64. The target power setting unit 91 outputs the set target value (target power) to the index calculation unit 93.

The adjustment target power detection unit 92 detects the adjustment target power. The adjustment target power detection unit 92 corresponds to the interconnection point power detection unit 22 when the adjustment target power is the interconnection point power P (t). When the power to be adjusted is the total system output P _total (t), it corresponds to the receiving unit 61 and the total output calculating unit 62 (62'). The adjustment target power detection unit 92 outputs the detected adjustment target power to the index calculation unit 93.

The index calculation unit 93 calculates an index for matching the adjustment target power with the target power. In the present embodiment, since the photovoltaic power generation system PVS9 includes a plurality of power conditioners PCS _PVi and PCS _Bk , the index calculation unit 93 calculates the suppression index pr _PV and the charge / discharge index pr _B. Further, the index calculation unit 93 _{prevents the suppression index pr PV} and the charge / discharge index pr _B from diverging. This is called "divergence prevention control". As shown in FIG. 26, the index calculation unit 93 includes a calculation unit 931, a determination unit 932, and a determination unit 933 for divergence prevention control.

The calculation unit 931 calculates the Lagrange multiplier λ. Specifically, in the calculation unit 931, the target power is input from the target power setting unit 91, and the adjustment target power is input from the adjustment target power detection unit 92. Then, the Lagrange multiplier λ is calculated by the following equation (36), where the power to be adjusted is _Padj , the target power is P _{tar, and the gradient coefficient is ε.} The calculation unit 931 outputs the Lagrange multiplier λ as a calculation result to the determination unit 932.
dλ / dt = ε (P _adj −P _tar ) ・ ・ ・ (36)

The determination unit 932 determines whether or not the Lagrange multiplier λ, which is the calculation result of the calculation unit 931, tends to diverge. In the present embodiment, the determination unit 932 determines that the input Lagrange multiplier λ tends to diverge when it is outside the preset divergence determination range. On the other hand, if it is within the divergence determination range, it is determined that there is no divergence tendency. For example, the determination unit 932 determines by the divergence determination range in which the lower limit value is -100 and the upper limit value is 100. The divergence determination range is not limited to this. The judgment unit 932 corresponds to the " second judgment means" described in the claims.

_{The determination unit 933 determines the suppression index pr PV} and the charge / discharge index pr _B based on the determination result by the determination unit 932. Specifically, when the determination unit 932 determines that there is no divergence tendency, the determination unit 933 uses the above equation (22) to calculate the Lagrange multiplier λ by the calculation unit 931 as a suppression index pr _PV and charge / discharge. Determined as index pr _B. On the other hand, when the determination unit 932 determines that the divergence tends to occur, predetermined alternative values are determined as the suppression index pr _PV and the charge / discharge index pr _B. At this time, if the Lagrange multiplier λ is larger than the upper limit value of the divergence determination range, the upper limit value is used as an alternative value. On the contrary, when the Lagrange multiplier λ is less than the lower limit of the divergence determination range, the lower limit is used as an alternative value. For example, when the divergence determination range is set to -100 to 100 as described above, the determination unit 933 sets the suppression index pr _PV and the charge / discharge index pr _{B when the Lagrange multiplier λ calculated by the calculation unit 931 is less than -100.} Determined to be -100. When the Lagrange multiplier λ calculated by the calculation unit 931 is larger than 100, the suppression index pr _PV and the charge / discharge index pr _B are determined to be 100. The determination unit 933 outputs the determined suppression index pr _PV and charge / discharge index pr _B to the transmission unit 94 as the calculation result of the index calculation unit 93.

The transmission unit 94 transmits the suppression index pr _PV calculated by the index calculation unit 93 to each power conditioner PCS _PVi, and transmits the charge / discharge index pr _B calculated by the index calculation unit 93 to each power conditioner PCS _Bk .

When the Lagrange multiplier λ calculated by the calculation unit 931 is out of the divergence judgment range, the centralized management device MC9 configured as described above sets the upper and lower limits of the divergence judgment range as the suppression index pr _PV and the charge / discharge index pr _B. It has been decided as. _{That is, when the suppression index pr PV} and the charge / discharge index pr _B calculated based on the adjustment target power and the target power are outside the divergence determination range, they are limited to the upper and lower limits of the divergence determination range. As a result, the suppression index pr _PV and the charge / discharge index pr _B are not larger than the upper limit of the divergence determination range or smaller than the lower limit of the divergence determination range. Therefore, it is possible to prevent the emission of the suppression index pr _PV and the charge / discharge index pr _B. That is, an index (suppression) when the adjusted power is below (exceeded) the target power in a situation where the adjusted power cannot be further increased (decreased) due to the amount of solar radiation or the physical reason of the SOC of the storage battery. It is possible to provide a photovoltaic power generation system that prevents the index pr _PV and the charge / discharge index pr _{B) from diverging.}

In divergence prevention control according to the ninth embodiment, further, the weight w _Bk regarding active power of the weight w _PVi (see (19a) above formula) and the power conditioner PCS _Bk regarding effective suppression of power each power conditioner PCS _PVi (Refer to the above equation (20a)) may be set as shown below.

Specifically, the value calculated by the following equation (37) is used as the _{weight w PVi} relating to the active power suppression of each power conditioner PCS _PVi. In the following equation (37), pr _PV ^lmt indicates the suppression index limit. The suppression index limit pr _PV ^lmt is a suppression index when the individual output power P _PVi ^{out is set} to 0, that is, a suppression index when the individual output power P _PVi ^out is suppressed 100%. The P _PVi ^lmt is the rated output of each of the above power conditioners PCS _PVi. Instead of the rated output P _PVi ^lmt of each power conditioner PCS _PVi , a pseudo effective output limit P _φi may be used. That is, the value calculated by the following equation (37') may be used.
w _PVi = pr _PV ^lmt / (2 × P _PVi ^lmt ) ・ ・ ・ (37)
w _PVi = pr _PV ^lmt / (2 × P _φi ) ・ ・ ・ (37')

_{Similarly, as the weight w Bk} relating to the active power of each power conditioner PCS _Bk , the value calculated by the following equation (38) is used. In the following equation (38), pr _B ^lmt shows charge and discharge index limit. The charge / discharge index limit pr _B ^lmt is a charge / discharge index when charging / discharging the _{storage battery B k} with the maximum output power _{, that is, the individual output power P Bk} ^out is charged / discharged at 100% of the rated output P _Bk ^lmt. It is a charge / discharge index when doing so. Further, w _SOCk indicates the weight of the storage battery B _k according to the SOC, and P _Bk ^max is the power that can be output to the maximum when various restrictions in the storage battery B _k are taken into consideration (hereinafter, “constraint maximum output”). ".) Is shown. The constraint maximum output P _Bk ^max is set based on the battery B _k charger rated output P _SMk ^lmt, rated output P _Bk ^lmt discharge rated output P _SPk ^lmt and power conditioner PCS _Bk of the battery B _k .. Specifically, the value obtained by reversing the positive and negative signs of the charge rated output P _SMk ^lmt _{is compared with the value of the discharge rated output P SPk} ^lmt , and the larger value is obtained. Then, the larger value is compared with the value of the rated output P _Bk ^lmt , and the smaller value is set as the constraint maximum output P _Bk ^max .
w _Bk = pr _B ^lmt / (2 x w _SOCk x P _Bk ^max ) ... (38)

Next, the operation and effect obtained by setting the weight w _Bk regarding active power weights w _PVi and the power conditioner PCS _Bk regarding effective suppression of power each power conditioner PCS _PVi as described above, FIGS. 27 and 28 Will be described using.

FIG. 27 shows the relationship between the suppression index pr _PV and the individual output power P _PVi ^{out in the} three power conditioner PCS _{PVi having different rated output P PVi} ^lmt. Since the individual output power P _PVi ^out _{is controlled to be the individual target power P PVi} ^ref calculated by the target power calculation unit 12', the figure shows the suppression index pr _PV and the individual target power P _PVi ^ref. It can be said that it shows the relationship with. _{FIG. 27A shows a case where the weights w PVi} related to the active power suppression set in the three power conditioners PCS _PVi have the same value (predetermined value). _{FIG. 27B shows a case where the weight w PVi} relating to the active power suppression set in the three power conditioners PCS _PVi is a value calculated by the above equation (37). In FIG. 27 (b), the suppression index limit pr _PV ^lmt was set to 100. In each figure, the one with the rated output P _PVi ^lmt of 500 kW is shown by the solid line, the one with the rated output P _PVi ^lmt of 250 kW is shown by the broken line, and the one with the rated output P _PVi ^lmt of 100 kW is shown by the alternate long and short dash line.

As shown in FIG. 27 (a), the individual output power P _PVi ^out _{of each power conditioner PCS PVi} decreases by about 50 kW each time the suppression index pr _{PV increases from 0 to 20.} That is, even if the rated output P _PVi ^lmt of each power conditioner PCS _PVi is different, the individual output power P _PVi ^out is uniformly reduced by the same amount. However, after the individual output power P _i ^out becomes 0, all the power becomes 0. On the other hand, as shown in FIG. 27 (b), the each of inhibition index pr _PV is 20 rises between 0 and 100 (inhibition index limit pr _PV ^lmt), when the rated output P _PVi ^lmt is 500kW 100 kW, rated output When the P _PVi ^lmt is 250 kW, the decrease is 50 kW, and when the rated output P _PVi ^lmt is 100 kW, the decrease is 20 kW. This means that the rated output P _PVi ^lmt of each power conditioner PCS _PVi is reduced by 20%. That is, the individual output power P _PVi ^out is suppressed by the _{ratio of each power conditioner PCS PVi to} the rated output P _PVi ^lmt. Therefore, even if the amount of change in the same suppression index pr _PV, the amount of suppression of the individual output power P _PVi ^out changes according to the rated output P _PVi ^lmt _{of each power conditioner PCS PVi.} Further, in each power conditioner PCS _PVi , the individual output power P _PVi ^out is 0 when the suppression index pr _PV is the suppression index limit pr _PV ^lmt. That is, it is suppressed 100%. Further, when the suppression index pr _PV is 0, the individual output power P _PVi ^out is the rated output P _PVi ^lmt . That is, the maximum output power is output. Then, as shown in FIG. 27 (b), in between the suppression indicators pr _PV inhibition index limit from the 0 pr _PV ^lmt (100), the individual output power P _PVi ^out of the power conditioner PCS _PVi is linearly changed doing. Since each power conditioner PCS _PVi ^{cannot output power equal to} or higher than its rated output P _PVi lmt, when the suppression index pr _PV is a negative value, as shown in FIG. 27, a constant value (rated output P). _PVi ^lmt ).

From the above, by using the above equation (37) in setting the _{weight w PVi} related to active power suppression, the ratio of each power conditioner PCS _{PVi to} the rated output P _PVi ^{lmt as} _{the suppression index pr PV changes.} , Individual output power P _PVi ^out can be suppressed. By doing so, in the plurality of power conditioners PCS _PVi of the photovoltaic power generation system PVS9, even if their rated outputs P _PVi ^lmt are different, when the suppression index pr _PV is the suppression index limit pr _PV ^lmt . , The output of the individual output power P _PVi ^out can be suppressed by 100%.

FIG. 28 shows the relationship between the charge / discharge index pr _B and the individual output power P _Bk ^{out in} three power conditioners PCS _{Bk having different rated outputs P Bk} ^lmt. Each power conditioner PCS _{Bk charges the storage battery B k} when the individual output power P _Bk ^out is a negative value, and discharges the _{storage battery B k} when the individual output power P _Bk ^out is a positive value. Further, since the individual output power P _Bk ^out _{is controlled to be the individual target power P Bk} ^ref calculated by the target power calculation unit 32, the figure shows the charge / discharge index pr _B and the individual target power P _Bk ^ref. It can be said that it shows the relationship with. _{FIG. 28A} shows a case where the weights w Bk related to the active power set in the three power conditioners PCS _Bk are the same values (predetermined values). _{FIG. 28B} shows a case where the weight w Bk relating to the active power set in the three power conditioners PCS _Bk is a value calculated by the above equation (38). ^{In FIG. 28B} , the charge / discharge index limit pr _B lmt was set to 100. In each figure, the one with the rated output P _Bk ^lmt of 500 kW is shown by the solid line, the one with the rated output P _Bk ^lmt of 250 kW is shown by the broken line, and the one with the rated output P _Bk ^lmt of 100 kW is shown by the alternate long and short dash line.

As shown in FIG. 28 (a), the individual output powers P _Bk ^out _{of each power conditioner PCS Bk} have a charge / discharge index pr _B of -100 (the charge / discharge index limit pr _B ^lmt is set to a negative value). ^Every time the charge / discharge index pr _B increases by 20 between 100 (charge / discharge index limit pr _B lmt), it decreases by 100 kW. That is, even if the rated output P _Bk ^lmt of each power conditioner PCS _Bk is different, the individual output power P _Bk ^out is uniformly reduced by the same amount. On the other hand, as shown in FIG. 28 (b), the charge / discharge index pr _B is between -100 (charge / discharge index limit pr _B ^lmt is a negative value) and 100 (charge / discharge index limit pr _B ^lmt ). Every time it increases by 20, it decreases by _{100 kW when the rated output P Bk} ^lmt is 500 kW, _{50 kW when the rated output P Bk} ^lmt is 250 kW, and 20 kW when the rated output P _Bk ^lmt is 100 kW. This means that the rated output P _Bk ^lmt of each power conditioner PCS _Bk is reduced by 20%. That is, the individual output power P _Bk ^out is controlled by the _{ratio of each power conditioner PCS Bk to} the rated output P _Bk ^lmt. Therefore, even if the charge / discharge index pr _B changes, the charge / discharge amount of the storage battery B _k changes according to the rated output P _Bk ^lmt of the power conditioner PCS _Bk. Further, each power conditioner PCS _Bk has the same value as the rated output P _Bk ^lmt when the charge / discharge index pr _B is the charge / discharge index limit pr _B ^{lmt set} to a negative value (-pr _B ^lmt). discharging the storage battery B _k at the individual output power P _Bk ^out. On the other hand, when the charge / discharge index pr _B is the charge / discharge index limit pr _B ^lmt , the storage battery B _k is charged with the individual output power P _Bk ^out having the same value as the rated output P _Bk ^lmt. That is, the storage battery B _k is charged and discharged with the maximum output power. Further, when the charge / discharge index pr _B is 0, the individual output power P _Bk ^out is 0. Then, as shown in FIG. 28 (b), the individual output power P _Bk ^out changes linearly.

From the above, by using the above equation (38) in setting the _{weight w Bk} for active power, the ratio of each power conditioner PCS _{Bk to} the rated output P _Bk ^{lmt as} _{the charge / discharge index pr B changes.} , The storage battery B _k can be charged and discharged. By doing so, in the plurality of power conditioners PCS _Bk of the photovoltaic power generation system PVS9, even if their rated outputs P _Bk ^lmt are different, the absolute value of the charge / discharge index pr _B is the charge / discharge index limit pr. _{When B} ^lmt , the storage battery B _k can be ^charged and discharged at 100% of the rated output P _{Bk lmt.} Specifically, when the charge / discharge index pr _B is a negative value of the charge / discharge index limit pr _B ^lmt , the storage battery B _{k is discharged at 100% of the rated output P Bk} ^lmt , and the charge / discharge index pr _{B is} charged. When the value of the discharge index limit pr _B ^lmt , the storage battery B _k can be charged _{at 100% of the rated output P Bk} ^lmt.

Further, in the ninth embodiment, the weight w related to the active power suppression of _{each power conditioner PCS PVi} is the value calculated by the above equation (37) as the _{PVi , and the weight w related to the active power of each power conditioner PCS Bk. When the} value calculated by the above equation (38) is used as Bk, the above is based on the suppression index limit pr _PV ^lmt and the charge / discharge index limit pr _B ^lmt _{used for calculating these weights w PVi} and w _Bk. It is advisable to set the divergence judgment range. Specifically, the divergence determination range in which the suppression index limit pr _PV ^lmt and the charge / discharge index limit pr _B ^lmt are set to the same value X, and the upper limit value is this value X and the lower limit value is negative −X of this value X ( -X to X) is set. For example, the suppression index limit pr _PV ^lmt is set to 100, the charge / discharge index limit pr _B ^lmt is set to 100, and the divergence determination range is set to -100 to 100 (see FIGS. 27 and 28). As a result, the _{timing of suppressing the output of each power conditioner PCS PVi} by 100% and the timing of determining that the suppression index pr _PV tends to diverge are the same. Similarly, the timing at which each power conditioner PCS _Bk charges / discharges the storage battery B _k at 100% of its rated output P _Bk ^lmt is the same as the timing at which the charge / discharge index pr _B is determined to be divergent. For example, in the example of each power conditioner PCS _PVi shown in FIG. 27 (b), when the upper limit value of the divergence determination range is 120, the calculated suppression index pr _PV is linearly suppressed from 0 to 100. Will be done. However, when the suppression index pr _PV is 100 to 120, the individual output power P _PVi ^out continues to be 0 because it cannot be suppressed any more. _{That is, the individual output power P PVi} ^out is only maintained at 0 until it is determined that the power tends to diverge. Further, when the upper limit value of the divergence determination range is set to 80, the calculated suppression index pr _PV is linearly suppressed from 0 to 80. Then, when the suppression index pr _PV reaches 80, it is determined that there is a tendency to diverge. Therefore, thereafter, the suppression index pr _PV is limited to the upper limit value 80 of the divergence determination range. However, when the suppression index pr _PV is 80, the individual output power P _PVi ^out is not 0. That is, the suppression index pr _PV is limited even though it can still be suppressed. Therefore, it is preferable to set the upper limit value of the divergence determination range to the suppression index limit pr _PV ^lmt . The same applies to the example of _{each power conditioner PCS Bk} shown in FIG. 28 (b). From the above, by setting the divergence determination range based on the suppression index limit pr _PV ^lmt and the charge / discharge index limit pr _B ^lmt , the photovoltaic power generation system PVS9 can efficiently perform the divergence prevention control. ..

In the ninth embodiment, the case where a plurality of power conditioners PCS _PVi and PCS _Bk are provided has been described as an example, but a plurality of power conditioners PCS _Bk may not be provided. In this case, the index calculation unit 93 calculates the suppression index pr. Further, in this case, as shown in FIG. 27, since all the indexes (suppression index pr) of 0 or less are rated outputs, the lower limit value of the divergence determination range may be set to 0.

In the ninth embodiment, the calculation unit 931 has described the case where only the calculation of the above formula (36) is performed as an example, but the calculation of the above formula (22) may be further performed. _{In this case, the calculation unit 931 calculates the suppression index pr PV} and the charge / discharge index pr _B by the above equation (22) using the Lagrange multiplier λ obtained by the above equation (36). Therefore, the calculation unit 931 _{outputs the suppression index pr PV} and the charge / discharge index pr _B to the determination unit 932 as the calculation result. Then, the determination unit 932 determines _{whether or not the suppression index pr PV} and the charge / discharge index pr _B tend to diverge depending on whether or not they are outside the divergence determination range. As a result, when it is determined that the divergence is outside the divergence determination range and the divergence tends to occur, the determination unit 933 sets the suppression index pr _PV and the charge / discharge index pr _B to predetermined alternative values (upper limit value outside the divergence determination range or It is replaced with the lower limit value) and output to the transmission unit 94 as _{a new suppression index pr PV} and charge / discharge index pr _B. On the other hand, if it is within the divergence determination range and it is determined that there is no divergence tendency, the determination unit 933 outputs the suppression index pr _PV and the charge / discharge index pr _B calculated by the calculation unit 931 to the transmission unit 94 as they are. Even in this case, the same effect as that of the ninth embodiment can be obtained.

_{In the divergence prevention control according to the ninth embodiment, the suppression index pr PV} and the charge / discharge index pr _B tend to diverge depending on whether or not the Lagrange multiplier λ calculated by the calculation unit 931 is outside the divergence determination range. It was determined whether or not there was, but it is not limited to this. For example, the calculated Lagrange multiplier λ and the power to be adjusted may be sequentially stored, and it may be determined _{from these changes whether or not the suppression index pr PV} and the charge / discharge index pr _{B tend to diverge.} This case will be described below as a modified example of the ninth embodiment.

FIG. 29 shows the centralized management device MC9'related to the modified example. The same or similar configurations as the centralized control device MC9 are designated by the same reference numerals, and the description thereof will be omitted. The centralized management device MC9'is different from the centralized management device MC9 in that it includes an index calculation unit 93'instead of the index calculation unit 93. As shown in the figure, the index calculation unit 93'includes a calculation unit 931, a storage unit 934, a determination unit 932', and a determination unit 933'.

The storage unit 934 stores various information in the divergence prevention control according to the modified example. In the present embodiment, the adjustment target power input from the adjustment target power detection unit 92 and the Lagrange multiplier λ calculated by the calculation unit 931 are sequentially stored.

The determination unit 932'determines whether or not the Lagrange multiplier λ tends to diverge. Specifically, the determination unit 932'determines whether or not there is a divergence tendency based on the adjustment target power stored in the storage unit 934 and the change in the Lagrange multiplier λ. For example, when the change in the power to be adjusted is small and the Lagrange multiplier λ is decreasing (or increasing), it is determined that the power tends to diverge. Therefore, the determination unit 932'has a different criterion for determining whether or not there is a divergence tendency as compared with the determination unit 932. The magnitude of the change in the adjustment target power may be determined by, for example, the dispersion of the plurality of adjustment target powers stored in the storage unit 934. Specifically, the determination unit 932'takes the sum of squares of the plurality of adjustment target powers stored in the storage unit 934 and divides by the number of the plurality of adjustment target powers (number of data). The variance is obtained by calculating the difference between the value obtained in this manner and the square of the average value of the plurality of adjusted powers. The determination unit 932'determines that the change in the power to be adjusted is small when the obtained variance is smaller than the threshold value. The method of calculating the variance is not limited to this. Further, the magnitude of the change in the power to be adjusted may be determined not only by the dispersion but also by a simple difference or a correlation. The judgment unit 932'corresponds to the " first judgment means" described in the claims.

_{The determination unit 933'determines the suppression index pr PV} and the charge / discharge index pr _B based on the determination result by the determination unit 932'. Specifically, when the determination unit 933'determines that the determination unit 932'does not have a divergence tendency, the determination unit 933'determines the Lagrange multiplier λ as the suppression index pr _PV and the charge / discharge index pr _{B using the above equation (22).} To do. On the other hand, when the determination unit 932'determines that there is a tendency to diverge, predetermined alternative values are determined as the suppression index pr _PV and the charge / discharge index pr _B. In the modification, the determination unit 933'uses the oldest Lagrange multiplier λ stored in the storage unit 934 as the alternative value. It should be noted that it is not the oldest Lagrange multiplier λ, but the one before it is judged to have a divergence tendency. Then, the determination unit 933'erases all the adjustment target power and the Lagrange multiplier λ stored in the storage unit 934. That is, the storage unit 934 is initialized. Therefore, the storage unit 934 stores information from the time when the previous determination of the divergence tendency to the time when the next determination of the divergence tendency is determined.

In the modified example configured in this way, the index calculation unit 93'has a tendency to diverge the _{suppression index pr PV} and the charge / discharge index pr _B based on the change of the adjustment target power and the Lagrange multiplier λ stored in the storage unit 934. Determine if it is in. Then, when it is determined that there is a divergence tendency, the calculated suppression index pr _PV and charge / discharge index pr _{B are used for the suppression index pr PV} and charge / discharge using the Lagrange multiplier λ stored before the determination that there is a divergence tendency. Set to index pr _B. Therefore, since the suppression index pr _PV and the charge / discharge index pr _B return to the values before the determination of the divergence tendency, the divergence of the suppression index pr _PV and the charge / discharge index pr _B can be prevented.

In the modified example of the ninth embodiment, similarly to the ninth embodiment, the calculation unit 931 uses the Lagrange multiplier λ obtained by the above equation (36), and the suppression index pr _{PV is calculated by the above equation (22).} And the charge / discharge index pr _B may be calculated. _{That is, the suppression index pr PV} and the charge / discharge index pr _B are used as the calculation result of the calculation unit 931. At this time, the storage unit 934 and the determination unit 932'may perform various processes using the _{suppression index pr PV} and the charge / discharge index pr _{B instead of the Lagrange multiplier λ.} In this case as well, the same effect as that of the above modification can be obtained. Further, even in the modified example of the ninth embodiment, it is not necessary to provide a _{plurality of power conditioners PCS Bk.} That is, it is possible to prevent the suppression index pr from diverging.

In the ninth embodiment and the modified example thereof, the case where the index calculation units 93 and 93'are provided respectively has been described, but the index calculation unit 93 and the index calculation unit 93'are used in combination. May be good. Specifically, it is determined whether or not the calculation result (Lagrange multiplier λ) of the calculation unit 931 tends to diverge based on whether or not it is outside the divergence determination range, and the Lagrange multiplier stored in the storage unit 934. Whether or not there is a divergence tendency is determined based on changes in λ (or suppression index pr _PV and charge / discharge index pr _{B) and the power to be adjusted.} Then, when it is determined by the former that there is a tendency to diverge, the suppression index pr _PV and the charge / discharge index pr _B are determined as in the determination unit 933. On the other hand, when it is determined that the latter tends to diverge, the suppression index pr _PV and the charge / discharge index pr _B are determined as in the determination unit 933'. As a result, it is possible to judge whether or not there is a tendency to diverge based on two judgment criteria. Therefore, it is possible to more appropriately judge the divergence of _{the suppression index pr PV} and the charge / discharge index pr _{B and prevent these divergence.} it can.

In the first to ninth embodiments, the case where the electric power system according to the present disclosure is a photovoltaic power generation system has been described as an example, but the present invention is not limited to this. The electric power system according to the present disclosure may be another power generation system. Other power generation systems include, for example, a wind power generation system, a fuel cell power generation system, a rotary generator power generation system, and a virtual power generation system that manages the load of consumers by an aggregator that conducts negative watt trading. Conceivable. It should be noted that the aggregator does not actually generate electricity because it considers the electricity saved by the negawatt transaction to be the generated electricity. Even in the case of these power generation systems, the centralized management device detects the interconnection point power or calculates the sum of the individual output powers to be the power to be adjusted, calculates the index, and transmits it to each power device. Then, each power device calculates the individual target power of its own device based on the optimization problem using the received index, and controls the individual output power so as to be the individual target power. In the case of a wind power generation system or a fuel cell power generation system, the power device is a power conditioner as well as a photovoltaic power generation system. Further, in the case of a power generation system using a rotary generator, the power device is a generator and a control device for controlling the generator. Further, in the case of a power generation system using an aggregator, the electric power device is a load of a consumer and a control device for controlling the load. In the power generation system using the aggregator, the saved power is regarded as the generated power, so the power reduced from the normal power consumption of the consumer's load becomes the individual output power. Further, the electric power system according to the present disclosure may be a combination of the above-mentioned power generation system. For example, a rotary generator is added to the photovoltaic power generation system, and the centralized management device sends an index to each power conditioner of the photovoltaic power generation system and the controller of the generator to control the overall output. May be.

The electric power system according to the present disclosure is not limited to the above-described embodiment, and the specific configuration of each part can be freely redesigned as long as the contents described in the claims of the present invention are not deviated. is there.

PVS1~PVS9 photovoltaic system A power system SP _i solar cell B _k accumulator PCS _i, PCS _PVi, PCS _Bk power conditioner G _PV first power conditioner group G _B second power conditioner groups 11 and 31 received 12 , 12', 32 Target power calculation unit 13,33 Output control unit 14 Output power detection unit 15 Transmission unit MC1 to MC9, MC9'Centralized management device 21 Output command value acquisition unit 22 Interconnection point power detection unit 23, 43, 43 ', 43' Index calculation unit 24,44 Transmission unit 45 Peak cut setting unit 46 Reverse power flow avoidance setting unit 51 RPR (reverse power relay)
61 Receiving unit 62, 62'Total output calculation unit 63, 63'Index calculation unit 64 Schedule setting unit 91 Target power setting unit 92 Adjustment target power detection unit 93 Index calculation unit 931 Calculation unit 932, 932'Judgment unit 933, 933' Determination unit 934 Storage unit 94 Transmission unit L Power load

Claims (6)

A power system connected to the power system
With multiple power devices
A centralized management device that manages the plurality of electric power devices, and
Is equipped with
The centralized management device is
A detection means for detecting the power to be adjusted and
An index calculation means for calculating an index for controlling the individual output power of each of the plurality of power devices based on the adjustment target power and the target power so that the adjustment target power becomes the target power.
A transmission means for transmitting the index to the plurality of electric power devices is provided.
Each of the plurality of electric power devices
A receiving means for receiving the index and
A target power calculation means for calculating an individual target power of each power device based on an optimization problem using the index, and a target power calculation means.
It is provided with a control means for controlling the individual output power of each power device so as to be the individual target power.
The index calculation means
An arithmetic means for performing an operation using the adjustment target electric power and the target electric power, and
A storage means for sequentially storing the adjusted power detected by the detection means and the calculation result calculated by the calculation means, and a storage means.
Whether the calculation result of the calculation means tends to diverge based on the change of the adjustment target power and the change of the calculation result by using the plurality of adjustment target powers and the plurality of calculation results stored in the storage means. The first means of determining whether or not to use
When the calculation result of the calculation means tends to diverge, a predetermined alternative value is used as the index, and when the calculation result does not tend to diverge, the determination means using the calculation result as the index is provided. Ori,
The first determination means determines that the change in the power to be adjusted is smaller than a predetermined threshold value and tends to diverge when the calculation result is decreasing or increasing.
When the determination means is determined by the first determination means to have a divergence tendency, any one of the plurality of calculation results stored in the storage means before the determination is used as the alternative value.
A power system characterized by that. The index calculation means
Further, it is provided with a second determination means for determining that the calculation result tends to diverge when the calculation result is out of the divergence determination range.
When the determination means is determined by the second determination means to have a divergence tendency, the lower limit value is used as the alternative value when the calculation result is less than the lower limit value of the divergence determination range, and the calculation result. Is greater than the upper limit of the divergence determination range, the upper limit is used as the alternative value.
The power system according to claim 1. The plurality of power devices include n solar power conditioners (n is a positive integer) to which power is input from the solar cell.
The index calculation means calculates a suppression index as the index for each solar power conditioner.
The transmitting means transmits the suppression index to each of the solar power conditioners.
The power system according to claim 2. Each of the n solar power conditioners is set with a weight related to the output control of each of the solar power conditioners.
The weight is a value that sets the individual target power calculated by each photovoltaic power conditioner to 0 when the suppression index is at a predetermined suppression index limit.
The upper limit of the divergence determination range is set based on the suppression index limit.
The power system according to claim 3. The plurality of power devices include m storage battery power conditioners (m is a positive integer) in which power is input from the storage battery or output to the storage battery.
The index calculation means calculates a charge / discharge index as the index for each storage battery power conditioner.
The transmission means transmits the charge / discharge index to each of the storage battery power conditioners.
The electric power system according to any one of claims 2 to 4. Each of the m storage battery power conditioners is set with a weight related to the output control of each storage battery power conditioner.
The weight is a power value that can output the individual target power calculated by each storage battery power conditioner to the maximum output from each storage battery power conditioner when the absolute value of the charge / discharge index is the predetermined charge / discharge index limit. Is the value to be
The divergence determination range is set based on the charge / discharge index limit.
The power system according to claim 5.

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