JP6535549B2 - Control device and control method - Google Patents

Description

  The present invention relates to a control device and control method.

  Introduction of generators using renewable energy such as solar light or wind power has been promoted for the purpose of reducing greenhouse gases. Since the power generation output of a generator that generates electric power using renewable energy fluctuates significantly depending on the environment such as the weather, there is a possibility that the power system may be affected by voltage fluctuation and the like. Therefore, an output that transmits power to the electric power system by combining the storage battery with a generator that generates power using renewable energy and combining the generated output of the generator that generates power using renewable energy and the discharge power of the storage battery Patent Document 1 discloses a distributed power source that smooths

  The distributed power source described in Patent Document 1 generates a target value of a combined output of the generated output of the renewable energy power source and the discharged output of the storage battery by smoothing the generated power output of the renewable energy power source. The distributed power source stores electricity in the storage battery when the power generation output of the renewable energy power source exceeds the combined output target, and the storage battery when the value of the power generation output of the renewable energy power source is less than the combined power target value Discharge from the

Patent No. 5391598 gazette

  In order to sufficiently smooth the combined output and provide stable power supply, the larger the output capacity of the storage battery, the better, and the larger the amount of power that can be discharged, the better. However, the larger the output capacity, the more the amount of power that can be discharged, the more expensive the storage battery. There is a limit to the output capacity of the storage battery actually used for smoothing and the amount of power that can be discharged.

  In addition, as described above, the power generation output of the renewable energy power source largely fluctuates depending on the weather and the like. When the output capacity of the storage battery is small compared to the generator output capacity, if a large fluctuation of the power generation output continues for a long time, the charge power to the storage battery and the discharge power from the storage battery will be short, and the combined output becomes the combined output target value. However, there is a case where it is not possible to perform smoothing sufficiently.

  The present invention has been made in view of the above situation, and can suppress the fluctuation range of the power generation output, and can suppress the fluctuation of the combined output with the charge and discharge output capacity of the storage battery smaller than the power generation output capacity. An object of the present invention is to provide a control device and a control method.

In order to achieve the above object, a control device according to a first aspect of the present invention is:
A power system comprising: a generator that generates electric power using renewable energy; and an electric power storage device that stores and discharges the electric power output of the electric generator, and combining the electric power output of the electric generator with the electric discharge power of the electric power storage device A control device that controls a power supply device that smoothes an output to be transmitted to the
A rising change rate limiting unit that outputs a value that fluctuates according to the fluctuation of the power generation output of the generator and that has a limited change rate at the time of rising;
A composite output that generates and outputs a composite output target of the generator and the power storage device by smoothing the value of the power generation output of the generator whose rate of change at rise is limited by the rise change rate limiting unit. An output target generation unit,
When the power generation output of the generator exceeds the combined output target, the power storage device is charged with the power generation output of the generator, and the power output of the generator is less than or equal to the combined output target. A charge / discharge control unit that controls the power storage device to perform discharge;
An addition unit that outputs a value obtained by adding a value corresponding to the charge amount of the power storage device to the combined output target as the upper limit value of the power generation output of the generator;
A generator control unit configured to control the generator such that a power generation output of the generator does not exceed an upper limit value of the power generation output;
Equipped with

In this case, a smoothing unit that smoothes the value of the power generation output of the generator;
A charge state target setting unit that sets a target value of the charge state of the power storage device based on the value smoothed by the smoothing unit;
A charge state measurement unit that measures the charge state of the power storage device;
A subtraction unit that calculates a deviation of the charge state of the power storage device measured by the charge state measurement unit with respect to the target value of the charge state of the power storage device set by the charge state target setting unit;
Equipped with
The combined output target generation unit
The synthetic output target is generated by smoothing an added value obtained by adding a correction value according to the deviation from the target value of the state of charge of the power storage device to the value output from the rising change rate limiting unit. Do,
You may do it.

In this case, when the state of charge of the power storage device measured by the state of charge measurement unit exceeds the target value set by the state of charge target setting unit, the combined output target is a value corresponding to the deviation. A synthetic output target correction unit that pulls up the
You may do it.

Also, when the state of charge of the power storage device measured by the state of charge measurement unit exceeds the upper limit value,
The combined output target generation unit
Instead of the value of the power generation output of the generator in which the rate of change at the time of rise is limited by the rise change rate limiting unit, the generator further smoothes the value smoothed by the smoothing unit, Generating and outputting as a combined output target of the power storage device,
The adding unit is
A value corresponding to the charge amount of the power storage device is added to the combined output target, and the added value is output as the upper limit value of the power generation output of the generator.
You may do it.

And a low pass filter for removing high frequency components of the value of the power generation output of the generator.
The rising change rate limiting unit
Limiting the rate of change of the generator output of the generator at the time of rising, which is obtained via the low pass filter,
You may do it.

The control method according to the second aspect of the present invention is
A power system comprising: a generator that generates electric power using renewable energy; and an electric power storage device that stores and discharges the electric power output of the electric generator, and combining the electric power output of the electric generator with the electric discharge power of the electric power storage device A control method for controlling a power supply device that smoothes an output to be transmitted to
A rising change rate limiting step that outputs a value that fluctuates according to the fluctuation of the power generation output of the generator and the rate of change at rising is limited;
A composite output target that generates and outputs a combined output target of the generator and the power storage device by smoothing the value of the power generation output of the generator whose rate of change at rise is limited in the rising change rate limiting step. An output target generation step,
When the power generation output of the generator exceeds the combined output target, the power storage device is charged with the power generation output of the generator, and the power output of the generator is less than or equal to the combined output target. A charge / discharge control step of controlling the power storage device to perform discharge;
An addition step of outputting a value obtained by adding a value according to the charge amount of the power storage device to the combined output target as an upper limit value of the power generation output of the generator;
A generator control step of controlling the generator such that a power generation output of the generator does not exceed an upper limit value of the power generation output;
Including
Repeat each step.

  According to the present invention, the rate of change when the value of the power generation output of the generator rises is limited, and the combined output target value is generated with the power generation output whose rate of change when rising is limited. As a result, as the fluctuation of the power generation output of the generator increases, and as the fluctuation passes over a longer period of time, the combined output target becomes lower than the average value of the power generation output of the generator. Therefore, more power can be stored in the storage battery. In addition, since the power generation output of the generator is limited to a value obtained by adding a value corresponding to the charge amount of the storage battery to the combined output target, the fluctuation range of the power generation output of the generator is suppressed. As a result, even in a state in which a large fluctuation of the power generation output continues for a long time, the fluctuation of the combined output can be suppressed with the charge / discharge output capacity of the storage battery smaller than the output capacity of the generator.

It is a block diagram which shows the whole structure of the distributed power supply which concerns on Embodiment 1 of this invention. It is a block diagram which shows the structure of the renewable energy power supply in the distributed power supply of FIG. It is a block diagram which shows the structure of the storage battery system in the distributed power supply of FIG. It is a block diagram which shows the structure of the control system of the control part in the distributed power supply of FIG. It is a table which shows operation | movement of a rising change rate limitation part of FIG. It is a graph which shows operation | movement of the rising change rate limitation part of FIG. It is a block diagram which shows the structure of the smoothing part (the 1) of FIG. It is a block diagram which shows the structure of the SOC maintenance setting part of FIG. It is a block diagram which shows the structure of the smoothing part (the 2) of FIG. It is a block diagram which shows the structure of the SOC process part of FIG. It is a block diagram which shows the structure of the output raise limiter signal creation part of FIG. It is a flowchart of the flow of operation | movement of the distributed power supply centering on the control part of FIG. It is a graph which shows operation | movement of the control part of FIG. FIG. 14 (A) is a graph showing the fluctuation of the power generation output etc. of the conventional distributed power supply. FIG. 14 (B) is a graph showing fluctuations of the power generation output etc. of the distributed power supply of FIG. FIG. 15A is a graph showing a correlation between a wind turbine estimated output fluctuation rate and a power generation output fluctuation rate in the conventional distributed power supply. FIG. 15 (B) is a graph showing the correlation between the estimated wind power output fluctuation rate and the generated power output fluctuation rate in the distributed power supply of FIG. 1. FIG. 16A is a graph showing the correlation between the generated output fluctuation rate and the combined output fluctuation rate in the conventional distributed power supply. FIG. 16 (B) is a graph showing the correlation between the power generation output fluctuation rate and the combined output fluctuation rate in the distributed power supply of FIG.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The same reference numerals are given to the same components in each figure.

  As shown in FIG. 1, the distributed power supply 100 includes a renewable energy power supply 1, a storage battery system 2, a control unit 3, transformers 4 and 5, and current sensors 6 and 7. Distributed power supply 100 combines the power generated by renewable energy power supply 1 and the power discharged from storage battery system 2, and transmits the combined power to power system 10.

  The renewable energy power source 1 transmits a power generation output generated using renewable energy such as wind power or sunlight to the power grid 10. The storage battery system 2 charges the generated output transmitted from the renewable energy power source 1 via the power grid 10 or discharges the power stored in the power grid 10.

  The control unit 3 inputs voltage information in the power system 10 through the transformers 4 and 5 and also inputs current information flowing in a branch connecting the power system 10 and the renewable energy power supply 1 through the current sensor 6 Then, the current information flowing in the branch connecting the power system 10 and the storage battery system 2 is inputted through the current sensor 7.

  The control unit 3 can regenerate an output increase limiter signal for limiting an increase in generated output based on voltage information input via the transformer 4 and current information input via the current sensor 6. Output to Thereby, the control unit 3 controls the renewable energy power source 1.

  Further, control unit 3 receives, from storage battery system 2, information (SOC signal) related to the state of charge (SOC; State Of Charge). The SOC is generally a relative charge level of the storage location, and is defined as a ratio of the remaining charge to the charge capacity of the storage location. Control unit 3 determines a storage battery based on voltage information input via transformer 5, current information input via current sensor 7, and an SOC signal indicating a state of charge (SOC) of storage battery system 2. A charge / discharge control signal for controlling charge / discharge of the system 2 is output. Thereby, control unit 3 controls charge / discharge in storage area system 2.

  Hereinafter, the renewable energy power source 1, the storage battery system 2, and the control unit 3 will be described in more detail.

  As shown in FIG. 2, the renewable energy power source 1 includes a generator 1A and an output control unit 1B. The generator 1A generates electric power using renewable energy such as wind power or sunlight. The power generated by the generator 1A is transmitted to the power system 10. The output control unit 1 B receives an output increase limiter signal from the control unit 3. The output increase limiter signal is a signal for limiting the increase in the power generation output of the generator 1A, and is output from the control unit 3. The output control unit 1B restricts the increase in the power generation output of the generator 1A based on the output increase limiter signal.

  As shown in FIG. 3, the storage battery system 2 includes a storage battery 2A, a bidirectional power converter 2B, a converter controller 2C, and a storage battery controller 2D. The storage battery 2A is a chargeable / dischargeable battery, for example, a NaS (sodium-sulfur) battery, but may be another type of battery such as a lithium ion battery.

  The bidirectional power converter 2B has a function of discharging the storage battery 2A and outputting it to the power system 10, and a function of charging the power from the power system 10 to the storage battery 2A. Both functions can be switched.

  Converter controller 2C outputs a switching signal to bidirectional power converter 2B, and controls charging / discharging of storage battery 2A by switching the input / output direction of bidirectional power converter 2B.

  The storage battery controller 2D includes a protection circuit 2E and an SOC measurement circuit 2F. The protection circuit 2E is provided to protect the storage battery 2A from damage and deterioration of the storage battery 2A due to overcharging and overdischarging of the storage battery 2A. The charge / discharge control signal is input to the converter controller 2C via the protection circuit 2E. The SOC measurement circuit 2F measures the state of charge (SOC) of the storage battery 2A based on the output of the storage battery 2A.

  The control unit 3 is a programmable logic controller (PLC) including a central processing unit (CPU), a memory, and an input / output device. The control unit 3 executes the program stored in the memory, and performs control calculation using various signals input from the input / output device. Thus, a control system as shown in FIG. 4 is constructed in the control unit 3.

  As shown in FIG. 4, the control system of the control unit 3 includes a power conversion unit 3A, a low pass filter (LPF) 3B, a rising change rate restriction unit 3C, a switching unit 3D, an addition unit 3E, and a smoothing unit. 3F, SOC maintenance setting unit 3G, subtraction unit 3H, output control unit 3I, power conversion unit 3J, smoothing unit 3K, SOC processing unit 3L, and output increase limiter signal creation unit 3M .

  Power conversion unit 3A calculates the value of the power generation output of renewable energy power supply 1 based on the voltage information (from transformer 4) and current information (from current sensor 6) of renewable energy power supply 1, and the value thereof Output a signal indicating.

  The low pass filter 3B removes and outputs the high frequency component of the signal indicating the value of the power generation output converted by the power conversion unit 3A.

  The rising change rate limiting unit 3C limits the rate of change when the value of the power generation output of the generator 1A rises to the upper limit value. The rising change rate limiting unit 3C changes the output of the rising change rate limiting unit 3C with the upper limit value of the change rate, when the change rate at the rising of the input (power generation output) exceeds the upper limit value of the change rate. That is, the rising change rate limiting unit 3C outputs a signal indicating a value that fluctuates according to the fluctuation of the power generation output of the generator 1A, and the change rate at the rising is limited.

  FIG. 5 shows the relationship between the input and output of the rising change rate limiting unit 3C. Here, the input of the rising change rate limiting unit 3C is IN, and the output is OUT. The rising change rate limit value is V1 (kW / s), and the sampling period is ΔT. As shown in FIG. 5, when the difference between the input IN and the output OUT is equal to or greater than the rising change rate limit value (V1 × ΔT) per sampling period ΔT, the output OUT of the rising change rate limiting unit 3C is The value is obtained by adding V1 × ΔT to the previous output OUT. On the other hand, when the difference between the input IN and the output OUT falls below the upper limit change rate limit value (V1 × ΔT) per sampling period ΔT, the output OUT is made the same as the input IN.

  For example, as shown in FIG. 6, consider the case where the power generation output of the generator 1A changes. It is assumed that the power generation output increases in the periods T1, T3 and T5, and decreases in the periods T2, T4 and T6. Further, the rate of increase of the power generation output in the periods T1, T3 and T5 is equal to or higher than the upper limit value V1 of the rate of change. In this case, as shown in FIG. 6, the output of the rising change rate limiting unit 3C is limited by the rising change rate limit value as compared to the power generation output. Further, in the periods T2, T4 and T6, the output of the rising change rate limiting unit 3C continues to rise at the rising change rate limit value (V1 × ΔT) until it becomes equal to the value of the power generation output, and is equal to the value of the power generation output Then, follow the power generation output.

  Returning to FIG. 4, the switching unit 3D includes a switch 30D and an SOC level detection unit 31D. The switch 30D normally connects the b-contact and the c-contact, and the output of the rising change rate limiter 3C is input to the adder 3E. When the SOC level detection unit 31D receives the SOC of the storage battery 2A from the SOC processing unit 3L and detects that the SOC exceeds the upper limit, the c contact of the switch 30D is disconnected from the b contact and the c contact is connected to the a contact . In this state, the output of the smoothing unit 3K is input to the addition unit 3E.

  The adding unit 3E adds the output from the c-contact of the switching unit 3D (usually, the output of the rising change rate limiting unit 3C) and the SOC correction signal output from the SOC processing unit 3L. The SOC correction signal is a signal for correcting the power generation output according to the SOC in the storage battery 2A. When the measured value of SOC, which will be described later, is higher than the target value, the SOC correction signal is positive, so the combined output target to which the signal is added becomes higher. On the other hand, when the measured value of SOC is lower than the target value, the SOC correction signal becomes negative, and the combined output target to which the signal is added becomes lower in value.

  The smoothing unit 3F smoothes the signals added by the adding unit 3E, and outputs the smoothed signal as a combined output target. As shown in FIG. 7, the smoothing unit 3F includes a fluctuation range restriction unit 30F, a change rate restriction unit 31F, and a fluctuation range upper and lower limit setting unit 32F.

  The fluctuation range limiting unit 30F limits the amplitude level of the input signal to the set upper and lower width. Here, the maximum value and the minimum value of the signal within a fixed time are limited so as to fall within the set upper and lower width. The change rate limiting unit 31F limits the change rate of the output signal such that the change rate of the signal limited by the variation range limiting unit 30F falls within the upper limit value and the lower limit value. The fluctuation range upper and lower limit setting unit 32F sets the upper and lower limits of the fluctuation range in the fluctuation range limiting unit 30F based on the fluctuation range of the signal whose change rate is limited by the change rate limiting unit 31F.

  Returning to FIG. 4, the SOC maintenance setting unit 3G outputs a signal indicating the combined output target when the SOC of the storage battery 2A falls below the upper limit, and the power generation output when the SOC of the storage battery 2A exceeds the upper limit. Output a signal indicating.

  As shown in FIG. 8, SOC maintenance setting unit 3G includes subtraction unit 30G, fluctuation range restriction unit 31G, primary delay element 32G, addition unit 33G, upper / lower limit setting unit 35G, and zero level setting unit 36G. , A switch 37G, and a high and low maintenance point detection unit 38G.

  The subtracting unit 30G subtracts the signal indicating the combined output target output from the smoothing unit 3F from the signal indicating the generated output output from the power conversion unit 3A. The fluctuation range limiting unit 31G limits the signal indicating the subtraction result of the subtracting unit 30G to be between the upper limit value and the lower limit value. The signal limited to the upper limit value and the lower limit value is input to the addition unit 33G through the first-order delay element 32G.

  The addition unit 33G adds the output signal of the first-order lag element 32G to the output of the smoothing unit 3F (combined output target). A signal indicating the addition result of the addition unit 33G is output as an output signal of the SOC maintenance setting unit 3G.

  The upper and lower limit setting unit 35G sets an upper limit value and a lower limit value limited by the fluctuation range limiting unit 31G. The zero level setting unit 36G outputs 0. The switch 37G switches the setting unit connected to the fluctuation range limiting unit 31G to either the upper / lower limit setting unit 35G or the zero level setting unit 36G. However, there are two circuits for upper limit setting and lower limit setting of the switch 37G, and the switches 37G are individually switched according to the high keeping point detection output and the low keeping point detection output of the high and low keeping point detection unit 38G. When connected to the upper and lower limit setting unit 35G, the non-zero upper limit value and the lower limit value are set in the fluctuation range limiting unit 31G. On the other hand, when connected to the zero level setting unit 36G, the upper limit value and the lower limit value of the fluctuation range limiting unit 31G are zero.

  The height maintenance point detection unit 38G receives the signal of the SOC of the storage battery 2A from the SOC processing unit 3L, outputs a signal indicating whether the SOC exceeds the upper limit or the lower limit, and switches the switch 37G. The switch 37G normally connects the b-contact and the c-contact to connect the zero level setting unit 36G to the fluctuation range limiting unit 31G.

  When the SOC is in the normal range, the output of the high and low maintenance point detection unit 38G is off, and the switch 37G connects the b contact and the c contact. In this case, the upper limit value and the lower limit value of the fluctuation range limiting unit 31G are set to zero, the output of the fluctuation range limiting unit 31G is zero, and the output of the first-order delay element 32G is also zero. In this case, the output of the adding unit 33G (the output of the SOC maintenance setting unit 3G) is a signal indicating a combined output target. In this case, the subtracting unit 3H inputs a signal obtained by subtracting the power generation output from the combined output target to the output control unit 3I.

  On the other hand, when the SOC becomes equal to or higher than the high maintenance point, the output for setting the upper limit of the high and low maintenance point detection unit 38G is turned on, and the switch 37G (for setting the upper limit) connects the a contact and the c contact. In this case, the upper limit setting value of the upper and lower limit setting unit 35G is set as the upper limit side setting value of the fluctuation range limiting unit 31G. As a result, only when the generated output is higher than the combined output target, the output of the fluctuation range limiting unit 31G becomes a difference between the generated output and the combined output target, and the output of the adding unit 33G (the output of the SOC maintenance setting unit 3G) is , Equal to the power output. In this case, in the subtraction unit 3H, the power generation outputs are subtracted from each other, and zero is input to the output control unit 3I.

  As described above, when the SOC exceeds the upper limit value and the power generation output exceeds the combined output target, the SOC maintenance setting unit 3G outputs a signal indicating the power generation output. In this case, in the subtraction unit 3H, the signals indicating the power generation output are subtracted, and the output becomes zero. On the other hand, when the SOC exceeds the upper limit value and the generated output does not exceed the combined output target, the SOC maintenance setting unit 3G outputs the combined output target. In this case, the power generation output is subtracted from the combined output target in the subtraction unit 3H, and the subtraction value is input to the output control unit 3I. That is, when the SOC exceeds the upper limit value, as described later, the entire control system operates to lower the SOC and return it to the normal range by performing only the discharge without performing the charge.

  Furthermore, when the SOC falls below the lower limit value, the lower limit setting output of the high and low keeping point detection unit 38G turns on, and the switch 37G (for lower limit setting) connects the a contact and the c contact, and the upper and lower limit setting unit 35G The lower limit setting value of is set as the lower limit side setting value of the fluctuation range limiting unit 31G. As a result, only when the generated output is lower than the combined output target, the output of the fluctuation range limiting unit 31G becomes the difference between the generated output and the combined output target, and the output of the adding unit 33G (the output of the SOC maintenance setting unit 3G) Is equal to the power output. In this case, in the subtraction unit 3H, the power generation outputs are subtracted from each other, and zero is input to the output control unit 3I.

  As described above, when the SOC is lower than the lower limit value and the generated output is lower than the combined output target, the SOC maintenance setting unit 3G outputs the generated output. In this case, in the subtraction unit 3H, the power generation outputs are subtracted from each other, and the output becomes zero. On the other hand, when the SOC is below the lower limit value and the generated output is not below the combined output target, the SOC maintenance setting unit 3G outputs a signal indicating the combined output target. In this case, the subtraction unit 3H subtracts the generated power from the combined output target, and the subtraction value is input to the output control unit 3I. That is, when the SOC falls below the lower limit value, the entire control system operates to raise the SOC and return it to the normal range by discharging only and charging only as described later.

  When the SOC returns to the normal range (between the upper limit value and the lower limit value), the output of the SOC high and low maintenance point detection unit 38G is turned off, and the SOC maintenance setting unit 3G outputs a combined output target, and the subtraction unit 3H inputs a signal obtained by subtracting the power generation output from the combined output target to the output control unit 3I.

  Returning to FIG. 4, the output control unit 3I controls charging and discharging of the storage battery system 2 based on the signal output from the subtracting unit 3H. For example, when the generated output is larger than the combined output target, the output control unit 3I controls the storage battery system 2 to perform charging. Further, the output control unit 3I controls the storage battery system 2 to perform discharge when the generated output is lower than the combined output target.

  On the other hand, power conversion unit 3J calculates the value of charge / discharge power of storage battery system 2 based on the voltage information and current information from storage battery system 2, and inputs the signal to output control unit 3I. In output control unit 3I, the difference between the power generation output and the combined output target is used as a preceding signal, and the deviation between this and the charge / discharge power of storage battery system 2 is added by proportional-plus-integral (PID) and added to perform control. Control the charge and discharge of As described above, the output control unit 3I improves the response characteristic of the storage battery system 2 by adding the differential operation using the charge / discharge power of the storage battery system 2 as a feedback signal.

  The smoothing unit 3K smoothes the information indicating the value of the generated output output from the power conversion unit 3A. As shown in FIG. 9, the smoothing unit 3K includes a low pass filter 30K, a variation range limiting unit 31K, a change rate limitation unit 32K, and a variation range upper and lower limit setting unit 33K. The low pass filter 30K removes high frequency components of the input signal. The fluctuation range limiting unit 31K puts the output of the low pass filter 30K between the set upper limit and lower limit. The change rate limiting unit 32K puts the change rate of the output signal stored in the range between the upper limit and the lower limit between the upper limit and the lower limit. The maximum value and the minimum value of the signal whose fluctuation range is thus limited are set in the fluctuation range upper and lower limit setting unit 33K as the new upper and lower limits of the fluctuation range.

  Returning to FIG. 4, the SOC processing unit 3L corrects the combined output target mainly based on the state of charge (SOC) of the storage battery 2A in the storage battery system 2. As shown in FIG. 10, SOC processing unit 3L includes SOC target setting unit 30L, SOC output conversion unit 31L, subtraction unit 32L, SOC control unit 33L, fluctuation range restriction unit 34L, and SOC function unit 35L. , A lower limit limiting unit 36L, and a subtracting unit 37L.

  The SOC target setting unit 30L determines an SOC target value based on the smoothed power generation output output from the smoothing unit 3K. The SOC output conversion unit 31L receives the SOC signal output from the storage battery system 2, calculates an output conversion charge state (SOC) of the storage battery 2A based on the SOC signal, and outputs the SOC.

  Subtraction unit 32L subtracts the SOC target value from the SOC output from SOC output conversion unit 31L, and outputs the deviation. The SOC control unit 33L outputs an SOC correction signal (P or PI control signal) according to the deviation. The fluctuation range limiting unit 34L outputs the SOC correction signal limited to the set fluctuation range to the adding unit 3E.

  The SOC calculated by the SOC output conversion unit 31L is also output to the SOC function unit 35L. The SOC function unit 35L determines the fluctuation range in the fluctuation range limiting unit 34L using the SOC function.

In general, the following relationship exists between the output (storage battery output) of the storage battery 2A and the SOC correction signal (SOC correction value).
(Smoothing battery output) = (Battery output)-(SOC correction value)
Therefore, when the SOC correction value becomes large, the frequency at which the smoothing storage battery output runs short (because the output upper limit is limited by the rated value) increases, and the quality of the smoothing decreases. The fluctuation range limiting unit 34L limits the SOC correction value to the minimum in order to prevent deterioration in the quality of smoothing. The positive limit value of the fluctuation range limiter 34L is given as a function of the SOC measurement value. As the SOC becomes higher than the normal fluctuation range, the fluctuation range limiting unit 34L increases the positive limit value, allows an increase in the SOC correction value, and suppresses the SOC increase.

  The lower limit limiting unit 36L outputs only the positive correction value of the SOC correction signal. The subtracting unit 37L subtracts the positive SOC correction signal from the combined output target to obtain a combined output target (SOC) in consideration of the SOC, Output to the output rise limiter signal creation unit 3M. This mechanism is to prevent the SOC from further rising when the output upper limit limiter signal to the generator 1A is increased by the positive side correction of the SOC when the SOC is higher than the target value and the power generation output is increased. It is provided.

  The SOC generated by the SOC output conversion unit 31L is output to the switching unit 3D, the SOC maintenance setting unit 3G, and the output increase limiter signal generation unit 3M.

  Returning to FIG. 4, the output increase limiter signal creation unit 3M receives the signal of the generated output from the power conversion unit 3A, receives the SOC and the combined output target (SOC) from the SOC processing unit 3L, and regenerates the output increase limiter signal. Possible energy supply 1 is output.

  As shown in FIG. 11, the output rise limiter signal creation unit 3M includes a bias output unit 30M, an addition unit 31M, a rise / fall change rate limitation unit 32M, an upper limit limitation unit 33M, and a charge power upper limit setting unit 34M. A charge power lower limit setting unit 35M, a switch 36M, an SOC level detection unit 37M, and an addition unit 38M are provided.

  The bias output unit 30M outputs a positive bias signal. The addition unit 31M adds a positive bias signal to the power generation output and outputs it. The rising and falling change rate limiting unit 32M limits the rising change rate and the falling change rate of the output of the adding unit 31M. The upper limit limiting unit 33M limits the upper limit of the signal output from the rising and falling change rate limiting unit 32M. The signal whose upper limit is limited by the upper limit limiter 33M is output to the renewable energy power source 1 as an output increase limiter signal. The renewable energy power source 1 limits the power generation output to the upper limit value limited by the output increase limiter signal.

  On the other hand, an upper limit value of charging power is set in charging power upper limit setting unit 34M. The rated output of the storage battery 2A is usually set to this upper limit value.

  The lower limit value (for example, about 0 to 100 kW) of the charging power is set in the charging power lower limit setting unit 35M. The lower limit value changes depending on the rated output of the generator 1A and the accuracy of the output control.

  The switch 36M connects the c-contact to either the a-contact or the b-contact. The a-contact is connected to the charging power lower limit setting unit 35M, and the b-contact is connected to the charging power upper limit setting unit 34M. The switch 36M normally connects the b contact and the c contact. Thus, the upper limit value of charging power upper limit setting unit 34M is output to addition unit 38M. In this case, a value obtained by adding the upper limit value to the combined output target is the upper limit value of the power generation output set by the output increase limiter signal.

  When the SOC reaches the upper limit value, the SOC level detection unit 37M outputs a switching signal to the switch 36M. When the switching signal is input from the SOC level detection unit 37M, the switch 36M is connected to the c-contact and the a-contact. As a result, the lower limit value of charging power lower limit setting unit 34M is output to addition unit 38M. In this case, a value obtained by adding the lower limit value to the combined output target is the upper limit value of the power generation output set by the output increase limiter signal. Thus, when the SOC exceeds the upper limit value. The overall control is performed such that only the discharge is performed, with the signal output to the upper limit limiting unit 33M substantially the same as the combined output target.

  When the charge power lower limit value is set to 0 kW, the generator output often decreases gradually. Therefore, the charge power lower limit value is set to about 2 to 5% of the rated output of the generator, and the output of the generator 1A is maintained or gradual increase is permitted when the input to the generator 1A is continuously increased. It is desirable to do so.

  Next, the operation of the distributed power supply 100 centering on the control unit 3 according to the present embodiment will be described.

  A flowchart of the flow of the operation of the control unit 3 is shown in FIG. This flowchart is a series of characteristic operations of the control unit 3 and the like in time series, and individual detailed operations are omitted as appropriate.

  First, the control unit 3 (the rising change rate limiting unit 3C) receives the power generation output of the generator 1A that has passed through the power conversion unit 3A and the LPF 3B, and fluctuates according to the fluctuation of the power generation output. Outputs a restricted value (step S1).

  Subsequently, the control unit 3 (smoothing unit 3F) limits the rate of change at the time of rising in step S1, and smoothes the value of the generated output of the generator 1A that has passed through the switching unit 3D. A combined output target of the storage area 2A is generated and output (step S2).

  Subsequently, control unit 3 (SOC maintenance setting unit 3G and output control unit 3I) charges the power generation output of generator 1A to storage area 2A when the power generation output of generator 1A exceeds the combined output target. If the power generation output of the generator 1A is less than or equal to the combined output target, the storage area 2A is controlled to perform discharge (step S3).

  Further, control unit 3 (output increase limiter signal creation unit 3M) adds a value obtained by adding the value corresponding to the charge amount of power storage location 2A to the combined output target that has passed through SOC processing unit 3L. An upper limit value (output increase limiter signal) is output (step S4).

  Furthermore, the output control unit 1B of the renewable energy power supply 1 controls the generator 1A based on the input output increase limiter signal so that the generated output of the generator 1A does not exceed the upper limit of the generated output ( Step S5).

  Thereafter, steps S1 to S5 are repeated at high speed, and smoothing control of the power generation output is executed. Note that step S3 and steps S4 and S5 are executed simultaneously and in parallel.

  FIG. 13 shows an example of changes in the power generation output controlled by the control unit 3 according to the present embodiment, the output of the rising change rate limiting unit 3C, and the combined output target. As shown in FIG. 13, the power generation output of the generator 1A fluctuates with time, and the output of the rising change rate limiter 3C also fluctuates following the fluctuation of the power generation output of the generator 1A. However, if the rate of rise change of the power generation output of the generator 1A exceeds the upper limit value, the output of the rise change rate limiting unit 3C will increase at the upper limit value so as to fall below the power generation output of the generator 1A. Become. Since the combined output target is generated based on the output of the rising change rate limiting unit 3C, it shifts lower than the combined output target when generated from the generated output.

  Although the power generation output of generator 1A changes without an upper limit as shown by the dotted line if there is no limit, in the present embodiment, the power generation output of generator 1A is a battery output target with the output increase limiter signal. The upper limit is limited to a value obtained by adding a value corresponding to the charge amount of 2A.

  FIG. 14A shows the relationship between the generated output of the renewable energy power supply 1 and the combined output target when the rising change rate limiting unit 3C according to the present embodiment does not limit the rising change rate. It is done. As shown in FIG. 14A, when the power generation output exceeds the combined output target, the storage battery system 2 is charged, and when the generated output falls below the storage power target, the storage battery system 2 is discharged. When the fluctuation of the power generation output becomes large, the power generation output of the renewable energy power source 1 is limited to a value obtained by adding a value corresponding to the charge amount to the combined output target. Therefore, a value obtained by subtracting the combined output target from the generated output is within the range of the charging capacity of the storage battery system 2, and the combined output does not fluctuate. In this situation, if the generated output falls below the combined output target, the storage battery is discharged, but if the difference between the generated power and the combined output target value exceeds the discharge capacity of the storage battery and the generated power decreases, the discharged output will be insufficient. This causes the combined output to fall below the combined output target.

  FIG. 14B shows the relationship between the generated output of the renewable energy power supply 1 and the combined output target when the rising change rate limiting unit 3C according to the present embodiment limits the rising change rate. ing. As shown in FIG. 14 (B), when the power generation output exceeds the combined output target, the storage battery system 2 is charged, and when the generated output falls below it, the storage battery system 2 is discharged. Since the output of the rising change rate limiting unit 3C falls below the generated output when the fluctuation of the generated output increases and the rising rate of the generated output exceeds the upper limit of the rising change rate limiting unit 3C, the output is generated The combined output target is shifted downward. When the power generation output rises in this state, the power generation output of the renewable energy power source 1 is limited similarly to FIG. 14A, and the value obtained by subtracting the combined output target from the power generation output is The combined output does not change. When the power generation output decreases in this state, the value obtained by subtracting the power generation output from the combined output target decreases by the shift amount of the combined output target as compared to FIG. 14 (A). Therefore, the required output value of storage battery 2A falls within the range of the discharge capacity, and a decrease in combined output does not occur. In addition, if the combined output target shifts downward, it is possible to charge more the power charged in the storage battery 2A by that amount. Therefore, the discharge shortage of the storage battery 2A can be eliminated.

  In FIG. 15A, the fluctuation rate of the estimated output of the renewable energy power supply 1 (here, a wind turbine) when combined output shift control is not performed (the wind turbine estimated output fluctuation rate) and the power generation output fluctuation rate The correlation of the change rate for 20 minutes is shown. As shown in FIG. 15 (A), in this case, the wind turbine estimated output and the fluctuation rate of the power generation output show substantially the same value, and the wind turbine output suppression hardly occurs.

  Fig. 15 (B) shows the correlation of the fluctuation rate of the wind turbine estimated output (wind turbine estimated output fluctuation rate) in the case where shift control of the combined output target is performed and the generation output fluctuation rate over a 20-minute period. ing. As shown in FIG. 15 (B), in this case, it can be seen that the power generation output fluctuation is suppressed and the power generation output fluctuation is suppressed to about 50% or less when the estimated wind power output fluctuation rate exceeds 40%. . The setting of rise change rate limiter 3C of the power generation output at this time is 0.15% / sec, and the output signal of rise change rate limiter 3C has a fluctuation range of 45% against fluctuation of 10 minutes or less in period It is limited to 0.15 × 600 seconds / 2) or less, and the combined output target is an intermediate value of its fluctuation. Further, the output of the output increase limiter signal creation unit 3M is a value obtained by adding 25%, which is the upper limit of the charge output of the storage battery, to the combined output target. As a result, the output of the wind turbine is suppressed to a value obtained by adding 25% to the combined output target, and the fluctuation range is suppressed to 47.5% (45% / 2 + 25%) or less. As a result, although the fluctuation rate of the estimated wind turbine output is larger than that of FIG. 15 (A), the fluctuation of the power generation output is suppressed to about 50% or less.

  FIG. 16 (A) shows the correlation between the 20-minute fluctuation rate of the generated output fluctuation rate and the synthesized output fluctuation rate when shift control of the synthesized output target is not performed. As shown in FIG. 16A, it can be seen that the fluctuation of the combined output increases as the fluctuation of the generated power exceeds 50%. This is because, since the output range of the storage battery is ± 25%, when the fluctuation of the power generation output exceeds 50%, there are parts that can not be smoothed.

  FIG. 16 (B) shows the correlation between the rate of change of the generated output fluctuation rate and the rate of fluctuation of the combined output in 20 minutes when shift control of the combined output target is performed. As shown in FIG. 16 (B), as a result of suppressing the power generation output fluctuation to 50% or less, it is shown that the smoothing can be sufficiently achieved in the output range of 25% of the storage battery.

  As described above in detail, according to the present embodiment, the rate of change when the value of the power generation output of the generator 1A is rising is limited, and the power generation output with the rate of change when rising is limited the combined output target value Is generated. Thereby, as the fluctuation of the power generation output of the generator 1A increases, and as the fluctuation passes over a long time, the combined output target becomes lower than the average value of the power generation output of the generator 1A. More electric power can be stored in the storage area 2A by an amount, and the discharge shortage can be suppressed. Furthermore, the power generation output of generator 1A is limited to the value obtained by adding the value corresponding to the charge amount of storage battery 2A to the combined output target, so that the fluctuation range of the generator output is within the range of charge / discharge capacity of storage battery 2A. Suppressed. As a result, even under conditions where large fluctuations in generated power continue for a long time, fluctuations in generated output can be suppressed, and fluctuations in combined output can be suppressed. Such control is also called shift control of a combined output target.

  Further, in the present embodiment, the combined output target is corrected in accordance with the SOC in order to prevent the SOC from becoming too large by the shift control of the combined output target described above. Furthermore, when the SOC of the storage battery 2A exceeds the allowable value, the shift control of the combined output target is temporarily stopped, and the discharge of the storage battery 2A is prioritized. Moreover, the mechanism which prevents that the charge amount of 2 A of storage batteries falls by repetition of charging / discharging of 2 A of storage batteries is also provided. By providing such a mechanism, the amount of charge of the storage battery 2A can be maintained in a state without excess or deficiency, and smoothing of the combined output can be continued without delay.

  The block configuration of the control system or the like constructed in the control unit 3 according to the above-described embodiment is merely an example, and can be changed as appropriate.

  The present invention is capable of various embodiments and modifications without departing from the broad spirit and scope of the present invention. In addition, the embodiment described above is for explaining the present invention, and does not limit the scope of the present invention. That is, the scope of the present invention is indicated not by the embodiments but by the claims. And, various modifications applied within the scope of the claims and the meaning of the invention are considered to be within the scope of the present invention.

  The present invention can be applied to a generator using renewable energy such as sunlight or wind power.

  1 Renewable energy power supply, 1A generator, 1B output control unit, 2 storage battery system, 2A storage battery, 2B bidirectional power converter, 2C converter controller, 2D storage area controller, 2E protection circuit, 2F SOC measurement circuit, 3 Control unit, 3A power conversion unit, 3B low pass filter (LPF), 3C rising change rate limiting unit, 3D switching unit, 3E addition unit, 3F smoothing unit, 3G SOC maintenance setting unit, 3H subtraction unit, 3I output control unit, 3J power conversion unit, 3K smoothing unit, 3L SOC processing unit, 3M output increase limiter signal creation unit, 4, 5 transformer, 6, 7 current sensor, 10 power system, 30D switch, 31D SOC level detection unit, 30F fluctuation Width limiter, 31F change rate limiter, 32F fluctuation range upper and lower limit setting unit, 30G subtraction unit, 31G fluctuation range control Part, 32G first-order delay element (LAG), 33G addition part, 35G upper / lower limit setting part, 36G zero level setting part, 37G switch, 38G high / low keeping point detection part, 30K low pass filter (LPF), 31K fluctuation width restriction part, 32K Change rate limiter, 33K fluctuation range upper and lower limit setting unit, 30L SOC target setting unit, 31L SOC output conversion unit, 32L subtraction unit, 33L SOC control unit, 34L fluctuation range limiter, 35L SOC function unit, 36L lower limit limiter, 37L subtraction unit, 30M bias output unit, 31M addition unit, 32M rise / fall change rate restriction unit, 33M upper limit restriction unit, 34M charge power upper limit setting unit, 35M charge power lower limit setting unit, 36M switch, 37M SOC level detection unit, 38M Adder, 100 distributed power supplies.

Claims (6)

A power system comprising: a generator that generates electric power using renewable energy; and an electric power storage device that stores and discharges the electric power output of the electric generator, and combining the electric power output of the electric generator with the electric discharge power of the electric power storage device A control device that controls a power supply device that smoothes an output to be transmitted to the
A rising change rate limiting unit that outputs a value that fluctuates according to the fluctuation of the power generation output of the generator and that has a limited change rate at the time of rising;
A composite output that generates and outputs a composite output target of the generator and the power storage device by smoothing the value of the power generation output of the generator whose rate of change at rise is limited by the rise change rate limiting unit. An output target generation unit,
When the power generation output of the generator exceeds the combined output target, the power storage device is charged with the power generation output of the generator, and the power output of the generator is less than or equal to the combined output target. A charge / discharge control unit that controls the power storage device to perform discharge;
An addition unit that outputs a value obtained by adding a value corresponding to the charge amount of the power storage device to the combined output target as the upper limit value of the power generation output of the generator;
A generator control unit configured to control the generator such that a power generation output of the generator does not exceed an upper limit value of the power generation output;
Control device comprising: A smoothing unit that smoothes the value of the power generation output of the generator;
A charge state target setting unit that sets a target value of the charge state of the power storage device based on the value smoothed by the smoothing unit;
A charge state measurement unit that measures the charge state of the power storage device;
A subtraction unit that calculates a deviation of the charge state of the power storage device measured by the charge state measurement unit with respect to the target value of the charge state of the power storage device set by the charge state target setting unit;
Equipped with
The combined output target generation unit
The synthetic output target is generated by smoothing an added value obtained by adding a correction value according to the deviation from the target value of the state of charge of the power storage device to the value output from the rising change rate limiting unit. Do,
The control device according to claim 1. When the state of charge of the power storage device measured by the state of charge measurement unit exceeds the target value set by the state of charge target setting unit, the composite output target is increased by a value according to the deviation. Including an output target correction unit,
The control device according to claim 2. When the charge state of the power storage device measured by the charge state measurement unit exceeds the upper limit value,
The combined output target generation unit
Instead of the value of the power generation output of the generator in which the rate of change at the time of rise is limited by the rise change rate limiting unit, the generator further smoothes the value smoothed by the smoothing unit, Generating and outputting as a combined output target of the power storage device,
The adding unit is
A value corresponding to the charge amount of the power storage device is added to the combined output target, and the added value is output as the upper limit value of the power generation output of the generator.
The control device according to claim 2. A low pass filter for removing high frequency components of the value of the power generation output of the generator;
The rising change rate limiting unit
Limiting the rate of change of the generator output of the generator at the time of rising, which is obtained via the low pass filter,
The control device according to any one of claims 1 to 4. A power system comprising: a generator that generates electric power using renewable energy; and an electric power storage device that stores and discharges the electric power output of the electric generator, and combining the electric power output of the electric generator with the electric discharge power of the electric power storage device A control method for controlling a power supply device that smoothes an output to be transmitted to
A rising change rate limiting step that outputs a value that fluctuates according to the fluctuation of the power generation output of the generator and the rate of change at rising is limited;
A composite output target that generates and outputs a combined output target of the generator and the power storage device by smoothing the value of the power generation output of the generator whose rate of change at rise is limited in the rising change rate limiting step. An output target generation step,
When the power generation output of the generator exceeds the combined output target, the power storage device is charged with the power generation output of the generator, and the power output of the generator is less than or equal to the combined output target. A charge / discharge control step of controlling the power storage device to perform discharge;
An addition step of outputting a value obtained by adding a value according to the charge amount of the power storage device to the combined output target as an upper limit value of the power generation output of the generator;
A generator control step of controlling the generator such that a power generation output of the generator does not exceed an upper limit value of the power generation output;
Including
The control method which repeats said each step.

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