JP7811527B2 - Load-following control device for fuel cell system - Google Patents

Description

The present invention relates to a load-following control device for a fuel cell system that receives a load-adjustment command and contributes electric power.

Home appliance control devices or home appliance control systems (HEMS, "Home Energy Management Systems") are known as prior art for controlling energy such as electricity used in homes. In recent years, with the spread of small-scale power generation facilities installed in homes and buildings, a virtual power plant (VPP, "Virtual Power Plant") technology has emerged that controls multiple small-scale power generation facilities and treats them as if they were a single power plant.

Small-scale power generation facilities, such as household fuel cell systems, are equipped with a power generation device. They may also be equipped with a storage battery to store the generated electricity.

The VPP's coordinating entity (e.g., a resource aggregator) can issue adjustment commands to the home fuel cell system, aggregating the electricity from multiple home fuel cell systems and making them function as if they were a single power plant.

Here, for example, power generation in a household fuel cell system operates in load-following mode in response to fluctuations in the household load.

At this time, the speed at which the fuel cell stack's output fluctuates is slower than the household's load fluctuations, and this tracking delay can result in an increase in the amount of power received (power consumption from commercial power sources).

Patent Document 1 describes a method for enabling a fuel cell system to respond to load fluctuations without adversely affecting the system. Specifically, the fuel cell system in Patent Document 1 includes a fuel cell, a reforming section, a raw material gas supply device, a reforming water supply device, an oxidant gas supply device that supplies oxidant gas, a combustible material, and a control device that sets a target output based on a required output and controls the raw material gas supply device, reforming water supply device, and oxidant gas supply device so that the fuel cell output approaches the target output. It also describes that, when the required output increases, the control device increases the rate of increase of the target output when the current fuel cell output is small compared to when it is large.

Japanese Patent Application Laid-Open No. 2020-27678

However, when a home fuel cell system is used as a VPP, the increase in received power due to the aforementioned tracking delay may lead to a reduction in the remote control effectiveness of the VPP.

Patent Document 1 describes increasing the fuel cell's rate of increase when the required output increases, but does not include any technology related to VPP, and there is no technical basis for considering the remote control effect of VPP as an issue.

The objective of the present invention is to provide a load-following control device for a fuel cell system that can improve the responsiveness of power load following under remote control by a VPP, rather than the responsiveness of power load following in a stand-alone fuel cell system.

A first aspect of the load following control device for a fuel cell system according to the present invention is a load following control device for a fuel cell system that, when receiving an adjustment capability command from the electricity market that sets the time period for providing power and the amount of power required, follows the power load consumed by the fuel cell system that provides power and controls power generation in the fuel cell system. The load following control device includes a determination unit that determines whether the adjustment capability command has been received, and a transition unit that, when the determination unit determines that the adjustment capability command has been received, suspends individual load following operation control and transitions to remote control that remotely follows the power load from the electricity market. During the period when the transition is made to remote control to follow the power load, the transition unit performs a follow-up adjustment that at least one of slows the rate of decrease in power generation following a decrease in the power load and accelerates the rate of increase in power generation following an increase in the power load, compared to the individual load following operation control.

A second aspect of the load following control device for a fuel cell system according to the present invention is the same as the first aspect, characterized in that the following adjustment increases the load by operating power consuming devices that constitute the fuel cell system during the period of power load following operation under the remote control, thereby slowing the rate of decrease in power generation that follows a decrease in the power load.

A third aspect of the load following control device for a fuel cell system according to the present invention is the first or second aspect, characterized in that the following adjustment modifies a preset power load following operation program in order to perform power generation following the power load, thereby slowing the rate of decrease in power generation following a decrease in the power load.

A fourth aspect of the load following control device for a fuel cell system according to the present invention is the first or second aspect, characterized in that the following adjustment modifies a preset power load following operation program in order to perform power generation following the power load, thereby accelerating the rate of increase in power generation following an increase in the power load.

A fifth aspect of the load following control device for a fuel cell system according to the present invention is the first or second aspect, characterized in that the following adjustment modifies a preset power load following operation program in order to perform power generation following the power load, slowing the rate of decrease in power generation following a decrease in the power load and accelerating the rate of increase in power generation following an increase in the power load.

As explained above, the present invention can improve the responsiveness of power load following under remote control by VPP compared to the responsiveness of power load following in a fuel cell system alone.

1 is an overall configuration diagram of a virtual power generation system according to an embodiment of the present invention; 3 is a block diagram showing the flow of processing in a command system of the virtual power generation system according to the present embodiment. FIG. 1A is a timing chart of load following control according to a first embodiment of the present invention, and FIG. 1B is a flowchart showing the flow of load following control according to the first embodiment. 10A is a timing chart of load following control according to a second embodiment of the present invention, and FIG. 10B is a flowchart showing the flow of load following control according to the second embodiment. 10A is a timing chart of load following control according to a third embodiment of the present invention, and FIG. 10B is a flowchart showing the flow of load following control according to the third embodiment. 10A is a timing chart of load following control according to a fourth embodiment of the present invention, and FIG. 10B is a flowchart showing the flow of load following control according to the fourth embodiment.

[Virtual power generation system]
FIG. 1 shows a schematic diagram of a virtual power generation system 10 (VPP/Virtual Power Plant) according to this embodiment.

The virtual power generation system 10 generally refers to a mechanism that combines various power sources such as renewable energy sources, storage batteries, and private power generation equipment, and can provide a stable supply of electricity to the area as if there was a single large power plant.

The virtual power generation system 10 according to this embodiment is a system that virtually controls, for example, power supply sources (fuel cell systems 16, described below) within the same area, and functions as a power infrastructure that replaces conventional so-called large-scale power plants.

The virtual power generation system 10 is composed of an electricity market 12 (such as a supply-demand adjustment market where general electricity transmission and distribution companies balance supply and demand) that can utilize virtual power plants, multiple adjustment entities 14 that receive adjustment capacity commands (described in detail below) from the electricity market 12, and multiple power contribution control devices 18 that control the contribution of electricity from the fuel cell system 16 based on the adjustment capacity commands from each of the multiple adjustment entities.

Note that the electricity market 12 is not limited to general electricity transmission and distribution companies, but also includes, for example, cases where companies specializing in the power generation or retail sectors independently procure adjustment capacity.

A regulation capacity command is command information requesting the contribution of power, which specifies the response time from receiving the regulation capacity command until the contribution of power, and the duration of time during which the requested amount of power (requested power amount) is to be continuously contributed. The electricity market 12 outputs the regulation capacity command to the adjustment entity 14.

Here, within the electricity market 12, there are five types of adjustment capacity commands issued by the supply and demand balancing market, as shown in Table 1 below, which differ in the response time until electricity is contributed and the duration for which a predetermined requested amount of electricity is continuously contributed.

In the electricity market 12 of the virtual power generation system 10 according to this embodiment, a control capacity command is sent with the target control capacity being "tertiary control capacity [1] (alternative display of the circled number [1])" in Table 1, and power is contributed from the fuel cell system 16 installed in each home under the control of the power contribution control device 18.

The target control capacity is not limited to "tertiary control capacity [1]" (an alternative notation for [1] in a circle), but may also be primary control capacity and secondary control capacity.

As shown in Figure 1, the coordination entity 14 is hierarchical. In this embodiment, it has a two-tier structure consisting of multiple aggregation coordinators 20 on the upper tier and multiple resource aggregators 22 on the lower tier.

The number of hierarchical levels is not limited to two, and may be three or more. Furthermore, at one level, the aggregation coordinator 20 may directly control multiple resources 24. A resource 24 is a collection of multiple fuel cell systems 16 and power contribution control devices 18 managed by a single resource aggregator 22.

The upper-level aggregation coordinator 20 is responsible for distributing adjustment capacity commands requested by the electricity market 12 to the lower-level resource aggregator 22.

The resource aggregator 22 receives adjustment capability commands for which it is responsible (e.g., commands with the same response time and duration time period but different requested power amounts) from the aggregation coordinator 20.

Each of the resources 24 connected to each of the multiple resource aggregators 22 is equipped with a power contribution control device 18.

The power contribution control device 18 manages the contribution of power output from the fuel cell system 16 to the resource aggregator 22.

The fuel cell system 16 is a cogeneration system that uses both power from a commercial power source (not shown) and power generated by the fuel cell 26 to serve as a power supply source for each household. However, this does not preclude the provision of a storage battery to store the power generated by the fuel cell 26.

The power generated by the fuel cell 26, including power from commercial power sources, is managed centrally by the system control unit 29, and an amount of power equivalent to the amount consumed in the home is supplied.

In addition to controlling the power supply within the home using the system control unit 29, the power contribution control device 18 controls the use of power generated by the fuel cell 26 of the fuel cell system 16 as power contributed to the resource aggregator 22 (contributed power) based on adjustment capability commands from the resource aggregator 22.

Figure 2 is a functional block diagram for coordination command control for power contribution to the power market 12 and contributed power monitoring control during power contribution, by linking the power market 12, the coordinating entity 14 (aggregation coordinator 20 and resource aggregator 22), and the power contribution control device 18 (the entity that controls power contribution from the fuel cell system 16) described in Figure 1.

Note that the blocks in the functional block diagram in Figure 2 do not limit the hardware configuration of each section, but are classified by function, and some or all of them may be constructed using software that operates based on the adjustment capacity command control program and the contributed power monitoring and control program.

Furthermore, since the multiple aggregation coordinators 20, the multiple resource aggregators 22, and the multiple resources 24 all have the same configuration, we will only explain the configuration of one of them and omit explanations of the others.

(Aggregation Coordinator 20)
The aggregation coordinator 20 includes a regulation capacity receiving unit 30 that receives a regulation capacity command from the electricity market 12. In this embodiment, the received regulation capacity command is the tertiary regulation capacity [1] (alternative display of the circled number [1]) shown in Table 1.

The adjustment power receiving unit 30 sends the received adjustment power to the adjustment power allocation unit 32. The adjustment power allocation unit 32 allocates adjustment power (requested power generation amount) according to the power contribution capacity (information obtained in advance) of the multiple resource aggregators 22 under its jurisdiction.

The adjustment power allocation unit 32 is connected to the transmission unit 34 and transmits the adjustment power (distribution adjustment power) of the allocated requested power amount to the multiple resource aggregators 22 under its jurisdiction.

Distribution adjustment capacity basically requests a portion of the total amount of electricity required, with the same response time and duration.

The allocation adjustment capacity transmitted to multiple resource aggregators 22 may be varied in response time and duration over time, so as to collectively satisfy the tertiary adjustment capacity [1] (alternatively represented by the circled number [1]) received by the aggregation coordinator 20 from the electricity market 12.

The aggregation coordinator 20 also includes an upper-layer power information monitoring unit 35 that monitors information about power (power information) collected from multiple resource aggregators 22 via power supply lines (not shown).

The upper-layer power information monitoring unit 35 monitors the adjustment capacity based on the power information from each resource aggregator 22, and aggregates the power information and contributes it to the power market 12. In the power market 12, the power set as the tertiary adjustment capacity [1] (alternatively represented by a circled number [1]) is provided to power consumers.

(Resource aggregator 22)
The resource aggregator 22 includes a distribution adjustment capacity receiving unit 36 and receives the distribution adjustment capacity from the transmitting unit 34 of the aggregation coordinator 20 described above.

The distribution adjustment capacity receiving unit 36 is connected to the selection unit 38 and transmits the received distribution adjustment capacity.

The selection unit 38 selects the power contribution control device 18 that belongs to the resource 24 managed by the resource aggregator 22. The power contribution control devices 18 monitor the capabilities (information is obtained in advance) of the fuel cell systems 16 that they are responsible for.

The selection unit 38 transmits the adjustment capacity (individual adjustment capacity) of the requested amount of power to each of the power contribution control devices 18 selected by the selection unit 38 via the distribution adjustment capacity transmission unit 40.

The resource aggregator 22 also includes a lower-level power information monitoring unit 42 that monitors information about power (power information) collected from multiple resources 24 via power supply lines (not shown).

The lower-layer power information monitoring unit 42 monitors the adjustment capacity based on the power information received from each power contribution control device 18 of the resource 24, and aggregates the respective power information and contributes it to the aggregation coordinator 20.

(Resource 24)
A resource 24 is a collection of power contribution controllers 18 managed by one resource aggregator 22 .

The power contribution control devices 18 each control the power contribution by the fuel cell systems 16.

The fuel cell system 16 includes a system control unit 29 and a fuel cell 26. The system control unit 29 controls the power consumed in the house (e.g., home) in which the fuel cell system 16 is installed, and comprehensively controls the power from a commercial power source (not shown) and the power generated by the fuel cell 26, which uses, for example, city gas as a raw material, to ensure the power consumed in the house.

Meanwhile, the power contribution control device 18 controls the contribution of power from the fuel cell system 16 based on the adjustment power (individual adjustment power) requested by the resource aggregator 22, separate from the power consumed within the house.

(Flow of normal operation control of virtual power generation system 10)

The power contribution control device 18 activates the power generation device based on the adjustment power command and contributes the requested amount of power.

When adjustment capacity command information is received from the electricity market 12, the type of adjustment capacity is identified and a distribution adjustment capacity command is issued to each resource aggregator.

When it receives a distribution adjustment power command from the aggregation coordinator 20, it selects a corresponding power contribution control device 18 from the resources 24 it is responsible for, and issues and monitors the individual adjustment power to the selected power contribution control device 18.

When an individual adjustment power command is received from the resource aggregator 22, some or all of the control by the system control unit 29 of the fuel cell system 16 is transferred to the power contribution control device 18.

If the fuel cell 26 is not generating electricity, it will start up, and if it is generating electricity, it will check the amount of electricity being generated by the fuel cell 26.

When the specified adjustment time (corresponding to the duration time period) has elapsed (for example, the duration time period is 3 hours in the case of tertiary control capability [1] (alternative display of a circled number [1])), control of the fuel cell system 16 is transitioned to normal control (control by the system control unit 29), and power contribution control ends.

(Load following control)
The fuel cell system 16 performs load-following operation in response to the power consumption within the home, but the output fluctuation speed of the fuel cell 26 is slower than the load fluctuation speed based on the power consumption within the home, and the follow-up delay can result in an increase in the use of commercial power (received power).

In the virtual power generation system 10, when the fuel cell system 16 is controlled by the power contribution control device 18 based on the adjustment capability command, an increase in received power due to a tracking delay results in a state in which the output of the fuel cell 26 is low, resulting in a delay in the response time required to obtain the required amount of power generation (reducing the effectiveness of remote control).

Therefore, in the present invention, when it is determined that an adjustment capability command has been received, load following control is executed to increase the output of the fuel cell 26 in the fuel cell system 16.

Specifically, at least one of the following load following controls is executed: a first load following control that delays the rate of decrease in power generation following a decrease in the power load, and a second load following control that accelerates the rate of increase in power generation following an increase in the power load, compared to the individual load following operation controls executed by the system control unit 29.

Below is a detailed description of an embodiment that can implement load following control.

(First embodiment of load following control)
FIG. 3 is a characteristic diagram of the load following control of the fuel cell system 16 according to the first embodiment of the present invention.

As shown by the dotted line X in Figure 3(A), household load characteristics can change dramatically depending on whether the load power supply switch is turned on or off. When the load power supply switch is turned off, resulting in a transition from a high load state to a low load state (see arrow A in Figure 3(A)), the power generation characteristics of the fuel cell 26 follow this transition at a predetermined rate of change (slope θ1), as shown by the dashed-dotted line Y in Figure 3(A). The longer this low load state lasts, the more gradually the power generation amount will decrease.

After that, when the load power supply switch is turned on to transition from a low load state to a high load state (see point B in Figure 3(A)), the amount of power generated by the fuel cell 26 follows at a predetermined rate of change (slope θ2). However, with the rated tracking control (slope θ2), it takes time t1 (hereinafter referred to as the tracking delay period) for the amount of power generated to return to the amount before the load power supply switch was turned off (before point A in Figure 3(A)), and the commercial power source (received power) is used during this predetermined time t1.

In the first embodiment, as a means of reducing the tracking delay period, when an adjustment capability command is received, a power consuming device (e.g., an internal heater) that constitutes the fuel cell system 16 and is required to be equipped in the fuel cell system 16 is used to increase the load after the load power supply switch is turned off (see arrow A in Figure 3(A)).

The internal heater is a so-called backup heat source, and is used to heat the water in the hot water storage tank in addition to the heat generated by power generation. Note that the power consuming device is not limited to an internal heater, and any device with a load (power consumption) greater than a predetermined value may be installed as a new power consuming device of the present invention.

When an adjustment command is received and this internal heater is operated in response to changes in household load, the gradient of the slope θ3, at which the amount of power generated gradually decreases, becomes smaller than the slope θ1 (θ3 < θ1), as shown by the solid line Z in Figure 3(A).

As a result, when the load power supply switch is turned on (see arrow B in Figure 3(A)) and the household load transitions from a low load state to a high load state, even if the slope θ4 during this transition is equal to the slope θ2 (θ4 ≒ θ2), the time t2 required to return to the power generation amount indicated by arrow A in Figure 3(A) will be shorter than time t1 due to the increase in the overall load (household load + internal heater load).

The operation of the power contribution control device 18 in the first embodiment of load following control is explained below with reference to the flowchart in Figure 3 (B).

In step 100, it is determined whether a regulation capability command has been received. If the determination is affirmative, the process proceeds to step 102, where the power contribution control device 18 acquires some of the control functions (remote control functions) of the system control unit 29, and the process proceeds to step 104.

In step 104, the operation of power-consuming devices within the fuel cell system 16 is instructed. Specifically, this includes the internal heater, auxiliary equipment, etc. As a result, the load-following characteristic has a slope θ3 (<θ1), as shown in Figure 3(A).

In the next step 106, power contribution control is executed based on the adjustment capability command. If the release of the adjustment capability command is confirmed in the next step 108 (positive judgment), the process proceeds to step 110, where remote control is released, and then to step 112, where the power consuming devices in the fuel cell system 16 are returned to their normal operating state based on the acceptance of the adjustment capability command, and then the process returns to step 100, and the above process is repeated.

(Second embodiment of load following control)
FIG. 4 is a characteristic diagram of the load following control of the fuel cell system 16 according to the second embodiment of the present invention.

As shown by the dotted line X in Figure 4(A), household load characteristics can change drastically depending on whether the load power supply switch is turned on or off. When the load power supply switch is turned off, resulting in a transition from a high load state to a low load state (see arrow A in Figure 4(A)), the power generation characteristics of the fuel cell 26 follow this transition at a predetermined rate of change (slope θ1), as shown by the dashed-dotted line Y in Figure 4(A). The longer this low load state lasts, the more gradually the power generation amount will decrease.

After that, when the load power supply switch is turned on to transition from a low load state to a high load state (see point B in Figure 4(A)), the amount of power generated by the fuel cell 26 follows at a predetermined rate of change (slope θ2). However, with the rated tracking control (slope θ2), it takes time t1 (hereinafter referred to as the tracking delay period) for the amount of power generated to return to the amount before the load power supply switch was turned off (before point A in Figure 4(A)), and the commercial power source (received power) is used during this predetermined time t1.

In the second embodiment, as a means of reducing the tracking delay period, when a regulation capability command is received, the power generation control program (tracking characteristics) during load drop is changed, and the tracking characteristics are made less sensitive after the load power supply switch is turned off (see point A indicated by arrow in Figure 4(A)).

When an adjustment command is received, if the power generation control program (tracking characteristics) for load drops is changed in response to changes in household load, the gradient of the slope θ5, at which the amount of power generation gradually decreases, becomes smaller than the slope θ1 (θ5 < θ1), as shown by the solid line Z in Figure 4(A).

As a result, when the household load transitions from a low load state to a high load state by turning on the load power supply switch (see arrow B in Figure 4(A)), even if the slope θ6 during this transition is equivalent to the slope θ2 (θ6 ≒ θ2), the time t3 required to return to the power generation amount indicated by arrow A in Figure 4(A) will be shorter than the time t1.

The operation of the power contribution control device 18 in the second embodiment of load following control is explained below with reference to the flowchart in Figure 4(B).

In step 200, it is determined whether a regulation power command has been received. If the determination is affirmative, the process proceeds to step 202, where the power contribution control device 18 acquires some of the control functions (remote control functions) of the system control unit 29, and the process proceeds to step 204.

In step 204, the power generation control program (following characteristics) during load drop is changed. Specifically, the responsiveness (slope θ5) during load following in Figure 4(A) after the change is made less sensitive than the responsiveness (slope θ1) during load following in Figure 4(A) (θ5<θ1).

In the next step 206, power contribution control is executed based on the adjustment capability command. If the release of the adjustment capability command is confirmed in the next step 208 (positive judgment), the process proceeds to step 210, where remote control is released, and then to step 212, where the power generation control program for load reduction is returned to normal based on the acceptance of the adjustment capability command, and then the process returns to step 200, and the above process is repeated.

(Third embodiment of load following control)
FIG. 5 is a characteristic diagram of the load following control of the fuel cell system 16 according to the third embodiment of the present invention.

As shown by the dotted line X in Figure 5(A), household load characteristics can change dramatically depending on whether the load power supply switch is turned on or off. When the load power supply switch is turned off, resulting in a transition from a high load state to a low load state (see arrow A in Figure 5(A)), the power generation characteristics of the fuel cell 26 follow this transition at a predetermined rate of change (slope θ1), as shown by the dashed-dotted line Y in Figure 5(A). The longer this low load state lasts, the more gradually the power generation amount will decrease.

After that, when the load power supply switch is turned on to transition from a low load state to a high load state (see point B in Figure 5(A)), the amount of power generated by the fuel cell 26 follows at a predetermined rate of change (slope θ2). However, with the rated tracking control (slope θ2), it takes time t1 (hereinafter referred to as the tracking delay period) for the amount of power generated to return to the amount before the load power supply switch was turned off (before point A in Figure 5(A)), and the commercial power source (received power) is used during this predetermined time t1.

In the third embodiment, as a means of reducing the tracking delay period, when a regulation capability command is received, the power generation control program (tracking characteristics) during load drop is changed, and the tracking characteristics are made more sensitive after the load power supply switch is turned on (see arrow B in Figure 5(A)).

When an adjustment command is received, if the power generation control program (tracking characteristics) for load increases is changed in response to changes in household load, the gradient of the slope θ7 at which the amount of power generated gradually increases becomes greater than the slope θ2 (θ7 > θ2), as shown by the solid line Z in Figure 5(A).

As a result, the time t4 required to return to the power generation amount indicated by arrow A in Figure 5(A) is shorter than time t1.

The operation of the power contribution control device 18 in the third embodiment of load following control is explained below with reference to the flowchart in Figure 5(B).

In step 300, it is determined whether a regulation capability command has been received. If the determination is affirmative, the process proceeds to step 302, where the power contribution control device 18 acquires some of the control functions (remote control functions) of the system control unit 29, and the process proceeds to step 303. In step 303, it is determined whether the time is within the allowable time for the life cycle, and if the determination is affirmative, the process proceeds to step 304. If the determination is negative in step 303, the process proceeds to step 306.

In step 304, the power generation control program (following characteristics) during load increase is changed. Specifically, the response (slope θ7) during load decrease in Figure 4(A) after the change is made steeper than the response (slope θ2) during load follow-up in Figure 4(A) (θ7 > θ2).

In the next step 306, power contribution control is executed based on the adjustment capability command. If the release of the adjustment capability command is confirmed in the next step 308 (positive judgment), the process proceeds to step 310, where remote control is released, and then to step 312, where the power generation control program for load increase is returned to normal based on the acceptance of the adjustment capability command, and then the process returns to step 300, and the above process is repeated.

Figure 5 (C) shows a routine that is interrupted during a change to the power generation control program. In step 314, it is determined whether the change is within the time allowed for one operation. If the determination is negative, the power generation control program change continues and the program returns. If the determination is positive in step 314, the program proceeds to step 316, an instruction to cancel the change to the power generation control program is issued, and the program returns.

(Fourth embodiment of load following control)
FIG. 6 is a characteristic diagram of the load following control of the fuel cell system 16 according to the fourth embodiment of the present invention.

As shown by the dotted line X in Figure 6(A), household load characteristics can change drastically depending on whether the load power supply switch is turned on or off. When the load power supply switch is turned off, resulting in a transition from a high load state to a low load state (see arrow A in Figure 6(A)), the power generation characteristics of the fuel cell 26 follow this transition at a predetermined rate of change (slope θ1), as shown by the dashed-dotted line Y in Figure 6(A). The longer this low load state lasts, the more gradually the power generation amount will decrease.

After that, when the load power supply switch is turned on to transition from a low load state to a high load state (see point B in Figure 6(A)), the amount of power generated by the fuel cell 26 follows at a predetermined rate of change (slope θ2). However, with the rated tracking control (slope θ2), it takes time t1 (hereinafter referred to as the tracking delay period) for the amount of power generated to return to the amount before the load power supply switch was turned off (before point A in Figure 6(A)), and the commercial power source (received power) is used during this predetermined time t1.

In the fourth embodiment, as a means of reducing the tracking delay period, when a regulation capability command is received, the power generation control program (tracking characteristics) during load drop is changed to make the tracking characteristics less sensitive after the load power supply switch is turned off (see arrow A in Figure 6(A)), and more sensitive after the load power supply switch is turned on (see arrow B in Figure 5(A)).

When an adjustment command is received and the power generation control program (tracking characteristics) for load drops is changed in response to changes in household load, as shown by solid line Z in Figure 6(A), the gradient of the slope θ5 at which the amount of power generation gradually decreases becomes smaller than the slope θ1 (θ8<θ1), and the gradient of the slope θ9 at which the amount of power generation gradually increases becomes larger than the slope θ2 (θ9>θ2).

As a result, when the load power supply switch is turned on (see arrow B in Figure 6(A)) and the household load transitions from a low load state to a high load state, the time t5 required to return to the power generation amount indicated by arrow A in Figure 6(A) is shorter than time t1.

The operation of the fourth embodiment of load-following control in the power contribution control device 18 is explained below with reference to the flowchart in Figure 6 (B).

In step 400, it is determined whether a regulation power command has been received. If a positive determination is made, the process proceeds to step 402, where the power contribution control device 18 acquires some of the control functions (remote control functions) of the system control unit 29, and the process proceeds to step 404.

In step 404, the power generation control program (following characteristics) during load drop is changed. Specifically, the responsiveness during load decrease (slope θ8) in Figure 6(A) after the change is made less sensitive than the responsiveness during load follow (slope θ1) in Figure 6(A) (θ8<θ1), and the responsiveness during load increase (slope θ9) in Figure 6(A) after the change is made more sensitive than the responsiveness during load follow (slope θ2) in Figure 6(A).

In the next step 406, power contribution control is executed based on the adjustment capability command. If the release of the adjustment capability command is confirmed in the next step 408 (positive judgment), the process proceeds to step 410, where remote control is released, and then to step 412, where the power generation control program for load reduction is returned to normal based on the acceptance of the adjustment capability command, and then the process returns to step 400, and the above process is repeated.

In the first to fourth embodiments, we have explained load following control for increasing the output of the fuel cell 26 in the fuel cell system 16 when it is determined that a regulation capability command has been received.

In other words, by executing at least one of the load following controls, namely, first load following control, which delays the rate of decrease in power generation following a decrease in the power load, and second load following control, which accelerates the rate of increase in power generation following an increase in the power load, rather than the individual load following operation control executed by the system control unit 29, the responsiveness of power load following by the power contribution control device 18 under remote control of the virtual power generation system 10 can be improved compared to the responsiveness of power load following by the fuel cell system 16 alone.

10 Virtual power generation system 12 Electricity market 14 Adjustment entity 16 Fuel cell system 18 Power contribution control device (judgment unit, transition unit)
20 Aggregation coordinator 22 Resource aggregator 24 Resource 26 Fuel cell 29 System control unit 30 Adjustment power receiving unit 32 Adjustment power distributing unit 34 Transmission unit 35 Upper layer power information monitoring unit 36 Distribution adjustment power receiving unit 38 Selection unit 40 Distribution adjustment power transmitting unit 42 Lower layer power information monitoring unit

Claims (5)

A load following control device for a fuel cell system that follows an electric power load consumed in a home and controls power generation in a fuel cell system that contributes electric power when a time period for contributing electric power and a required amount of electric power are received from an electric power market and an adjustment capability command is set,
a determination unit that determines whether the adjustment capability command has been received;
a transition unit that, when the determination unit determines that the adjustment capability command has been received, suspends load following operation control that is performed individually by the fuel cell system and transitions to remote control in which the load following control device remotely performs follow-up operation of the power load,
During a period in which the transition unit is transitioning to the power load follow-up operation under the remote control, the transition unit executes a follow-up adjustment to at least one of slowing down a rate of decrease in the amount of power generated that follows a decrease in the power load and speeding up a rate of increase in the amount of power generated that follows an increase in the power load compared to the load follow-up operation control performed individually.
Load-following control device for fuel cell systems. The tracking adjustment is
2. A load following control device for a fuel cell system as described in claim 1, wherein during the period of the power load following operation under the remote control, the load is increased by operating power consuming devices that constitute the fuel cell system in accordance with changes in the power load, thereby slowing down the rate of decrease in the amount of power generated that follows a decrease in the power load. The tracking adjustment is
2. A load following control device for a fuel cell system according to claim 1, wherein, in order to perform power generation following of the power load, a preset power load following operation program is changed to slow down the rate of decrease in power generation following a decrease in the power load. The tracking adjustment is
2. A load following control device for a fuel cell system according to claim 1, wherein, in order to perform power generation following of the power load, a preset power load following operation program is changed to accelerate the rate of increase in power generation following an increase in the power load. The tracking adjustment is
2. A load following control device for a fuel cell system as described in claim 1, wherein, in order to perform power generation following of the power load, a preset power load following operation program is modified to slow down the rate of decrease in power generation following a decrease in the power load and to speed up the rate of increase in power generation following an increase in the power load.