Load-following control device for fuel cell system

Abstract

To enhance responsiveness to a power load-following under remote control by VPP more than responsiveness to a power load-following in a fuel cell system alone.SOLUTION: A load is increased by making use of a power consumption device when receiving an adjustment force command. When an internal heater is put into operation, the gradient of the inclination θ3, in which an amount of generated power gradually decreases, becomes smaller than the inclination θ1 (θ3<θ1). When a household load shifts in a state of from low load to high load, even though the inclination θ4 at the time of the shift is almost equal to the inclination θ2 (θ4≒θ2), the time t2 that is a time to recover to the previous amount of generated power is shorter than the time t1 because of the increase of an overall load (household load + internal heater load).SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a load following control device for a fuel cell system that receives a regulation capability command and contributes electric power. [Background technology]

[0002] A home appliance control device or home appliance control system (HEMS, "Home Energy Management System") is known as a conventional technology 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 become known, which controls multiple small-scale power generation facilities and treats them as if they were a single power plant.

[0003] Small-scale power generation facilities, such as household fuel cell systems, include a power generation device, and may also include a storage battery for storing the generated electricity.

[0004] The VPP's coordinating entity (e.g., a resource aggregator) can issue adjustment commands to the home fuel cell system, allowing it to aggregate electricity from multiple home fuel cell systems and function as if they were a single power plant.

[0005] Here, for example, power generation in a home fuel cell system performs load following operation in response to fluctuations in the home load.

[0006] At this time, the speed of output fluctuations of the fuel cell stack is slower than the load fluctuations of the home, and this follow-up delay can cause the amount of power received (power consumption from the commercial power source) to increase.

[0007] Patent Document 1 describes a fuel cell system that enables response to load fluctuations without adversely affecting the system. Specifically, the fuel cell system in Patent Document 1 includes a fuel cell, a reforming unit, a raw material gas supply device, a reforming water supply device, an oxidant gas supply device that supplies oxidant gas, a combustor, and a control device that sets a target output based on a required output and controls the raw material gas supply device, the reforming water supply device, and the oxidant gas supply device so that the output of the fuel cell approaches the target output. The control device is described as increasing the target output at a faster rate when the current output of the fuel cell is small compared to when the required output is large. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Publication No. 2020-27678 Summary of the Invention [Problem to be solved by the invention]

[0009] However, when a home fuel cell system is used as a VPP, the increase in received power due to the tracking delay described above may lead to a decrease in the remote control effect of the VPP.

[0010] Patent Document 1 describes that when the required output increases, the fuel cell's rising speed increases, but it 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.

[0011] The object 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 of the fuel cell system alone. [Means for solving the problem]

[0012] 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 contributing electricity and the amount of electricity required, follows the power load consumed by the fuel cell system that contributes electricity and controls power generation in the fuel cell system, and has a judgment unit that judges whether the adjustment capability command has been received, and a transition unit that, when the judgment unit determines that the adjustment capability command has been received, pauses individual load following operation control and transitions to remote control that remotely follows the power load from the electricity market, and is characterized in that, during the period when transitioning to the power load following operation under the remote control, the transition unit performs a follow-up adjustment that does at least one of slowing the rate of decrease in the power generation amount that follows a decrease in the power load and accelerating the rate of increase in the power generation amount that follows an increase in the power load compared to the individual load following operation control.

[0013] A second aspect of the load following control device for a fuel cell system according to the present invention is characterized in that, in the first aspect, the following adjustment increases the load by operating power consuming devices that constitute the fuel cell system during the period of following operation of the power load under the remote control, thereby slowing the rate of decrease in the power generation amount that follows the decrease in the power load.

[0014] A third aspect of the load following control device for a fuel cell system according to the present invention is characterized in that, in the first or second aspect, the following adjustment changes a preset operation program for following the power load in order to perform power generation following the power load, and slows down the rate of decrease in the power generation amount that follows a decrease in the power load.

[0015] A fourth aspect of the load following control device for a fuel cell system according to the present invention is characterized in that, in the first or second aspect, the following adjustment changes a preset operation program for following the power load in order to perform power generation following the power load, thereby accelerating the rate of increase in the amount of power generation that follows an increase in the power load.

[0016] A fifth aspect of the load following control device for a fuel cell system according to the present invention is characterized in that, in the first or second aspect, the following adjustment changes a preset power load following operation program in order to perform power generation following of the power load, thereby slowing down 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. [Effects of the Invention]

[0017] As described above, in the present invention, the responsiveness of power load following under remote control by a VPP can be improved compared to the responsiveness of power load following in a fuel cell system alone. [Brief explanation of the drawings]

[0018] [Figure 1] 1 is an overall configuration diagram of a virtual power generation system according to an embodiment of the present invention; [Figure 2] 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. [Figure 3] 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. [Figure 4] 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. [Figure 5] 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. [Figure 6] 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. DETAILED DESCRIPTION OF THE INVENTION

[0019] [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.

[0020] 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 devices, and can stably supply electricity to the area as if there was one large power plant.

[0021] The virtual power generation system 10 according to this embodiment is a system that virtually controls, for example, a power supply source (a fuel cell system 16, described later) within the same area, and functions as a power infrastructure that replaces conventional so-called large-scale power plants.

[0022] The virtual power generation system 10 is composed of an electricity market 12 (such as a supply and 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 a fuel cell system 16 based on the adjustment capacity commands from each of the multiple adjustment entities.

[0023] 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 sector or the retail sector independently procure adjustment power.

[0024] The adjustment capacity command is command information requesting the contribution of electric power, which includes a response time from receiving the adjustment capacity command until the contribution of electric power and a duration during which the requested amount of electric power (requested electric power amount) is continuously contributed. The electricity market 12 outputs the adjustment capacity command to the adjustment entity 14.

[0025] Here, in the electricity market 12, the adjustment capacity command issued by the supply and demand adjustment market has five types of adjustment capacity as shown in Table 1 below, which differ in the response time until the supply of electricity and the duration of time during which a predetermined requested amount of electricity is continuously supplied.

[0026] [Table 1]

[0027] In the electricity market 12 of the virtual power generation system 10 according to this embodiment, a control capability command is sent with the target control capability being "tertiary control capability [1] (alternative display of circled number [1])" in Table 1, and electricity is contributed from the fuel cell system 16 installed in each home under the control of the power contribution control device 18.

[0028] The target control capacity is not limited to "tertiary control capacity [1]" (alternative notation of circled numbers in [1]), but may also be primary control capacity and secondary control capacity.

[0029] As shown in FIG. 1, the coordinating entity 14 is hierarchical, and in this embodiment, it has a two-tier structure consisting of multiple aggregation coordinators 20 on the upper tier side and multiple resource aggregators 22 on the lower tier side.

[0030] The number of hierarchical levels is not limited to two, and may be three or more. Also, 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 one resource aggregator 22.

[0031] The aggregation coordinator 20 on the upper layer has a role of distributing adjustment capacity commands requested by the power market 12 to the resource aggregator 22 on the lower layer.

[0032] The resource aggregator 22 receives from the aggregation coordinator 20 an adjustment capability command for which it is responsible (for example, a command having the same response time and duration time period but a different requested amount of power).

[0033] Each of the resources 24 connected to each of the plurality of resource aggregators 22 includes a power contribution controller 18 .

[0034] The power contribution controller 18 manages the contribution of power output from the fuel cell system 16 to the resource aggregator 22 .

[0035] The fuel cell system 16 is a cogeneration system that serves as a power supply source for each home, using both power from a commercial power source (not shown) and power generated by the fuel cell 26. However, this does not exclude the possibility of providing a storage battery for storing the power generated by the fuel cell 26.

[0036] The power generated by the fuel cell 26, including the power from the commercial power source, is managed collectively by the system control unit 29, and an amount of power corresponding to the power consumed in the home is supplied.

[0037] 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 the power generated by the fuel cell 26 of the fuel cell system 16 as power to be contributed to the resource aggregator 22 (contributed power) based on an adjustment power command from the resource aggregator 22.

[0038] FIG. 2 is a functional block diagram for coordination command control for power contribution to the power market 12 and contributed power monitoring control when contributing power, by coordinating the power market 12, the adjustment 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 FIG. 1 .

[0039] Note that each block in the functional block diagram of Figure 2 does not limit the hardware configuration of each part, but is classified by function, and some or all of it may be constructed using software that operates based on the adjustment capacity command control program and the contributed power monitoring and control program.

[0040] Furthermore, since the multiple aggregation coordinators 20, the multiple resource aggregators 22, and the multiple resources 24 all have the same configuration, only one of them will be described, and the description of the other configurations will be omitted.

[0041] (Aggregation Coordinator 20) The aggregation coordinator 20 includes a regulation capacity receiver 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.

[0042] The adjustment power receiving unit 30 sends the received adjustment power to the adjustment power allocating unit 32. The adjustment power allocating unit 32 allocates adjustment power (requested power generation amount) according to the power contribution capabilities (information grasped in advance) of the multiple resource aggregators 22 under its jurisdiction.

[0043] The adjustment power allocation unit 32 is connected to the transmission unit 34, and transmits the adjustment power of the allocated requested power amount (distribution adjustment power) to the multiple resource aggregators 22 under its jurisdiction.

[0044] The distribution adjustment capacity basically requests a portion of the total amount of power required, with the same response time and duration.

[0045] In addition, the distribution adjustment capacity transmitted to multiple resource aggregators 22 may be varied in response time and duration in a time series, so that the aggregation coordinator 20 can collectively satisfy the tertiary adjustment capacity [1] (alternative display of circled number [1]) received from the electricity market 12.

[0046] The aggregation coordinator 20 also includes an upper-layer power information monitoring unit 35 that monitors information about power (power information) collected from a plurality of resource aggregators 22 via a power supply line (not shown).

[0047] 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 respective power information to contribute to the power market 12. In the power market 12, the power set in the tertiary adjustment capacity [1] (alternative display of the circled number [1]) is provided to the power consumers.

[0048] (Resource Aggregator 22) The resource aggregator 22 includes a distribution adjustment power receiving unit 36, which receives the distribution adjustment power from the transmitting unit 34 of the aggregation coordinator 20 described above.

[0049] The distribution adjustment force receiving unit 36 ​​is connected to the selecting unit 38 and sends out the received distribution adjustment force.

[0050] The selection unit 38 selects a 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 grasped in advance) of the fuel cell systems 16 that they are responsible for.

[0051] The selector 38 transmits the adjustment capability (individual adjustment capability) of the requested amount of power to each of the power contribution control devices 18 selected by the selector 38 via the distribution adjustment capability transmitter 40.

[0052] The resource aggregator 22 also includes a lower-layer power information monitoring unit 42 that monitors information (power information) related to power collected from the plurality of resources 24 via a power supply line (not shown).

[0053] The lower-layer power information monitor 42 monitors the adjustment capability based on the power information received from each power contribution control device 18 of the resource 24 , and also aggregates the respective power information and contributes it to the aggregation coordinator 20 .

[0054] (Resource 24) A resource 24 is a collection of power contribution controllers 18 managed by one resource aggregator 22 .

[0055] The power contribution controllers 18 control the power contribution by the respective fuel cell systems 16 .

[0056] 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., a 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 using, for example, city gas as a raw material, to ensure the power consumed in the house.

[0057] On the other hand, the power contribution control device 18 controls the contribution of power from the fuel cell system 16 based on the adjustment capability (individual adjustment capability) requested by the resource aggregator 22, separate from the power consumed in the house.

[0058] (Flow of normal operation control of virtual power generation system 10)

[0059] The power contribution control device 18 starts the power generation device based on the adjustment power command and contributes the requested amount of power.

[0060] When the control capacity command information is received from the power market 12, the control capacity command information processor 11 identifies the type of control capacity and commands each resource aggregator to allocate control capacity.

[0061] When a distribution adjustment power command is received from the aggregation coordinator 20, the power contribution control device 18 that will respond is selected from the resources 24 that it is responsible for, and individual adjustment power is commanded to the selected power contribution control device 18 and monitored.

[0062] When an individual adjustment capability command is received from the resource aggregator 22 , a part 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 .

[0063] If the fuel cell 26 is not generating power, it is started up, and if it is generating power, the amount of power generated by the fuel cell 26 is confirmed.

[0064] When a predetermined adjustment time (corresponding to the duration time period) has elapsed (for example, the duration time period is 3 hours in the case of tertiary adjustment power [1] (alternative display of circled number [1])), the control of the fuel cell system 16 is transitioned to normal control (control by the system control unit 29), and the power contribution control ends.

[0065] (Load following control) The fuel cell system 16 performs load-following operation in response to 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 increased use of commercial power (received power).

[0066] 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 delay in the response time required to obtain the required amount of power generation, since the output of the fuel cell 26 is low (reducing the remote control effect).

[0067] Therefore, in the present invention, when it is determined that a regulation capability command has been received, load following control is executed to increase the output of the fuel cell 26 of the fuel cell system 16.

[0068] Specifically, at least one of the following load following controls is executed: a first load following control that delays the rate of decrease in the amount of power generated following a decrease in the power load, and a second load following control that accelerates the rate of increase in the amount of power generated following an increase in the power load, rather than the individual load following operation control executed by the system control unit 29.

[0069] An embodiment capable of realizing load following control will be described in detail below.

[0070] (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.

[0071] 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 to 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 change at a predetermined rate (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 decreases.

[0072] Thereafter, when the load power supply switch is turned on to transition from a low load state to a high load state (see point B of arrow 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 tracking control (slope θ2) set as the rated value, 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 of arrow in Figure 3(A)), and the commercial power source (received power) is used during this predetermined time t1.

[0073] In the first embodiment, as a means for 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 essential for the fuel cell system 16 is used to increase the load after the load power supply switch is turned off (see point A of arrow in Figure 3(A)).

[0074] The internal heater is a so-called backup heat source device, 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 the internal heater, and any device with a load (power consumption) equal to or greater than a predetermined value may be newly installed as the power consuming device of the present invention.

[0075] When an adjustment command is received, if this internal heater is operated in response to changes in the household load, the gradient of the slope θ3, at which the amount of power generation gradually decreases, becomes smaller than the slope θ1 (θ3<θ1), as shown by the solid line Z in Figure 3(A).

[0076] 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 to return to the power generation amount indicated by arrow A in Figure 3(A) becomes shorter than the time t1 because the total load (household load + internal heater load) has increased.

[0077] The operation of the power contribution control device 18 in relation to the first embodiment of load following control will be described below with reference to the flowchart of FIG. 3(B).

[0078] In step 100, it is determined whether or not an adjustment power command has been received, and if a positive determination is made, 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.

[0079] In step 104, the operation of the power consuming devices in the fuel cell system 16 is instructed. Specifically, this includes the internal heater, auxiliary equipment, etc. As a result, the slope of the load following characteristic becomes θ3 (<θ1), as shown in FIG. 3(A).

[0080] 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 determination), the process proceeds to step 110, where the 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 states based on the acceptance of the adjustment capability command, and then the process returns to step 100, and the above process is repeated.

[0081] (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.

[0082] As shown by the dotted line X in Figure 4(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 to 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 change at a predetermined rate (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 decreases.

[0083] Thereafter, when the load power supply switch is turned on to transition from a low load state to a high load state (see point B of arrow 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 tracking control (slope θ2) set as the rated value, 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 of arrow in Figure 4(A)), and the commercial power source (received power) is used during this predetermined time t1.

[0084] In the second embodiment, as a means for reducing the tracking delay period, when an adjustment 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 of arrow in Figure 4(A)).

[0085] When an adjustment command is received, if the power generation control program (tracking characteristics) for load drops is changed in accordance with 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).

[0086] As a result, when the load power supply switch is turned on (see arrow B in Figure 4(A)) and the household load transitions from a low load state to a high load state, 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) is shorter than the time t1.

[0087] The operation of the power contribution control device 18 in the second embodiment of load following control will be described below with reference to the flowchart of FIG. 4(B).

[0088] In step 200, it is determined whether or not an adjustment power command has been received, and if a positive determination is made, 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.

[0089] In step 204, the power generation control program (following characteristics) during load drop is changed. Specifically, the responsiveness (slope θ5) during load following in Fig. 4(A) after the change is made less sensitive than the responsiveness (slope θ1) during load following in Fig. 4(A) (θ5<θ1).

[0090] 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 (affirmative determination), the process proceeds to step 210, where the 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, where the above process is repeated.

[0091] (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.

[0092] 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 to 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 change at a predetermined rate (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 decreases.

[0093] Thereafter, when the load power supply switch is turned on to transition from a low load state to a high load state (see point B of arrow 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 tracking control (slope θ2) set as the rated value, 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 of arrow in Figure 5(A)), and the commercial power source (received power) is used during this predetermined time t1.

[0094] In the third embodiment, as a means for reducing the tracking delay period, when an adjustment capability command is received, the power generation control program (tracking characteristics) during load drop is changed to make the tracking characteristics more sensitive after the load power supply switch is turned on (see point B of arrow in Figure 5(A)).

[0095] When an adjustment command is received, if the power generation control program (tracking characteristics) for load increases is changed in response to changes in the household load, the gradient of the slope θ7 at which the amount of power generation gradually increases becomes larger than the slope θ2 (θ7>θ2), as shown by the solid line Z in Figure 5(A).

[0096] As a result, the time t4 required to return to the power generation amount indicated by arrow A in FIG. 5(A) is shorter than the time t1.

[0097] The operation of the power contribution control device 18 in the third embodiment of load following control will be described below with reference to the flowchart of FIG. 5(B).

[0098] In step 300, it is determined whether or not an adjustment capability command has been received, and 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 or not the time is within the allowable time in the life cycle, and if the determination is affirmative, the process proceeds to step 304. On the other hand, if the determination is negative in step 303, the process proceeds to step 306.

[0099] In step 304, the power generation control program (following characteristics) during load increase is changed. Specifically, the response (slope θ7) during load decrease in Fig. 4(A) after the change is made steeper than the response (slope θ2) during load follow in Fig. 4(A) (θ7>θ2).

[0100] 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 (affirmative determination), the process proceeds to step 310, where the remote control is released, and then to step 312, where the power generation control program for when the load increases 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.

[0101] 5(C) is a routine that is interrupted during the program change of the power generation control, and in step 314, it is determined whether or not the change is within the time allowed for one operation, and if the determination is negative, the program change of the power generation control continues and the routine returns. On the other hand, if the determination is positive in step 314, the routine proceeds to step 316, where an instruction to cancel the change of the power generation control program is issued and the routine returns.

[0102] (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.

[0103] As shown by the dotted line X in Figure 6(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 to 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 change at a predetermined rate (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 decreases.

[0104] Thereafter, when the load power supply switch is turned on to transition from a low load state to a high load state (see point B of arrow 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 tracking control (slope θ2) set as the rated value, 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 of arrow in Figure 6(A)), and the commercial power source (received power) is used during this predetermined time t1.

[0105] In the fourth embodiment, as a means for reducing the tracking delay period, when an adjustment capability command is received, the power generation control program (tracking characteristics) during load drop is changed so that the tracking characteristics are insensitive after the load power supply switch is turned off (see point A in FIG. 6(A)) and are sensitive after the load power supply switch is turned on (see point B in FIG. 5(A)).

[0106] When an adjustment command is received, if the power generation control program (tracking characteristics) for load drops is changed in accordance with changes in household load, as shown by the 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).

[0107] 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 at which the power generation amount returns to the amount indicated by arrow A in Figure 6(A) becomes shorter than the time t1.

[0108] The operation of the power contribution control device 18 in the fourth embodiment of load following control will be described below with reference to the flowchart of FIG. 6(B).

[0109] In step 400, it is determined whether or not an adjustment power command has been received, and 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.

[0110] In step 404, the power generation control program (following characteristics) during load drop is changed. Specifically, the responsiveness (slope θ8) during load decrease in Fig. 6(A) after the change is made less sensitive than the responsiveness (slope θ1) during load follow in Fig. 6(A) (θ8<θ1), and the responsiveness (slope θ9) during load increase in Fig. 6(A) after the change is made more sensitive than the responsiveness (slope θ2) during load follow in Fig. 6(A).

[0111] 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 (affirmative determination), the process proceeds to step 410, where the 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.

[0112] In the first to fourth embodiments described above, the load following control for increasing the output of the fuel cell 26 of the fuel cell system 16 when it is determined that an adjustment capability command has been received has been described.

[0113] In other words, by performing at least one of the load following controls, namely, the first load following control that delays the rate of decrease in the amount of power generated following a decrease in the power load, and the second load following control that accelerates the rate of increase in the amount of power generated following an increase in the power load, rather than the individual load following operation control performed by the system control unit 29, the responsiveness of the power load following by the power contribution control device 18 under the remote control of the virtual power generation system 10 can be improved rather than the responsiveness of the power load following by the fuel cell system 16 alone. [Explanation of symbols]

[0114] 10 Virtual Power Generation System 12 Electricity Market 14 Coordinating body 16 Fuel Cell System 18 Power contribution control device (judgment section, transition section) 20 Aggregation Coordinator 22 Resource Aggregators 24 resources 26 Fuel Cell 29 System control section 30 Adjustment power receiving unit 32 Adjustment Power Distribution Department 34 Transmitter 35 Upper Level Power Information Monitoring Department 36 Distribution adjustment power receiving unit 38 Selection section 40 Distribution control power transmission section 42 Lower layer power information monitoring department

Claims

1. 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.

2. 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.

3. 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.

4. 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.

5. The follow-up 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.

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