Power supply system, controller, control and method

Abstract

To provide a technology capable of more appropriately performing power supply from a fuel battery and a power storage device with respect to variation in requirement on the demand side.SOLUTION: A power supply system 30 comprises: a fuel battery system 40; a power storage device 50; a power conversion device 60 that is electrically connected with the fuel battery system 40 and the power storage device 50 and can output power of at least one of the fuel battery system 40 and the power storage device 50 to a demand side; and a controller 70 that controls the fuel battery system 40 and the power conversion device 60 to cause power corresponding to a requirement on the demand side to be output from the power conversion device 60. The controller 70 varies output of the fuel battery system 40 so as to be capable of supplying power corresponding to a requirement on the demand side in accordance with a relatively quick variation with respect to a predetermined reference of the requirement on the demand side and causes the power storage device 50 to perform power charging / discharging in accordance with a delay of variation in output of the fuel battery system 40 for variation in the requirement on the demand side.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present disclosure relates to a power supply system and the like. [Background technology]

[0002] For example, there is known a power supply system that includes a fuel cell and a power storage device (eg, a storage battery or a capacitor) and is capable of outputting electric power from both the fuel cell and the power storage device to a demand side (see Patent Documents 1 to 4). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-190305 [Patent Document 2] JP 2009-176666 A [Patent Document 3] JP 2018-060655 A [Patent Document 4] JP 2022-157050 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, for example, there are cases where the demand side demand changes suddenly (e.g., stepwise). In such a case, Patent Documents 1 to 4 do not mention at all how to supply power from the fuel cell and the power storage device to the demand side in response to the change in the demand side demand.

[0005] In view of the above-mentioned problems, an object of the present invention is to provide a technique that enables more appropriate power supply from fuel cells and power storage devices in response to changes in demand-side requirements. [Means for solving the problem]

[0006] In order to achieve the above object, in one embodiment of the present disclosure, A fuel cell; A power storage device; a power conversion device electrically connected to the fuel cell and the power storage device and capable of outputting electric power of at least one of the fuel cell and the power storage device to a demand side; a control device that controls the fuel cell and the power conversion device and causes the power conversion device to output electric power according to a request from the demand side; the control device changes the output of the fuel cell in response to a relatively fast change in the demand on the demand side with respect to a predetermined standard so as to be able to supply power corresponding to the demand on the demand side, and causes the power storage device to perform charging and discharging in response to a delay in a change in the output of the fuel cell in response to a change in the demand on the demand side. A power supply system is provided.

[0007] In another embodiment of the present disclosure, A control device that controls a fuel cell and a power conversion device that is electrically connected to the fuel cell and a power storage device and is capable of outputting power of at least one of the fuel cell and the power storage device to a demand side, and causes the power conversion device to output power in response to a request from the demand side, changing an output of the fuel cell so as to supply electric power corresponding to the demand on the demand side in response to a relatively fast change in the demand on the demand side with respect to a predetermined standard, and causing the power storage device to perform charging and discharging in response to a delay in a change in the output of the fuel cell in response to the change in the demand on the demand side; A controller is provided.

[0008] In still another embodiment of the present disclosure, A control method comprising: a control device controlling a fuel cell and a power conversion device electrically connected to the fuel cell and a power storage device and capable of outputting power from at least one of the fuel cell and the power storage device to a demand side, and causing the power conversion device to output power in response to a request from the demand side, the method comprising: changing an output of the fuel cell so as to supply electric power corresponding to the demand on the demand side in response to a relatively fast change in the demand on the demand side with respect to a predetermined standard, and causing the power storage device to perform charging and discharging in response to a delay in a change in the output of the fuel cell in response to the change in the demand on the demand side; A control method is provided. Effect of the Invention

[0009] According to the above-described embodiment, power can be supplied from the fuel cell and the power storage device more appropriately in response to changes in demand side requirements. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram illustrating a configuration of an example of a power system. [Diagram 2] FIG. 13 is a diagram illustrating the configuration of another example of a power system. [Diagram 3] FIG. 1 is a diagram showing a configuration of an example of a fuel cell system. [Figure 4] 4 is a time chart illustrating a first example of a method for controlling a power supply system in response to a change in a demand side request. [Diagram 5] 4 is a flowchart illustrating a first example of a process related to control of a power supply system in response to a change in a demand side requirement. [Figure 6] 6 is a time chart illustrating a second example of a method for controlling a power supply system in response to a change in a demand side request. [Figure 7] 10 is a flowchart illustrating a second example of a process related to control of a power supply system in response to a change in a demand side requirement. [Figure 8] 13 is a time chart illustrating a third example of a method for controlling a power supply system in response to a change in a demand side request. [Figure 9] 10 is a flowchart illustrating a third example of a process related to control of a power supply system in response to a change in a demand side requirement. [Figure 10] 13 is a time chart illustrating a fourth example of a method for controlling a power supply system in response to a change in a demand side request. [Figure 11] 10 is a flowchart illustrating a fourth example of a process related to control of a power supply system in response to a change in a demand side requirement. [Figure 12] 5 is a time chart illustrating a comparative example of a method for controlling a power supply system during a refresh operation of a fuel cell system. [Figure 13] 5 is a time chart illustrating an example of a method for controlling a power supply system during a refresh operation of a fuel cell system. [Figure 14] 4 is a flowchart illustrating an example of a process related to control of the power supply system during a refresh operation of the fuel cell system. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, an embodiment will be described with reference to the drawings.

[0012] [Power system configuration] The configuration of a power system 1 according to this embodiment will be described with reference to FIG.

[0013] Fig. 1 is a diagram showing a configuration of an example of the power system 1. Fig. 2 is a diagram showing a configuration of another example of the power system 1.

[0014] As shown in FIGS. 1 and 2, the power system 1 includes an AC power system 10, a transformer 20, and a power supply system 30.

[0015] The power system 1 connects a power supply system 30 to an AC power system 10 via a transformer 20, and supplies the power output from the power supply system 30 to a demand side connected to the AC power system 10.

[0016] The AC power system 10 transmits, to a demand side, the power output from the power supply system 30 via a transformer 20. The AC power system 10 transmits three-phase AC power by a three-phase three-wire system.

[0017] The transformer 20 transforms (eg, steps down) the AC power output from the power supply system 30 and supplies the AC power to the AC power system 10.

[0018] The power supply system 30 is connected to the AC power system 10 through a transformer 20, and supplies power to the AC power system 10. As shown in Fig. 1 and Fig. 2, the power supply system 30 includes a fuel cell system 40, a power storage device 50, a power conversion device 60, and a control device 70.

[0019] The fuel cell system 40 supplies electric power to the outside of the power supply system 30 through the power conversion device 60. In this example, the fuel cell system 40 supplies electric power to the AC power system 10 through the power conversion device 60 and the transformer 20. The fuel cell system 40 is electrically connected to the power storage device 50 and the power conversion device 60 via a DC link unit 55.

[0020] For example, as shown in Fig. 1, one fuel cell system 40 is provided. Alternatively, as shown in Fig. 2, a plurality of fuel cell systems 40 may be provided. In this case, the plurality of fuel cell systems 40 are connected to the DC link unit 55 in parallel.

[0021] The power storage device 50 can discharge power to the outside of the power supply system 30 through the power conversion device 60, and can charge (store) power for the fuel cell system 40. The power storage device 50 is, for example, a capacitor such as a lithium ion capacitor (LIC). The power storage device 50 may also be, for example, a storage battery (secondary battery) such as a lithium ion battery with a liquid electrolyte or an all-solid-state battery with a solid electrolyte. The power storage device 50 is electrically connected to the fuel cell system 40 and the power conversion device 60 via a DC link unit 55.

[0022] The power conversion device 60 converts the DC of the DC link unit 55 into AC of a predetermined voltage and frequency, and outputs it toward the transformer 20. For example, the power conversion device 60 is a power conditioner (PCS: Power Conditioning System) including an inverter circuit that converts the DC into three-phase AC of a predetermined voltage and frequency.

[0023] For example, as shown in Fig. 1, one power conversion device 60 is provided. Also, as shown in Fig. 2, when a plurality of fuel cell systems 40 are provided, a plurality of power conversion devices 60 may be provided. In this case, the power conversion devices 60 are connected in parallel to the DC link unit 55, and a transformer 20 is provided for each of the plurality of power conversion devices 60. That is, the same number of transformers 20 as the power conversion devices 60 are provided, and the plurality of transformers 20 are connected in parallel to the AC power system 10.

[0024] The control device 70 controls the operation of the power supply system 30 .

[0025] For example, the control device 70 controls the fuel cell system 40 and the power conversion device 60 in accordance with power requested by a demand side connected to the AC power system 10 (hereinafter simply referred to as "demand side request"), and causes the power conversion device 60 to output power corresponding to the demand side request. Specifically, the control device 70 controls the load of the power conversion device 60 so as to output AC power corresponding to the demand side request from the DC of the DC link unit 55, and controls the fuel cell system 40 so as to output power corresponding to the demand side request. In this way, the control device 70 can cause the fuel cell system 40 to output power corresponding to the demand side request to the AC power system 10 side via the power conversion device 60.

[0026] The control device 70 may control the output of the fuel cell system 40 by directly controlling the amount of hydrogen supplied to the fuel cell 41A described below by outputting commands to a valve or the like (not shown), or may indirectly control the output of the fuel cell system 40 by outputting commands to a control unit built into the fuel cell system 40.

[0027] The functions of the control device 70 are realized by any hardware or any combination of hardware and software. For example, the control device 70 is mainly configured with a computer including a CPU (Central Processing Unit), a memory device, an auxiliary storage device, an interface device, etc. In this case, the control device 70 can realize various functions by, for example, loading a program installed in the auxiliary storage device into the memory device and executing it with the CPU. The control device 70 is, for example, a PLC (Programmable Logic Controller).

[0028] [Fuel cell system configuration] Next, the configuration of a fuel cell system 40 according to this embodiment will be described with reference to FIG.

[0029] FIG. 3 is a diagram showing an example of the configuration of a fuel cell system 40. As shown in FIG.

[0030] As shown in FIG. 3, the fuel cell includes a fuel cell module 41, a hydrogen tank , a radiator 43, a heat exchanger 44, an ion exchanger 45, and an air cleaner .

[0031] The fuel cell module 41 includes a fuel cell 41A, a cooling section 41B, and a converter device 41C.

[0032] The fuel cell 41A generates electricity by chemically reacting hydrogen supplied from a hydrogen tank 42 with oxygen in the air taken in from the outside. The fuel cell 41A is, for example, a polymer electrolyte fuel cell (PEFC). For example, the fuel cell 41A as a polymer electrolyte fuel cell has a stack structure in which a large number of unit cells are stacked.

[0033] The single cell in the fuel cell 41A has a membrane electrode assembly (MEA) including a polymer electrolyte membrane and a pair of electrodes provided on both sides of the polymer electrolyte membrane. The polymer electrolyte membrane selectively transports hydrogen ions. Each electrode is made of a porous material. Each of the pair of electrodes has a catalyst layer mainly composed of carbon powder carrying a platinum-based metal catalyst (electrode catalyst), for example, and a gas diffusion layer having both air permeability and electronic conductivity. Furthermore, the single cell has a pair of separators that sandwich the membrane electrode assembly (MEA) from both sides.

[0034] From the fuel cell module 41, exhaust gas is discharged after a chemical reaction between hydrogen from the fuel cell 41A and oxygen contained in the air SA.

[0035] The fuel cell 41A may be, for example, a phosphoric acid fuel cell (PAFC) or a solid oxide fuel cell (SOFC). The fuel cell 41A may be, for example, a molten carbonate fuel cell (MCFC).

[0036] The cooling section 41B cools the fuel cell 41A. Specifically, a coolant flows inside the cooling section 41B. The cooling section 41B can cool the fuel cell 41A by exchanging heat between the fuel cell 41A and the coolant.

[0037] The converter device 41C boosts the voltage output from the fuel cell 41A and outputs it to the outside of the fuel cell module 41. An output terminal of the converter device 41C is connected to the DC link unit 55.

[0038] The hydrogen tank 42 stores high-pressure hydrogen and supplies high-pressure hydrogen gas to the fuel cell 41A of the fuel cell module 41. The hydrogen tank 42 is, for example, a hydrogen cartridge.

[0039] The radiator 43 cools the coolant in the cooling circuit CC1. As a result, the heat exchanger 44 performs heat exchange between the coolant in the cooling circuit CC1 and the coolant in the cooling circuit CC2 as described above, and can cool the coolant in the cooling circuit CC2. The radiator 43 is, for example, a fin-tube type or a fin-and-tube type radiator.

[0040] The heat exchanger 44 exchanges heat between the coolant in the cooling circuit CC1 including the radiator 43 and the coolant in the cooling circuit CC2 including the cooling unit 41B, thereby cooling the coolant in the cooling circuit CC2. As a result, the cooling circuit CC2 can supply the coolant cooled by the heat exchanger 44 to the cooling unit 41B, thereby cooling the fuel cell 41A.

[0041] The ion exchanger 45 is provided in the cooling circuit CC2 and removes ionic impurities from the cooling liquid in the cooling circuit CC2, thereby ensuring the insulation of the cooling liquid.

[0042] The air cleaner 46 removes dust, impurities, etc. from the air SA taken in from the outside, and supplies the air SA from which dust, impurities, etc. have been removed to the fuel cell 41A.

[0043] [First example of a method for controlling a power supply system in response to changes in demand side requirements] Next, a first example of a method for controlling the power supply system 30 in response to a change in demand on the demand side will be described with reference to Figs.

[0044] <Control method overview> 4 is a time chart illustrating a first example of a method for controlling the power supply system 30 in response to a change in a demand side request. Specifically, FIG. 4 shows the change over time in the demand side request, the load of the power conversion device 60, and the output of the fuel cell system 40.

[0045] In FIG. 4, in order to eliminate overlapping of the time charts of the demand side demand, the load of the power conversion device 60, and the output of the fuel cell system 40, the values ​​are drawn with a shift even when they have the same value at the same time, and the time is drawn with a shift even when they have the same change in the time direction. The same applies to the cases of FIG. 6, FIG. 8, and FIG. 10 described below. In addition, in this example (FIG. 4), when the power supply system 30 includes a plurality of power conversion devices 60, the "load of the power conversion device 60" is read as the sum of the loads of all the power conversion devices 60. The same applies to the cases of FIG. 6, FIG. 8, FIG. 10, FIG. 12, and FIG. 13 described below. Similarly, in this example (FIG. 4), when the power supply system 30 includes a plurality of fuel cell systems 40, the "output of the fuel cell system 40" is read as the sum of the outputs of all the fuel cell systems 40. The same applies to the cases of FIG. 6, FIG. 8, and FIG. 10 described below.

[0046] As shown in Fig. 4, before time t11, the demand side demand is maintained constant at a relatively high level. At this time, the control device 70 controls the fuel cell system 40 so as to output power corresponding to the demand side demand, and controls the load of the power conversion device 60 so as to output power corresponding to the demand side demand to the AC power system 10. This allows the fuel cell system 40 to supply power corresponding to the demand side demand to the AC power system 10 via the power conversion device 60.

[0047] Thereafter, at time t11, the demand side demand changes (drops) instantaneously (i.e., stepwise) to a relatively low state, and after time t11, the demand side demand is maintained constant at the relatively low state. At this time, at time t11, the control device 70 controls the load of the power conversion device 60 to a state in which the load outputs a relatively low power corresponding to the demand side demand, in response to the instantaneous drop in the demand side demand. As a result, as shown in FIG. 4, the power conversion device 60 instantaneously transitions to a state in which the load outputs the same power as the demand side demand. At the same time, at time t11, the control device 70 controls the fuel cell system 40 to output a relatively low power corresponding to the demand side demand, in response to the instantaneous drop in the demand side demand. However, as shown in FIG. 4, the fuel cell system 40 cannot instantaneously change its output like the load of the power conversion device 60, and transitions to a state in which the load outputs a power corresponding to the demand side demand over a period of time from time t11 to time t12. This is because while the power conversion device 60 can electrically change the load, the fuel cell system 40 needs to adjust the amount of hydrogen supply, etc. by adjusting valves, etc., resulting in a relatively large delay in control response.

[0048] In the section from time t11 to time t12, the output of the fuel cell system 40 is larger than the load of the power conversion device 60, that is, the power output from the power conversion device 60 to the AC power system 10. Therefore, in the section from time t11 to time t12, the difference between the output of the fuel cell system 40 and the load of the power conversion device 60 is charged (stored) in the power storage device 50 through the DC link unit 55. Specifically, the accumulated value 401 of the difference between the output of the fuel cell system 40 and the load of the power conversion device 60 in the section from time t11 to time t12 is charged in the power storage device 50. In this way, the control device 70 can cause the power storage device 50 to perform charging in response to the delay in the change in the output of the fuel cell system 40 in response to a relatively fast change in the demand on the demand side. Therefore, by utilizing the free capacity of the power storage device 50, the control device 70 can maintain a state in which the power conversion device 60 outputs power according to the demand on the demand side even if there is a delay in the decrease in the output of the fuel cell system 40.

[0049] In the interval from time t11 to time t13, the demand side demand is kept constant at a relatively low level. At this time, the control device 70 controls the fuel cell system 40 so as to output power corresponding to the demand side demand, and controls the load of the power conversion device 60 so as to output power corresponding to the demand side demand to the AC power system 10. As a result, in the interval from time t12 to time t13, the fuel cell system 40 can supply power corresponding to the demand side demand to the AC power system 10 through the power conversion device 60.

[0050] Thereafter, at time t13, the demand side demand changes (rises) instantaneously (i.e., stepwise) to a relatively high state, and after time t13, the demand side demand is maintained constant at the relatively high state. At this time, at time t13, the control device 70 controls the load of the power conversion device 60 to a state in which the load outputs a relatively high power corresponding to the demand side demand, in response to the instantaneous rise in the demand side demand. As a result, as shown in FIG. 4, the power conversion device 60 instantaneously transitions to a state in which the load outputs the same power as the demand side demand. At the same time, at time t13, the control device 70 controls the fuel cell system 40 to output a relatively high power corresponding to the demand side demand, in response to the instantaneous rise in the demand side demand. However, as shown in FIG. 4, the fuel cell system 40 cannot instantaneously change its output like the load of the power conversion device 60, and transitions to a state in which the load outputs a power corresponding to the demand side demand over a period of time from time t13 to time t14.

[0051] In the section from time t13 to time t14, the output of the fuel cell system 40 is smaller than the load of the power conversion device 60, that is, the power output from the power conversion device 60 to the AC power system 10 side. Therefore, in the section from time t13 to time t14, the difference between the output of the fuel cell system 40 and the load of the power conversion device 60 is discharged from the power storage device 50 to the AC power system 10 side through the DC link unit 55 and the power conversion device 60. Specifically, an accumulated value 402 of the difference between the output of the fuel cell system 40 and the load of the power conversion device 60 in the section from time t13 to time t14 is discharged from the power storage device 50. In this way, the control device 70 can cause the power storage device 50 to discharge in response to a delay in the change in the output of the fuel cell system 40 relative to a relatively fast change in the demand on the demand side. Therefore, by utilizing the power already stored in the power storage device 50, the control device 70 can maintain a state in which the power conversion device 60 outputs power according to the demand on the demand side even if there is a delay in the increase in the output of the fuel cell system 40.

[0052] It should be noted that the length of the section from time t11 to time t12 may be different from the length of the section from time t13 to time t14. In other words, the rate at which the output of the fuel cell system 40 decreases may be different from the rate at which it increases. For example, as shown in Fig. 4, the length of the section from time t13 to time t14 is longer than the length of the section from time t11 to time t12, and the rate at which the output of the fuel cell system 40 increases is slower than the rate at which it decreases.

[0053] In this way, the control device 70 changes the output of the fuel cell system 40 so as to supply power corresponding to the demand side request in response to a relatively fast change in the demand side request with respect to a predetermined standard. This predetermined standard corresponds to an upper limit value of the change speed of the output of the fuel cell module 41, and as described above, may differ between when the output increases and when the output decreases. In addition, the control device 70 changes the load of the power conversion device 60 to a state in which the power conversion device 60 outputs power corresponding to the demand side request in response to the change. This allows the control device 70 to charge and discharge the power storage device 50 in response to a delay in the change in the output of the fuel cell system 40 in response to the change in the demand side request. Therefore, the control device 70 uses the power storage device 50 to compensate for the delay in the change in the output of the fuel cell system 40 and maintain a state in which the power conversion device 60 outputs power corresponding to the demand side request.

[0054] <Control flow> FIG. 5 is a flowchart illustrating a first example of a process related to control of the power supply system 30 in response to a change in demand side requirements.

[0055] This flowchart is repeatedly executed at predetermined processing intervals during operation of the power supply system 30. The same may be true for the flowcharts in Figs. 7, 9, and 11 described below.

[0056] 5, in step S102, the control device 70 determines whether the demand side request has changed based on an input representing the demand side request from the outside. If the demand side request has changed, the process proceeds to step S104, and if not, the process of this flowchart ends.

[0057] In step S104, the control device 70 outputs a load command to the power conversion device 60 to set the load of the power conversion device 60 to a state corresponding to the demand side request after the change.

[0058] This allows the power conversion device 60 to immediately transition to a state in which it outputs power corresponding to the changed demand on the demand side to the AC power system 10 side.

[0059] When the process of step S104 is completed, the control device 70 proceeds to step S106.

[0060] In step S106, the control device 70 outputs an output command to the fuel cell system 40 to bring the output of the fuel cell system 40 into a state corresponding to the changed demand side requirement.

[0061] As a result, the fuel cell system 40 can transition to a state in which it outputs power corresponding to the changed demand side request to the AC power system 10 side through the power conversion device 60. However, depending on the speed of change in the demand side request, there may be a delay in the change in the output of the fuel cell system 40 relative to the change in the demand side request. In this case, the load of the power conversion device 60 is immediately transitioned to a state corresponding to the changed demand side request by the process of step S104, so that the power storage device 50 can be charged or discharged according to the delay in the change in the output of the fuel cell system 40 relative to the change in the demand side request. Therefore, the control device 70 can charge the surplus power to the power storage device 50 according to the delay in the decrease in the output of the fuel cell system 40, or discharge the shortage to the power storage device 50 according to the delay in the increase in the output of the fuel cell system 40.

[0062] When the process of step S106 is completed, the control device 70 ends the process of this flowchart.

[0063] [Second example of a method for controlling a power supply system in response to changes in demand side requirements] Next, a second example of a method for controlling the power supply system 30 in response to a change in a demand side request will be described with reference to Figs.

[0064] In this example, the description will be centered on the differences from the above-mentioned first example, and description of the same or corresponding content as the above-mentioned first example may be omitted.

[0065] <Control method overview> Fig. 6 is a time chart illustrating a second example of a method for controlling a power supply system in response to a change in a demand side request. Specifically, Fig. 6 includes Fig. 6A showing the time changes in the demand side request, the load of the power conversion device 60, and the output of the fuel cell system 40, and Fig. 6B showing the time change in the voltage of the power storage device 50.

[0066] As shown in FIG. 6A, before time t21, the demand side requirements, the load of the power conversion device 60, and the output of the fuel cell system 40 are the same as the states before time t11 in FIG.

[0067] 6B, before time t21, the load of the power conversion device 60 and the output of the fuel cell system 40 are both maintained in a state corresponding to the demand side requirements, so that the power storage device 50 is not charged or discharged, and the voltage of the power storage device 50 is maintained at the reference voltage V_ref. The voltage of the power storage device 50 is correlated with the state of charge, i.e., the charging rate (SOC: State Of Charge), of the power storage device 50, and the reference voltage V_ref corresponds to a reference value of the SOC of the power storage device 50. The reference value of the SOC of the power storage device 50 is, for example, 80%.

[0068] Thereafter, at time t21, the demand side demand instantly drops from a relatively high state to a relatively low state, and in the section from time t21 to time t24, the demand side demand is maintained constant at a relatively low state.

[0069] In the interval from time t21 to time t22, the demand side request, the load of the power conversion device 60, and the output of the fuel cell system 40 are in the same state as in the interval from time t11 to time t12 in FIG.

[0070] In this section, as described above (see FIG. 4), the surplus output of the fuel cell system 40 is charged to the power storage device 50 in accordance with the delay in the decrease in the fuel cell system 40 relative to the decrease in demand on the demand side. Therefore, in this section, the voltage of the power storage device 50 rises from the reference voltage V_ref and approaches the upper limit voltage V_lim2. The upper limit voltage V_lim2 corresponds to a predetermined upper limit value of the SOC of the power storage device 50. The upper limit value of the SOC corresponding to the upper limit voltage V_lim2 is, for example, 95%.

[0071] Thereafter, in the section from time t22 to time t23, the control device 70 maintains the load of the power conversion device 60 in a state corresponding to the demand-side request. Meanwhile, in this section, the control device 70 reduces the output of the fuel cell system 40 to a state lower than the demand-side request, and then increases it to return it to a state corresponding to the demand-side request. That is, in this section, the control device 70 temporarily changes the output of the fuel cell system 40 to a state lower than the demand-side request. As a result, in this section, the output of the fuel cell system 40 is insufficient for the demand-side request, and the insufficient amount is discharged from the power storage device 50 to the AC power system 10 side through the power conversion device 60. Therefore, in this section, the voltage of the power storage device 50 decreases toward the reference voltage V_ref, and returns to the reference voltage V_ref at time t23. Specifically, in this section, the control device 70 controls the output of the fuel cell system 40 so that the deviation between the voltage of the power storage device 50 and the reference voltage V_ref becomes zero. Therefore, the control device 70 can prevent a situation in which the voltage of the power storage device 50 exceeds the upper limit voltage V_lim2 and the power storage device 50 is overcharged.

[0072] In the section from time t23 to time t24, the demand side request, the load of the power conversion device 60, and the output of the fuel cell system 40 are in the same state as in the section from time t12 to time t13 in FIG.

[0073] In this section, the load of the power conversion device 60 and the output of the fuel cell system 40 are both maintained in a state corresponding to the demand side requirements, so that the storage device 50 is not charged or discharged, and the voltage of the storage device 50 is maintained at the reference voltage V_ref.

[0074] Thereafter, at time t24, the demand side demand instantly rises from a relatively low state to a relatively high state, and in the section from time t24 to time t26, the demand side demand is maintained constant at a relatively high state.

[0075] In the section from time t24 to time t25, the demand side request, the load of the power conversion device 60, and the output of the fuel cell system 40 are in the same state as in the section from time t13 to time t14 in FIG.

[0076] In this section, as described above (see FIG. 4), in response to a delay in the increase in the fuel cell system 40 relative to the increase in demand on the demand side, the shortfall in the output of the fuel cell system 40 is discharged from the power storage device 50 to the AC power grid 10 side via the power conversion device 60. Therefore, in this section, the voltage of the power storage device 50 drops from the reference voltage V_ref and approaches the lower limit voltage V_lim1. The lower limit voltage V_lim1 corresponds to a predetermined lower limit value of the SOC of the power storage device 50. The lower limit value of the SOC corresponding to the lower limit voltage V_lim1 is, for example, 65%.

[0077] Thereafter, in the section from time t25 to time t26, the control device 70 maintains the load of the power conversion device 60 in a state corresponding to the demand side request. Meanwhile, in this section, the control device 70 increases the output of the fuel cell system 40 to a state higher than the demand side request, and then reduces it again to return to a state corresponding to the demand side request. That is, in this section, the control device 70 temporarily changes the output of the fuel cell system 40 to a state higher than the demand side request. As a result, in this section, the output of the fuel cell system 40 exceeds the demand side request, and the surplus is charged to the power storage device 50. Therefore, in this section, the voltage of the power storage device 50 increases toward the reference voltage V_ref and returns to the reference voltage V_ref at time t26. Specifically, in this section, the control device 70 controls the output of the fuel cell system 40 so that the deviation between the voltage of the power storage device 50 and the reference voltage V_ref becomes zero. Therefore, the control device 70 can prevent a situation in which the voltage of the power storage device 50 falls below the lower limit voltage V_lim1 and the power storage device 50 is over-discharged.

[0078] In this way, after the completion of charging / discharging of the power storage device 50 in accordance with the delay in the change in the output of the fuel cell system 40 in response to the change in demand on the demand side, the control device 70 controls the output of the fuel cell system 40 and charges / discharges the power storage device 50 so that the SOC of the power storage device 50 approaches the reference value. This allows the control device 70 to prevent the power storage device 50 from being overcharged or overdischarged.

[0079] <Control flow> FIG. 7 is a flowchart illustrating a second example of a process related to control of the power supply system 30 in response to a change in demand side requirements.

[0080] As shown in FIG. 7, steps S202, S204, and S206 are the same as the processes in steps S102, S104, and S106 in FIG. 5, and therefore a description thereof will be omitted.

[0081] When the process of step S206 is completed, specifically, when the output of the fuel cell system 40 reaches a state corresponding to the changed demand on the demand side, the process proceeds to step S208.

[0082] In step S208, the control device 70 controls the output of the fuel cell system 40 and adjusts the deviation between the voltage of the power storage device 50 and the reference voltage V_ref to be zero. The control device 70 can obtain a measured value of the voltage of the power storage device 50, for example, by obtaining the output of a voltage sensor built into the power storage device 50 from the power storage device 50. The control device 70 controls the output of the fuel cell system 40 and adjusts the voltage of the power storage device 50, for example, by feedback control such as PID (Proportional Integral Differential) control. The control device 70 may also control the output of the fuel cell system 40 and adjust the voltage of the power storage device 50 by combining feedforward control in addition to feedback control.

[0083] When the process of step S208 is completed (specifically, when the voltage of the power storage device 50 reaches the reference voltage V_ref), the control device 70 ends the process of this flowchart.

[0084] [Third example of a method for controlling a power supply system in response to changes in demand side requirements] Next, a third example of a method for controlling the power supply system 30 in response to a change in a demand side request will be described with reference to Figs.

[0085] In this example, the differences from the first and second examples will be mainly described, and descriptions of contents that are the same as or correspond to the first and second examples may be omitted.

[0086] <Control method overview> Fig. 8 is a time chart illustrating a third example of a method for controlling a power supply system in response to a change in a demand-side request. Specifically, Fig. 8 includes Fig. 8A showing the time changes in the demand-side request, the load of the power conversion device 60, and the output of the fuel cell system 40, and Fig. 8B showing the time change in the voltage of the power storage device 50.

[0087] As shown in FIG. 8, before time t31, the demand side request, the load of the power conversion device 60, the output of the fuel cell system 40, and the voltage of the power storage device 50 are the same as the states before time t21 in FIG.

[0088] Thereafter, at time t31, the demand side demand instantly drops from a relatively high state to a relatively low state, and in the section from time t31 to time t36, the demand side demand is maintained constant at a relatively low state.

[0089] In the section from time t31 to time t32, the demand side request, the load of the power conversion device 60, the output of the fuel cell system 40, and the voltage of the power storage device 50 are in the same state as in the section from time t21 to time t22 in FIG.

[0090] Thereafter, in the section from time t32 to time t33, the control device 70 maintains the load of the power conversion device 60 in a state corresponding to the demand side request. Meanwhile, in this section, the control device 70 reduces the output of the fuel cell system 40 to a state lower than the demand side request. Specifically, in this section, the control device 70 controls the output of the fuel cell system 40 so that the deviation between the voltage of the power storage device 50 and the reference voltage V_ref becomes zero. As a result, in this section, the output of the fuel cell system 40 is insufficient for the demand side request, and the shortage is discharged from the power storage device 50 to the AC power system 10 side through the power conversion device 60. However, in this example, the surplus power due to the delay in the decrease in the output of the fuel cell system 40 in response to the decrease in the demand side request in the section from time t31 to time t32 is relatively large, and the voltage of the power storage device 50 continues to rise even in the section from time t32 to time t33. Therefore, in this section, the voltage of the power storage device 50 rises to near the upper limit voltage V_lim2. For example, if the power supply system 30 includes multiple fuel cell systems 40, the delay in the output reduction for each fuel cell system 40 is accumulated, so the surplus power due to the delay in the reduction in the output of the fuel cell system 40 in response to the reduction in demand on the demand side may become relatively large.

[0091] Thereafter, in the section from time t33 to time t34, the control device 70 maintains the output of the fuel cell system 40 in a state lower than the demand side request. Furthermore, in this section, the control device 70 increases the load of the power conversion device 60 to a state higher than the demand side request, and then reduces it again to return to a state corresponding to the demand side request. That is, in this section, the control device 70 temporarily changes the load of the power conversion device 60 to a state higher than the demand side request. Specifically, in this section, the control device 70 controls the output of the fuel cell system 40 and the load of the power conversion device 60 so that the deviation between the voltage of the power storage device 50 and the reference voltage V_ref becomes zero. As a result, the power output from the power conversion device 60 to the AC power system 10 side increases, and as a result, the increase in the voltage of the power storage device 50 stops just before the upper limit voltage V_lim2 and starts to decrease. Therefore, the control device 70 can suppress overcharging of the power storage device 50 by setting the output of the fuel cell system 40 to a state lower than the demand side requirement, and by setting the load of the power conversion device 60 to a state higher than the demand side requirement.

[0092] Thereafter, in the section from time t34 to time t35, the control device 70 increases the output of the fuel cell system 40 from a state lower than the demand-side request, and restores the state to one that meets the demand-side request. Specifically, in this section, the control device 70 controls the output of the fuel cell system 40 so that the deviation between the voltage of the power storage device 50 and the reference voltage V_ref becomes zero. As a result, the voltage of the power storage device 50 further decreases, and reaches the reference voltage V_ref at time t35.

[0093] Thereafter, in the section from time t35 to time t36, the demand side request, the load of the power conversion device 60, the output of the fuel cell system 40, and the voltage of the power storage device 50 are in the same state as in the section from time t23 to time t24 in FIG.

[0094] Thereafter, at time t36, the demand side demand instantly rises from a relatively low state to a relatively high state, and in the section from time t36 to time t30, the demand side demand is maintained constant at a relatively high state.

[0095] In the section from time t36 to time t37, the demand side request, the load of the power conversion device 60, the output of the fuel cell system 40, and the voltage of the power storage device 50 are in the same state as in the section from time t24 to time t25 in FIG.

[0096] Thereafter, in the section from time t37 to time t38, the control device 70 maintains the load of the power conversion device 60 in a state corresponding to the demand side request. Meanwhile, in this section, the control device 70 increases the output of the fuel cell system 40 to a state higher than the demand side request. Specifically, in this section, the control device 70 controls the output of the fuel cell system 40 so that the deviation between the voltage of the power storage device 50 and the reference voltage V_ref becomes zero. As a result, in this section, the output of the fuel cell system 40 becomes surplus to the demand side request, and the surplus is charged to the power storage device 50. However, in this example, the shortage of power due to the delay in the increase in the output of the fuel cell system 40 relative to the increase in the demand side request in the section from time t36 to time t37 is relatively large, and the voltage of the power storage device 50 continues to decrease even in the section from time t37 to time t38. Therefore, in this section, the voltage of the power storage device 50 increases to near the lower limit voltage V_lim1. For example, if the power supply system 30 includes multiple fuel cell systems 40, the delay in the increase in output of each fuel cell system 40 is accumulated, so the power shortage caused by the delay in the increase in output of the fuel cell system 40 in response to an increase in demand on the demand side may become relatively large.

[0097] Thereafter, in the section from time t38 to time t39, the control device 70 maintains the output of the fuel cell system 40 in a state higher than the demand-side request. Furthermore, in this section, the control device 70 reduces the load of the power conversion device 60 to a state lower than the demand-side request, and then increases it again to return to a state corresponding to the demand-side request. That is, in this section, the control device 70 temporarily changes the load of the power conversion device 60 to a state lower than the demand-side request. Specifically, in this section, the control device 70 controls the output of the fuel cell system 40 and the load of the power conversion device 60 so that the deviation between the voltage of the power storage device 50 and the reference voltage V_ref becomes zero. As a result, the power output from the power conversion device 60 to the AC power system 10 side is reduced, and as a result, the power charged from the fuel cell system 40 to the power storage device 50 is increased, so that the decrease in the voltage of the power storage device 50 stops just before the lower limit voltage V_lim1 and starts to increase. Therefore, the control device 70 can suppress the occurrence of over-discharge of the storage device 50 by making the output of the fuel cell system 40 higher than the demand side requirement, and by making the load of the power conversion device 60 lower than the demand side requirement.

[0098] Thereafter, in the section from time t39 to time t30, the control device 70 reduces the output of the fuel cell system 40 from a state higher than the demand-side request, and restores the state to one that meets the demand-side request. Specifically, in this section, the control device 70 controls the output of the fuel cell system 40 so that the deviation between the voltage of the power storage device 50 and the reference voltage V_ref becomes zero. As a result, the voltage of the power storage device 50 further increases, and reaches the reference voltage V_ref at time t30.

[0099] In this way, after the completion of charging and discharging of the power storage device 50 in response to a delay in the change in the output of the fuel cell system 40 in response to a change in demand on the demand side, the control device 70 controls the output of the fuel cell system 40 and the load of the power conversion device 60, and charges and discharges the power storage device 50 so that the SOC of the power storage device 50 approaches the reference value. In this way, even when the power supply system 30 includes a plurality of fuel cell systems 40, the control device 70 can more appropriately prevent the power storage device 50 from being overcharged or overdischarged. Furthermore, in order to prevent the power storage device 50 from being overcharged or overdischarged, the control device 70 can prevent a situation in which the capacity of the power storage device 50 increases, resulting in an increase in costs.

[0100] <Control flow> FIG. 9 is a flowchart illustrating a third example of a process related to control of the power supply system 30 in response to a change in demand side requirements.

[0101] As shown in FIG. 9, steps S302, S304, and S306 are the same as the processes in steps S102, S104, and S106 in FIG. 5, and therefore a description thereof will be omitted.

[0102] When the process of step S306 is completed, specifically, when the output of the fuel cell system 40 reaches a state corresponding to the changed demand on the demand side, the process proceeds to step S308.

[0103] In step S308, the control device 70 controls the output of the fuel cell system 40 and the load of the power conversion device 60, and adjusts the deviation between the voltage of the power storage device 50 and the reference voltage V_ref to zero. As in the second example described above, the control device 70 controls the output of the fuel cell system 40 and the load of the power conversion device 60 by feedback control such as PID control, and adjusts the voltage of the power storage device 50. The control device 70 may also control the output of the fuel cell system 40 and the load of the power conversion device 60 by combining feedforward control in addition to feedback control, and adjust the voltage of the power storage device 50.

[0104] At this time, for example, the control device 70 prioritizes the control of the output of the fuel cell system 40, and further controls the load of the power conversion device 60 when the difference between the voltage of the power storage device 50 and the lower limit voltage V_lim1 or the upper limit voltage V_lim2 becomes relatively small with respect to a predetermined standard (see FIG. 8). The control device 70 may also determine whether or not to control the load of the power conversion device 60 depending on the degree of change in the demand side determined in step S302. Specifically, the control device 70 may control only the output of the fuel cell system 40 when the change in the demand side demand is relatively small with respect to a predetermined standard, and may control both the output of the fuel cell system 40 and the load of the power conversion device 60 when the change is relatively large with respect to the predetermined standard. The control device 70 may also control both the output of the fuel cell system 40 and the load of the power conversion device 60 regardless of the conditions. When changing the load of the power conversion device 60 to a state different from the demand side request, the control device 70 may obtain permission from the demand side in advance, notify the demand side in advance, or mediate with the demand side. When arbitrating with the demand side, a priority order may be set in advance for equipment on the demand side, such as production facilities, that receive power from the AC power system 10, and whether or not to operate each piece of equipment and whether or not to limit the available power may be determined in accordance with that priority order.

[0105] When the process of step S308 is completed (specifically, when the voltage of the power storage device 50 reaches the reference voltage V_ref), the control device 70 ends the process of this flowchart.

[0106] [Fourth example of a method for controlling a power supply system in response to changes in demand side requirements] Next, a fourth example of the method for controlling the power supply system 30 in response to a change in demand on the demand side will be described with reference to Figs.

[0107] In this example, the differences from the first to third examples described above will be mainly described, and descriptions of contents that are the same as or correspond to the first to third examples described above may be omitted.

[0108] <Control method overview> Fig. 10 is a time chart illustrating a fourth example of a method for controlling a power supply system in response to a change in a demand-side request. Specifically, Fig. 10 includes Fig. 10A showing the time changes in the demand-side request, the load of the power conversion device 60, and the output of the fuel cell system 40, and Fig. 10B showing the time change in the voltage of the power storage device 50.

[0109] Before time t41, the demand side request, the load of the power conversion device 60, the output of the fuel cell system 40, and the voltage of the power storage device 50 are the same as the states before time t21 in FIG.

[0110] Thereafter, in the period from time t41 to time t42, the demand side demand continues to be maintained constant at a relatively high state. In this section, the control device 70 controls the load of the power conversion device 60 to a state corresponding to the demand side demand. Meanwhile, the control device 70 detects the decrease in the demand side demand at time t42 in advance, and in this section, the control device 70 decreases the output of the fuel cell system 40 to a state lower than the demand side demand in advance in response to the decrease in the demand side demand at time t42. As a result, in this section, the power storage device 50 discharges to the AC power system 10 side through the power conversion device 60 in a manner that compensates for the shortage of the output of the fuel cell system 40, and the voltage of the power storage device 50 decreases to a state lower than the reference voltage V_ref. The degree of decrease in the output of the fuel cell system 40 in this section can be appropriately controlled within a range smaller than the degree of decrease in the demand side demand at time t42. For example, the control device 70 adjusts the degree of decrease in the output of the fuel cell system 40 so that the amount of decrease in the voltage of the power storage device 50 in this section is relatively small with respect to a predetermined reference.

[0111] At time t42, the demand side demand instantly drops from a relatively high state to a relatively low state, and in the section from time t42 to time t45, the demand side demand remains constant at a relatively low state.

[0112] In the section from time t42 to time t43, the control device 70 reduces the output of the fuel cell system 40 to a state corresponding to the changed demand on the demand side. At that time, the control device 70 controls the rate of reduction in the output of the fuel cell system 40 so that the voltage of the power storage device 50 rises and returns to the reference voltage V_ref using the surplus output of the fuel cell system 40. In this way, the control device 70 can restore the voltage of the power storage device 50 to the reference voltage V_ref at time t43 while reducing the output of the fuel cell system 40 to the changed demand on the demand side.

[0113] Thereafter, in the section from time t43 to time t44, the demand side request, the load of the power conversion device 60, the output of the fuel cell system 40, and the voltage of the power storage device 50 are in the same state as in the section from time t23 to time t24 in FIG.

[0114] Thereafter, in the section from time t44 to time t45, the demand side demand continues to be kept constant at a relatively low state. In this section, the control device 70 controls the load of the power conversion device 60 to be in a state corresponding to the demand side demand. Meanwhile, the control device 70 detects the increase in the demand side demand at time t45 in advance, and in this section, increases the output of the fuel cell system 40 to a state higher than the demand side demand in advance in response to the increase in the demand side demand at time t45. As a result, in this section, the power storage device 50 is charged in a manner that absorbs the surplus of the output of the fuel cell system 40, and the voltage of the power storage device 50 increases to a state higher than the reference voltage V_ref. The degree of increase in the output of the fuel cell system 40 in this section can be appropriately controlled within a range smaller than the degree of increase in the demand side demand at time t45. For example, the control device 70 adjusts the degree of increase in the output of the fuel cell system 40 so that the amount of increase in the voltage of the power storage device 50 in this section is relatively small with respect to a predetermined reference.

[0115] At time t45, the demand side demand rises instantaneously from a relatively low state to a relatively high state, and in the section from time t45 to time t46, the demand side demand remains constant at a relatively high state.

[0116] In the period from time t45 to time t46, the control device 70 increases the output of the fuel cell system 40 to a state corresponding to the changed demand on the demand side. At that time, the control device 70 controls the rate of increase in the output of the fuel cell system 40 so that the voltage of the power storage device 50 drops to and returns to the reference voltage V_ref due to the shortfall in the output of the fuel cell system 40. In this way, the control device 70 can increase the output of the fuel cell system 40 to the changed demand on the demand side, while at time t46 restoring the voltage of the power storage device 50 to the reference voltage V_ref.

[0117] In this way, the control device 70 detects a change in the demand side requirement in advance, and changes the output of the fuel cell system 40 in advance in accordance with the direction of the change in the demand side requirement in response to the change in the demand side requirement. Then, when the change in the demand side requirement occurs, the control device 70 changes the output of the fuel cell system 40 to a state corresponding to the changed demand on the demand side so that the SOC of the power storage device 50 returns to the reference value. In this way, the control device 70 can optimize the change in the SOC of the power storage device 50 accompanying the change in the demand side requirement, and suppress the fluctuation range of the SOC of the power storage device 50 from the reference value to a small value. Therefore, the control device 70 can more appropriately suppress the occurrence of overcharging and overdischarging of the power storage device 50. For example, when the power supply system 30 includes a plurality of fuel cell systems 40, the surplus or shortage of the output of the fuel cell system 40 accompanying the delay in the change in the output of the fuel cell system 40 in response to the change in the demand side requirement may be accumulated and become relatively large. As a result, the possibility of overcharging and overdischarging of the power storage device 50 becomes relatively high. In contrast, the control method of this embodiment can appropriately suppress the occurrence of overcharging and over-discharging of the power storage device 50, even when multiple fuel cell systems 40 are provided. In addition, for example, since there is less need to make the capacity of the power storage device 50 relatively large in order to suppress the occurrence of overcharging and over-discharging of the power storage device 50, it is possible to suppress a situation in which costs would increase in the future.

[0118] <Method of detecting changes in demand side requirements> The controller 70 detects changes in demand side demand in advance based on information about the demand side demand.

[0119] For example, the control device 70 detects changes in demand side requirements in advance by acquiring information representing a schedule or plan for the most recent changes in demand side requirements, which is input from a specified external device that manages demand side requirements.

[0120] The controller 70 may also detect changes in demand side demand in advance by predicting demand side demand based on information regarding demand side demand.

[0121] For example, the control device 70 predicts future demand-side requirements based on information about plans for operation of equipment such as production facilities on the demand side that receive power from the AC power system 10. Information about plans for operation of the equipment may include, for example, information about plans for the types of products to be produced by the target equipment and information about plans for the production volume to be produced by the target equipment. This allows the control device 70 to predict future demand-side requirements by capturing, for example, the timing of switching the production volume or type of product.

[0122] The control device 70 may also predict demands on the demand side based on time series data of information on past demands on the demand side. Specifically, the control device 70 may predict future demands on the demand side from information on events that will affect current and immediate future demands on the demand side by statistically capturing the relationship with events that will affect the demand side based on the time series data of past demands on the demand side. Events that will affect the demand side demands include time positions in time cycles such as a time period in a day, a day in a week, a time position in a month (e.g., the first, middle, last, end of the month, etc.), and a time position in a year (e.g., a month, a season, etc.). Events that will affect the demand side demands may also include environmental conditions such as temperature, humidity, and weather in which equipment such as production facilities on the demand side is used. Events that will affect the demand side demands may also include the operating status of target equipment such as production facilities that receive power from the AC power system 10 and events related to the operating status. Events related to the operating status of equipment include, for example, the type and production volume of products produced by the equipment. The control device 70 may also use a trained model obtained by supervised learning using training data that is a combination of data on past demand-side demands and data on events that affect the demand-side demands. This allows the control device 70 to obtain prediction results for future demand-side demands from the trained model using information on events that affect current and near future demands as input. In this case, the trained model is obtained by applying a known algorithm such as deep learning and adjusting the weights of artificial neurons in a direction that reduces the error between the training data (correct answer data) and the output of the trained model using an error backpropagation method.

[0123] <Control flow> FIG. 11 is a flowchart illustrating a fourth example of a process related to control of the power supply system 30 in response to a change in demand side requirements.

[0124] 11, in step S402, the control device 70 determines whether the demand side demand has changed based on an input representing the demand side demand from the outside. If the demand side demand has changed, the process proceeds to step S414, and if not, the process proceeds to step S404.

[0125] In step S404, the control device 70 predicts the demand side request after the lapse of the most recent predetermined period of time. The predetermined period of time corresponds to the period from time t41 to time t42 in FIG.

[0126] When the process of step S404 is completed, the control device 70 proceeds to step S406.

[0127] In step S406, the control device 70 judges whether the prediction result in step S404 represents a change in the demand side demand after a predetermined period has elapsed. If the prediction result in step S404 represents a change in the demand side demand after a predetermined period has elapsed, the control device 70 proceeds to step S408, otherwise, the control device 70 ends the processing of this flowchart.

[0128] In step S408, the control device 70 outputs an output command to the fuel cell system 40 to change the output of the fuel cell system 40 in the same direction (decrease or increase) as the predicted result of the change in the demand side requirement. For example, the control device 70 outputs an output command to the fuel cell system 40 to change the output of the fuel cell system 40 by a predetermined amount that is set within a range smaller than the predicted amount of change in the demand side requirement.

[0129] This allows the control device 70 to change the output of the fuel cell system 40 in advance in the same direction as the change in demand side requirements.

[0130] When the process of step S408 is completed, the control device 70 proceeds to step S410.

[0131] In step S410, the control device 70 controls the output of the fuel cell system 40, and adjusts the output of the fuel cell system 40 by a predetermined amount in the same direction as the demand side requirement within a predetermined period of time, while adjusting the fluctuation range of the voltage of the storage device 50 within a standard range.

[0132] When the process of step S410 is completed, the control device 70 proceeds to step S412.

[0133] In step S412, the control device 70 determines whether the demand side request has changed within a predetermined period before or after the timing predicted in the process of step S404. If the demand side request has changed as predicted, the control device 70 proceeds to step S414, otherwise proceeds to step S416.

[0134] In step S414, the control device 70 outputs a load command to the power conversion device 60 to bring the load of the power conversion device 60 into a state corresponding to the changed demand side request.

[0135] When the process of step S414 is completed, the control device 70 proceeds to step S416.

[0136] In step S416, the controller 70 outputs an output command to the fuel cell system 40 to bring the output of the fuel cell system 40 into a state corresponding to the changed demand side requirement.

[0137] When the process of step S416 is completed, the control device 70 proceeds to step S418.

[0138] In step S418, the control device 70 controls the output of the fuel cell system 40 and adjusts the deviation between the voltage of the power storage device 50 and the reference voltage V_ref to zero.

[0139] In this way, the control device 70 can change the output of the fuel cell system 40 to a state corresponding to the changed demand on the demand side, while changing the voltage of the power storage device 50 to return to the reference voltage V_ref. Furthermore, when the demand on the demand side does not change as predicted, the control device 70 can change the output of the fuel cell system 40 to return to a state corresponding to the demand on the demand side, while changing the voltage of the power storage device 50 to return to the reference voltage V_ref.

[0140] When the process of step S418 is completed, the control device 70 ends the process of this flowchart.

[0141] [Method of controlling power supply system during refresh operation of fuel cell system] Next, a method for controlling the power supply system 30 during the refresh operation of the fuel cell system 40 will be described with reference to FIGS.

[0142] The refresh operation of the fuel cell system 40 refers to a series of operations in which the fuel cell system 40 is restarted after being stopped, and in conjunction with the restart, a refresh process is performed on the fuel cell 41A of the fuel cell module 41. The refresh process on the fuel cell 41A is a known process that adjusts the cathode potential of the fuel cell 41A and removes an oxide film from the catalyst surface to restore power generation performance.

[0143] In the following, the control method according to this embodiment will be described only in the case where the power supply system 30 includes a plurality of fuel cell systems 40.

[0144] <Comparative Example> Fig. 12 is a time chart illustrating a comparative example of a control method for the power supply system 30 during refresh operation of the fuel cell system 40. Specifically, Fig. 12 includes Fig. 12A showing the time changes in the demand side request, the load of the power conversion device 60, the output of the fuel cell system 40 that is the target of the refresh operation, and the output of the fuel cell system 40 that is not the target of the refresh operation during the refresh operation of the fuel cell system 40, and Fig. 12B showing the time changes in the voltage of the power storage device 50.

[0145] In the following description, the subject of the control method according to the comparative example will be referred to as a "control device" without a reference symbol. In the comparative example, a case will be described in which the power supply system 30 includes only two fuel cell systems 40. The same applies to the embodiment of FIG. 13 described below.

[0146] In Fig. 12A, in order to eliminate overlapping of the time charts of the demand side request, the load of the power conversion device 60, and the output of the fuel cell system 40 that is the target of the refresh operation and that is not the target of the refresh operation, the values ​​are shifted even if they have the same value at the same time. The same applies to Fig. 13A described below.

[0147] 12A, in the section from before time t51 to time t54, the demand side demand is maintained at a constant state. In addition, in this section, the control device maintains the load of the power conversion device 60 at a constant state corresponding to the demand side demand.

[0148] Before time t51, the control device controls the outputs of the two fuel cell systems 40 so that they are equal to each other and the sum of the outputs corresponds to the demand on the demand side.

[0149] Thereafter, at time t51, the control device stops the fuel cell system 40 that is the target of the refresh operation and starts the refresh operation of that fuel cell system 40. At that time, the control device increases the output of the fuel cell system 40 that is not the target of the refresh operation in accordance with the drop in output of the fuel cell system 40 that is the target of the refresh operation due to the stop of the fuel cell system 40 that is the target of the refresh operation, and maintains a state in which the sum of both outputs matches the demand side requirements. Then, when the output of the fuel cell system 40 that is the target of the refresh operation drops to zero, the control device transitions the output of the fuel cell system 40 that is not the target of the refresh operation to a state that corresponds to the demand side requirements and maintains that state.

[0150] Thereafter, at time t52, the control device restarts the fuel cell system 40 that is the subject of the refresh operation, and in conjunction with the restart, performs a refresh process on the fuel cell 41A. At that time, the control device reduces the output of the fuel cell system 40 that is not the subject of the refresh operation in accordance with the increase in output of the fuel cell system 40 that is the subject of the refresh operation in response to the restart, and maintains a state in which the sum of the outputs of both systems matches the demand side requirements. Then, at time t53, when the restart of the fuel cell system 40 that is the subject of the refresh operation is completed, the control device realizes a state in which the outputs of the two fuel cell systems 40 are the same and the sum matches the demand side requirements.

[0151] As shown in FIG. 12B, in the section from before time t51 to time t52, the voltage of the power storage device 50 is maintained at the reference voltage V_ref.

[0152] Thereafter, at time t52, in response to restarting the fuel cell system 40 that is the target of the refresh operation, power for operating the auxiliaries of the fuel cell system 40 that is the target of the refresh operation is supplied from the power storage device 50. Therefore, after time t52, the voltage of the power storage device 50 drops to a state lower than the reference voltage V_ref. The auxiliaries of the fuel cell system 40 include, for example, devices such as valves and pumps in a cooling circuit for cooling the fuel cell 41A, devices such as valves in a path that supplies hydrogen to the fuel cell 41A, and devices such as valves and compressors in a path that supplies air to the fuel cell 41A.

[0153] Starting from time t53, the control device increases the outputs of the two fuel cell systems 40 to a state where the outputs are the same and the sum is higher than the demand side requirement. As a result, the surplus of the outputs of the two fuel cell systems 40 is charged to the power storage device 50, and the voltage of the power storage device 50 changes from a decrease to an increase. When the voltage of the power storage device 50 starts to increase, the control device gradually decreases the outputs of the two fuel cell systems 40 to a state where the outputs are the same and the sum is higher than the demand side requirement. Then, at the timing when the voltage of the power storage device 50 reaches the reference voltage V_ref, the control device returns the outputs of the two fuel cell systems 40 to a state where the outputs are the same and the sum matches the demand side requirement. As a result, the voltage of the power storage device 50 can be returned to the reference voltage V_ref.

[0154] However, since the voltage of the power storage device 50 drops from the reference voltage V_ref in accordance with the start of the fuel cell system 40 to be refreshed, the fluctuation range (amount of drop) of the voltage of the power storage device 50 with respect to the reference voltage V_ref is relatively large. Therefore, for example, when the capacity of the power storage device 50 is relatively small, the voltage of the power storage device 50 may drop to a state relatively low with respect to the lower limit voltage V_lim1, and over-discharge of the power storage device 50 may occur. In particular, when the power supply system 30 includes three or more fuel cell systems 40, two or more fuel cell systems 40 may require refresh operation at similar timing, and as a result, the possibility of over-discharging of the power storage device 50 becomes even higher. In addition, it is possible to prevent the voltage of the power storage device 50 from dropping to a state relatively low with respect to the lower limit voltage V_lim1 by making the capacity of the power storage device 50 relatively large, but this may lead to an increase in the cost of the power storage device 50. In particular, when the power supply system 30 includes three or more fuel cell systems 40, there is a possibility that two or more fuel cell systems 40 require refresh operation at similar times, which may result in the required capacity of the power storage device 50 becoming very large.

[0155] <Control method overview> Fig. 13 is a time chart illustrating an example of a method for controlling the power supply system 30 during refresh operation of the fuel cell system 40. Specifically, Fig. 13 includes Fig. 13A showing the time changes in the demand side request during refresh operation of the fuel cell system 40, the load of the power conversion device 60, the output of the fuel cell system 40 that is the target of the refresh operation, and the output of the fuel cell system 40 that is not the target of the refresh operation, and Fig. 13B showing the time change in the voltage of the power storage device 50.

[0156] The following description will focus on the differences from the above-mentioned comparative example, and description of the same contents as the above-mentioned comparative example may be omitted.

[0157] 13A, the demand side demand is maintained at a constant state in the section from before time t55 to time t59. Also, in this section, the control device 70 maintains the load of the power conversion device 60 at a constant state corresponding to the demand side demand.

[0158] The outputs of the two fuel cell systems 40 before time t55 and immediately after time t55 (i.e., immediately after the start of the refresh operation of the fuel cell system 40) are the same as the states before time t51 and immediately after time t51 in the comparative example described above (Figure 12).

[0159] At time t56 while the fuel cell system 40 subject to the refresh operation is stopped, the control device 70 increases the output of the fuel cell system 40 not subject to the refresh operation to a state higher than the demand side request, and then maintains a constant state. As a result, the surplus of the output of the fuel cell system 40 not subject to the refresh operation is charged to the power storage device 50, and the voltage of the power storage device 50 increases to a state higher than the reference voltage V_ref.

[0160] Then, at time t57, the control device 70 restarts the fuel cell system 40 that is the target of the refresh operation, and in conjunction with the restart, causes the refresh process of the fuel cell 41 A to be carried out. Then, at time t58, the output of the fuel cell system 40 reaches the level before the shutdown, i.e., half the demand on the demand side, and the start-up of the fuel cell system 40 is completed.

[0161] In the section from time t57 to time t58, power is supplied from the power storage device 50 to operate the auxiliary devices of the fuel cell system 40 that is the target of the refresh operation. Therefore, in this section, the voltage of the power storage device 50 drops from a state higher than the reference voltage V_ref to near the reference voltage V_ref.

[0162] In the section from time t58 to time t59, the control device 70 controls the outputs of the two fuel cell systems 40 so that the voltage of the power storage device 50 converges to the reference voltage V_ref.

[0163] After time t58, the voltage of the power storage device 50 continues to decrease due to the influence of the power supply to the auxiliary equipment of the fuel cell system 40 that is the target of the refresh operation, and the voltage of the power storage device 50 decreases to a state lower than the reference voltage V_ref. In response to this, the control device 70 controls the outputs of the two fuel cell systems 40 so that the sum of the outputs is higher than the demand side requirement. As a result, the voltage of the power storage device 50 changes from decreasing to increasing around the middle between time t58 and time t59. Thereafter, the control device 70 gradually decreases the outputs of the two fuel cell systems 40 so that they both converge to half the demand side requirement, thereby adjusting the increase in the voltage of the power storage device 50. Then, at time t59, the outputs of the two fuel cell systems 40 both reach half the demand side requirement, and the voltage of the power storage device 50 reaches the reference voltage V_ref.

[0164] In this way, before starting one of the fuel cell systems 40 in the refresh operation, the control device 70 increases the output of the other fuel cell systems 40 that are not the target of the refresh operation above the state corresponding to the demand side request. This allows the control device 70 to increase the voltage of the power storage device 50 to a state higher than the reference voltage V_ref. That is, the control device 70 can increase the SOC of the power storage device 50 to a state higher than the reference value. Therefore, even if the power storage device 50 is discharged for the operation of the auxiliary equipment when the target fuel cell system 40 in the refresh operation is started, it is possible to prevent a situation in which the SOC of the power storage device 50 drops significantly from the reference value. Therefore, the control device 70 can prevent the over-discharge of the power storage device 50 of the fuel cell system 40 and also prevent an increase in the capacity of the power storage device 50, and as a result, can prevent an increase in costs.

[0165] <Control flow> FIG. 14 is a flowchart showing an example of a process related to the control of the power supply system 30 during the refresh operation of the fuel cell system 40.

[0166] 14 is executed when starting a refresh operation of the fuel cell system 40. At this time, the fuel cell system 40 to be subjected to the refresh operation may be one or two or more fuel cell systems 40 that are part of all the fuel cell systems 40 included in the power supply system 30.

[0167] In step S502, the control device 70 outputs an output command to the fuel cell systems 40 that are not the target of the refresh operation so as to bring the total output of the fuel cell systems 40 that are not the target of the refresh operation into a state that matches the demand side request. When there are multiple fuel cell systems 40 that are not the target of the refresh operation, the outputs of the fuel cell systems 40 may be the same as each other, or at least a part of the outputs may be different.

[0168] As a result, only the fuel cell system 40 that is not the target of the refresh operation can output power to the AC power system 10 in response to the demand side request.

[0169] When the process of step S502 is completed, the control device 70 proceeds to step S504.

[0170] In step S504, the control device 70 determines whether a predetermined timing has arrived before the start-up of the fuel cell system 40 that is the target of the refresh operation. The predetermined timing corresponds to time t56 in Fig. 13, and may be a timing that precedes the start-up timing of the fuel cell system 40 that is the target of the refresh operation by a certain time (corresponding to the section between times t56 and t57 in Fig. 13). If the predetermined timing has arrived, the control device 70 proceeds to step S506, and if the predetermined timing has not arrived, the control device 70 repeats this process until the predetermined timing arrives.

[0171] In step S506, the control device 70 outputs an output command to the fuel cell systems 40 that are not the target of the refresh operation to bring the total output of the fuel cell systems 40 that are not the target of the refresh operation into a predetermined state that exceeds the demand side requirement. At this time, the control device 70 may increase the output of all of the fuel cell systems 40 that are not the target of the refresh operation so that the total output exceeds the demand side requirement, or may satisfy that condition by increasing the output of some of them.

[0172] As a result, the power storage device 50 is charged with the total surplus of the outputs of the fuel cell systems 40 that are not subject to the refresh operation, and the SOC of the power storage device 50 can be increased to a state higher than the reference value.

[0173] When the process of step S506 is completed, the control device 70 proceeds to step S508.

[0174] In step S508, the control device 70 determines whether or not the start-up of the fuel cell system 40 that is the target of the refresh operation has been completed. If the start-up of the fuel cell system 40 that is the target of the refresh operation has been completed, the control device 70 proceeds to step S510, and if not, repeats this process until it is completed.

[0175] In step S510, the control device 70 outputs an output command to all the fuel cell systems 40 included in the power supply system 30 so that the sum of the outputs of all the fuel cell systems 40 corresponds to the demand side requirements. At this time, the outputs of all the fuel cell systems 40 included in the power supply system 30 may be the same as each other, or at least some of them may be different.

[0176] When the process of step S510 is completed, the control device 70 proceeds to step S512.

[0177] In step S512, the control device 70 controls the output of the fuel cell system 40 and adjusts the deviation between the voltage of the power storage device 50 and the reference voltage V_ref to zero. At this time, the fuel cell systems 40 to be controlled may be all of the fuel cell systems 40 included in the power supply system 30, or may be some of the fuel cell systems 40.

[0178] When the process of step S512 is completed (specifically, when the voltage of the power storage device 50 converges to the reference voltage V_ref), the control device 70 ends the process of this flowchart.

[0179] [Other embodiments] Next, another embodiment will be described.

[0180] The above-described embodiment may be modified or altered as appropriate.

[0181] For example, in the above-described embodiment (third example of a method for controlling the power supply system 30 in response to changes in demand side requirements), the control device 70 may adjust the voltage (SOC) of the power storage device 50 by controlling the load of the power conversion device 60 instead of controlling the output of the fuel cell system 40.

[0182] Furthermore, in the above embodiment (fourth example of the method for controlling the power supply system 30 in response to a change in demand-side requirements), the control device 70 may adjust the voltage (SOC) of the power storage device 50 by controlling the load of the power conversion device 60 instead of or in addition to the output of the fuel cell system 40, as in the above third example and its modified and altered examples. In this case, when the control device 70 detects a change in the demand-side requirements, it may control the output of the fuel cell system 40 if the degree of the predicted change is relatively small with respect to a predetermined standard, and may control both the output of the fuel cell system 40 and the load of the power conversion device 60 if the degree of the predicted change is relatively large.

[0183] Furthermore, in the above-described embodiment and its modified and altered examples, the total output of all fuel cell systems 40 may exceed the demand side requirement by increasing the output of some or all of the fuel cell systems 40 included in the power supply system 30 before the start of the refresh operation of the fuel cell systems 40. This allows the control device 70 to increase the SOC of the power storage device 50 above the reference value before the start of the refresh operation of the fuel cell systems 40. In this case, the fuel cell systems 40 whose output is to be increased may include the fuel cell system 40 that is the target of the refresh operation.

[0184] In the above-described embodiment and its modified examples, a function for detecting changes in demand-side requirements in advance may be combined with the control of the power supply system 30 during the refresh operation. For example, when the control device 70 detects changes in demand-side requirements before, during, or after the refresh operation of the fuel cell system 40, the control device 70 adjusts the output of the fuel cell system 40 in consideration of both an increase or decrease in the SOC of the power storage device 50 due to the changes in demand-side requirements and a decrease in the SOC of the power storage device 50 due to the restart of the fuel cell system 40 that is the target of the refresh operation. In this case, the adjustment of the output of the fuel cell system 40 is performed before the restart of the fuel cell system 40 that is the target of the refresh operation and before the timing of the change in demand-side requirements. This allows the control device 70 to adjust the voltage (SOC) of the power storage device 50 in advance in response to both the changes in demand-side requirements and the restart of the fuel cell system 40 that is the target of the refresh operation. [Effect] Next, the operation of the power supply system, the control device, and the control method according to the present embodiment will be described.

[0185] In a first aspect of this embodiment, the power supply system includes a fuel cell, a power storage device, a power conversion device, and a control device. The power supply system is, for example, the power supply system 30 described above. The fuel cell is, for example, the fuel cell system 40 described above. The power storage device is, for example, the power storage device 50 described above. The power conversion device is, for example, the power conversion device 60 described above. The control device is, for example, the control device 70 described above. Specifically, the power conversion device is electrically connected to the fuel cell and the power storage device, and is capable of outputting power from at least one of the fuel cell and the power storage device to the demand side. In addition, the control device controls the fuel cell and the power conversion device, and causes the power conversion device to output power corresponding to the demand side request. Then, the control device changes the output of the fuel cell so as to be able to supply power corresponding to the demand side request in response to a relatively fast change in the demand side request with respect to a predetermined standard, and causes the power storage device to perform charging and discharging in response to a delay in the change in the output of the fuel cell in response to the change in the demand side request.

[0186] In addition, a first aspect of this embodiment is a control method in which a control device controls a fuel cell and a power conversion device electrically connected to the fuel cell and the power storage device and capable of outputting power from at least one of the fuel cell and the power storage device to a demand side, and causes the power conversion device to output power according to a demand from the demand side. In this control method, the control device changes the output of the fuel cell in response to a relatively fast change in the demand from the demand side with respect to a predetermined standard so as to be able to supply power corresponding to the demand from the demand side, and causes the power storage device to charge and discharge in response to a delay in the change in the output of the fuel cell in response to the change in the demand from the demand side.

[0187] As a result, the control device can charge the power storage device with the surplus fuel cell output even if, for example, there is a delay in the decrease in the fuel cell output in response to a sudden decrease in demand on the demand side. Also, the control device can discharge the shortage of the fuel cell output from the power storage device to the demand side even if, for example, there is a delay in the increase in the fuel cell output in response to a sudden increase in demand on the demand side. Therefore, the control device can more appropriately supply power from the fuel cell and the power storage device in response to changes in demand on the demand side.

[0188] In addition, in a second aspect of this embodiment, based on the above-mentioned first aspect, the control device may charge and discharge the energy storage device so that the storage state of the energy storage device approaches a reference state after completion of charging and discharging of the energy storage device in response to a delay in the change in the fuel cell output relative to a change in demand on the demand side.

[0189] This enables the control device to prevent a situation in which the charge state of the power storage device deviates significantly from the reference state and falls into an overcharged state or an overdischarged state, and to prevent deterioration of the power storage device.

[0190] Furthermore, in a third aspect of this embodiment, based on the first or second aspect described above, the control device may adjust the output of the fuel cell after completion of charging / discharging of the power storage device in response to a delay in the change in the output of the fuel cell in response to a change in demand on the demand side, thereby causing the power storage device to charge / discharge so that the storage state of the power storage device approaches a reference state while maintaining the supply of power in response to demand from the power conversion device to the demand side.

[0191] As a result, after the power storage device is charged due to a delay in the decrease in the fuel cell output in response to a decrease in the demand-side demand, the control device can discharge the power storage device to bring the power storage state closer to the reference state by decreasing the output of the fuel cell below the demand-side demand. Also, after the power storage device is discharged due to a delay in the increase in the fuel cell output in response to an increase in the demand-side demand, the control device can charge the power storage device to bring the power storage state closer to the reference state by increasing the output of the fuel cell above the demand-side demand.

[0192] Furthermore, in a fourth aspect of this embodiment, based on the second or third aspect described above, the control device may, after completion of charging / discharging of the energy storage device in response to a delay in the change in the output of the fuel cell in response to a change in demand on the demand side, adjust the output from the power conversion device to the demand side, thereby charging / discharging the energy storage device so that the storage state of the energy storage device approaches a reference state.

[0193] As a result, the control device can increase the output from the power conversion device to the demand side after the power storage device is charged due to a delay in the decrease in the output of the fuel cell in response to a decrease in the demand side demand, thereby discharging the power storage device and bringing the power storage state closer to the reference state. Also, the control device can reduce the output from the power conversion device to the demand side after the power storage device is discharged due to a delay in the increase in the output of the fuel cell in response to an increase in the demand side demand, thereby charging the power storage device with the output of the fuel cell and bringing the power storage state closer to the reference state.

[0194] In addition, in a fifth aspect of this embodiment, based on the first to fourth aspects described above, the control device may detect a change in demand on the demand side in advance and, in response to the change in demand on the demand side, change the output of the fuel cell in advance so as to be able to supply power corresponding to the demand on the demand side.

[0195] This allows the control device to change the output of the fuel cell before the demand side requirements change, thereby improving the ability of the control device to change the output of the fuel cell to follow changes in the demand side requirements.

[0196] In addition, in a sixth aspect of this embodiment, based on the above-mentioned fifth aspect, the control device may detect a change in demand side demand in advance based on information input from the demand side indicating the timing of the change in demand side demand.

[0197] This allows the control device to detect changes in demand side requirements in advance.

[0198] In addition, in a seventh aspect of this embodiment, based on the above-mentioned fifth aspect, the control device may detect changes in demand side demand in advance by predicting future demand side demand based on information regarding the demand side demand.

[0199] This allows the control device to detect changes in demand side requirements in advance.

[0200] In addition, in an eighth aspect of this embodiment, on the premise of the above-mentioned seventh aspect, the control device may predict future demands on the demand side based on information related to operation plans of equipment on the demand side.

[0201] This allows the controller to predict changes in demand side requirements.

[0202] In addition, in a ninth aspect of the present embodiment, on the premise of the above-mentioned seventh aspect, the control device may predict future demand side demands based on time-series data of information regarding past demand side demands.

[0203] This allows the controller to predict changes in demand side requirements.

[0204] In addition, in a tenth aspect of this embodiment, on the premise of the above-mentioned first to ninth aspects, a plurality of fuel cells may be provided.

[0205] For example, when the power storage device is charged or discharged in response to a delay in the change in output of the multiple fuel cells, the change in the power storage device's power storage state may be relatively large, and as a result, the charge state of the power storage device may deviate significantly from the reference state. In response to this, the control device can, for example, as described above, charge or discharge the power storage device so as to bring the power storage device's power storage state closer to the reference state, thereby suppressing the occurrence of overcharging or overdischarging of the power storage device.

[0206] Furthermore, in an eleventh aspect of this embodiment, based on the above-mentioned tenth aspect, when the control device performs a refresh operation of one of the plurality of fuel cells, the control device may increase the state of charge of the energy storage device by increasing the output of some or all of the plurality of fuel cells prior to starting up the one fuel cell for the refresh operation.

[0207] This allows the control device to compensate in advance for the power discharged from the power storage device to supply power to the auxiliary devices of the target fuel cell when the fuel cell is started up for refresh operation by charging the power storage device with the increase in output of some or all of the fuel cells. Therefore, the control device can prevent the occurrence of a situation in which the charge state of the power storage device drops relatively significantly from the reference state, and as a result, can prevent over-discharging of the power storage device.

[0208] Furthermore, in a twelfth aspect of this embodiment, based on the above-mentioned eleventh aspect, when the control device performs a refresh operation of one fuel cell, the control device may increase the state of charge of the storage device by increasing the output of the other fuel cell prior to starting up the one fuel cell in the refresh operation.

[0209] This allows the control device to increase the state of charge of the power storage device before starting up the fuel cell that is the target of the refresh operation.

[0210] Furthermore, in a thirteenth aspect of this embodiment, based on the above-mentioned eleventh aspect, when the control device performs a refresh operation of one fuel cell, the control device may increase the state of charge of the fuel cell by increasing the output of the one fuel cell before starting the refresh operation of the one fuel cell.

[0211] This allows the control device to increase the state of charge of the power storage device before starting up the fuel cell that is the target of the refresh operation.

[0212] Although the embodiments have been described in detail above, the present disclosure is not limited to such specific embodiments, and various modifications and variations are possible within the scope of the gist described in the claims. [Explanation of symbols]

[0213] 1. Power System 10 AC power system 20. Transformers 30 Power Supply System 40 Fuel Cell System 41 Fuel Cell Module 41A Fuel Cell 41B Cooling section 41C Converter Device 42 Hydrogen Tank 43 Radiator 44 Heat exchanger 45 Ion Exchanger 46 Air cleaner 50 Energy storage device 55 DC link section 60 Power conversion device 70 Control device CC1,CC2 Cooling circuit

Claims

1. A fuel cell; A power storage device; a power conversion device electrically connected to the fuel cell and the power storage device and capable of outputting electric power of at least one of the fuel cell and the power storage device to a demand side; a control device that controls the fuel cell and the power conversion device and causes the power conversion device to output electric power according to a request from the demand side; the control device changes the output of the fuel cell in response to a relatively fast change in the demand on the demand side with respect to a predetermined standard so as to be able to supply power corresponding to the demand on the demand side, and causes the power storage device to perform charging and discharging in response to a delay in a change in the output of the fuel cell in response to a change in the demand on the demand side. Power supply system.

2. the control device causes charging and discharging of the power storage device to be performed so that the charge state of the power storage device approaches a reference state after charging and discharging of the power storage device is completed in response to a delay in a change in the output of the fuel cell in response to a change in the demand side requirement. The power supply system according to claim 1 .

3. the control device adjusts the output of the fuel cell after completion of charging and discharging of the power storage device in response to a delay in a change in the output of the fuel cell in response to a change in the demand on the demand side, thereby charging and discharging the power storage device so that the storage state of the power storage device approaches the reference state while maintaining a supply of power in response to the demand from the power conversion device to the demand side. The power supply system according to claim 2 .

4. the control device, after completion of charging and discharging of the power storage device in response to a delay in a change in the output of the fuel cell in response to a change in a demand on the demand side, adjusts an output from the power conversion device to the demand side, thereby charging and discharging the power storage device so that the storage state of the power storage device approaches the reference state. The power supply system according to claim 2 .

5. the control device detects a change in the demand of the demand side in advance, and changes the output of the fuel cell in advance in response to the change in the demand of the demand side so as to be able to supply electric power corresponding to the demand of the demand side; The power supply system according to claim 1 .

6. The control device detects a change in the demand on the demand side in advance based on information indicating a timing of the change in the demand on the demand side input from the demand side. The power supply system according to claim 5 .

7. The control device predicts future demand on the demand side based on information on the demand side demand, thereby detecting a change in the demand on the demand side in advance. The power supply system according to claim 5 .

8. The control device predicts future demands on the demand side based on information regarding plans for operation of the demand side equipment. The power supply system according to claim 7.

9. The control device predicts future demands on the demand side based on time series data of information related to past demands on the demand side. The power supply system according to claim 7.

10. A fuel cell system comprising: The power supply system according to any one of claims 1 to 9.

11. when performing a refresh operation of one of the plurality of fuel cells, the control device increases an output of a part or all of the plurality of fuel cells before starting up the one of the fuel cells in the refresh operation, thereby increasing a state of charge of the power storage device; The power supply system according to claim 10.

12. when performing a refresh operation of one of the fuel cells, the control device increases the output of the other fuel cell before starting up the one of the fuel cells in the refresh operation, thereby increasing the state of charge of the power storage device; The power supply system according to claim 11.

13. when performing a refresh operation on one of the fuel cells, the control device increases the output of the one of the fuel cells before starting the refresh operation on the one of the fuel cells, thereby increasing the state of charge of the one of the fuel cells; The power supply system according to claim 11.

14. A control device that controls a fuel cell and a power conversion device that is electrically connected to the fuel cell and a power storage device and is capable of outputting power of at least one of the fuel cell and the power storage device to a demand side, and causes the power conversion device to output power in response to a request from the demand side, changing an output of the fuel cell so as to supply electric power corresponding to the demand on the demand side in response to a relatively fast change in the demand on the demand side with respect to a predetermined standard, and causing the power storage device to perform charging and discharging in response to a delay in a change in the output of the fuel cell in response to the change in the demand on the demand side; Control device.

15. A control method comprising: a control device controlling a fuel cell and a power conversion device electrically connected to the fuel cell and a power storage device and capable of outputting power from at least one of the fuel cell and the power storage device to a demand side, and causing the power conversion device to output power in response to a request from the demand side, the method comprising: changing an output of the fuel cell so as to supply electric power corresponding to the demand on the demand side in response to a relatively fast change in the demand on the demand side with respect to a predetermined standard, and causing the power storage device to perform charging and discharging in response to a delay in a change in the output of the fuel cell in response to the change in the demand on the demand side; Control methods.

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