Power supply system for fuel cell, fuel cell system, and power supply method for fuel cell

Abstract

To provide a power supply system for a fuel cell, a fuel cell system, and a power supply method for a fuel cell that allow supply of power for starting up fuel cell devices when an external power source fails.SOLUTION: According to an embodiment, a power supply system for a fuel cell 200 is provided with: a power switching device 20 that can supply power to auxiliary machines 13 of fuel cell devices 10, in any of an external power supply mode of supplying power from an external power source 1, a backup power supply mode of supplying power from a backup power source 2, and an autonomous operation mode of supplying autonomous power of the fuel cell devices 10; and a power control device 100. The power switching device 20 has an external power source changeover switch 33 that switches between the external power supply mode and the backup power supply mode, an autonomous power source changeover switch 35 that switches between the external power supply mode or the backup power supply mode and the autonomous operation mode, and a plurality of switches 30b. The power control device 100 controls the plurality of switches 30b and the fuel cell devices 10 when the external power source 1 fails.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] FIELD Embodiments of the present invention relate to a fuel cell power supply system, a fuel cell system, and a fuel cell power supply method. [Background technology]

[0002] Fuel cells are a clean power source that can convert hydrogen into electricity with high efficiency. They are also useful as a distributed power source in environments where commercial power grids are unavailable.

[0003] For this reason, fuel cells have recently attracted attention and are being widely developed and used. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-110820 Summary of the Invention [Problem to be solved by the invention]

[0005] The operation of a fuel cell requires the operation of auxiliary equipment such as pumps, blowers, and valves. Therefore, the operation of a fuel cell requires power for these auxiliary equipment. Here, the fuel cell and auxiliary equipment are collectively referred to as a fuel cell device.

[0006] For reasons of operating costs, an external power source such as commercial electricity is usually used to power the auxiliary machinery of this fuel cell device, but it is necessary to secure a means and establish a startup method in the event of a power outage of the external power source.

[0007] The problem to be solved by the present invention is to provide a fuel cell power supply system, a fuel cell system, and a fuel cell power supply method that enable power to be supplied to a fuel cell device when an external power source fails. [Means for solving the problem]

[0008] In order to achieve the above-mentioned object, the fuel cell power supply system of this embodiment is a fuel cell power supply system comprising: a power switching device configured to be able to supply AC power to each auxiliary device of a plurality of fuel cell devices in any of the following modes: an external power supply mode in which AC power is received from an external power source and supplied; a backup power supply mode in which AC power is received from a backup power source that replaces the external power source and supplied; and an independent operation mode in which AC power is supplied from independent power from at least one of the plurality of fuel cell devices; and a power supply control device, wherein the power switching device has an external power supply selector switch for switching between the external power supply mode and the backup power supply mode, an independent power supply selector switch for switching between the external power supply mode or the backup power supply mode and the independent operation mode, and a plurality of open / close switches, and the power supply control device controls the plurality of open / close switches of the power switching device and the plurality of fuel cell devices in the event of a power outage of the external power source. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a block diagram showing the configuration of a fuel cell system according to an embodiment; [Figure 2] 1 is a block diagram showing the configuration of a power supply control device of a fuel cell power supply system according to an embodiment; [Figure 3] 10 is a diagram showing an example of a priority setting table used by a fuel cell device priority setting unit in a power supply control device of a fuel cell power supply system according to an embodiment; FIG. [Figure 4] FIG. 10 is a flow chart showing the procedure in the case of a power outage during FC operation in the fuel cell power supply method according to the embodiment. [Figure 5] FIG. 10 is a flow chart showing details of the procedure for transitioning to independent operation of the fuel cell device in the case of a power outage during FC operation in a fuel cell power supply method according to an embodiment. [Figure 6]FIG. 10 is a flow chart showing details of the procedure for transitioning to operation of another fuel cell device in the event of a power outage during FC operation in a fuel cell power supply method according to an embodiment. [Figure 7] FIG. 10 is a block diagram showing the state of an external power supply mode, which is the initial state in the case of a power outage during FC operation, in the fuel cell power supply method according to the embodiment. [Figure 8] FIG. 10 is a block diagram showing the state of an independent power supply mode in which the transition to independent operation of the fuel cell device has been completed in the case of a power outage during FC operation in a fuel cell power supply method according to an embodiment. [Figure 9] FIG. 10 is a block diagram showing the state of an independent power supply mode in which the transition to operation of another fuel cell device has been completed during independent operation of the fuel cell device in the case of a power outage during FC operation in a fuel cell power supply method according to an embodiment. [Figure 10] FIG. 10 is a flow chart showing the procedure in the case of a power outage while the FC is stopped in the fuel cell power supply method according to the embodiment. [Figure 11] FIG. 10 is a block diagram showing an initial state in the case of a power outage while the FC is stopped in the fuel cell power supply method according to the embodiment. [Figure 12] FIG. 10 is a block diagram showing a state of a backup power supply mode in which power is received from a backup power source in the case of a power outage during FC operation in a fuel cell power supply method according to an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, a power supply switching device, a fuel cell system, and a power supply switching method according to embodiments of the present invention will be described with reference to the drawings. Hereinafter, identical or similar parts will be denoted by common reference numerals, and overlapping descriptions will be omitted.

[0011] FIG. 1 is a block diagram showing the configuration of a fuel cell system 300 according to an embodiment.

[0012] The fuel cell system 300 includes a plurality of fuel cell devices 10 and a fuel cell power supply system 200. The fuel cell power supply system 200 includes a power switching device 20 and a power supply control device 100.

[0013] <Fuel cell device 10> The fuel cell device 10 is a collective term for a first fuel cell device 10a, a second fuel cell device 10b, a third fuel cell device 10c, a fourth fuel cell device 10d, and a fifth fuel cell device 10e. Although Fig. 1 shows an example in which five fuel cell devices 10 are provided, any number of fuel cell devices may be provided as long as there is more than one.

[0014] Each fuel cell device 10 has a fuel cell stack (FC) 11, a power conditioner (PCS) 12, accessories 13, and an internal control unit (not shown). In Fig. 1, only the first fuel cell device 10a is shown with the reference numerals (11, 12, 13) for these components, but the second fuel cell device 10b through the fifth fuel cell device 10e also have these components.

[0015] The FC11 is an assembly of stacked fuel cells electrically connected in series. Each fuel cell that makes up the FC11 generates DC power by receiving a supply of raw gas, i.e., an oxidizing gas (such as air) containing an oxidizing agent such as oxygen, and hydrogen gas.

[0016] The PCS 12 has a DA converter (not shown) that converts the DC power output from the FC 11 into AC power. The PCS 12 also has a system protection function. In grid-connected operation, when the fuel cell device 10 is not in operation, the fuel cell device 10 receives power from the grid.

[0017] The PCS 12 outputs information about the received power to the power supply control device 100. For example, if the power supply from the outside is lost, the power supply to the auxiliary device 13 is also lost, and this information is also output from the internal control unit to the power supply control device 100.

[0018] The accessories 13 are devices that need to be operated for the fuel cell device 10 to generate power. Examples of the accessories 13 include blowers and pumps that are operated to supply hydrogen and oxidizing gas to the FC 11, cool the FC 11, etc. A gas system 15, which serves as a path for transporting these gases, is connected from a gas supply source 15a to each fuel cell device 10. Furthermore, a cooling system 16, which serves as a path for transporting a cooling medium, is connected from each fuel cell device 10 to a cooling source 16a. The accessories 13 also include valves provided on these paths.

[0019] The operating state of FC11 is controlled by the flow rate of the raw material gas supplied to FC11. For example, if the flow rate of the raw material gas becomes zero, FC11 transitions from an operating state to a standby state. Here, the flow rate of the FC11 raw material gas and the flow rate of the cooling medium for each fuel cell device 10 are adjusted by the auxiliary device 13. In addition, the state of the auxiliary device 13, such as the number of revolutions of the blower and the opening and closing of the valves, is controlled by an internal control unit of the device.

[0020] 1 illustrates an example in which each fuel cell device 10 has an auxiliary device 13, but this is not limiting. For example, the fuel cell devices 10 may share some of the auxiliary device 13.

[0021] The DC power generated in each fuel cell device 10 is supplied from the PCS 12 to each FC load 50 either as DC power or as AC power via a DA converter in the PCS 12. That is, the power generated in the first fuel cell device 10a, the second fuel cell device 10b, the third fuel cell device 10c, the fourth fuel cell device 10d, and the fifth fuel cell device 10e is supplied to the first FC load 50a, the second FC load 50b, the third FC load 50c, the fourth FC load 50d, and the fifth FC load 50e, respectively. The FC load 50 is a collective term for the first FC load 50a, the second FC load 50b, the third FC load 50c, the fourth FC load 50d, and the fifth FC load 50e.

[0022] The DC power generated by each fuel cell device 10 is converted to AC power by a DA converter in the PCS 12. This power is used to power the FC load 50 and auxiliary machinery 13 of the fuel cell device 10, in both grid-connected operation and stand-alone operation, described below, except when the fuel cell device 10 is started up.

[0023] <Fuel cell power supply system 200> The power switching device 20 and the power supply control device 100 of the fuel cell power supply system 200 will be described below in order. The power switching device 20 is shown in the area enclosed by the two-dot chain line in FIG.

[0024] <Power switching device 20> The power switching device 20 is a part that constitutes a path for supplying power from a power source to each fuel cell device 10 for operating its auxiliary equipment 13. The power switching device 20 is configured to be able to form paths for power supply from multiple power sources. For this purpose, it has power lines (hereinafter referred to as "lines") that form the paths for power supply, and multiple changeover switches 30a and multiple open / close switches 30b provided on these lines. The open / close switches 30b may be replaced with circuit breakers. The power switching device 20 is provided, for example, in the form of a relay panel or the like.

[0025] 1 shows a case where the power sources are an external power source 1, a backup power source 2, and the independent power of a fuel cell device 10. For ease of explanation, each power source and the power supply mode from that power source will be described first.

[0026] The external power source 1 is, for example, a normally available AC power source such as a commercial power source. Hereinafter, the AC power supplied from the external power source 1 will be referred to as "external power." Furthermore, the configuration of the power switching device 20 when the fuel cell device 10 is operating with external power supply will be referred to as "external power supply mode."

[0027] The backup power source 2 is, for example, power for limited users, such as power from a private power plant or local power. The backup power source 2 may be a power storage device that outputs AC power using a DA converter. The backup power source 2 temporarily replaces the external power source 1. In other words, the fuel cell system 10 is often not a normal load on the backup power source 2. For this reason, the backup power source 2 is a power source that can be used temporarily when there is excess capacity and it is available for use. Hereinafter, the AC power supplied from the backup power source 2 will be referred to as backup power. Furthermore, the configuration of the power switching device 20 when the fuel cell system 10 is operating on backup power supply will be referred to as the backup power supply mode. For example, a contract or agreement may be made with the owner of the backup power source 2 that allows the backup power source 2 to be used for a specified period of time.

[0028] The configuration of the power switching device 20 when at least one fuel cell device 10 is in an independent operation state is referred to as an independent operation mode. Here, independent operation refers to the fuel cell device 10 operating without receiving an external power supply and supplying power to the FC load 50 and auxiliary machinery 13 of the fuel cell device 10. The independent operation mode includes, for example, the case where the first fuel cell device 10a is operating independently, the case where the first fuel cell device 10a is also supplying AC power to other fuel cell devices 10 during independent operation, and the case where either the first fuel cell device 10a or the other fuel cell devices 10 are also operating independently.

[0029] In order to distinguish the external power source 1 and the backup power source 2 from the independent power source, the external power source 1 and the backup power source 2 will be collectively referred to as the non-independent power source 3.

[0030] As described above, the power switching device 20 includes the changeover switch 30a and a plurality of open / close switches 30b.

[0031] The changeover switch 30a has an external power supply changeover switch 33 and an independent power supply changeover switch 35. The changeover switch 30a is, for example, a double-throw type power supply changeover switch such as a double-throw switch (DTSW). The changeover switch 30a switches based on predetermined conditions. Specifically, the changeover switch 30a will not switch to the unconnected side just because the voltage on the unconnected side is secured. The changeover switch 30a will switch to the unconnected side only when the voltage on the connected side is lost and the voltage on the unconnected side is established.

[0032] The open / close switch 30b includes a normal power supply open / close switch 31, a first backup power supply open / close switch 32a, a second backup power supply open / close switch 32b, an independent output switch 34, and a supply switch 37, which will be described later. The open / close switch 30b is a general term for these.

[0033] The open / close switch 30b is, for example, an electromagnetic contactor, and is controlled by the power supply control device 100. That is, depending on whether a control input, which is a command signal from the power supply control device 100, is ON or OFF, the open / close switch 30b is in a closed state (conducting) or an open state (non-conducting), respectively.

[0034] A normal power supply line 21 is provided as a power supply path from the connection point 1a of the power switching device 20 with the external power supply 1, i.e., the joint, to the external power supply changeover switch 33. A normal power supply on / off switch 31 is also provided on the normal power supply line 21. The normal power supply on / off switch 31 may be an air circuit breaker (ACB) with a detector that has a power supply side power outage detection function. A voltmeter 21a is also provided on the normal power supply line 21.

[0035] A backup power supply line 22 is provided as a power supply path from a connection point 2a between the power switching device 20 and the backup power supply, i.e., the joint, to an external power supply selector switch 33. A first backup power supply on / off switch 32a and a second backup power supply on / off switch 32b are provided on the backup power supply line 22. A voltmeter 22a is also provided on the backup power supply line 22.

[0036] Electric power is supplied to the facility loads 5 by branching from the connection point 1a with the external power source 1 and the connection point 2a with the backup power source. The facility loads 5 are various devices within the facility that has the fuel cell system 300.

[0037] The primary contacts of the external power supply changeover switch 33 are connected to the normal power supply line 21 and the backup power supply line 22, and the secondary contacts are connected to the non-independent power supply line 23. The external power supply changeover switch 33 can be switched between three states. Here, the three states are a state in which the normal power supply line 21 and the non-independent power supply line 23 are connected, a state in which the backup power supply line 22 and the non-independent power supply line 23 are connected, and a neutral state in which the non-independent power supply line 23 is not connected to either. Here, the primary side is the upstream side in terms of current flow, and the secondary side is the downstream side in terms of current flow.

[0038] The non-independent power supply line 23 is provided to connect the secondary contact of the external power supply changeover switch 33 and the primary contact of the independent power supply changeover switch 35 .

[0039] The other contact on the primary side of the independent power supply selector switch 35 is connected to the line on the independent operation power supply side. The line on the independent operation power supply side consists of an independent-side power supply line 25 connected to the independent power supply selector switch 35, and independent output lines 24 connecting each fuel cell device 10 to the independent-side power supply line 25. Each independent output line 24 consists of a first independent output line 24a, a second independent output line 24b, a third independent output line 24c, a fourth independent output line 24d, and a fifth independent output line 24e, which connect the first fuel cell device 10a, the second fuel cell device 10b, the third fuel cell device 10c, the fourth fuel cell device 10d, and the fifth fuel cell device 10e to the independent-side power supply line 25, respectively. The independent output line 24 is a collective term for these.

[0040] The first independent output line 24a, the second independent output line 24b, the third independent output line 24c, the fourth independent output line 26d, and the fifth independent output line 24e are provided with the first independent output switch 34a, the second independent output switch 34b, the third independent output switch 34c, the fourth independent output switch 34d, and the fifth independent output switch 34e, respectively, as independent output switches 34. The independent output switch 34 is a general term for these switches.

[0041] The two contacts on the primary side of the independent power supply changeover switch 35 are connected to the non-independent-side power supply line 23 and the independent-side power supply line 25, respectively. The secondary contact of the independent power supply changeover switch 35 is connected to the supply-side line 26. The independent power supply changeover switch 35 can be switched between three states. The three states are a state in which the non-independent-side power supply line 23 and the supply-side line 26 are connected, a state in which the independent-side power supply line 25 and the supply-side line 26 are connected, and a neutral state in which the supply-side line 26 is not connected to either.

[0042] Although the above-described changeover switch 30a, that is, the external power supply changeover switch 33 and the independent power supply changeover switch 35, has a neutral state, it is also possible that the changeover switch does not have a neutral state.

[0043] The supply line 26, which connects to the secondary contact of the independent power supply selector switch 35, branches into supply lines 27 that connect to each fuel cell device 10. More specifically, the supply line 26 branches into a first supply line 27a, a second supply line 27b, a third supply line 27c, a fourth supply line 27d, and a fifth supply line 27e that connect to the first fuel cell device 10a, the second fuel cell device 10b, the third fuel cell device 10c, the fourth fuel cell device 10d, and the fifth fuel cell device 10e, respectively. The supply line 26 is also connected to a system load supply line 27f, which is a power supply line to an FC system load 51, including an emergency load.

[0044] The first supply line 27a, the second supply line 27b, the third supply line 27c, the fourth supply line 27d, the fifth supply line 27e, and the system load supply line 27f are provided with a first supply switch 37a, a second supply switch 37b, a third supply switch 37c, a fourth supply switch 37d, a fifth supply switch 37e, and a system load supply breaker 37f, respectively, as supply switches 37. Supply switch 37 is a general term for these switches.

[0045] <Power supply control device 100> FIG. 2 is a block diagram showing the configuration of the power supply control device 100 of the fuel cell power supply system 200 according to the embodiment.

[0046] The power supply control device 100 includes an input unit 110 , an information acquisition unit 120 , a storage unit 130 , a calculation unit 140 , a progress control unit 150 , and an output unit 160 .

[0047] The power supply control device 100 may be, for example, a computer system or a collection of individual devices. The input unit 110 and the output unit 160 may be, for example, a man-machine interface capable of two-way communication. The power supply for the power supply control device 100 is preferably a power supply that does not depend on external power or an uninterruptible power supply, but may also depend on external power.

[0048] The input unit 110 receives external inputs such as conditions and designated inputs required for the power supply control device 100 to perform control.

[0049] The information acquisition unit 120 includes a fuel cell device operation information acquisition unit 121, a switching device state acquisition unit 122, a power source information acquisition unit 123, and an in-station load information acquisition unit .

[0050] The fuel cell device operation information acquisition unit 121 acquires operation information of each fuel cell device 10. The operation information of the fuel cell device 10 includes power reception information of the PCS 13. Here, the power reception information of the PCS 13 is information regarding the presence or absence of AC power supplied to the PCS 13 and the AC power level. The power reception information of the PCS 13 is sent to the internal control unit, and then sent from the internal control unit to the fuel cell device operation information acquisition unit 121.

[0051] The switching device state acquisition unit 122 acquires switching device state information, which is information relating to the states of the changeover switch 30a and each open / close switch 30b of the power switching device 20. Here, the switching device state information includes information received from the changeover switch 30a and each open / close switch 30b. The switching device state acquisition unit 122 may estimate the final state, i.e., the current state, of the changeover switch 30a and the open / close switch 30b from the history of command output stored in the output history storage unit 133, which will be described later.

[0052] The power supply information acquisition unit 123 acquires power supply information relating to the status of the external power supply 1 and the backup power supply 2. The power supply information includes, for example, the output of the voltmeter 21a on the normal power supply line 21 and the output of the voltmeter 22a on the backup power supply line 22. Alternatively, if a power meter is provided, the power supply information includes the output of the power meter. The power supply information may also be detection information from an air circuit breaker (ACB) with a detector.

[0053] The station load information acquisition unit 124 acquires information relating to the operating state of the station load 5, that is, the load status.

[0054] The storage unit 130 includes a fuel cell device operation record storage unit 131 , a fuel cell to be started storage unit 132 , and an output history storage unit 133 .

[0055] The fuel cell device operation performance memory unit 131 stores operation performance information of each fuel cell device 10. Here, operation performance information is information relating to the time history of the output level of each fuel cell device 10. The operation performance information also includes an integrated value of the output generated by each fuel cell device 10, i.e., an integrated output. Here, the operation performance information is acquired by the fuel cell device operation information acquisition unit 121.

[0056] The startup target fuel cell storage unit 132 stores the startup priority of the other fuel cell devices 10 after the fuel cell device 10 that was operating when the external power source 1 lost power has entered an independent operating state. Also, if all fuel cell devices 10 were stopped before the power outage, it stores the priority of the fuel cell device 10 that should be started after power is restored. Priority information is set by the fuel cell device priority setting unit 141 of the calculation unit 140 and stored in the startup target fuel cell storage unit 132.

[0057] The output history storage unit 133 stores the command signal output from the command signal output unit 161 of the output unit 160 together with the time history.

[0058] The calculation unit 140 includes a fuel cell device priority setting unit 141 , a starting fuel cell device selection unit 142 , and an open / close switch state setting unit 143 .

[0059] The fuel cell device priority setting unit 141 sets the startup priority of the fuel cell devices 10 in the event of a power outage of the external power source 1. The priority setting by the fuel cell device priority setting unit 141 is performed based on information on each fuel cell device 10 (fuel cell device information) and information on the load of each fuel cell device 10 (FC load information).

[0060] The activation fuel cell device selection unit 142 selects the fuel cell device 10 to be activated in an independent operation state based on the priority stored in the activation target fuel cell storage unit 132. Furthermore, it sets the command content to the internal control unit of the fuel cell device 10 to control the fuel cell device 10 to be activated. Here, the command content is, for example, the operating state of the fuel cell device 10, such as starting or stopping the fuel cell device 10, whether or not to output from the fuel cell device 10 to an FC load, or whether or not to perform independent output. Note that if an internal control device is not provided in each fuel cell device 10, it may also be possible to directly control the auxiliary devices 13, such as the number of rotations of a blower, the opening and closing of a valve, etc.

[0061] The open / close switch state setting unit 143 sets command contents for controlling the open / close switch 30b of the power switching device 20. The open / close switch state setting unit 143 has built-in state tables for each open / close switch 30b in each of the external power supply mode, backup power supply mode, and independent operation mode, and derives and sets changes to the state of each open / close switch 30b required as the steps progress. The results are output to the target open / close switch 30b via the command signal output unit 161.

[0062] The progress control unit 150 controls the progress of each flow in the fuel cell power supply method by the fuel cell power supply system 200. At each determination step in these flows, the progress control unit 150 makes the determination unless otherwise specified below. The progress control unit 150 has a built-in time counter. The progress control unit 150 progresses through the steps according to the flows shown in Figures 4 to 6 and 10, which will be described later. That is, at each step, the progress control unit 150 commands the part in the fuel cell power supply system 200 that is to perform the function to perform that function. The progress control unit 150 may be, for example, a programmable logic controller.

[0063] The output unit 160 includes a command signal output unit 161 and an information output unit 162 .

[0064] The command signal output unit 161 outputs a command signal to each open / close switch 30b of the fuel cell power supply system 200 and to the internal control unit of each fuel cell device 10 as a control operation.

[0065] The information output unit 162 outputs information to an operator or manager of the facility including the fuel cell system 300. The information output unit 162 may be configured to include, together with the input unit 110, a device capable of bidirectional information transmission, such as an HMI (Human Machine Interface).

[0066] Fig. 3 is a diagram showing an example of a priority setting table 141a used by the fuel cell device priority setting unit 141 in the power supply control device 100 of the fuel cell power supply system according to the embodiment. Fig. 3 illustrates a case where an integrated output level is used as fuel cell device information and an emergency level is used as FC load information.

[0067] Each vertical row of the priority setting table 141a indicates a grouping based on emergency level. Here, a high emergency level means that an interruption in power supply will have a greater impact on the FC loads 50 of the fuel cell device 10. In other words, an interruption in power supply will have a greater impact on the FC loads 50 in the group with emergency level 4 than on the FC loads 50 in the group with emergency level 1.

[0068] Each horizontal column of the priority setting table 141a indicates a grouping based on the integrated output level. Here, a high integrated output level means that the integrated output of the fuel cell device 10 is large. In other words, the fuel cell device 10 in the group with integrated output level 4 has a larger integrated output than the fuel cell device 10 in the group with integrated output level 1.

[0069] For each fuel cell device 10 and its FC load 50, the cell position in the table is determined by the corresponding emergency level and corresponding integrated power level. The startup priority of that fuel cell device 10 is set according to the priority of that position. For example, if the emergency level is 3 and the integrated power level is 2, the priority is set to B. Priorities are set in this manner. The fuel cell device 10 with priority A has the highest priority, followed by those with priorities B, C, D, E, and F. Note that if there are multiple fuel cell devices 10 with the same priority, the one with the smaller integrated power value has a higher priority. Here, the reason why a group with a smaller integrated power is given a higher priority is because it is preferable for multiple fuel cell devices 10 (10a-10e) to have the same integrated power. This is because replacing all devices at once due to their lifespan reduces the number of shutdowns and improves the availability of the fuel cell system 300 rather than replacing them one by one.

[0070] The fuel cell device priority setting unit 141 sets the priority of each fuel cell device 10 for each predetermined period of time. This is because, for example, different installation environments for each fuel cell device 10 may have different effects on degradation, or the emergency level may change due to a review of the load operation.

[0071] Although the example described above uses an integrated power level as fuel cell apparatus information and an emergency level as FC load information, other parameters may be used. For example, the number of starts and stops may be used as fuel cell apparatus information instead of the integrated power level. Alternatively, the magnitude of the load (kW) may be used as FC load information. Alternatively, the fuel cell apparatus priority setting unit 141 may set priorities using three or all of the integrated power level and number of starts and stops as fuel cell apparatus information and the emergency level and magnitude of the load (kW) as FC load information, rather than using only the two parameters shown in the example.

[0072] 3, the two parameters are each divided into multiple levels, but they may be based on continuous values ​​that are not divided into levels. In this case, multiple fuel cell devices 10 are not classified as having the same priority, and the priority can be uniquely determined.

[0073] <Power supply method for fuel cell device> To operate the fuel cell device 10, the auxiliary equipment 13 of the fuel cell device 10 must be operating while receiving a power supply. Three types of power can be supplied to the auxiliary equipment 13: power from an external power source 1, power from a backup power source 2, and stand-alone power from the fuel cell device 10 itself or another operating fuel cell device 10.

[0074] Power from an external power source 1 such as a commercial power source is considered to be the most cost-effective. On the other hand, a backup power source 2 is a temporary power source and has a capacity limit. For this reason, power to the auxiliary equipment 13 of a fuel cell device 10 is usually supplied from the external power source 1. In other words, the normal state is often when the fuel cell device 10 is operating in grid-connected mode. Therefore, in the following, the normal state is defined as when the fuel cell device 10 is operating in grid-connected mode. Therefore, in the fuel cell power supply method, a problem arises when the power supply from the external power source 1 is stopped, that is, when the external power source 1 experiences a power outage.

[0075] In the case of a power outage of the external power source 1, there are two cases: one in which at least one fuel cell device 10 is in operation immediately before the power outage (power outage during FC operation), and one in which none of the fuel cell devices 10 is in operation (power outage during FC stoppage). The flow of the fuel cell power supply method differs in these two cases. Below, the fuel cell power supply method for the power outage during FC operation will be explained with reference to Figures 4 to 9. Also, the fuel cell power supply method for the power outage during FC stoppage will be explained with reference to Figures 10 to 12.

[0076] Although some terms have already been used, they are defined as follows:

[0077] When a fuel cell device 10 is generating power, the "power generation" means at least the state of outputting to the FC load of the fuel cell device 10. Therefore, in addition to the output to the FC load, it shall also include the case where self-generated power is output by self-sustaining operation.

[0078] When a fuel cell device 10 has completed startup, the "completion of startup" refers to the state of reaching the power generation state.

[0079] When a fuel cell device 10 is in self-sustaining operation, the "self-sustaining operation" means that, as described above, the fuel cell device 10 operates without receiving power supply from the external (non-self-sustaining power source 3) and supplies power (self-generated power) to the FC load 50 and auxiliary equipment 13 of the fuel cell device 10. In the case of a power outage after the non-self-sustaining power source, the self-sustaining output switch 34 of the self-sustaining output line 24 of the fuel cell device 10 is in the ON state. Note that the "self-sustaining operation" shall also include the case where another fuel cell device 10 is in the startup or operating state by the supply of self-generated power from the fuel cell device 10.

[0080] When a fuel cell device 10 is in idle power generation, the "idle operation" means that, in the transition stage to self-sustaining operation, the fuel cell device 10 supplies power to the FC load 50 of the fuel cell device 10 but does not output self-generated power from the fuel cell device 10. That is, in this case, the self-sustaining output switch 34 of the self-sustaining output line 24 of the fuel cell device 10 is not in the ON state but in the open state.

[0081] When a fuel cell device 10 is in grid-connected operation, the "grid-connected operation" means that the fuel cell device 10 operates in a state where power is supplied from an external power source 1 to the fuel cell device 10, that is, in a state of being electrically connected to the power grid of the external power source 1.

[0082] <Procedures in the case of a power outage during FC operation> 4 is a flow diagram showing the procedure for a power outage during FC operation in a fuel cell power supply method according to an embodiment. In this case, the initial state before the power outage of the external power source 1 is that the external power source 1 is alive and at least one fuel cell device 10 is in grid-connected operation. The following description will be given taking as an example a case where only the first fuel cell device 10a is in operation.

[0083] First, the power supply control device 100 determines whether or not the external power supply 1 has experienced a power outage (step S11). More specifically, the power supply information acquisition unit 123 of the power supply control device 100 determines whether or not the external power supply 1 is alive based on the output of the voltmeter 21a on the normal power supply line 21. Alternatively, the power supply information acquisition unit 123 may determine whether or not the external power supply 1 has experienced a power outage based on whether or not power is being supplied to the auxiliary machinery 13 based on the output from the PCS 12 of the fuel cell device 10. Alternatively, the power supply information acquisition unit 123 may make a determination using OR logic of these two pieces of information.

[0084] In step S11, if it is not determined that the external power supply 1 has experienced a power outage (NO in step S11), the progress control unit 150 repeats step S11.

[0085] If it is determined in step S11 that the external power supply 1 has experienced a power outage (step S11: YES), the fuel cell power supply system 200 transitions to independent operation of the fuel cell device 10 (first fuel cell device 10a) (step S30). Details of step S30 will be explained later with reference to FIG.

[0086] Following step S30, the fuel cell power supply system 200 transitions to a state in which other fuel cell devices 10 are also in operation (step S40). Details of step S40 will be explained later with reference to FIG.

[0087] After step S40, the power supply control device 100 determines whether or not power has been restored to the external power supply 1 (step S50). If it is not determined in step S50 that power has been restored to the external power supply 1 (step S50 NO), the progress control unit 150 repeats step S50 at predetermined time intervals.

[0088] If it is determined in step S50 that power has been restored to the external power source 1 (step S50: YES), the fuel cell power supply system 200 transitions to a configuration in which power is received from the external power source 1 (step S60). In particular, the power supply control device 100 turns OFF the first independent output switch 34a of the first independent output line 24a, so that the primary side of the independent power source changeover switch 35 automatically switches from the independent-side power source line 25, where the voltage has dropped, to the non-independent-side power source line 23, where the voltage has been established. As a result, a power feed line is formed in the fuel cell power supply system 200 from the external power source 1 to the first fuel cell device 10a. In other words, the power switching device 20 transitions to a configuration in which the first fuel cell device 10a receives power from the external power source 1, performing grid-connected operation in a normal external power supply mode.

[0089] 5 is a flowchart showing details of the procedure for transitioning the fuel cell device 10 to independent operation in the case of a power outage during FC operation in the fuel cell power supply method according to the embodiment, that is, a flowchart showing details of step S30.

[0090] As described above, the case where the fuel cell device 10 that was initially operating is the first fuel cell device 10a is illustrated, and therefore this fuel cell device 10 will be referred to as the first fuel cell device 10a.

[0091] In step S30, first, the power supply control device 100 issues a close command to turn on the first independent output switch 34a of the first independent output line 24a of the first fuel cell device 10a (step S31). This command is output to the first independent output switch 34a via the command signal output unit 161. As a result, the first independent output switch is turned on, and the first independent output line 24a is brought into a conductive state.

[0092] Next, the power supply control device 100 commands the first fuel cell device 10a to output to the first independent output line 24a via the command signal output unit 161 (step S32). As a result, the first fuel cell device 10a outputs AC power to the first independent output line 24a. This establishes the voltage on one of the independent-side power supply lines 25 on the primary side of the independent power supply selector switch 35.

[0093] On the other hand, when the external power supply 1 is in a power outage state, the voltage of the non-independent power supply line 23, which is the other primary side of the independent power supply changeover switch 35, is zero.

[0094] Therefore, the primary side of the independent power supply changeover switch 35 is automatically switched to the side of the independent-side power supply line 25. As a result, the independent power supply changeover switch 35 is connected to the independent-side power supply line 25 (step S33). That is, the independent-side power supply line 25 and the supply-side line 26 are connected by the independent power supply changeover switch 35, and the first fuel cell device 10a transitions to an independent operation state.

[0095] 6 is a flow diagram showing details of the procedure for transitioning to operation of another fuel cell device 10 in the case of a power outage during FC operation in the fuel cell power supply method according to the embodiment. That is, it is a flow diagram showing details of step S40. The fuel cell device 10 to be started up is determined by the starting fuel cell device selection unit 142 based on the priorities stored and stored in the start-up target fuel cell storage unit 132. The following description will be given taking as an example a case where the other fuel cell devices 10, i.e., the fuel cell devices 10 to be started up, are the second fuel cell device 10b and the third fuel cell device 10c.

[0096] In step S40, the power supply control device 100 issues a command to each of the auxiliary machines 13 of the second fuel cell device 10b and the third fuel cell device 10c to transition to a raw material gas supply state (step S41). As a result, the second fuel cell device 10b and the third fuel cell device 10c transition from a standby state to an idle operation in which they supply power only to their respective FC loads 50, the second FC load 50b and the third FC load 50c.

[0097] The progress control unit 150 determines whether all of the fuel cell devices 10 to be started up have started up (step S42). If the progress control unit 150 does not determine that all of the fuel cell devices 10 to be started up have started up (step S42 NO), step S42 is repeated.

[0098] If it is determined that all of the fuel cell devices 10 to be started have started up (YES in step S42), the power supply control device 100 issues a command to transition the fuel cell devices 10 to independent operation (step S43). Specifically, the power supply control device 100 issues a close command via the command signal output unit 161 to turn on the second independent output switch 34b on the second independent output line 24b and the third independent output switch 34c on the third independent output line 24c. As a result, the second fuel cell device 10b and the third fuel cell device 10c transition to an independent operation state.

[0099] Next, the power supply control device 100 issues a close command to turn on the system load supply circuit breaker 37f of the system load supply line 27f (step S44). As a result, power is also supplied to the FC system load 51.

[0100] FIG. 7 is a block diagram showing the external power supply mode, which is the initial state in the case of a power outage during FC operation in a fuel cell power supply method according to an embodiment. FIG. 7 shows the initial state of the flow diagram shown in FIG. 4. That is, the initial state in the case of a power outage during FC operation is a state in which the first fuel cell device 10a is operating in grid-connected mode, receiving power from the external power source 1. In FIG. 7, the state in which the first fuel cell device 10a is supplying power to the first FC load 50a is indicated by an arrow on the line. Even if current flows from the fuel cell device 10 to the external power source 1 during grid-connected operation, the current is kept within the power value stored in the station load information acquisition unit 124 to prevent reverse power flow to the power grid. This adjustment is performed by the PCS 12 of the first fuel cell device 10a.

[0101] Details of the power switching device 20 in the initial external power supply mode are as follows: The normal power on / off switch 31 of the normal power line 21 is in the ON (closed) state. The external power selector switch 33 is in a state in which it connects the normal power line 21 and the non-independent power line 23. The independent power selector switch 35 is in a state in which it connects the non-independent power line 23 and the supply side line 26. In addition, the supply switches 37 of each supply line 27 are all in the ON (closed) state.

[0102] 8 is a block diagram showing the state of the fuel cell power supply method according to the embodiment, in which the fuel cell device 10 has completed transitioning to independent operation in the case of a power outage during FC operation, in an independent power supply mode. That is, the figure shows the state in which the first fuel cell device 10a is operating independently, using its own power to cover the power of the auxiliary equipment 13.

[0103] In the independent power supply mode, the first independent output switch 34a of the first independent output line 24a is in the ON (closed) state, and the voltage of the independent-side power supply line 25 is established. As a result, the connection state of the independent power supply changeover switch 35 is changed, and the independent-side power supply line 25 and the supply-side line 26 are connected, and independent power is supplied to the first fuel cell device 10a. In Figure 8, the line from the first fuel cell device 10a to the first independent output line 24a is indicated by an arrow.

[0104] 9 is a block diagram showing the state of the fuel cell power supply method according to the embodiment in which the first fuel cell device 10a is in independent operation in the case of a power outage during FC operation, and the other fuel cell devices 10 have also completed their transition to independent operation. That is, FIG. 9 shows the state in which the second fuel cell device 10b and third fuel cell device 10c, which are to be started, are also in independent operation, and power is being supplied to the FC system load 51.

[0105] In this self-powered mode, specifically, the second supply switch 37b of the second supply line 27b and the third supply switch 37c of the third supply line 27c are in the ON (closed) state. Also, the second self-powered output switch 34b of the second self-powered output line 24b and the third self-powered output switch 34c of the third self-powered output line 24c are in the ON (closed) state. Further, the system load supply breaker 37f of the system load supply line 27f is in the ON (closed) state. In FIG. 9, the lines from the second fuel cell device 10b to the second self-powered output line 24b and the lines from the third fuel cell device 10c to the third self-powered output line 24c are also indicated by arrows.

[0106] As described above, in the case of a power outage during FC operation, the power outage of the external power source 1 is detected, and the fuel cell device 10 that has been operating until then is quickly shifted to the self-powered operation state. As a result, it becomes possible to maintain the operating state of the fuel cell device 10 that has been operating until then. <000**********>

[0107] <Procedure in the case of a power outage during FC stop> FIG. 10 is a flowchart showing the procedure of the power outage case during FC stop in the power supply method for a fuel cell according to the embodiment. As an initial condition in this case, regardless of whether the external power source 1 is alive or not, all the fuel cell devices 10 are stopped. The start fuel cell device selection unit 142 determines the fuel cell device 10 to be started later based on the priority stored and accommodated in the start target fuel cell storage unit 132. Hereinafter, the case of first starting the first fuel cell device 10a will be described as an example.

[0108] Hereinafter, the case where the power source of the power control device 100 is a power source that does not depend on the external power source 1 is shown as an example. When the power source of the power control device 100 depends on the external power source 1, the functions of the power control device 100 are temporarily lost due to the power outage of the external power source 1. In this case, the following flow will be the steps after the external power source 1 is restored.

[0109] First, the power supply control device 100 determines whether there is a fuel cell device 10 to be started (step S21). More specifically, first, the start-up fuel cell device selection unit 142 selects the fuel cell device 10 to be started up based on priority. Next, the progress control unit 150 determines whether it is time to start up the selected fuel cell device 10. This timing is information that is part of the operation plan for the fuel cell system 300, received by the input unit 110 as an external input and stored in the start-up target fuel cell storage unit 132.

[0110] In step S21, if it is not determined that the fuel cell device 10 is to be started (step S21 NO), the progress control unit 150 repeats step S21 at predetermined time intervals.

[0111] If it is determined in step S21 that the fuel cell device 10 is to be started (step S21 YES), the power supply control device 100 determines whether or not there is a power outage in the external power supply 1 (step S22). In detail, the power supply information acquisition unit 123 of the power supply control device 100 determines whether or not there is a power outage in the external power supply 1 based on the output of the voltmeter 21a of the normal power supply line 21.

[0112] If it is determined in step S22 that there is no power outage of the external power supply 1 (step S22 YES), the fuel cell power supply system 200 transitions to grid-connected operation of the first fuel cell device 10a (step S23). The grid-connected operation state of the first fuel cell device 10a is the state shown in Figure 7, so a description thereof will be omitted.

[0113] If it is determined in step S22 that there is a power outage in the external power supply 1 (YES in step S22), the power supply control device 100 determines whether the backup power supply 2 is usable or not (step S24). In detail, the power supply information acquisition unit 123 of the power supply control device 100 determines whether the backup power supply 2 is alive or not based on the output of the voltmeter 22a of the backup power line 22.

[0114] If it is determined in step S24 that the backup power supply 2 is available (step S24: YES), the fuel cell power supply system 200 transitions to a configuration for receiving power from the backup power supply 2 (step S25). In detail, the power supply control device 100 outputs a close command to turn on the backup power supply first open / close switch 32a and the backup power supply second open / close switch 32b of the backup power supply line 22. The power switching device 20 transitions to the instructed state.

[0115] In this case of a power outage while the FC is stopped, the first fuel cell device 10a was in grid-connected operation before the power outage of the external power source 1. Therefore, a power supply line from the external power source 1 to the first fuel cell device 10a has already been established. By turning on the two switches of the backup power source line 22, the primary side of the external power source selector switch 33 automatically switches from the normal power source line 21, where the voltage has dropped, to the backup power source line 22, where the voltage has been established. As a result, in the fuel cell power supply system 200, a power supply line from the backup power source 2 to the first fuel cell device 10a is established. In other words, the power switching device 20 transitions to a configuration in which the first fuel cell device 10a receives power from the backup power source 2.

[0116] As a result, it becomes possible to supply power to each auxiliary device 13 of each fuel cell device 10. The power supply control device 100 outputs a command to the auxiliary device 13 of the first fuel cell device 10a to be started up, causing the first fuel cell device 10a to start operating (step S25).

[0117] Next, the power supply control device 100 transitions the first fuel cell device 10a to an independent operation state (step S30). More specifically, the progress control unit 150 confirms that a predetermined time has passed since receiving the supply of backup power. If the predetermined time has passed, the startup fuel cell device selection unit 142 transitions the first fuel cell device 10a to an independent operation state. Here, the predetermined time is the time during which the use of the backup power source is permitted under an agreement, contract, or the like with the backup power source 2. The details of step S30 are the same as step S30 in the procedure for the case of a power outage during FC operation, so a detailed explanation will be omitted.

[0118] Next, the power supply control device 100 also transitions the other fuel cell devices 10 to be started up into the independent operation state (step S40). The details of step S40 are the same as step S40 in the procedure for the power outage during FC operation, so a detailed explanation will be omitted.

[0119] Next, the power supply control device 100 determines whether or not power has been restored to the external power supply 1 (step S50). If it is determined that power has not been restored to the external power supply 1 (step S50 NO), the progress control unit 150 repeats step S50.

[0120] If it is determined that the external power supply 1 has been restored (YES in step S50), the power supply control device 100 transitions the power switching device 20 to the external power supply mode configuration (step S60). The state of step S60 is the same as the initial state in the procedure in the case of a power outage during FC operation (see FIG. 7), so a description thereof will be omitted.

[0121] Fig. 11 is a block diagram showing the initial state in the case of a power outage while FC is stopped in the fuel cell power supply method according to the embodiment. Fig. 11 shows the initial state of the flow chart shown in Fig. 10. That is, the initial state in the case of a power outage while FC is stopped is a state in which none of the fuel cell devices 10 is operating.

[0122] In detail, the normal power supply open / close switch 31 of the normal power supply line 21 is in the ON (closed) state. The external power supply selector switch 33 is in a state in which it connects the normal power supply line 21 and the non-independent power supply line 23. The independent power supply selector switch 35 is in a state in which it connects the non-independent power supply line 23 and the supply side line 26. In addition, the supply switches 37 of the supply line 27 are all in the ON (closed) state. Thus, in the initial state of the FC-stopped power outage case, power can be supplied to each fuel cell device 10, but the accessories 13 of none of the fuel cell devices 10 are operating. In other words, each fuel cell device 10 is in a standby state in which it does not generate power.

[0123] 12 is a block diagram showing the state of the backup power supply mode in which the first fuel cell device 10a receives power from the backup power source 2 in the event of a power outage during FC operation in the fuel cell power supply method according to the embodiment. That is, FIG. 12 shows the state in which the first fuel cell device 10a receives power from the backup power source 2.

[0124] The backup power supply mode differs from the initial external power supply mode as follows. First, the first backup power supply on / off switch 32a and the second backup power supply on / off switch 32b of the backup power line 22 are in the ON (closed) state. Also, the normal power supply on / off switch 31 of the normal power supply line 21 is in the OFF (open) state. Alternatively, the normal power supply on / off switch 31 of the normal power supply line 21 may remain in the ON (closed) state. As a result, the primary side of the external power supply selector switch 33 is switched to the side of the backup power supply line 22, which has a higher voltage. As a result, the external power supply selector switch 33 is in a state in which the backup power supply line 22 and the non-autonomous-side power supply line 23 are connected.

[0125] As described above, in the case of a power outage while the FC is stopped, if it is detected that the external power source 1 is in a power outage state when attempting to start the fuel cell device 10, the fuel cell device 10 can first be started using power from the backup power source 2.

[0126] As described above, the configuration of the fuel cell system 300 equipped with the fuel cell power supply system 200 according to this embodiment, and the fuel cell power supply method, ensure the operation of the necessary fuel cell devices 10 when the external power source 1, which is the normal power source, experiences a power outage, whether any of the fuel cell devices 10 is in operation or none of the fuel cell devices 10 is in operation.

[0127] According to the embodiments described above, it is possible to provide a fuel cell power supply system, a fuel cell system, and a fuel cell power supply method that enable power to be supplied to a fuel cell when an external power source fails.

[0128] [Other embodiments] Although the embodiments of the present invention have been described above, they are presented as examples and are not intended to limit the scope of the invention. Furthermore, features of each embodiment may be combined. Furthermore, the embodiments may be implemented in various other forms, and various omissions, substitutions, and modifications may be made without departing from the spirit of the invention. The embodiments and their modifications are intended to be included within the scope and spirit of the invention, as well as within the scope of the invention and its equivalents as set forth in the claims. [Explanation of symbols]

[0129] 1...external power source, 1a...connection point, 2...backup power source, 2a...connection point, 3...non-independent power source, 5...station load, 10...fuel cell device, 10a...first fuel cell device, 10b...second fuel cell device, 10c...third fuel cell device, 10d...fourth fuel cell device, 10e...fifth fuel cell device, 11...fuel cell cell stack, 12...power conditioner (PCS), 13...auxiliary equipment, 15...gas system, 15a...gas supply source, 16...cooling system, 16a...cooling source, 20...power switching device, 21...normal power line, 21a...voltmeter, 22...backup power line, 22a...voltmeter, 23...Non-independent side power supply line, 24...Independent output line, 24a...First independent output line, 24b...Second independent output line, 24c...Third independent output line, 24d...Fourth independent output line, 24e...Fifth independent output line, 25...Independent side power supply line, 26...Supply side line, 27...Supply line, 27a...First supply line, 27b...Second supply line, 27c...Third supply line, 27d...Fourth supply line, 27e...Fifth supply line, 27f...System load supply line, 30a...Selection switch, 30b...Open / close switch, 31...Normal power supply open / close switch, 32a...Backup First power supply open / close switch, 32b...Second backup power supply open / close switch, 33...External power supply selector switch, 34...Independent output switch, 34a...First independent output switch, 34b...Second independent output switch, 34c...Third independent output switch, 34d...Fourth independent output switch, 34e...Fifth independent output switch, 35...Independent power supply selector switch, 37...Supply switch, 37a...First supply switch, 37b...Second supply switch, 37c...Third supply switch, 37d...Fourth supply switch, 37e...Fifth supply switch, 37f...System load supply breaker, 50...FC load, 5 0a...first FC load, 50b...second FC load, 50c...third FC load, 50d...fourth FC load, 50e...fifth FC load, 51...FC system load, 100...power supply control device, 110...input unit, 120...information acquisition unit, 121...fuel cell device operation information acquisition unit, 122...switching device status acquisition unit, 123...power supply information acquisition unit, 124...in-station load information acquisition unit, 130...storage unit, 131...fuel cell device operation record storage unit, 132...start-up target fuel cell storage unit, 133...output history storage unit, 140...calculation unit, 141...fuel cell device priority setting unit, 142...start-up fuel cell device selection unit,150... progress control unit, 160... output unit, 161... command signal output unit, 162... information output unit, 200... fuel cell power supply system, 300... fuel cell system,

Claims

1. a power switching device configured to be able to supply AC power to each auxiliary device of a plurality of fuel cell devices in any of the following modes: an external power supply mode in which AC power is received from an external power source and supplied; a backup power supply mode in which AC power is received from a backup power source that replaces the external power source and supplied; and an independent operation mode in which AC power is supplied from independent power from at least one of the plurality of fuel cell devices; a power supply control device; A fuel cell power supply system comprising: the power switching device includes an external power supply selector switch for switching between the external power supply mode and the backup power supply mode, an independent power supply selector switch for switching between the external power supply mode or the backup power supply mode and the independent operation mode, and a plurality of open / close switches; the power supply control device controls the plurality of open / close switches of the power switching device and the plurality of fuel cell devices in the event of a power outage of the external power supply. A power supply system for a fuel cell.

2. 2. The fuel cell power supply system according to claim 1, wherein the power supply control device has a fuel cell device priority setting unit that sets startup priorities for the plurality of fuel cell devices in the event of a power outage of the external power source.

3. 3. The fuel cell power supply system according to claim 2, wherein the fuel cell device priority setting unit sets the priority based on fuel cell device information relating to each of the plurality of fuel cell devices and load information relating to the load of each of the plurality of fuel cell devices.

4. 2. The fuel cell power supply system according to claim 1, wherein the external power supply changeover switch and the independent power supply changeover switch are double-throw power supply changeover switches.

5. a plurality of the fuel cell devices; The fuel cell power supply system according to any one of claims 1 to 4, A fuel cell system comprising:

6. A fuel cell power supply method using a fuel cell power supply system including a power switching device configured to be able to supply AC power to each auxiliary device of a plurality of fuel cell devices in any of an external power supply mode in which AC power is received from an external power source and supplied, a backup power supply mode in which AC power is received from a backup power source that replaces the external power source and supplied, and an independent operation mode in which AC power is supplied from independent power from at least one of the plurality of fuel cell devices, and a power supply control device that controls the power switching device and the plurality of fuel cell devices, When at least one of the fuel cell devices is operating in the external power supply mode, a step of the power supply control device determining whether or not the external power supply has experienced a power outage; when it is determined that the external power supply has experienced a power outage, the power supply control device switches the power switching device from the external power supply mode to the independent operation mode; 1. A method for supplying power to a fuel cell, comprising:

7. When the power switching device is in the external power supply mode and none of the plurality of fuel cell devices is in operation, The method further includes a step in which the power supply control device determines whether or not there is a fuel cell device that should be started up among the plurality of fuel cell devices, before the step in which the power supply control device determines whether or not there is a power outage in the external power supply, when it is determined that the external power supply has experienced a power outage, the power supply control device determines whether the backup power supply is available; when it is determined that the backup power supply is available, the power supply control device switches the power switching device from the external power supply mode to the backup power supply mode; further comprising 7. The method for supplying power to a fuel cell according to claim 6.

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