Power supply system, control device, control method

Abstract

This technology provides the ability to appropriately supply power to load devices using energy storage devices or fuel cells during power grid outages. [Solution] A power supply system 30 according to one embodiment includes a fuel cell module 110, a power storage device 200 electrically connected to the fuel cell module 110, a power converter 300 electrically connected to the fuel cell module 110 and the power storage device 200 and capable of outputting power supplied from at least one of the fuel cell module 110 and the power storage device 200 to an external load device 20, and a control device 500 that controls the fuel cell module 110 and the power converter 300. When the AC power system 10 that supplies power to the load device 20 experiences a power outage while the fuel cell module 110 and the power converter 300 are shut down, the control device 500 uses the power from the power storage device 200 to start the fuel cell module 110 and the power converter 300.

Description

Technical Field

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

Background Art

[0002] For example, when a power system that supplies power to a load device experiences a power outage, there are known techniques for supplying power from a power storage device to the load device, self-starting a fuel cell with power from the power storage device, and supplying power from the fuel cell to the load device (see Patent Documents 1 to 3).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, there is room for improvement in the method of supplying power to the load device during a power outage of the power system.

[0005] Therefore, in view of the above problems, an object is to provide a technology capable of appropriately supplying power to a load device using a power storage device and a fuel cell during a power outage of a power system.

Means for Solving the Problems

[0006] To achieve the above object, in one embodiment of the present disclosure, a fuel cell, a power storage device electrically connected to the fuel cell, A power converter that is electrically connected to the fuel cell and the energy storage device and capable of outputting power supplied from at least one of the fuel cell and the energy storage device to an external load device, The system comprises a control device for controlling the fuel cell and the power converter, When the power supply system providing power to the load device experiences a power outage while the fuel cell and the power converter are shut down, the control device uses the power from the energy storage device to start the fuel cell and the power converter. A power supply system will be provided.

[0007] In other embodiments of this disclosure, A power supply system comprising a fuel cell, an energy storage device electrically connected to the fuel cell, and a power converter electrically connected to the fuel cell and the energy storage device, capable of outputting power supplied from at least one of the fuel cell and the energy storage device to an external load device, If the power grid supplying power to the load device experiences a power outage while the fuel cell and the power converter are shut down, the power storage device is used to start the fuel cell and the power converter. A control device is provided.

[0008] Furthermore, in yet another embodiment of this disclosure, A control method performed by a control device for a power supply system comprising a fuel cell, an energy storage device electrically connected to the fuel cell, and a power converter electrically connected to the fuel cell and the energy storage device, capable of outputting power supplied from at least one of the fuel cell and the energy storage device to an external load device, wherein If the power grid supplying power to the load device experiences a power outage while the fuel cell and the power converter are shut down, the power storage device is used to start the fuel cell and the power converter. A control method is provided. [Effects of the Invention]

[0009] According to the above embodiment, when there is a power outage in the power system, the power storage device and the fuel cell can be used to appropriately supply power to the load device.

Brief Description of Drawings

[0010] [Figure 1] It is a diagram showing the configuration of the first example of the power system. [Figure 2] It is a diagram showing the configuration of the second example of the power system. [Figure 3] It is a diagram showing the configuration of the third example of the power system. [Figure 4] It is a diagram showing the configuration of an example of the fuel cell system. [Figure 5] It is a flowchart schematically showing an example of the control process related to the normal startup of the fuel cell system. [Figure 6] It is a time chart explaining a comparative example of the control method related to the self-startup of the fuel cell system. [Figure 7] It is a flowchart schematically showing the first example of the control process related to the self-startup of the fuel cell system 100. [Figure 8] It is a time chart explaining the first example of the control method related to the self-startup of the fuel cell system. [Figure 9] It is a flowchart schematically showing the second example of the control process related to the self-startup of the fuel cell system 100. [Figure 10] It is a time chart explaining the second example of the control method related to the self-startup of the fuel cell system. [Figure 11] It is a flowchart showing the third example of the operation of the power supply system when there is a power outage in the AC power system. [Figure 12] It is a time chart explaining the third example of the control method related to the self-startup of the fuel cell system. [Figure 13] It is a flowchart showing the fourth example of the operation of the power supply system when there is a power outage in the AC power system. [Figure 14] It is a flowchart showing the fourth example of the operation of the power supply system when there is a power outage in the AC power system. [Figure 15] It is a flowchart showing a fourth example of the operation of the power supply system during a power outage in an AC power system. [Figure 16] It is a time chart explaining a fourth example of a control method related to the self-startup of a fuel cell system.

Embodiments for Carrying Out the Invention

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

[0012] [Configuration of Power System] Referring to FIGS. 1 to 3, the configuration of the power system 1 according to this embodiment will be described.

[0013] FIG. 1 is a diagram showing a first example of the configuration of the power system 1. FIG. 2 is a diagram showing a second example of the configuration of the power system 1. FIG. 3 is a diagram showing a third example of the configuration of the power system 1.

[0014] In FIG. 2, since the configurations of the plurality of fuel cell systems 100 are all the same, only the fuel cell module 110 and the auxiliary machine 120 are drawn for one of the plurality of fuel cell systems 100. Further, in FIG. 3, since the configuration of each of the plurality of power supply systems 30 is the same as that in FIG. 1 or FIG. 2, the illustration of each component is omitted.

[0015] As shown in FIGS. 1 to 3, the power system 1 includes an AC power system 10, a load device 20, and a power supply system 30.

[0016] The power system 1 can connect the power supply system 30 to the AC power system 10 through the distribution system 40 and supply the power output from the power supply system 30 to the demand side connected to the AC power system 10. Further, the power system 1 can distribute power from the AC power system 10 to the load device 20 and the power supply system 30 through the distribution system 40. Further, the power system 1 can supply power from the power supply system 30 to the load device 20 through the distribution system 40.

[0017] The AC power system 10 transmits power output from the power supply system 30 and other power generation facilities to the demand side in alternating current. The AC power system 10 transmits three-phase alternating current, for example, using a three-phase three-wire system.

[0018] The load device 20 is electrically connected to the AC power system 10 and the power supply system 30 through the power distribution system 40, and operates on power supplied from at least one of the AC power system 10 and the power supply system 30. The load device 20 may be one or more, as shown in Figures 1 to 3, for example. The load device 20 is, for example, various equipment installed in the same factory as the power supply system 30. Various equipment in the factory includes, for example, outlets, lighting, production equipment, etc. The power supply system 30 is connected to the AC power system 10 through the distribution system 40 and can supply power to the AC power system 10. The power supply system 30 can also receive power from the AC power system 10 through the distribution system 40. Furthermore, the power supply system 30 is electrically connected to the load device 20 through the distribution system 40 and can supply power to the load device 20.

[0019] As shown in Figures 1 and 2, one power supply system 30 is provided for each power distribution system 40. Alternatively, as shown in Figure 3, multiple power supply systems 30 may be connected in parallel to a single power distribution system 40.

[0020] As shown in Figures 1 and 2, the power supply system 30 includes a fuel cell system 100, an energy storage device 200, a power converter 300, a transformer 400, and a control device 500.

[0021] The fuel cell system 100 supplies power to the AC power grid 10 through the power converter 300 and the transformer 400. The fuel cell system 100 is electrically connected to the energy storage device 200 and the power converter 300 via the DC link section 250.

[0022] For example, as shown in Figure 1, one fuel cell system 100 is provided. Alternatively, as shown in Figure 2, multiple fuel cell systems 100 may be provided. In this case, multiple fuel cell systems 100 are connected in parallel to the DC link section 250.

[0023] The fuel cell system 100 includes a fuel cell module 110 that generates electricity upon receiving fuel, and an auxiliary unit 120 for operating the fuel cell module 110. The auxiliary unit 120 is powered by electricity supplied from the DC link unit 250.

[0024] The energy storage device 200 can discharge power to the outside of the power supply system 30 through the power converter 300 and the transformer 400, and can also charge (store) power distributed from the AC power system 10 or the power of the fuel cell system 100 through the DC link section 250. The energy storage device 200 is, for example, a capacitor such as a lithium-ion capacitor (LIC). Alternatively, the energy storage device 200 may be a battery (secondary battery) such as a lithium-ion battery with a liquid electrolyte or an all-solid-state battery with a solid electrolyte. The energy storage device 200 is electrically connected to the fuel cell system 100 and the power converter 300 via the DC link section 250.

[0025] Furthermore, as shown in Figures 1 and 2, there may be one or more energy storage devices 200. In the latter case, the multiple energy storage devices 200 may be connected in series with respect to the DC link section 250, or in parallel, or two or more direct connections of energy storage devices 200 may be connected in parallel with respect to the DC link section 250.

[0026] The power converter 300 converts the DC from the DC link section 250 into AC of a predetermined voltage and frequency and outputs it to the transformer 400. For example, the power converter 300 is a power conditioner (PCS) that includes an inverter circuit that converts DC into three-phase AC of a predetermined voltage and frequency.

[0027] Furthermore, an inrush current prevention circuit (also called a "precharge circuit") may be provided on the DC power line (DC line) on the DC side of the DC link section 250 or the power converter 300. The inrush current prevention circuit has a first circuit for supplying the DC from the DC link section 250 directly to the inverter circuit of the power converter 300, and a second circuit provided in parallel with the first circuit and including a resistor for preventing inrush current. The control device 500 can electrically connect the DC link section 250 and the inverter circuit of the power converter 300 by connecting either one of the relays provided on both the first circuit and the second circuit, which can switch between electrical connection and disconnection. For example, immediately after starting up the power converter 300, the smoothing capacitor located on the DC side of the power converter 300 is not charged, and when the DC link section 250 and the inverter circuit are connected through the first circuit, a very large current (inrush current) flows, which may cause damage to the circuit. In contrast, immediately after starting up the power converter 300 from a stopped state, the control device 500 connects the relay of the second circuit and disconnects the relay of the first circuit. As a result, a relatively small current flows from the DC link section 250 to the power converter 300 due to the action of the resistor for preventing inrush current in the second circuit, and the capacitor is charged (precharged) relatively slowly. Then, when the control device 500 determines that the capacitor has been sufficiently charged, it changes the relay of the first circuit to the connected state and changes the relay of the second circuit to the disconnected state.

[0028] The transformer 400 transforms (specifically, boosts) the AC output from the power converter 300 and outputs it to the AC power system 10 and load devices 20 via the distribution system 40.

[0029] For example, as shown in Figure 1, if the power supply system 30 includes only one fuel cell system 100, only one combination of power converter 300 and transformer 400 is provided. Alternatively, if the power supply system 30 includes only one fuel cell system 100, multiple combinations of power converter 300 and transformer 400 may be provided in parallel. Furthermore, if the power supply system 30 includes multiple fuel cell systems 100, only one combination of power converter 300 and transformer 400 may be provided, or multiple combinations may be provided in parallel, as shown in Figure 2. As shown in Figure 2, if multiple combinations of power converter 300 and transformer 400 are provided, the power converter 300 and transformer 400 are connected in parallel to the power distribution system 40 and the DC link section 250. Furthermore, as shown in Figure 2, when multiple combinations of power converters 300 and transformers 400 are provided, the number of combinations of power converters 300 and transformers 400 and the number of fuel cell systems 100 may be the same or different.

[0030] The control device 500 controls the operation of the power supply system 30. For example, as shown in Figures 1 and 2, the control device 500 operates using power supplied from the power distribution system 40. In this case, if the AC power system 10 experiences a power outage while the fuel cell system 100 and the power converter 300 are shut down, the control device 500 operates using power from an auxiliary power source (not shown). Alternatively, the control device 500 may also operate using power supplied from the DC link section 250.

[0031] For example, the control device 500 controls the fuel cell system 100 and the power converter 300 in accordance with the power requested by the demanding side connected to the AC power grid 10 (demanding side request), and causes the power converter 300 to output power corresponding to the demanding side request. Specifically, the control device 500 may control the load of the power converter 300 so as to output AC power corresponding to the demanding side request from the DC of the DC link section 250, and may also control the fuel cell system 100 so as to output power corresponding to the demanding side request. In this way, the control device 500 can cause the fuel cell system 100 to output power corresponding to the demanding side request to the AC power grid 10 through the power converter 300.

[0032] Furthermore, for example, the control device 500 performs processes to start up the fuel cell system 100 in a stopped state (start-up process) and processes to stop the fuel cell system 100 in an operating state (stop-down process). Starting up the fuel cell system 100 means starting up the auxiliary equipment 120 of the fuel cell system 100 while the fuel cell system 100 is stopped, and then starting up the fuel cell module 110 while the auxiliary equipment 120 is running. Stopping the fuel cell system 100 means stopping the operation of the fuel cell module 110 by stopping the auxiliary equipment 120.

[0033] The functions of the control device 500 can be arbitrarily implemented using any hardware, or any combination of hardware and software. For example, the control device 500 is a PLC (Programmable Logic Controller). Alternatively, the control device 500 may be configured around a computer including a CPU (Central Processing Unit), main memory (memory device), auxiliary memory, and interface device. In this configuration, the control device 500 can implement various functions by having the CPU execute a program pre-installed in the memory (e.g., auxiliary memory).

[0034] [Fuel cell system configuration] Referring to Figure 4, the configuration of the fuel cell system 100 according to this embodiment will be described.

[0035] Figure 4 shows the configuration of an example of a fuel cell system 100.

[0036] As shown in Figure 4, the fuel cell system 100 includes a fuel cell module 110, a fuel supply unit 130, an air supply unit 140, an exhaust unit 150, and a cooling unit 160.

[0037] The fuel cell module 110 includes a fuel cell cell 112, a cooling unit 114, and a converter device 116.

[0038] The fuel cell 112 generates electricity by chemically reacting hydrogen, which is supplied as fuel from the fuel supply unit 130, with oxygen from the air taken in from the air intake unit 140. The fuel cell 112 is, for example, a polymer electrolyte fuel cell (PEFC). For example, a fuel cell 112 as a polymer electrolyte fuel cell has a stack structure in which a large number of single cells are stacked.

[0039] A single cell in the fuel cell cell 112 has a membrane electrode assembly (MEA) that includes 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 formed of a porous material. Each of the pair of electrodes has, for example, a catalyst layer mainly composed of carbon powder supporting a platinum-based metal catalyst (electrode catalyst), and a gas diffusion layer that has both permeability and electronic conductivity. Furthermore, the single cell has a pair of separators that sandwich the membrane electrode assembly (MEA) from both sides.

[0040] Furthermore, the fuel cell 112 may be, for example, a phosphate fuel cell (PAFC) or a solid oxide fuel cell (SOFC). Alternatively, the fuel cell 112 may be, for example, a molten carbonate fuel cell (MCFC).

[0041] The water and exhaust gas remaining after the chemical reaction between hydrogen and oxygen in the air are discharged from the fuel cell cell 112 to the exhaust section 150.

[0042] The cooling unit 114 cools the fuel cell 112. Specifically, a coolant flows through the inside of the cooling unit 114. The cooling unit 114 cools the fuel cell 112 by performing heat exchange between the fuel cell 112 and the coolant.

[0043] The converter device 116 boosts the voltage output from the fuel cell cell 112 and outputs it to the outside of the fuel cell module 110. The output terminal of the converter device 116 is connected to the DC link section 250.

[0044] The fuel supply unit 130 supplies hydrogen as fuel to the fuel cell cell 112. The fuel supply unit 130 includes a hydrogen supply source 131, an on / off valve 132, a pump 133, and a gas-liquid separator 134.

[0045] The hydrogen supply source 131 stores high-pressure hydrogen and supplies high-pressure hydrogen gas to the fuel cell cell 112 of the fuel cell module 110 through the supply path L1. The hydrogen supply source 131 is, for example, a hydrogen cradle.

[0046] The on-off valve 132 is a valve that opens and closes the supply path L1. When the on-off valve 132 is closed, it indicates that the supply path L1 is blocked and the supply of hydrogen from the hydrogen supply source 131 to the fuel cell 112 has stopped. When the on-off valve 132 is open, it indicates that hydrogen is being pumped from the hydrogen supply source 131 to the fuel cell 112. The on-off valve 132 operates under the control of the control device 500 and uses power supplied from the power distribution system 40. The on-off valve 132 is one of the auxiliary devices 120.

[0047] Pump 133 is located in a circulation path L2 that returns excess hydrogen gas discharged from the fuel cell cell 112 back to the supply path L1. The circulation path L2 merges with the supply path L1 downstream of the on-off valve 132. Pump 133 pumps the hydrogen gas from the circulation path L2 back to the supply path L1. Pump 133 operates using electricity supplied from the power distribution system 40 under the control of the control device 500. Pump 133 is one of the auxiliary devices 120.

[0048] The gas-liquid separator 134 is installed in the circulation path L2. The gas-liquid separator 134 separates the liquid component (water) from the multiphase fluid containing hydrogen gas discharged from the fuel cell cell 112, and discharges the hydrogen gas to the downstream side of the circulation path L2.

[0049] The air intake unit 140 takes in air from the outside and supplies it to the fuel cell cell 112 through the air intake path L3. The air intake unit 140 includes an air cleaner 142, a compressor 144, and an on / off valve 146.

[0050] The air cleaner 142 removes dust, impurities, and other contaminants from the air taken in from one end of the air intake path L3.

[0051] The compressor 144 is located downstream of the air cleaner 142 in the air intake path L3. The compressor 144 compresses the air after it has passed through the air cleaner 142 and sends the compressed air to the fuel cell cell 112 through the downstream air intake path L3. The compressor 144 operates using power supplied from the power distribution system 40 under the control of the control device 500. The compressor 144 is one of the auxiliary devices 120.

[0052] The on-off valve 146 is a valve that opens and closes the air supply path L3. The on-off valve 146 is installed between the compressor 144 and the fuel cell cell 112 in the air supply path L3. When the on-off valve 146 is closed, it indicates that the air supply path L3 is blocked and the supply of air to the fuel cell cell 112 is stopped. When the on-off valve 146 is open, it indicates that air can be supplied to the fuel cell cell 112 through the air supply path L3. The on-off valve 146 operates using power supplied from the power distribution system 40 under the control of the control device 500. The on-off valve 146 is one of the auxiliary devices 120.

[0053] The discharge section 150 discharges water and remaining air (exhaust gas) produced by the chemical reaction between hydrogen and oxygen in the air in the fuel cell cell 112 to the outside through the discharge path L4. The discharge section 150 includes an on / off valve 152, a mixer 154, and a gas-liquid separator 156.

[0054] The on-off valve 152 is a valve that opens and closes the discharge path L4. The on-off valve 152 is located at the uppermost part of the discharge path L4. When the on-off valve 152 is closed, it indicates that the discharge of water and exhaust gas from the fuel cell cell 112 is stopped. When the on-off valve 152 is open, it indicates that water and exhaust gas can be discharged to the outside from the fuel cell cell 112 through the discharge path L4. The on-off valve 152 operates under the control of the control device 500 using electricity supplied from the power distribution system 40. The on-off valve 152 is one of the auxiliary devices 120.

[0055] The mixer 154 connects the water separated by the gas-liquid separator 134 to the discharge path L4.

[0056] Furthermore, the water separated by the gas-liquid separator 134 may be discharged to the outside through a discharge route other than the discharge route L4.

[0057] The gas-liquid separator 156 is installed downstream of the mixer 154 in the discharge path L4. The gas-liquid separator 156 separates the gas-liquid two-phase mixed fluid in the discharge path L4 into liquid (water) and gas (exhaust gas) and discharges them to the outside.

[0058] The cooling unit 160 supplies coolant to the cooling unit 114 for cooling the fuel cell cell 112. The cooling unit 160 includes a cooler 161, a fan 162, a pump 163, a heat exchanger 164, a pump 165, and an ion exchanger 166.

[0059] Cooler 161 cools the coolant in cooling circuit CC1. As a result, heat exchanger 164 can exchange heat between the coolant in cooling circuit CC1 and the coolant in cooling circuit CC2, thereby cooling the coolant in cooling circuit CC2. Cooler 161 is, for example, a cooling tower. Alternatively, cooler 161 may be a radiator. The radiator may be, for example, a fin-tube type or a fin-and-tube type radiator.

[0060] Fan 162 generates an airflow that passes through the cooler 161. This promotes the cooling of the coolant in the cooling circuit CC1 that passes through the cooler 161. Fan 162 operates using power supplied from the power distribution system 40 under the control of the control device 500. Fan 162 is one of the auxiliary devices 120.

[0061] Pump 163 is installed in the cooling circuit CC1 and circulates the coolant in the cooling circuit CC1. Pump 163 operates using power supplied from the power distribution system 40 under the control of the control device 500. Pump 163 is one of the auxiliary equipment 120.

[0062] The heat exchanger 164 performs heat exchange between the coolant of the cooling circuit CC1, which includes the cooler 161, and the coolant of the cooling circuit CC2, which includes the cooling unit 114, thereby cooling the coolant of the cooling circuit CC2. As a result, the cooling circuit CC2 can supply the coolant cooled by the heat exchanger 164 to the cooling unit 114, thereby cooling the fuel cell cell 112.

[0063] Pump 165 is installed in the cooling circuit CC2 and circulates the coolant in the cooling circuit CC2. Pump 165 operates using power supplied from the power distribution system 40 under the control of the control device 500. Pump 165 is one of the auxiliary equipment 120.

[0064] The ion exchanger 166 is installed in the cooling circuit CC2 and removes ionic impurities from the coolant in the cooling circuit CC2. This ensures the insulating properties of the coolant.

[0065] Hereinafter, the auxiliary equipment 120 included in the cooling unit 160 may be referred to as "cooling auxiliary equipment 120".

[0066] [Control method for normal startup of fuel cell systems] In addition to Figures 1 to 4, Figure 5 will be used to explain the control method for the normal startup of the fuel cell system 100 (Examples 1 to 3).

[0067] Normal startup of the fuel cell system 100 means starting up the fuel cell system 100 in a state where power can be supplied to the fuel cell system 100 from the AC power grid 10 through the power distribution grid 40.

[0068] <Overview> When the fuel cell system 100 is in a stopped state (hereinafter simply referred to as the "stopped state"), the control device 500 starts the fuel cell system 100 when the conditions for normal startup of the fuel cell system 100 (normal startup conditions) are met. Specifically, the control device 500 starts the fuel cell module 110 by operating the auxiliary equipment 120 with power supplied from the AC power grid 10.

[0069] The normal startup conditions for the fuel cell system 100 are, for example, that the fuel cell system 100 is stopped, the AC power system 10 is in a state where power can be supplied normally, and a start command for the fuel cell system 100 is input.

[0070] The start command for the fuel cell system 100 is input to the control device 500, for example, in response to user input to an operating unit connected to the control device 500. Alternatively, the start command for the fuel cell system 100 may be input to the control device 500 via communication from an external device, such as a higher-level device of the control device 500 or a user terminal held by the user, in response to user input to an external device. The higher-level device of the control device 500 is, for example, a management terminal device or edge server installed at the facility where the power supply system 30 is installed. Alternatively, the higher-level device of the control device 500 may be, for example, a management on-premise server or cloud server installed at a management center located in a different location from the facility where the power supply system 30 is installed. Furthermore, the start command for the fuel cell system 100 may be automatically generated according to predetermined rules. For example, it may be generated internally within the control device 500 at a predetermined time and then virtually input to the control device 500. Alternatively, it may be generated by an external device at a predetermined time and input to the control device 500 via communication from the external device.

[0071] The control device 500 uses power supplied from the AC power system 10 through the power distribution system 40 to start all the auxiliary equipment 120 of the fuel cell system 100, thereby performing a normal startup of the fuel cell system 100.

[0072] <Control Processing> Figure 5 is a flowchart illustrating an example of the control process for the normal startup of the fuel cell system 100.

[0073] This flowchart is executed repeatedly at predetermined processing cycles, for example, while the control device 500 is in operation. The same applies to the processing shown in Figures 7, 9, 11, and 13 below.

[0074] As shown in Figure 5, in step S10, the control device 500 determines whether the normal startup conditions for the fuel cell system 100 are met. If the normal startup conditions for the fuel cell system 100 are met, the control device 500 proceeds to step S20. If the normal startup conditions for the fuel cell system 100 are not met, the control device 500 terminates the process in this flowchart.

[0075] In step S20, the control device 500 uses the power from the energy storage device 200 to operate the auxiliary equipment 120 and start the fuel cell module 110. If the power supply system 30 includes multiple fuel cell systems 100, the control device 500 starts all fuel cell modules 110 included in each of the fuel cell systems 100.

[0076] Once the process in step S20, i.e., the startup of the fuel cell module 110, is complete, the control device 500 proceeds to step S30. If multiple fuel cell modules 110 are to be started, the control device 500 proceeds to step S30 once the startup of all fuel cell modules 110 is complete.

[0077] In step S30, the control device 500 controls the fuel cell system 100 and starts generating power from the fuel cell module 110. If the power supply system 30 includes multiple fuel cell systems 100, the control device 500 starts generating power from all fuel cell modules 110 included in each of the fuel cell systems 100.

[0078] Once the process in step S30 is complete, the control device 500 proceeds to step S40.

[0079] In step S40, the control device 500 activates the power converter 300. If the power supply system 30 includes multiple power converters 300, the control device 500 activates all of the power converters 300.

[0080] Once the processing in step S40, i.e., the startup of the power converter 300, is complete, the control device 500 proceeds to step S50. If the power supply system 30 includes multiple power converters 300, once the startup of all power converters 300 is complete, the control device 500 proceeds to step S50.

[0081] In step S50, the control device 500 starts outputting power from the power converter 300 to the outside (i.e., to the transformer 400). If the power supply system 30 includes multiple power converters 300, the control device 500 starts outputting power from each of the power converters 300 to the outside (i.e., to the transformer 400).

[0082] As a result, the control device 500 can supply power from the power converter 300 to the power distribution system 40 via the transformer 400.

[0083] Once the process in step S50 is complete, the control device 500 terminates the process in this flowchart.

[0084] [Comparative Examples of Control Methods for Autonomous Startup of Fuel Cell Systems] In addition to Figures 1 to 5, Figure 6 will be used to describe a comparative example of a control method for the autonomous startup of the fuel cell system 100.

[0085] Independent startup of the fuel cell system 100 means the startup of the fuel cell system 100 without external power supply in the event of a power outage in the AC power system 10, that is, when power supply to the fuel cell system 100 from the AC power system 10 through the power distribution system 40 is impossible.

[0086] Figure 6 is a time chart illustrating a comparative example of a control method for the autonomous startup of the fuel cell system 100. Specifically, it is a time chart showing a comparative example of the time change in the amount of energy stored in the energy storage device 200 and the operation flow of the power supply system during the autonomous startup of the fuel cell system 100.

[0087] In this comparative example, a control method for the autonomous startup of the fuel cell system 100 is realized by control processing similar to that used in the normal startup of the fuel cell system 100 (Figure 5).

[0088] Specifically, instead of step S10 in Figure 5, it is determined whether the conditions for autonomous startup of the fuel cell system 100 (autonomous startup conditions) are met. If the autonomous startup conditions for the fuel cell system 100 are met, the processes from step S20 onward are executed. If the autonomous startup conditions for the fuel cell system 100 are not met, the process in this flowchart is terminated.

[0089] The conditions for the self-starting of the fuel cell system 100 are, for example, that the fuel cell system 100 is stopped and the AC power system 10 is experiencing a power outage. Alternatively, the conditions for the self-starting of the fuel cell system 100 may also be that the fuel cell system 100 is stopped, the AC power system 10 is experiencing a power outage, and a start command for the fuel cell system 100 is input. For example, the control device 500 can determine whether or not there is a power outage in the AC power system 10 by receiving measurement results from measuring instruments installed in the power distribution system 40 or signals input via communication from a management device that manages the AC power system 10.

[0090] Then, once the process in step S50 is complete, the load devices, which have been shut down due to a power outage in the AC power system 10, are started up by the power supplied from the fuel cell system 100 to the power distribution system 40, and the flowchart process is completed.

[0091] As shown in Figure 6, when the conditions for the self-starting of the fuel cell system 100 are met, the fuel cell module 110 starts up at time t01 (step S20 in Figure 5). Then, at time t02, when the startup of the fuel cell module 110 is complete, power generation by the fuel cell module begins (step S30 in Figure 5), and the startup of the power converter 300 begins (step S40 in Figure 5). Then, at time t03, when the startup of the power converter 300 is complete, power supply from the fuel cell system 100 to the power distribution system 40 begins (step S50 in Figure 5), and accordingly, the operation (operation) of the load device 20 begins.

[0092] In the comparative example, during the period from time t01 to time t02, when the fuel cell module 110 is started, power is supplied from the energy storage device 200 to the auxiliary equipment 120, and the amount of energy stored in the energy storage device 200 decreases over time. Then, at time t02, when the fuel cell module 110 starts generating power, the decrease in the amount of energy stored in the energy storage device 200 stops, and from time t02 onward, the amount of energy stored in the energy storage device 200 is maintained at a constant level.

[0093] Furthermore, during the period from the start of power generation by the fuel cell module 110 until the completion of startup of the power converter 300, that is, from time t02 to time t03, the energy storage device 200 may be charged with power from the fuel cell module 110, and the amount of energy stored in the energy storage device 200 may increase. Also, during the period from time t03 onward, the fuel cell system 100 may be controlled so that the power generated by the fuel cell module 110 is greater than the load-side requirements, including the power consumption of the load device 20. In this case, the energy storage device 200 is charged with surplus power from the fuel cell module 110 (see the dashed line from time t03 onward in the figure).

[0094] In this comparative example, the power converter 300 is started after the fuel cell module 110 has finished starting up. Therefore, a waiting period (in this example, the period from time t02 to time t03) occurs between the start of power generation by the fuel cell module 110 and the start of operation of the load device 20, resulting in a delay in the start of operation of the load device 20.

[0095] Furthermore, at the time the fuel cell module 110 has finished starting up, the remaining amount of energy stored in the energy storage device 200 (hereinafter referred to as "remaining energy") is sufficiently greater than the allowable lower limit, resulting in surplus power. In other words, the energy storage device 200 not only supplies the power required to start up the fuel cell module 110, but also has enough surplus power to operate the load device 20 before the fuel cell module 110 has finished starting up. Therefore, in the control method of this comparative example, the resources of the energy storage device 200 are not fully utilized when starting up the load device 20.

[0096] Thus, the control method of the comparative example has room for improvement in terms of accelerating the timing of the start of operation of the load device 20 and accelerating the timing of the start of power supply from the fuel cell module 110 to the load device 20.

[0097] [First example of a control method for the autonomous startup of a fuel cell system] In addition to Figures 1 to 4, a first example of a control method for the autonomous startup of the fuel cell system 100 will be described with reference to Figures 7 and 8.

[0098] <Control Processing> Figure 7 is a flowchart illustrating a schematic example of the control process for the autonomous startup of the fuel cell system 100.

[0099] As shown in Figure 7, in step S102, the control device 500 determines whether the automatic startup conditions for the fuel cell system 100 are met. If the automatic startup conditions are met, the control device 500 executes the processes in steps S104 and S106, and steps S108, S110, and S112 in parallel. On the other hand, if the automatic startup conditions are not met, the control device 500 terminates the process in this flowchart.

[0100] Steps S104 and S106 are the same as the processes in steps S20 and S30 in Figure 5, so their explanation is omitted.

[0101] Steps S108 and S110 are the same as the processes in steps S40 and S50 in Figure 5, so their explanation is omitted.

[0102] Once the processing in step S110 is complete, the control device 500 proceeds to step S112.

[0103] In step S112, the control device 500 starts the operation (operation) of the load device 20. If there are multiple load devices 20, the control device 500 starts the operation of all load devices 20.

[0104] Furthermore, the control device 500 may start the operation of the load device 20 by directly outputting a command to the load device 20, or it may start the operation of the load device 20 by outputting a command to another control device capable of directly controlling the load device 20.

[0105] Once both steps S106 and S112 are completed, the control device 500 terminates the processing of this flowchart.

[0106] <Operation of the power supply system> Figure 8 is a time chart illustrating a first example of a control method for the autonomous startup of the fuel cell system 100. Specifically, it is a time chart showing a first example of the time change in the amount of energy stored in the energy storage device 200 and the operation flow of the power supply system during the autonomous startup of the fuel cell system 100.

[0107] As shown in Figure 8, in response to the fulfillment of the conditions for the self-starting of the fuel cell system 100, at time t11, the fuel cell module 110 is started by supplying power from the energy storage device 200 to the auxiliary equipment 120 (step S104 in Figure 7), and the power converter 300 is also started (step S108 in Figure 7). Subsequently, at time t12, when the power converter 300 has finished starting up before the fuel cell module 110, power is supplied from the fuel cell system 100 to the power distribution system 40 through the power converter 300 (step S110 in Figure 7), and the load device 20 begins to operate (start up) accordingly (step S112 in Figure 7). Subsequently, at time t13, when the fuel cell module 110 has finished starting up, power generation by the fuel cell module 110 begins (step S106 in Figure 7).

[0108] Thus, in this example, unlike the comparative example described above, the control device 500 starts the power converter 300 before the fuel cell module 110 has finished starting up. This allows the control device 500 to accelerate the timing of the power converter 300's startup completion. As a result, the control device 500 can operate the load device 20 with the power generated by the fuel cell module 110 at an earlier stage.

[0109] Furthermore, unlike the comparative example described above, in this example, the control device 500 starts the fuel cell module 110 and the power converter 300 in parallel. In other words, in this example, the time required to start up the fuel cell module 110 and the time required to start up the power converter 300 overlap. As a result, the control device 500 can shorten the time required from the point when the self-starting conditions are met until both the fuel cell module 110 and the power converter 300 are started up. Therefore, the control device 500 can operate the load device 20 with the power generated by the fuel cell module 110 at an earlier stage.

[0110] Furthermore, assuming that the startup times for the fuel cell module 110 and the power converter 300 overlap, the startup timing of the fuel cell module 110 and the power converter 300 may be the same as described above, or either one may start earlier than the other.

[0111] Furthermore, in this example, the control device 500 completes the startup of the power converter 300 before the startup of the fuel cell module 110 is completed. As a result, at time t13, immediately after the startup of the fuel cell module 110, the control device 500 can begin supplying power from the fuel cell module 110 to the power distribution system 40 through the power converter 300. Therefore, the control device 500 can operate the load device 20 with the power generated by the fuel cell module 110 at an earlier stage.

[0112] Furthermore, assuming that the power converter 300 completes startup before the fuel cell module 110 completes startup, the timing of the power converter 300's startup start may be either before or after the timing of the fuel cell module 110's startup start.

[0113] As shown in Figure 8, during the period from the start-up of the fuel cell module 110 and the power converter 300 until the start-up of the power converter 300 is completed, that is, from time t11 to time t12, power is supplied only to the auxiliary equipment 120 from the energy storage device 200. Therefore, during this period, the amount of energy stored in the energy storage device 200 decreases over time. At time t12, when the start-up of the power converter 300 is completed and power output from the power converter 300 to the power distribution system 40 begins, the operation of the load device 20 starts. Therefore, during the period until the start-up of the fuel cell module 110 is completed, that is, from time t12 to time t13, power is supplied from the energy storage device 200 to the load device 20 in addition to the auxiliary equipment 120. Thus, during this period, the amount of energy stored in the energy storage device 200 decreases faster than in the previous period (from time t11 to time t12). Then, at time t13, when the fuel cell module 110 starts generating power, the decrease in the amount of energy stored in the energy storage device 200 stops, and from time t13 onward, the amount of energy stored in the energy storage device 200 (remaining energy) is maintained at a constant level slightly above the allowable lower limit.

[0114] Furthermore, during the period from time t13 onward, the fuel cell system 100 may be controlled so that the power generated by the fuel cell module 110 is greater than the power consumed by the load device 20. In this case, the energy storage device 200 is charged by the surplus power from the fuel cell module 110 (see the dashed line from time t13 onward in the figure).

[0115] Thus, in this example, the control device 500 outputs power from the power converter 300 to the power distribution system 40 and supplies power to the load device 20 during the period from when the power converter 300 is fully started (time t12) until the fuel cell module 110 is fully started. As a result, the control device 500 can start supplying power to the load device 20 before the fuel cell module 110 is fully started. Therefore, the control device 500 can quickly restart the load device 20 in the event of a power outage in the AC power system 10.

[0116] [Second example of a control method for the autonomous startup of a fuel cell system] In addition to Figures 1 to 4, a second example of a control method for the autonomous startup of the fuel cell system 100 will be described with reference to Figures 9 and 10.

[0117] In the following example, we will focus on explaining the differences from the first example of the control method described above, and may omit explanations of parts that are the same as or correspond to the first example of the control method described above.

[0118] <Control Processing> Figure 9 is a flowchart illustrating a second example of the control process for the autonomous startup of the fuel cell system 100.

[0119] As shown in Figure 9, in step S202, the control device 500 determines whether the conditions for the self-starting of the fuel cell system 100 are met. If the conditions for the self-starting of the fuel cell system 100 are met, the control device 500 proceeds to step S204. If the conditions for the self-starting of the fuel cell system 100 are not met, the control device 500 terminates the process in this flowchart.

[0120] In step S204, the control device 500 calculates the operating time TW of the load device 20.

[0121] The operating time TW of the load device 20 refers to the time during which the load device 20 can be operated solely by power supplied from the energy storage device 200, under the premise that the fuel cell module 110 is started using the power from the energy storage device 200. In other words, the operating time TW of the load device 20 is the time during which the load device 20 can be operated using the amount of power that can be supplied externally (i.e., discharged) from the remaining amount of energy storage device 200, obtained by subtracting the amount of power required from the start-up of the fuel cell module 110 to the completion of the start-up from the current amount of energy storage device 200 (i.e., the time before the start-up of the fuel cell module 110). For example, the energy storage device 200 has a predetermined lower limit for the amount of energy storage device (remaining amount of energy) from the viewpoint of suppressing degradation, and the amount of power that the energy storage device 200 can supply externally is the amount of energy storage device (remaining amount of energy) minus that lower limit. In this example, if the power supply system 30 includes multiple fuel cell systems 100, the operating time TW of the load device 20 is defined on the premise that all fuel cell modules 110 corresponding to all fuel cell systems 100 are started with the power from the energy storage device 200. Furthermore, if there are multiple load devices 20 that should be powered by electricity from the power distribution system 40, in this example, the operating time TW of the load device 20 means the time during which all load devices 20 can be operated (activated).

[0122] For example, the control device 500 calculates the operating time TW of the load device 20 using the following equation (1).

[0123]

number

[0124] The amount of energy S1 is the amount of energy that the energy storage device 200 can supply to the outside (i.e., can discharge) before the fuel cell module 110 starts up. The amount of energy S1 corresponds to the difference between the amount of energy stored in the energy storage device 200 (remaining amount) before the fuel cell module 110 starts up and the allowable lower limit of the amount of energy stored in the energy storage device 200 (or the allowable lower limit plus a margin).

[0125] The energy quantity S2 is the amount of energy required to start up the fuel cell module 110, specifically the amount of energy required to operate the auxiliary equipment 120 from the start-up of the fuel cell module 110 to the completion of the start-up. If the power supply system 30 includes multiple fuel cell systems 100, the energy quantity S2 corresponds to the sum of the energy required to start up each of the fuel cell modules 110 corresponding to all fuel cell systems 100. For example, the energy quantity S2 is predetermined as a constant. Alternatively, the energy quantity S2 may be predetermined as a variable that changes according to various conditions such as the ambient temperature of the fuel cell system 100 and the temperature of a predetermined part of the fuel cell system 100.

[0126] The conversion efficiency η is the conversion efficiency (orthogonal conversion efficiency) of the power converter 300 from DC to AC. The conversion efficiency η is predetermined as a constant. Alternatively, the conversion efficiency η may be predetermined as a variable that changes according to various conditions such as the ambient temperature of the power converter 300 and the temperature of a predetermined location in the power converter 300.

[0127] Power Pc is the power consumption of the load device 20. If there are multiple load devices 20 to be operated, power Pc is the sum of the power consumption of each load device 20. Power Pc is predetermined as a constant based on the configuration of the load device 20. Alternatively, power Pc may be predetermined as a variable that changes according to various conditions such as the ambient temperature of the load device 20 and the temperature of a predetermined location within the load device 20.

[0128] The control device 500 can calculate the amount of energy S1 (estimated value) based on the measured voltage of the energy storage device 200. For example, if the energy storage device 200 is a capacitor such as an LIC, the control device 500 can calculate the amount of energy S1 based on the following equation (2).

[0129]

number

[0130] Capacitance C is the capacitance of the energy storage device 200.

[0131] Voltage V1 is the voltage of the energy storage device 200 before the fuel cell module 110 is started up. Voltage V1 is measured, for example, by a voltage sensor built into the energy storage device 200, and the signal of the measurement result is input to the control device 500.

[0132] Voltage V2 is the lower limit of the voltage of the energy storage device 200 that is permissible due to discharge. Alternatively, voltage V2 may be the lower limit plus a margin. Voltage V2 is predetermined as a constant. Alternatively, voltage V2 may be predetermined as a variable that changes according to various conditions such as the ambient temperature of the energy storage device 200 and the temperature of a predetermined location within the energy storage device 200.

[0133] Once the processing in step S204 is completed, the control device 500 executes the processing in steps S206 and S208, and the processing in steps S210, S212, S214, and S216 in parallel.

[0134] Steps S206 and S208 are the same as the processes in steps S20 and S30 in Figure 5, so their explanation is omitted.

[0135] Steps S210 and S212 are the same as the processes in steps S40 and S50 in Figure 5, so their explanation is omitted.

[0136] Once the processing in step S212 is complete, the control device 500 proceeds to step S214.

[0137] In step S214, the control device 500 determines whether the waiting time TP has elapsed, starting from the start of power supply from the power converter 300 to the outside.

[0138] The waiting time TP is the time obtained by subtracting the operating time TW from the remaining time Tr from the start of power supply from the power converter 300 to the completion of startup of the fuel cell module 110. If the value obtained by subtracting the operating time TW from the remaining time Tr is zero (0) or less, the waiting time TP is set to zero (0).

[0139] If the waiting time TP has elapsed, the control device 500 proceeds to step S216. If the waiting time TP has not elapsed, it repeats the process in step S214 until the waiting time TP has elapsed.

[0140] As a result, the control device 500 can delay the start of operation of the load device 20 by a waiting time TP from the start of power supply to the outside of the power converter 300.

[0141] Furthermore, the processing in step S214 may be moved before the processing in step S210. In this case, a predicted value can be used as the remaining time Tr when calculating the waiting time TP. This is because the time required to start up the fuel cell module 110 and the time required to start up the power converter 300 can be estimated in advance. As a result, the control device 500 can delay the start-up timing of the power converter 300 by the waiting time TP from the start-up timing of the fuel cell module 110.

[0142] Step S216 is the same as the process in step S112 in Figure 7, so its explanation is omitted.

[0143] Once both steps S208 and S216 are completed, the control device 500 terminates the processing shown in this flowchart.

[0144] <Operation of the power supply system> Figure 10 is a time chart illustrating a second example of a control method for the autonomous startup of the fuel cell system 100. Specifically, it is a time chart showing a second example of the time change in the amount of energy stored in the energy storage device 200 and the operation flow of the power supply system during the autonomous startup of the fuel cell system 100.

[0145] As shown in Figure 10, in response to the fulfillment of the conditions for the self-starting of the fuel cell system 100, the fuel cell module 110 starts up at time t21 (step S206 in Figure 9), and the power converter 300 also starts up (step S210 in Figure 9). Subsequently, at time t22, if the power converter 300 has finished starting up before the fuel cell module 110, power supply from the fuel cell system 100 to the power distribution system 40 begins (step S212). Then, at time t23, which corresponds to the time when the waiting time TP has elapsed starting from time t22, the load device 20 starts operating (step S216 in Figure 9). Subsequently, at time t24, if the fuel cell module 110 has finished starting up, power generation by the fuel cell module 110 begins (step S208 in Figure 9).

[0146] During the period from the start-up of the fuel cell module 110 and the power converter 300 until the start-up of the power converter 300 is completed, that is, from time t21 to time t22, power is supplied only to the auxiliary equipment 120 from the energy storage device 200. Therefore, during this period, the amount of energy stored in the energy storage device 200 decreases relatively slowly over time. At time t22, the start-up of the power converter 300 is completed, and power output from the power converter 300 to the distribution system 40 begins. However, during the period until the waiting time TP has elapsed, that is, from time t22 to time t23, the load device 20 has not started operation. Therefore, during this period, power continues to be supplied only to the auxiliary equipment 120 from the energy storage device 200, and the amount of energy stored in the energy storage device 200 decreases over time at a rate of change similar to that of the previous period (from time t21 to time t22). When the load device 20 starts operating at time t23, power is supplied from the energy storage device 200 to the auxiliary equipment 120 as well as the load device 20 during the period from time t23 to time t24 until the fuel cell module 110 has finished starting up. Therefore, during this period, the amount of energy stored in the energy storage device 200 decreases faster than in the previous period (from time t22 to time t23). The period from time t23 to time t24 corresponds to the operating time TW of the load device 20. Then, when the fuel cell module 110 starts generating power at time t24, the decrease in the amount of energy stored in the energy storage device 200 stops, and from time t24 onward, the amount of energy stored in the energy storage device 200 (remaining energy) is maintained at a constant level slightly above the allowable lower limit.

[0147] Furthermore, during the period from time t24 onward, the fuel cell system 100 may be controlled so that the power generated by the fuel cell module 110 is greater than the power consumed by the load device 20. In this case, the energy storage device 200 is charged by the surplus power from the fuel cell module 110 (see the dashed line from time t24 onward in the figure).

[0148] Thus, in this example, when the power converter 300 has finished starting up, if the operating time TW of the load device 20 is shorter than the remaining time Tr until the fuel cell module 110 has finished starting up (i.e., power generation has started), the control device 500 delays the start of operation of the load device 20 by a waiting time TP equivalent to the difference. As a result, even if the total power consumption of the load device 20 is relatively large, the control device 500 can stably operate the load device 20 using power from the energy storage device 200 until the fuel cell module 110 has finished starting up.

[0149] Furthermore, if the operating time TW of the load device 20 is shorter than the predicted remaining time Tr until the fuel cell module 110 is fully started (i.e., power generation begins) at the time the power converter 300 is fully started, the control device 500 may delay the start-up timing of the power converter 300 by a waiting time TP equivalent to the difference. In this case as well, the same effect and benefits will be achieved.

[0150] [Third example of a control method for the autonomous startup of a fuel cell system] In addition to Figures 2 to 4, a third example of a control method for the autonomous startup of the fuel cell system 100 will be described with reference to Figures 11 and 12.

[0151] In this example, it is assumed that the power supply system 30 includes multiple fuel cell systems 100 (see Figure 2).

[0152] In the following examples, we will focus on explaining the differences from the first and second examples of the control method described above, and may omit explanations of parts that are the same as or correspond to the first and second examples of the control method described above.

[0153] <Control Processing> Figure 11 is a flowchart illustrating a third example of the control process for the autonomous startup of the fuel cell system 100.

[0154] As shown in Figure 11, in step S302, the control device 500 determines whether the conditions for the self-starting of the fuel cell system 100 are met. If the conditions for the self-starting of the fuel cell system 100 are met, the control device 500 proceeds to step S304. If the conditions for the self-starting of the fuel cell system 100 are not met, the control device 500 terminates the process in this flowchart.

[0155] In step S304, the control device 500 calculates the operating time TW of the load device 20.

[0156] In this example, the operating time TW of the load device 20 refers to the time during which the load device 20 can be operated (driven) solely by power supplied from the energy storage device 200, under the premise that only one specific fuel cell system 100 (hereinafter referred to as "specific fuel cell system 100") among the multiple fuel cell systems 100 is started using the power from the energy storage device 200.

[0157] For example, the control device 500 calculates the operating time TW of the load device 20 using equation (1), similar to the second example of the control method described above. However, in this example, the amount of energy S2 means the amount of energy required to start up a specific fuel cell module 110, specifically the amount of energy required to operate the auxiliary equipment 120 of a specific fuel cell system 100 from the start-up of the specific fuel cell module 110 to the completion of the start-up.

[0158] Once step S304 is completed, the control device 500 executes steps S306, S308, S310, S312 and steps S314, S316, S318, S320 in parallel.

[0159] In step S306, the control device 500 activates the auxiliary equipment 120 of a specific fuel cell system 100 to start a specific fuel cell module 110.

[0160] Once the processing in step S306 is complete, the control device 500 proceeds to step S308.

[0161] In step S308, the control device 500 controls a specific fuel cell system 100 and starts generating power from a specific fuel cell module 110.

[0162] Once the processing in step S308 is complete, the process proceeds to step S310.

[0163] In step S310, the control device 500 controls the auxiliary equipment 120 of the remaining fuel cell systems 100, excluding a specific fuel cell system 100, among the multiple fuel cell systems 100 included in the power supply system 30, and starts up all the remaining fuel cell modules 110.

[0164] Once the processing in step S310 is complete, the control device 500 proceeds to step S312.

[0165] In step S312, the control device 500 controls the remaining fuel cell systems 100 and starts generating power from all remaining fuel cell modules 110.

[0166] On the other hand, steps S314 and S316 are the same as the processes in steps S40 and S50 in Figure 5, so their explanation will be omitted.

[0167] Once the processing in step S316 is complete, the control device 500 proceeds to step S318.

[0168] In step S318, the control device 500 determines whether the waiting time TP has elapsed, starting from the start of power supply from the power converter 300 to the outside.

[0169] If a specific fuel cell module 110, after startup is complete, is only capable of outputting power to start up all other fuel cell modules 110, then the waiting time TP is equal to the remaining time Tr1 from the start of power supply from the power converter 300 to the completion of startup for all fuel cell modules 110, minus the operating time TW. On the other hand, if a specific fuel cell module 110, after startup is complete, is capable of outputting power to start up all other fuel cell modules 110 in addition to power to operate the load device 20, then the waiting time TP is equal to the remaining time Tr2 from the start of power supply from the power converter 300 to the completion of startup for that specific fuel cell module 110, minus the operating time TW. If the value obtained by subtracting the operating time TW from the remaining time Tr1 or remaining time Tr2 is zero (0) or less, then the waiting time TP is set to zero (0).

[0170] If the waiting time TP has elapsed, the control device 500 proceeds to step S320. If the waiting time TP has not elapsed, it repeats the process in step S318 until the waiting time TP has elapsed.

[0171] Furthermore, the processing in step S318 may be moved before the processing in step S314. In this case, predicted values ​​can be used as the remaining times Tr1 and Tr2 when calculating the waiting time TP.

[0172] Step S320 is the same as the process in step S112 in Figure 7, so its explanation is omitted.

[0173] Once both steps S312 and S320 are completed, the control device 500 terminates the processing shown in this flowchart.

[0174] <Operation of the power supply system> Figure 12 is a time chart illustrating a third example of a control method for the autonomous startup of the fuel cell system 100. Specifically, it is a time chart showing a third example of the time change in the amount of energy stored in the energy storage device 200 and the operation flow of the power supply system during the autonomous startup of the fuel cell system 100.

[0175] As shown in Figure 12, in response to the fulfillment of the self-starting conditions for the fuel cell system 100, at time t31, the startup of a specific fuel cell module 110 begins (step S306 in Figure 11), and the startup of the power converter 300 begins (step S314 in Figure 11). Subsequently, at time t32, if the startup of the power converter 300 is completed before that of the specific fuel cell module 110, power supply from the fuel cell system 100 to the power distribution system 40 begins (step S316 in Figure 11). Then, at time t23, which corresponds to the time when the waiting time TP has elapsed starting from time t32, the operation (operation) of the load device 20 begins (step S320 in Figure 11). Subsequently, at time t34, if the startup of the specific fuel cell module 110 is completed, power generation by the specific fuel cell module 110 begins (step S308 in Figure 11), and the startup of all remaining fuel cell modules 110 begins (step S310 in Figure 11). Subsequently, at time t35, once the startup of all remaining fuel cell modules 110 is complete, power generation by all remaining fuel cell modules 110 begins (step S312 in Figure 11).

[0176] During the period from the start-up of a specific fuel cell module 110 and power converter 300 until the power converter 300 is fully started, i.e., from time t31 to time t32, power is supplied from the energy storage device 200 only to the auxiliary equipment 120 of the specific fuel cell system 100. Therefore, during this period, the amount of energy stored in the energy storage device 200 decreases relatively slowly over time. At time t32, the power converter 300 is fully started and begins outputting power from the power converter 300 to the power distribution system 40. However, during the waiting time TP, i.e., from time t32 to time t33, the load device 20 is not yet operational. Therefore, during this period, power continues to be supplied from the energy storage device 200 only to the auxiliary equipment 120 of the specific fuel cell system 100, and the amount of energy stored in the energy storage device 200 decreases over time at a rate of change similar to that of the previous period (from time t31 to time t32). At time t33, when the load device 20 starts up, power is supplied from the energy storage device 200 to the auxiliary equipment 120 of the specific fuel cell system 100, as well as to the load device 20, for the period from time t33 to time t34 until the startup of the specific fuel cell module 110 is complete. Therefore, during this period, the amount of energy stored in the energy storage device 200 decreases faster than in the previous period (from time t32 to time t33). At time t34, when the startup of all remaining fuel cell modules 110 begins, power is supplied from the energy storage device 200 only to the load device 20 for the period from time t34 to time t35 until the startup of all remaining fuel cell modules 110 is complete. Therefore, during this period, the amount of energy stored in the energy storage device 200 decreases more slowly than in the previous period (from time t33 to time t34). The period from time t33 to time t35 corresponds to the operating time TW of the load device 20. Then, at time t35, when power generation begins for all remaining fuel cell modules 110, the decrease in the amount of energy stored in the energy storage device 200 stops, and from time t35 onward, the amount of energy stored in the energy storage device 200 (remaining energy) is maintained at a constant level slightly above the allowable lower limit.

[0177] Furthermore, during the period from time t35 onward, the fuel cell system 100 may be controlled so that the power generated by the fuel cell module 110 is greater than the power consumed by the load device 20. In this case, the energy storage device 200 is charged by the surplus power from the fuel cell module 110 (see the dashed line from time t35 onward in the figure).

[0178] Thus, in this example, the control device 500 uses the power from the energy storage device 200 to start only a specific fuel cell module 110, and uses the power generated by that specific fuel cell module 110 to start all the remaining fuel cell modules 110. This allows the control device 500 to shorten the waiting time TP when the total power consumption of the load device 20 is relatively large. Therefore, the control device 500 can restart the load device 20 more quickly in the event of a power outage in the AC power system 10.

[0179] Furthermore, similar to the second example of the control method described above, if the operating time TW of the load device 20 is shorter than the predicted remaining time Tr1 or remaining time Tr2 until the fuel cell module 110 is fully started (i.e., power generation begins) at the time the power converter 300 is fully started, the control device 500 may delay the start-up timing of the power converter 300 by a waiting time TP equivalent to the difference. In this case as well, the same effect and benefits will be achieved.

[0180] [Fourth example of a control method for the autonomous startup of a fuel cell system] In addition to Figures 1 to 4, a fourth example of a control method for the autonomous startup of the fuel cell system 100 will be described with reference to Figures 13 to 15.

[0181] In this example, it is assumed that there are multiple load devices 20 that operate using power from the power distribution system 40.

[0182] In the following examples, we will focus on explaining the differences from the first to third examples of the control method described above, and may omit explanations of parts that are the same as or correspond to the first to third examples of the control method described above.

[0183] <Control Processing> Figures 13 to 15 are flowcharts illustrating a fourth example of the control process for the autonomous startup of the fuel cell system 100. Specifically, Figure 13 is the main flowchart of the control process in this example, while Figures 14 and 15 are sub-flowcharts showing the details of steps S404 and S414 in Figure 13, respectively.

[0184] As shown in Figure 13, in step S402, the control device 500 determines whether the conditions for the self-starting of the fuel cell system 100 are met. If the conditions for the self-starting of the fuel cell system 100 are met, the control device 500 proceeds to step S404. If the conditions for the self-starting of the fuel cell system 100 are not met, the control device 500 terminates the process in this flowchart.

[0185] In step S404, the control device 500 calculates the available operating time TWx (TW1,...,TWn) for each of the load devices 20 with a predetermined operating priority (hereinafter referred to as "operating priority"), for each of the load devices 20 with an operating priority of x (x=1,...,n; n is an integer of 2 or more).

[0186] The operating priority order represents the priority order of devices that should be operated (restarted) using the power of the energy storage device 200 before the fuel cell module 110 has finished starting up, in the event of a power outage in the AC power system 10. The operating priority order is predetermined, for example, from the perspective of BCP (Business Continuity Planning). For example, the load devices 20 with a relatively high operating priority include, for example, electrical loads with relatively low power consumption that should be restored as quickly as possible for business continuity, such as outlets and lighting. The operating priority order may also be variable according to the amount of energy stored in the energy storage device 200 (remaining energy) when the self-sustaining startup conditions are met. For example, the smaller the amount of energy stored in the energy storage device 200 when the self-sustaining startup conditions are met, the higher the operating priority order for load devices with low power consumption (e.g., outlets and lighting). Alternatively, the larger the amount of energy stored in the energy storage device 200 when the self-sustaining startup conditions are met, the higher the operating priority order for load devices with high power consumption (e.g., factory machinery and equipment).

[0187] Of the multiple load devices 20 that receive power from the power distribution system 40, the load devices 20 for which an operating priority is defined (hereinafter referred to as "priority load devices") may be some or all of them, as described above. If only some of the multiple load devices 20 are priority load devices, the remaining load devices 20 will start operation, for example, after the fuel cell module 110 has finished starting up. In addition, the remaining load devices 20 do not need to be operated when a power outage occurs in the AC power system 10.

[0188] Each of the operating priority levels from 1st to nth may be assigned to only one priority load device, or it may be assigned to multiple priority load devices.

[0189] The operating time TWx, similar to the operating time TW described above, means the time during which the load device 20 can be operated (activated) solely by power supplied from the energy storage device 200, under the premise that the fuel cell module 110 is started using the power of the energy storage device 200. If the same operating priority is assigned to multiple priority load devices, the operating time TWx for the priority load device with operating priority x means the time during which all of the priority load devices with the same operating priority x can be operated (activated) solely by power supplied from the energy storage device 200, under the premise that the fuel cell module 110 has been fully started using the power of the energy storage device 200.

[0190] For example, the control device 500 calculates the operating time TWx of the priority load device through the processing of the subflowchart in Figure 14.

[0191] As shown in Figure 14, in step S4041, the control device 500 calculates the surplus power SPx.

[0192] The surplus power SPx is the amount of power that the energy storage device 200 can supply to the priority load device with operating priority rank x, assuming that the energy storage device 200 supplies the power required for the fuel cell module 110 from startup to completion. If the power supply system 30 includes multiple fuel cell systems 100, the surplus power SPx is the amount of power that the energy storage device 200 can supply to the priority load device with operating priority rank x, assuming that the energy storage device 200 supplies the power required for all fuel cell modules 110 from startup to completion.

[0193] For example, the surplus power SP1 corresponding to the priority load device with the highest operating priority is the amount of power obtained by subtracting the amount of power required to start the fuel cell module 110 from the current amount of energy stored in the energy storage device 200 (i.e., before the start-up of the fuel cell module 110). Similarly, the surplus power SPx corresponding to priority load devices with an operating priority of 2nd or lower is the value obtained by subtracting the amount of power consumed by the priority load device with the operating priority of (x-1) during its operating time TW(x-1) from the surplus power SP(x-1) corresponding to the priority load device with the operating priority of (x-1).

[0194] Once the processing in step S4041 is complete, the control device 500 proceeds to step S4042.

[0195] In step S4042, the control device 500 determines whether the following condition (2) is met.

[0196]

number

[0197] The energy consumption Pc_x is the power consumption of the priority load device with operating priority rank x. If there are multiple priority load devices with operating priority rank x, the energy consumption Pc_x is the sum of the power consumption of each of the priority load devices assigned operating priority rank x.

[0198] The maximum operating time TWMx is the maximum value of the operating time TWx predetermined for priority load devices with operating priority rank x. The maximum operating time TWMx is predetermined to be less than or equal to the remaining time Tr (predicted value) from the start of power supply from the power converter 300 to the completion of startup of the fuel cell module 110 (TWMx ≤ Tr). In addition, the maximum operating time TWMx for priority load devices with operating priority rank 2 or lower is predetermined to be less than or equal to the maximum operating time TWM(x-1) for operating priority rank (x-1) (TWMx ≤ TWM(x-1)).

[0199] The left side of equation (3) is the amount of energy that can be supplied to the priority load device with operating priority rank x by the surplus energy SPx of the energy storage device 200. The right side of equation (3) is the amount of energy consumed by the priority load device with operating priority rank x during its maximum operating time TWMx.

[0200] If the condition in equation (2) is met, the control device 500 proceeds to step S4043; otherwise, it proceeds to step S4045.

[0201] In step S4043, the control device 500 sets the operating time TWx of the priority load device with operating priority rank x to the maximum operating time TWMx.

[0202] Once the processing in step S4043 is complete, the control device 500 proceeds to step S4044.

[0203] In step S4044, the control device 500 determines whether there is a priority load device with an even lower operating priority. If there is a priority load device with an even lower operating priority, the control device 500 repeats the process from step S4041 onwards for the immediately lower priority load device. If there is no further lower priority load device, the process in this flowchart is terminated.

[0204] Meanwhile, in step S4045, the control device 500 sets the operating time TWx of the priority load device with operating priority x using the following equation (4).

[0205]

number

[0206] Once the processing in step S4045 is complete, the control device 500 proceeds to step S4046.

[0207] In step S4046, the control device 500 determines whether there are any priority load devices with an even lower operating priority. If there are priority load devices with an even lower operating priority, the control device 500 proceeds to step S4047. If there are no priority load devices with an even lower operating priority, the process in this flowchart is terminated.

[0208] In step S4047, the control device 500 sets the operating time TW(x+1),... of all priority load devices with a lower operating priority to zero (0).

[0209] Once step S4047 is completed, the control device 500 terminates the process in this flowchart.

[0210] Returning to Figure 13, once the processing in step S404 is completed, the control device 500 executes the processing in steps S406 and S408, and the processing in steps S410, S412, and S414 in parallel.

[0211] Steps S406 and S408 are the same as the processes in steps S20 and S30 in Figure 5, so their explanation is omitted.

[0212] Steps S410 and S412 are the same as the processes in steps S40 and S50 in Figure 5, so their explanation is omitted.

[0213] Once the processing in step S412 is complete, the control device 500 proceeds to step S414.

[0214] In step S414, the control device 500 performs processing related to the operation of priority load devices based on the operating priority.

[0215] For example, the control device 500 performs the processing shown in the subflowchart of Figure 15 in parallel for each predetermined operating priority, as processing related to the operation of priority load devices based on the operating priority.

[0216] As shown in Figure 15, the control device 500 determines whether the available operating time TWx corresponding to the target operating priority, set in step S404, is greater than 0. If the available operating time TWx corresponding to the target operating priority is greater than 0, the control device 500 proceeds to step S4142. If it is less than 0 (i.e., 0), the process in this flowchart is terminated.

[0217] In step S4142, the control device 500 sets the waiting time TPx of the priority load device corresponding to the target operating priority using the following equation (5).

[0218]

number

[0219] Once the process in step S4142 is complete, the control device 500 proceeds to step S4143.

[0220] In step S4143, the control device 500 determines whether the waiting time TPx has elapsed, starting from the start of power supply from the power converter 300 to the outside. If the waiting time TPx has elapsed, the control device 500 proceeds to step S4144. If the waiting time TPx has not elapsed, the process in step S4143 is repeated until the waiting time TPx has elapsed.

[0221] This allows the start of operation of the target priority load device to be delayed by a waiting time TPx from the start of power supply to the outside of the power converter 300.

[0222] In step S4144, the control device 500 starts operation of the priority load device of the target operating priority.

[0223] Once step S4144 is completed, the control device 500 will terminate the flowchart corresponding to the target operating priority.

[0224] Returning to Figure 13, once both steps S408 and S414 are completed, the control device 500 proceeds to step S416.

[0225] In step S416, the control device 500 starts the operation of all load devices.

[0226] The load devices targeted for operation commencement in step S416 are the load devices 20 that are powered by the distribution system 40 but are not designated as priority load devices, and the priority load devices that were not commenced in the process of step S414.

[0227] Once the process in step S416 is completed, the control device 500 terminates the process in this flowchart.

[0228] <Operation of the power supply system> Figure 16 is a time chart illustrating a fourth example of a control method for the autonomous startup of the fuel cell system 100. Specifically, it is a time chart showing the time change in the amount of energy stored in the energy storage device 200 and the operation flow of the power supply system during the autonomous startup of the fuel cell system 100, as well as a fourth example of this flow.

[0229] In this example, it is assumed that the waiting time TP1 of the priority load device with the highest operating priority is zero (0), and the waiting time TP2 of the priority load device with the second highest operating priority is greater than zero (0). Furthermore, in this example, it is assumed that no priority load devices with an operating priority of 3rd place or lower are set, or that priority load devices with an operating priority of 3rd place or lower are not started before the fuel cell module 110 is started (specifically, the operating time TWx is set to zero (0) in step S4047 of Figure 14).

[0230] As shown in Figure 16, in response to the fulfillment of the conditions for the self-starting of the fuel cell system 100, the fuel cell module 110 starts up at time t41 (step S406 in Figure 13), and the power converter 300 also starts up (step S410 in Figure 13). Subsequently, at time t42, once the power converter 300 has finished starting up before the fuel cell module 110, power supply from the fuel cell system 100 to the power distribution system 40 begins (step S412), and in conjunction with this, the operation (activation) of the priority load device with the highest operating priority starts (step S4144 in Figure 15, corresponding to the highest operating priority). Then, at time t43, which corresponds to the time when the waiting time TP2 has elapsed starting from time t42, the operation (activation) of the priority load device with the second highest operating priority starts (step S4144 in Figure 15, corresponding to the second highest operating priority). Subsequently, at time t44, once the fuel cell module 110 has finished starting up, power generation by the fuel cell module 110 begins (step S408 in Figure 13), and in conjunction with this, all load devices 20 begin operation (step S416 in Figure 13).

[0231] During the period from the start-up of the fuel cell module 110 and the power converter 300 until the start-up of the power converter 300 is completed, that is, from time t41 to time t42, power is supplied only to the auxiliary equipment 120 from the energy storage device 200. Therefore, during this period, the amount of energy stored in the energy storage device 200 decreases relatively slowly over time. At time t42, when the start-up of the power converter 300 is completed and power output from the power converter 300 to the distribution system 40 begins, the priority load device with the highest operating priority starts up. Therefore, during the period immediately following the start-up of the priority load device with the highest operating priority, that is, from time t42 to time t43, power is supplied from the energy storage device 200 to the auxiliary equipment 120 as well as the priority load device with the highest operating priority. Consequently, during this period, the amount of energy stored in the energy storage device 200 decreases faster than in the previous period (from time t41 to time t42). At time t43, starting from the power output from the power converter 300 to the power distribution system 40, once the waiting time TP2 has elapsed, power is supplied from the energy storage device 200 to the auxiliary equipment 120 and the priority load device with the highest operating priority, as well as the priority load device with the second highest operating priority, until the fuel cell module 110 has finished starting up, i.e., from time t43 to time t44. Therefore, during this period, the amount of energy stored in the energy storage device 200 decreases even faster than in the previous period (from time t42 to time t43). The period from time t42 to time t44 corresponds to the operating time TW1 of the priority load device with the highest operating priority, and the period from time t43 to time t44 corresponds to the operating time TW2 of the priority load device with the second highest operating priority. Then, at time t44, when the fuel cell module 110 starts generating power, the decrease in the amount of energy stored in the energy storage device 200 stops, and from time t44 onward, the amount of energy stored in the energy storage device 200 (remaining energy) is maintained at a constant level slightly above the allowable lower limit.

[0232] Furthermore, during the period from time t44 onward, the fuel cell system 100 may be controlled so that the power generated by the fuel cell module 110 is greater than the power consumed by the load device 20. In this case, the energy storage device 200 is charged by the surplus power from the fuel cell module 110 (see the dashed line from time t44 onward in the figure).

[0233] Thus, in this example, when a power outage occurs in the AC power system 10, the control device 500 uses the remaining energy stored in the energy storage device 200 to restart some of the load devices 20 as a priority, before the fuel cell module 110 has completed its independent startup. Specifically, in this example, when a power outage occurs in the AC power system 10, the control device 500 prioritizes restarting only some of the load devices 20 (priority load devices with operating priority 1 and 2) as a priority, before the fuel cell module 110 has completed its independent startup. This allows the control device 500 to quickly restart some of the load devices 20 when a power outage occurs in the AC power system 10. Furthermore, in this example, when a power outage occurs in the AC power system 10, the control device 500 restarts some of the load devices 20 (for example, priority load devices with operating priority 1) as a priority over other load devices, before the fuel cell module 110 has completed its independent startup. As a result, the control device 500 can restart some of the load devices 20 more quickly in the event of a power outage in the AC power system 10.

[0234] [Other examples of control methods for the autonomous startup of fuel cell systems] Other examples of control methods for the autonomous startup of the fuel cell system 100 are described below.

[0235] The control methods for the autonomous startup of the fuel cell system 100 described above (Examples 1 to 4) may be modified or changed as appropriate. Hereinafter, examples of modifications or changes made to Examples 1 to 4 of the control methods described above may be conveniently referred to as "modified versions".

[0236] For example, in the third example of the control method described above, when a power outage occurs in the AC power system 10, the control device 500 may use the power of the energy storage device 200 to start up only two or more of the fuel cell modules 110, and then use the power generated by the two or more fuel cell modules 110 that have already started up to start up the remaining fuel cell modules 110.

[0237] Furthermore, in the fourth example of the control method described above, similar to the third example of the control method and its modified form, the control device 500 may, in the event of a power outage in the AC power system 10, use the power from the energy storage device 200 to start up only some of the fuel cell modules 110 among the multiple fuel cell modules 110, and then use the power generated by the fuel cell modules 110 that have already started up to start up the remaining fuel cell modules 110.

[0238] Furthermore, in the first to third examples of the control method described above and their variations, the control device 500 may, in the event of a power outage in the AC power system 10, select from among a plurality of load devices 20 that operate using power supplied from the distribution system 40 to be operated using the power of the energy storage device 200 before the independent startup of the fuel cell module 110 is completed. In this case, the selected load devices 20 may be some of the load devices 20 of the plurality of load devices 20, or all of the load devices 20. The control device 500 may also automatically select some or all of the load devices 20 to be operated, or some or all of the load devices 20 to be operated may be selected in advance by user input. In the former case, for example, the control device 500 may select some or all of the load devices 20 to be operated in a manner that varies based on various conditions such as the remaining amount of energy stored in the energy storage device 200 when the independent startup conditions are met. Specifically, the control device 500 may increase the number of load devices 20 that are operated using the power of the energy storage device 200 as the remaining charge in the energy storage device 200 increases when the conditions for independent startup are met. Alternatively, the control device 500 may select load devices 20 with high power consumption as the remaining charge in the energy storage device 200 increases when the conditions for independent startup are met.

[0239] Furthermore, in the first to fourth examples of the control methods described above and their variations, the control device 500 may pre-control the remaining charge of the energy storage device 200 so that, in the event of a power outage in the AC power system 10, the remaining charge of the energy storage device 200 is equal to or exceeds a predetermined standard before the fuel cell module 110 and the power converter 300 are started up. The predetermined standard is, for example, predetermined according to the power consumption of the load device 20 to which the energy storage device 200 will supply power before the fuel cell module 110 has finished starting up in the event of a power outage in the AC power system 10. Specifically, the predetermined standard is set to increase as the power consumption of the load device 20 increases. For example, the control device 500 charges the energy storage device 200 with the power generated by the fuel cell module 110 so that the remaining charge of the energy storage device 200 is equal to or exceeds a predetermined standard when the fuel cell module 110 and the power converter 300 are shut down. Specifically, when the conditions for shutting down the fuel cell system 100 and the power converter 300 are met, the control device 500 controls the output of the fuel cell module 110 and charges the energy storage device 200 until the remaining energy storage capacity is above or exceeds a predetermined standard, and then shuts down the fuel cell system 100 and the power converter 300. As a result, in the event of a power outage in the AC power system 10, the control device 500 can secure enough power to supply from the energy storage device 200 to the load device 20 before the fuel cell module 110 has finished starting up. Therefore, in the event of a power outage in the AC power system 10, the control device 500 can reliably restart the load device 20 before the fuel cell module 110 has finished starting up.

[0240] Furthermore, in the first to fourth examples of the control methods described above and their variations, when the conditions for the self-starting of the fuel cell system 100 are met, the control device 500 may, unlike when the conditions for normal starting are met, start the fuel cell module 110 by operating only some of the auxiliary equipment 120 of the fuel cell system 100, and then start the remaining auxiliary equipment 120 after the fuel cell module 110 has finished starting up. This allows the control device 500 to reduce the amount of power required to start the fuel cell module 110 in the event of a power outage in the AC power system 10, and to secure a larger remaining amount of stored energy in the energy storage device 200 that can be supplied to operate the load device 20 before the fuel cell module 110 has finished starting up.

[0241] Of all the auxiliary equipment 120 of the fuel cell system 100, some of the auxiliary equipment 120 targeted for activation during the self-startup of the fuel cell system 100 include, for example, auxiliary equipment 120 essential for the operation of the fuel cell module 110. Examples of auxiliary equipment 120 essential for the operation of the fuel cell module 110 include the on-off valve 132, the pump 133, the compressor 144, the on-off valve 146, and the on-off valve 152. Furthermore, some or all of the cooling auxiliary equipment 120 are not included among the auxiliary equipment 120 targeted for activation during the self-startup of the fuel cell system 100. This is because, in the stopped state of the fuel cell system 100, the temperature of the fuel cell module 110 is expected to be relatively low. Additionally, when a PEFC is used as the fuel cell cell 112, the time required to start up the fuel cell module 110 is very short, making it unlikely that the temperature of the fuel cell cell 112 will be a problem during the startup time of the fuel cell module 110. If, among all the auxiliary equipment 120 of the fuel cell system 100, some of the auxiliary equipment 120 that are started during the self-starting of the fuel cell system 100 include a cooling auxiliary equipment 120, then, for example, a pump 165 is included in that cooling auxiliary equipment 120. As a result, the coolant in the cooling circuit CC2 circulates, and although the performance is lower compared to when the coolant in the cooling circuit CC1 circulates and the fan 162 is operating, the fuel cell cell 112 can be cooled to some extent through the cooling unit 114.

[0242] Furthermore, in the first to fourth examples of the control method described above, and in their variations, assuming a plurality of power converters 300, the control device 500 may start the fuel cell module 110 and also start only some of the power converters 300 among the plurality of power converters 300 when the self-starting conditions for the fuel cell system 100 are met. In other words, the power converters 300 that are started, overlapping in the start-up period with the fuel cell module 110, when the self-starting conditions for the fuel cell system 100 are met, may be only some of the plurality of power converters 300. In this case, the subset of power converters 300 to be started are predetermined to have a total capacity capable of outputting the necessary power from the fuel cell system 100 and the energy storage device 200 to the load device 20. The necessary power is, for example, less than the maximum power consumption when power can be supplied to the load device 20 from the AC power system 10, and is predetermined as the level of power necessary to operate the load device 20 with minimum functionality in the event of a power outage in the AC power system 10. As a result, the control device 500 can distribute and start up multiple power converters 300, assuming that it can output the necessary power from the power converters 300 to the load device 20 using the power from the fuel cell module 110 and the energy storage device 200 during a power outage in the AC power system 10. Then, the control device 500 starts up the remaining power converters 300 after some of the power converters 300 have finished starting up. In this case, the control device 500 may start up the remaining power converters 300 all at once, or it may start them sequentially in multiple stages. Furthermore, the remaining power converters 300 may be started at least after the fuel cell module 110, which is started first, has finished starting up, or they may be started at a predetermined timing corresponding to the completion of some of the power converters 300, regardless of whether the fuel cell module 110 has finished starting up or not.

[0243] For example, based on the third example of the control method described above and its variations, when the conditions for the self-starting of the fuel cell system 100 are met, the control device 500 starts some of the fuel cell modules 110 and also starts some of the power converters 300 that correspond to some of the fuel cell modules 110. Then, after the startup of some of the fuel cell modules 110 and some of the power converters 300 is complete, the control device 500 may start the remaining fuel cell modules 110 and the remaining power converters 300.

[0244] [Effect] The operation of the power supply system, control device, and control method according to this embodiment will be described.

[0245] In a first aspect of this embodiment, the power supply system comprises a fuel cell, a power storage device, a power converter, 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 module 110 described above. The power storage device is, for example, the power storage device 200 described above. The power converter is, for example, the power converter 300 described above. The control device is, for example, the control device 500 described above. Specifically, the power storage device is electrically connected to the fuel cell. The power converter is also electrically connected to the fuel cell and the power storage device and is capable of outputting power supplied from at least one of the fuel cell and the power storage device to an external load device. The load device is, for example, the load device 20 described above. The control device controls the fuel cell and the power converter. When the power system supplying power to the load device experiences a power outage while the fuel cell and the power converter are stopped, the control device uses the power from the power storage device to start the fuel cell and the power converter.

[0246] Furthermore, in the first aspect of this embodiment, the control device may be provided outside the power supply system.

[0247] Furthermore, in a first aspect of this embodiment, a control method is provided for a power supply system comprising a fuel cell, an energy storage device electrically connected to the fuel cell, and a power converter electrically connected to the fuel cell and the energy storage device, capable of outputting power supplied from at least one of the fuel cell and the energy storage device to an external load device. Specifically, the control method is provided such that when the power system supplying power to the load device experiences a power outage while the fuel cell and the power converter are stopped, the control device starts the fuel cell using the power from the energy storage device and also starts the power converter.

[0248] This allows the control device to start the fuel cell and power converter in parallel during a power outage. In other words, the control device can overlap at least a portion of the time it takes to start the fuel cell and power converter during a power outage. Therefore, the control device can shorten the time it takes for both the fuel cell and power converter to start up from a stopped state compared to, for example, starting them in series. Thus, the control device can start supplying power from the fuel cell to the load device more quickly.

[0249] Furthermore, in a second aspect of this embodiment, based on the first aspect described above, the control device may start the fuel cell and the power converter if the power system experiences a power outage while the fuel cell and the power converter are stopped, such that the timing of the completion of startup of the power converter is later than the timing of the start of startup of the fuel cell, and the timing of the start of startup of the power converter is earlier than the timing of the completion of startup of the fuel cell.

[0250] As a result, the control device can overlap at least a portion of the time it takes to start up the fuel cell and the power converter in the event of a power outage in the power grid, allowing it to start supplying power from the fuel cell to the load device more quickly.

[0251] Furthermore, in a third aspect of this embodiment, based on the first or second aspect described above, the control device may start the fuel cell and the power converter if the power system experiences a power outage while the fuel cell and the power converter are stopped, such that the timing of the power converter's startup completion is earlier than the timing of the fuel cell's startup completion.

[0252] As a result, the control unit can complete the startup of the power converter before the fuel cell has finished starting up in the event of a power outage in the power grid, and begin supplying power from the energy storage device to the load device through the power converter. Therefore, the control unit can restart the load device more quickly in the event of a power outage in the power grid.

[0253] Furthermore, in a fourth aspect of this embodiment, based on the third aspect described above, if the power system experiences a power outage while the fuel cell and the power converter are stopped, the control device may start the fuel cell and the power converter such that the timing of the power converter's startup completion is before the timing of the fuel cell's startup completion. Once the power converter has started up, the control device may wait until a predetermined timing before the fuel cell's startup completion before starting the load device. The predetermined timing is, for example, the timing after the waiting time TP has elapsed, starting from the completion of the power converter 300's startup.

[0254] This allows the control device to prevent a situation in which, during a power outage in the power grid, the power available from the energy storage device to the load device is depleted before the fuel cell has finished starting up, resulting in a loss of power supply to the load device.

[0255] Furthermore, in a fifth aspect of this embodiment, based on the third or fourth aspect described above, if the power system experiences a power outage while the fuel cell and the power converter are stopped, the control device may start the power converter after the start of the fuel cell has begun, wait until a predetermined timing, and start the fuel cell and the power converter such that the timing of the completion of the power converter's startup is before the timing of the completion of the fuel cell's startup. The predetermined timing is, for example, the timing after the waiting time TP has elapsed, starting from the start of the fuel cell module 110 described above.

[0256] This allows the control device to prevent a situation in which, during a power outage in the power grid, the power available from the energy storage device to the load device is depleted before the fuel cell has finished starting up, resulting in a loss of power supply to the load device.

[0257] Furthermore, in a sixth aspect of this embodiment, based on the fourth or fifth aspect described above, the predetermined timing may be determined based on the remaining charge of the energy storage device, the amount of power required from the start-up of the fuel cell to the completion of the start-up, and the power consumption of the load device.

[0258] This allows the control device to appropriately determine a predetermined timing so that, in the event of a power outage in the power grid, it can continue supplying power from the energy storage device to the load device until the fuel cell has finished starting up.

[0259] Furthermore, in the seventh aspect of this embodiment, assuming any one of the third to sixth aspects described above, there may be multiple fuel cells. If the power system experiences a power outage while the multiple fuel cells and the power converter are shut down, the control device may start some of the multiple fuel cells and the power converter, and after some of the fuel cells have finished starting up, it may start the remaining fuel cells. Some of the fuel cells are, for example, the specific fuel cell module 110 described above.

[0260] As a result, when a power outage occurs in the power system, the control device can start some of the fuel cells first, and use the power of some of the fuel cells that have completed startup to supply the power for starting the remaining fuel cells. Therefore, the control device can suppress the amount of power output from the power storage device for starting a plurality of fuel cells. Thus, when a power outage occurs in the power system, the control device can operate the load device for a longer period using the power supplied from the power storage device before the startup of a plurality of fuel cells is completed.

[0261] Also, in the eighth aspect of the present embodiment, on the premise of any one of the first to seventh aspects described above, there may be a plurality of the load devices. When a power outage occurs in the power system while the fuel cell and the power conversion device are stopped, the control device starts the fuel cell and starts the power conversion device, and between after the startup of the power conversion device is completed and before the startup of the fuel cell is completed, by outputting the power supplied from the power storage device from the power conversion device to the load device, some of the load devices among the plurality of load devices may be preferentially operated.

[0262] As a result, when a power outage occurs in the power system, before the startup of the fuel cell is completed, the control device can preferentially operate some of the load devices among the plurality of load devices using the limited power of the power storage device.

[0263] Also, in the ninth aspect of the present embodiment, on the premise of the eighth aspect described above, priorities may be defined in advance for each of the plurality of load devices. The priority is, for example, the operation priority order described above. When a power outage occurs in the power system while the fuel cell and the power conversion device are stopped, the control device starts the fuel cell and starts the power conversion device, and between after the startup of the power conversion device is completed and before the startup of the fuel cell is completed, by outputting the power supplied from the power storage device from the power conversion device to the load device, some of the load devices with a higher priority among the plurality of load devices may be preferentially operated.

[0264] Thereby, when a power outage occurs in the power system, before the fuel cell is started up, the control device can preferentially operate some of the plurality of load devices by using the power of the limited power storage device.

[0265] Also, in the tenth aspect of the present embodiment, on the premise of the above-described eighth or ninth aspect, the plurality of load devices may include a first load device and a second load device. The first load device and the second load device are, for example, a priority load device with an operation priority rank of 1 and a priority load device with an operation priority rank of 2. Then, when a power outage occurs in the power system while the fuel cell and the power conversion device are stopped, the control device starts up the fuel cell and starts up the power conversion device, and between after the start-up of the power conversion device and before the start-up of the fuel cell, by outputting the power supplied from the power storage device from the power conversion device to the load device, the first load device and the second load device may be started up at different timings.

[0266] Thereby, when a power outage occurs in the power system, before the fuel cell is started up, the control device can preferentially start up either one of the first load device and the second load device by using the power of the limited power storage device.

[0267] Also, in the eleventh aspect of the present embodiment, on the premise of any one of the above-described eighth to tenth aspects, when a power outage occurs in the power system while the fuel cell and the power conversion device are stopped, the control device starts up the fuel cell and starts up the power conversion device, and between after the start-up of the power conversion device and before the start-up of the fuel cell, by outputting the power supplied from the power storage device from the power conversion device to the load device, only some of the plurality of load devices may be operated.

[0268] This allows the control system, in the event of a power outage in the power grid, to prioritize restarting only some of the load devices among multiple load devices using the limited power of the energy storage device before the fuel cell has finished starting up.

[0269] Furthermore, in the twelfth aspect of this embodiment, assuming any one of the third to eleventh aspects described above, there may be multiple load devices. The control device may, when the power system experiences a power outage while the fuel cell and the power converter are stopped, start the fuel cell and the power converter, and between the completion of the power converter's startup and the completion of the fuel cell's startup, cause the power supplied from the energy storage device to be output from the power converter to the load devices, thereby operating some or all of the load devices selected according to the remaining charge of the energy storage device from among the multiple load devices.

[0270] This allows the control device to restart some or all of the load devices so that, in the event of a power outage in the power grid, power can be continuously supplied from the energy storage device to the load devices before the fuel cell has finished starting up.

[0271] Furthermore, in the 13th aspect of this embodiment, based on any one of the third to 12 aspects described above, the power supply system may include a plurality of electrically operated auxiliary devices for the fuel cell. The auxiliary devices are, for example, the auxiliary device 120 described above. The control device may start the fuel cell by using the power of the energy storage device to operate only some of the plurality of auxiliary devices if the power system experiences a power outage while the fuel cell and the power converter are shut down.

[0272] As a result, the control device can reduce the amount of power required from the start-up to the completion of the fuel cell startup in the event of a power outage in the power grid. Therefore, in the event of a power outage in the power grid, the control device can secure a larger amount of power that can be supplied from the energy storage device to the load device before the fuel cell startup is complete. Thus, in the event of a power outage in the power grid, the control device can operate the load device for a longer period of time using the power supplied from the energy storage device before the startup of multiple fuel cells is complete.

[0273] Furthermore, in the 14th aspect of this embodiment, based on any one of the third to 13 aspects described above, the control device may use the power of the fuel cell to charge the energy storage device so that the remaining amount of energy stored in the energy storage device when the fuel cell and the power converter are stopped is relatively large compared to a predetermined standard.

[0274] This allows the control device to pre-adjust the remaining charge of the energy storage device so that it can maintain a relatively large amount of charge in the event of a power outage in the power grid. As a result, in the event of a power outage in the power grid, the control device can operate the load equipment for a longer period of time using the power supplied from the energy storage device before the multiple fuel cells have finished starting up.

[0275] Furthermore, in the 15th aspect of this embodiment, based on the 14th aspect described above, the predetermined standard may be defined based on the power consumption of the load device.

[0276] This allows the control device to pre-adjust the remaining energy level of the energy storage device so that the energy storage device can maintain an energy level corresponding to the power consumption of the load device powered by the energy storage device.

[0277] Also, in the 16th aspect of the present embodiment, on the premise of any one of the above-described 1st to 15th aspects, there may be a plurality of the power conversion devices. And when a power outage occurs in the power system while the fuel cell and the power conversion devices are stopped, the control device uses the power of the power storage device to start the fuel cell and starts only some of the plurality of power conversion devices, and after the start of some of the power conversion devices, the remaining power conversion devices may be started.

[0278] Thereby, the control device can start the plurality of power conversion devices in a time series while the fuel cell is being started on the premise that, for example, necessary power from the fuel cell and the power storage device can be supplied to the load device by some of the power conversion devices.

[0279] Although the embodiments have been described in detail above, the present disclosure is not limited to such specific embodiments, and various modifications and changes are possible within the scope of the gist described in the claims.

Explanation of Signs

[0280] 1 Power system 10 AC power system 20 Load device 30 Power supply system 40 Power distribution system 100 Fuel cell system 110 Fuel cell module 112 Fuel cell 114 Cooling unit 116 Converter device 120 Auxiliary machine 130 Fuel supply unit 131 Hydrogen supply source 132 On-off valve 133 Pump 134 Gas-liquid separator 140 Air supply unit 142 Air cleaner 144 Compressor 146 On-off valve 150 Discharge unit 152 Shut-off valve 154 Mixer 156 Gas-liquid separator 160 Cooling section 161 Cooler 162 fans 163 Pump 164 Heat exchanger 165 pump 166 Ion exchanger 200 Energy storage devices 250 DC Link Section 300 Power converter 400 transformer 500 Control Device

Claims

1. Fuel cells and A power storage device electrically connected to the fuel cell, A power converter that is electrically connected to the fuel cell and the energy storage device and capable of outputting power supplied from at least one of the fuel cell and the energy storage device to an external load device, The system comprises a control device for controlling the fuel cell and the power converter, When the power supply system providing power to the load device experiences a power outage while the fuel cell and the power converter are shut down, the control device uses the power from the energy storage device to start the fuel cell and the power converter. Power supply system.

2. The control device, when the power system experiences a power outage while the fuel cell and the power converter are shut down, starts the fuel cell and the power converter such that the timing of the power converter's startup completion is later than the timing of the fuel cell's startup start-up, and the timing of the power converter's startup start-up is earlier than the timing of the fuel cell's startup completion. The power supply system according to claim 1.

3. The control device, when the power system experiences a power outage while the fuel cell and the power converter are shut down, starts the fuel cell and the power converter such that the timing of the power converter's startup completion is earlier than the timing of the fuel cell's startup completion. The power supply system according to claim 2.

4. If the power system experiences a power outage while the fuel cell and power converter are shut down, the control device will start the fuel cell and power converter so that the power converter completes startup before the fuel cell completes startup. Once the power converter has finished starting up, the control device will wait until a predetermined time before the fuel cell has finished starting up before starting up the load device. The power supply system according to claim 3.

5. If the power system experiences a power outage while the fuel cell and the power converter are shut down, the control device will wait until a predetermined timing after the fuel cell has started up before starting the power converter, and will start the fuel cell and the power converter such that the timing of the power converter's startup completion is before the timing of the fuel cell's startup completion. The power supply system according to claim 3.

6. The predetermined timing is determined based on the remaining charge of the energy storage device, the amount of electricity required from the start-up of the fuel cell to the completion of the start-up, and the power consumption of the load device. The power supply system according to claim 4 or 5.

7. There are multiple fuel cells, When the power grid experiences a power outage while the multiple fuel cells and the power converter are shut down, the control device starts some of the multiple fuel cells and the power converter, and after the start-up of some of the fuel cells is complete, it starts the remaining fuel cells. A power supply system according to any one of claims 3 to 5.

8. There are multiple load devices, The control device, when the power system experiences a power outage while the fuel cell and the power converter are shut down, starts the fuel cell and the power converter, and between the completion of the power converter's startup and the completion of the fuel cell's startup, outputs power supplied from the energy storage device to the load devices via the power converter, thereby prioritizing the operation of some of the multiple load devices. The power supply system according to any one of claims 3 to 5.

9. Each of the aforementioned load devices has a predetermined priority. The control device, when the power system experiences a power outage while the fuel cell and the power converter are shut down, starts the fuel cell and the power converter, and between the completion of the power converter's startup and the completion of the fuel cell's startup, outputs power supplied from the energy storage device to the load device from the power converter, thereby prioritizing the operation of some of the load devices with higher priority among the multiple load devices. The power supply system according to claim 8.

10. The plurality of load devices include a first load device and a second load device, The control device, when the power system experiences a power outage while the fuel cell and the power converter are shut down, starts the fuel cell and the power converter, and between the completion of the power converter's startup and the completion of the fuel cell's startup, outputs power supplied from the energy storage device to the load device from the power converter, thereby starting the first load device and the second load device at different timings. The power supply system according to claim 8.

11. The control device, when the power system experiences a power outage while the fuel cell and the power converter are shut down, starts the fuel cell and the power converter, and between the time the power converter has finished starting up and the time the fuel cell has finished starting up, outputs power supplied from the energy storage device to the load devices from the power converter, thereby operating only some of the load devices among the multiple load devices. The power supply system according to claim 8.

12. There are multiple load devices, The control device, when the power system experiences a power outage while the fuel cell and the power converter are shut down, starts the fuel cell and the power converter, and between the completion of the power converter's startup and the completion of the fuel cell's startup, outputs power supplied from the energy storage device to the load devices from the power converter, thereby operating some or all of the load devices selected according to the remaining charge of the energy storage device from among the multiple load devices. A power supply system according to any one of claims 3 to 5.

13. The fuel cell is equipped with multiple auxiliary devices that operate on electricity, The control device, when the power grid experiences a power outage while the fuel cell and the power converter are shut down, starts the fuel cell by using the power from the energy storage device to operate only some of the auxiliary equipment among the plurality of auxiliary equipment. A power supply system according to any one of claims 3 to 5.

14. The control device charges the energy storage device using the power of the fuel cell so that the remaining amount of energy in the energy storage device is relatively large compared to a predetermined standard when the fuel cell and the power converter are shut down. A power supply system according to any one of claims 3 to 5.

15. The aforementioned predetermined standard is defined based on the power consumption of the load device. The power supply system according to claim 14.

16. There are multiple power conversion devices, When the power grid experiences a power outage while the fuel cell and the power converter are shut down, the control device uses the power from the energy storage device to start the fuel cell, and starts only some of the power converters among the multiple power converters, and starts the remaining power converters after the start-up of some of the power converters is complete. A power supply system according to any one of claims 1 to 5.

17. A power supply system comprising a fuel cell, an energy storage device electrically connected to the fuel cell, and a power converter electrically connected to the fuel cell and the energy storage device, capable of outputting power supplied from at least one of the fuel cell and the energy storage device to an external load device, If the power grid supplying power to the load device experiences a power outage while the fuel cell and the power converter are shut down, the power storage device is used to start the fuel cell and the power converter. Control device.

18. A control method performed by a control device for a power supply system comprising a fuel cell, an energy storage device electrically connected to the fuel cell, and a power converter electrically connected to the fuel cell and the energy storage device, capable of outputting power supplied from at least one of the fuel cell and the energy storage device to an external load device, wherein If the power grid supplying power to the load device experiences a power outage while the fuel cell and the power converter are shut down, the power storage device is used to start the fuel cell and the power converter. Control method.

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