Power supply system

Abstract

To ensure that power is supplied to the control device when it is not possible to supply power to the control device through the power supply path via the uninterruptible power supply (UPS). [Solution] A power supply system connected to the power lines of a power grid via a switch, comprising: an AC bus connected to the power lines via the switch; an inverter electrically connected to the AC bus; a fuel cell connected to the inverter via a DC bus; a secondary battery electrically connected to the DC bus; a control device for controlling the power supply system; an uninterruptible power supply electrically connected to the AC bus; a first power supply system that supplies power to the control device via a first power supply path passing through the uninterruptible power supply; and a second power supply system that supplies power from the secondary battery to the control device via a second power supply path different from the first power supply path.

Description

Technical Field

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

Background Art

[0002] When there is an abnormality (power outage) in the commercial power system, a power generation system that is disconnected from the commercial power system and supplies power only to the self - supporting load system is known. This power generation system includes an AC power supply path connected to the commercial power system via a switch, a power conditioner connected to the AC power supply path, a power generation device connected to the power conditioner via a DC power supply path, a first storage battery connected to the DC power supply path, a control device for controlling the power generation system, and a second storage battery connected to the AC power supply path. The second storage battery is an uninterruptible power supply device that continues to supply power to the control device even when there is a power loss. Since the control device can receive power supply from the second storage battery (uninterruptible power supply device) when the power system has a power outage, it can perform a control operation to keep the power conditioner in a state where power can be supplied (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the conventional technology, when the power system has a power outage and power cannot be supplied from the uninterruptible power supply device to the control device due to an abnormality of the uninterruptible power supply device or the like, it becomes difficult to continue the control by the control device.

[0005] The present disclosure provides a power supply system capable of securing power supplied to a control device when power cannot be supplied to the control device through a power supply path passing through an uninterruptible power supply device.

Means for Solving the Problems

[0006] As one aspect of this disclosure, A power supply system connected to power grid lines via a switch, An AC bus connected to the aforementioned wire via the aforementioned switch, An inverse converter electrically connected to the aforementioned AC bus, A fuel cell connected to the aforementioned inverse converter via a DC bus, A secondary battery electrically connected to the DC bus, A control device for controlling the power supply system, An uninterruptible power supply electrically connected to the aforementioned AC bus, A first power supply system that supplies power to the control device via a first power supply path passing through the aforementioned uninterruptible power supply, A power supply system is provided, which includes a second power supply system that supplies power from the secondary battery to the control device via a second power supply path different from the first power supply path. [Effects of the Invention]

[0007] According to one aspect of this disclosure, power can be secured to supply power to a control device when power cannot be supplied to the control device through the power supply path via an uninterruptible power supply. [Brief explanation of the drawing]

[0008] [Figure 1] This figure shows an example configuration of a power supply system according to the first embodiment. [Figure 2] This flowchart shows an example of a power supply system control method. [Figure 3] This figure shows an example configuration of a power supply system according to the second embodiment. [Modes for carrying out the invention]

[0009] The embodiments will be described below with reference to the drawings.

[0010] Figure 1 is a diagram showing an example configuration of a power supply system according to the first embodiment. The power supply system 101 shown in Figure 1 is connected to the power lines 2 of the power grid 1 via a switch 3. The power supply system 101 is a fuel cell power generation system capable of supplying electricity generated by a fuel cell 40 to the power grid 1 or a load 4.

[0011] When power system 1 is functioning normally, power supply system 101 connects to power system 1 via switch 3, which is in the ON position. While connected to power system 1, power supply system 101 receives power from power system 1 or supplies power to power system 1.

[0012] On the other hand, in the event of a power outage or other abnormality in power system 1, the power supply system 101 is disconnected from the power lines 2 of power system 1 by switch 3. With the power supply system 101 disconnected from the power lines 2 of power system 1 by switch 3, it can, for example, supply power obtained from the fuel cell 40 or secondary battery 50 to the load 4 through independent operation, or it can stop its own operation.

[0013] Power system 1 transmits power output from power supply system 101 or a power generation facility (not shown) via alternating current. Power system 1 includes wires 2 and switches 3. Wires 2 transmit alternating current power. Specific examples of wires 2 include transmission lines and distribution lines. Switches 3 are installed between wires 2 and power supply system 101 and connect or disconnect wires 2 and power supply system 101. Switches 3 may also be components of power supply system 101. Specific examples of switches 3 include circuit breakers.

[0014] Load 4 is electrically connected to power grid 1 and power supply system 101 via AC busbar 11 and operates on power supplied from at least one of power grid 1 and power supply system 101. Load 4 is electrically connected to power line 2 via AC busbar 11 and switch 3. Load 4 is, for example, equipment installed in the same location as power supply system 101, and more specifically, production equipment installed in the same factory as power supply system 101. Load 4 is not limited to these examples.

[0015] The power supply system 101 includes an AC bus 11, an inverter device 20, a transformer 30, a fuel cell 40, a secondary battery 50, a control device 60, an uninterruptible power supply device 70, an auxiliary machine system 130, a first power supply system 80, and a second power supply system 90.

[0016] The AC bus 11 is a wire connected to the wire 2 via the switch 3 and transmits AC power.

[0017] The inverter device 20 is a power conversion device electrically connected to the AC bus 11. In this example, the inverter device 20 is electrically connected to the AC bus 11 via the transformer 30. The inverter device 20 converts the DC power input from the DC bus 12 into AC power and outputs the converted AC power to the AC bus 11.

[0018] When the switch 3 is on, the inverter device 20 is connected to the wire 2 of the power system 1, and when the switch 3 is off, the inverter device 20 is disconnected from the wire 2 of the power system 1.

[0019] When the power system 1 is normal, the inverter device 20 is connected to the wire 2 of the power system 1 and exchanges power between the power system 1 and the DC bus 12. When an abnormality such as a power outage occurs in the power system 1, the inverter device 20 is disconnected from the wire 2 of the power system 1 by the switch 3. In the state of being disconnected from the wire 2 by the switch 3, the inverter device 20 performs an independent operation of converting the power obtained from the fuel cell 40 or the secondary battery 50 via the DC bus 12 and supplying it to the load 4, or stops its own operation.

[0020] The inverter device 20 converts the DC of the DC bus 12 into AC with a predetermined voltage and frequency and outputs it toward the transformer 30. For example, the inverter device 20 is a power conditioner (PCS: Power Conditioning System) including an inverter circuit that converts DC into three-phase AC with a predetermined voltage and frequency.

[0021] The transformer 30 transforms (specifically, boosts) the AC output from the inverter 20, and outputs the boosted AC to the power system 1 or load 4 via the AC bus 11.

[0022] In Figure 1, the inverter 20 includes multiple inverters (in this example, four inverters 20a, 20b, 20c, and 20d) connected in parallel between the AC bus 11 and the DC bus 12. However, the inverter 20 may also be a single inverter electrically connected between the AC bus 11 and the DC bus 12. In Figure 1, the transformer 30 includes multiple transformers (in this example, four transformers 30a, 30b, 30c, and 30d) connected in parallel between the AC bus 11 and the DC bus 12. However, the transformer 30 may also be a single transformer electrically connected between the AC bus 11 and the DC bus 12. The series circuit of the inverter 20 and the transformer 30 may be multiple units connected in parallel between the AC bus 11 and the DC bus 12, or it may be a single unit.

[0023] The fuel cell 40 is connected to the inverter 20 via the DC bus 12. In Figure 1, the fuel cell 40 includes multiple fuel cells (in this example, four fuel cells 40a, 40b, 40c, and 40d) connected in parallel to the DC bus 12. However, the fuel cell 40 may be a single fuel cell electrically connected to the DC bus 12.

[0024] The fuel cell 40 generates electricity through a chemical reaction between hydrogen supplied from the fuel system 131 and oxygen contained in the air supplied from the air supply system. The fuel cell 40 may also be a unit including a fuel cell module and auxiliary equipment.

[0025] The fuel cell module includes, for example, a fuel cell stack that generates electricity through a chemical reaction between hydrogen supplied from a fuel system 131 and oxygen contained in air supplied from an air supply system. The fuel cell stack has a stack structure in which multiple cells are stacked. The fuel cell stack is, for example, a polymer electrolyte fuel cell (PEFC). However, the fuel cell stack may also be other types of fuel cells such as a phosphate fuel cell (PAFC), a solid oxide fuel cell (SOFC), or a molten carbonate fuel cell (MCFC).

[0026] The fuel cell module may include an air compressor that compresses air supplied from the air supply system and supplies it to the fuel cell stack, a coolant pump that circulates coolant between the heat exchanger and the fuel cell stack, and the like.

[0027] The auxiliary equipment included in the fuel cell 40 is equipment for operating the fuel cell stack and assists in the power generation operation of the fuel cell stack. The auxiliary equipment may include at least one of the following: fuel lines, air lines, air filters, exhaust lines, heat exchangers, etc. The fuel lines are pipes that supply hydrogen supplied from the fuel system 131 to the fuel electrodes of the fuel cell stack. The air lines are pipes that supply air supplied from the air supply system to the air electrodes of the fuel cell stack. The air filters remove impurities from the air supplied from the air supply system. The air purified by the air filters is supplied to the air compressor via the air lines. The exhaust lines discharge exhaust gas generated in the fuel cell stack to the exhaust system. The heat exchangers cool the coolant used to cool the fuel cell stack by exchanging heat with a cooling source.

[0028] The secondary battery 50 is electrically connected to the DC bus 12. The secondary battery 50 can discharge power to the outside of the power system 101 via the inverter 20 and the transformer 30, and can also charge (store) power supplied from the fuel cell 40 via the DC bus 12. The secondary battery 50 is, for example, a capacitor such as a lithium-ion capacitor (LIC). The secondary battery 50 may also be a storage battery such as a lithium-ion battery with a liquid electrolyte or an all-solid-state battery with a solid electrolyte. The secondary battery 50 is electrically connected to the inverter 20 and the fuel cell 40 via the DC bus 12.

[0029] The number of secondary batteries 50 may be one or more. The secondary batteries 50 may consist of multiple secondary batteries connected in parallel to the DC bus 12. The secondary batteries 50 may also include multiple secondary batteries connected in series.

[0030] The control device 60 controls the power supply system 101. For example, the control device 60 controls the inverter 20 and the auxiliary equipment system 130. The control device 60 is, for example, a PLC (Programmable Logic Controller).

[0031] The control device 60 includes, for example, an electronic circuit such as a CPU (Central Processing Unit), an FPGA (Field Programmable Gate Array), or an ASIC (Application Specific Integrated Circuit). The control device 60 may also be a computer having memory and a processor. The control device 60 performs the various control operations described in this specification by executing a program such as instruction code stored in memory, or by designing a circuit for a special application.

[0032] The control device 60 may have a function to detect whether the power system 1 is normal or abnormal based on the detection result of the voltage of the power system 1. The control device 60 may also detect whether or not there is an abnormality in the power system 1 by other known detection methods. For example, if the control device 60 detects that the state of the power system 1 is abnormal, such as a power outage, while the switch 3 is ON, it switches the switch 3 from ON to OFF. For example, if the control device 60 detects that the state of the power system 1 is normal (for example, the power system 1 has recovered from an abnormality such as a power outage) while the switch 3 is OFF, it switches the switch 3 from OFF to ON.

[0033] The control device 60 operates the inverter 20 in a grid-connected operation mode, for example, when switch 3 is on (i.e., when power system 1 is functioning normally), in which power is exchanged between power system 1 and DC bus 12. The control device 60 operates the inverter 20 in a standalone operation mode, for example, when switch 3 is off (i.e., when power system 1 is experiencing an abnormality such as a power outage), in which power obtained from the fuel cell 40 or secondary battery 50 via DC bus 12 is reverse-converted and supplied to load 4. The control device 60 may also stop the operation of the inverter 20 when switch 3 is off (i.e., when power system 1 is experiencing an abnormality such as a power outage). In this case, the control device 60 may also stop the fuel cell 40. The control device 60 may also stop the auxiliary system 130 and the fuel cell 40 simultaneously or sequentially.

[0034] The control device 60 may perform a process to start the power supply system 101 in a stopped state (start-up process), or it may perform a process to stop the power supply system 101 in an operating state (stop-down process). Starting the power supply system 101 means starting the auxiliary equipment system 130 of the power supply system 101 while the power supply system 101 is stopped, and starting the fuel cell 40 while the auxiliary equipment system 130 is running. Stopping the power supply system 101 means stopping the operation of the auxiliary equipment system 130 and the fuel cell 40 simultaneously or sequentially.

[0035] The uninterruptible power supply (UPS) 70 is electrically connected to the AC bus 11. The UPS is sometimes referred to as an UPS. The UPS 70 is installed in the AC power path connecting the AC bus 11 and the control device 60. The UPS 70 can store the power supplied through the AC bus 11. Specifically, the UPS 70 can store the power of the power system 1 supplied through the AC bus 11. The UPS 70 may also store power supplied from the fuel cell 40 or secondary battery 50 through the inverter 20 and the AC bus 11.

[0036] The uninterruptible power supply (UPS) 70 supplies AC driving power to the control device 60 and the auxiliary equipment system 130 via the first power supply path 81. For example, the UPS 70 supplies AC driving power to the control device 60 and the auxiliary equipment system 130 via the first power supply path 81 by discharging the power stored within itself and converting the discharged power into AC of a predetermined voltage and frequency. As a result, the UPS 70 can operate the control device 60 and the auxiliary equipment system 130 even when the power supply from the AC bus 11 is stopped, for example, due to the switch 3 being turned off or the inverter 20 being stopped.

[0037] The uninterruptible power supply (UPS) 70 may supply AC driving power to the control device 60 and the auxiliary equipment system 130 via the first power supply path 81 by converting the AC supplied from the AC bus 11 into AC of a predetermined voltage and frequency. This allows the UPS 70 to directly operate the control device 60 and the auxiliary equipment system 130 with the power supplied from the AC bus 11.

[0038] The uninterruptible power supply 70 includes, for example, a rectifier unit that converts the AC of the AC bus 11 to DC and outputs it to a DC link, a power storage unit connected to the DC link, and an inverter unit that converts the DC of the DC link to AC of a predetermined voltage and frequency and outputs it to the first power supply path 81.

[0039] The auxiliary system 130 is a system for operating the fuel cell 40 and receives power from the first power supply system 80. The auxiliary system 130 includes a first auxiliary system that receives power from both the first power supply system 80 and the second power supply system 90, and a second auxiliary system that receives power from the first power supply system 80 but not from the second power supply system 90. In the example shown in Figure 1, the auxiliary system 130 includes the fuel system 131 and the purge system 132 as the first auxiliary system, and the cooler 133 as the second auxiliary system.

[0040] The fuel system 131 supplies fuel such as hydrogen to the fuel cell 40. The fuel system 131 includes a fuel pipe that supplies fuel such as hydrogen to the fuel cell 40, and a fuel valve provided in the fuel pipe. The fuel valve is operated by electricity supplied from the first power supply system 80 or the second power supply system 90. The opening and closing of the fuel valve is controlled by the control device 60. When the fuel valve is open, fuel such as hydrogen is supplied to the fuel cell 40, and when the fuel valve is closed, the supply of fuel such as hydrogen to the fuel cell 40 is stopped.

[0041] The purge system 132 supplies an inert gas such as nitrogen to the fuel system 131. The purge system 132 includes a purge pipe that supplies an inert gas such as nitrogen to the fuel piping of the fuel system 131, and a purge valve provided in the purge pipe. The purge valve is operated by power supplied from the first power supply system 80 or the second power supply system 90. The opening and closing of the purge valve is controlled by the control device 60. When the purge valve is open, an inert gas such as nitrogen is supplied to the fuel piping of the fuel system 131, and when the purge valve is closed, the supply of an inert gas such as nitrogen to the fuel piping is stopped.

[0042] The cooler 133 is a device for cooling the fuel cell 40. The cooler 133 has a cooling source for cooling the coolant used to cool the fuel cell stack within the fuel cell 40, for example. Examples of coolers 133 include air-cooled coolers, open-type cooling towers, and closed-type cooling towers. However, the cooler 133 is not limited to these. The cooler 133 operates on power supplied from the first power supply system 80, but in this example, it cannot receive power from the second power supply system 90. However, as a modification of the power supply system 101, the cooler 133 may be a device that can receive power from the second power supply system 90. The operation of the cooler 133 is controlled by the control device 60.

[0043] The auxiliary system 130 may include other auxiliary systems besides these auxiliary systems (fuel system 131, purge system 132, and cooler 133). Examples of other auxiliary systems include an air supply system that supplies air to the fuel cell 40 and an exhaust system that discharges exhaust gas from the fuel cell 40. The other auxiliary system may be a first auxiliary system that receives power from both the first power supply system 80 and the second power supply system 90, or a second auxiliary system that receives power from the first power supply system 80 but not from the second power supply system 90. The other auxiliary system may have an auxiliary valve that operates using power supplied from the first power supply system 80 or the second power supply system 90. The opening and closing of this auxiliary valve is controlled by the control device 60.

[0044] The power supply system 101 may include an auxiliary unit 140 that cannot receive power from the first power supply system 80 but can receive power directly from the AC bus 11. The auxiliary unit 140 is an auxiliary unit not included in the auxiliary unit system 130 and operates on power supplied from the AC bus 11. The auxiliary unit 140 is a device that is operated when the fuel cell 40 is started up, but it does not necessarily have to be operated when the fuel cell 40 is started up, and it does not need to receive power (backup) from the first power supply system 80. An example of the auxiliary unit 140 is a fan that generates an airflow that passes through the cooler 133. If at least one of the supply air system that supplies air to the fuel cell 40 and the exhaust system that discharges exhaust gas from the fuel cell 40 is not included in the auxiliary unit system 130, the auxiliary unit 140 may be at least one of those systems. For example, if the cooler 133 is not included in the auxiliary unit system 130, the auxiliary unit 140 may be the cooler 133. The auxiliary unit 140 is controlled by the control device 60.

[0045] The first power supply system 80 supplies power to the control device 60 and the auxiliary equipment system 130 via a first power supply path 81 that passes through the uninterruptible power supply 70. The first power supply system 80 supplies power to the control device 60 and the auxiliary equipment system 130 via the uninterruptible power supply 70. In this example, the first power supply system 80 includes a transformer 71 and the first power supply path 81.

[0046] The transformer 71 transforms (specifically, steps down) the AC from the AC bus 11 and outputs the stepped-down AC to the uninterruptible power supply 70. The first power supply path 81 is a power supply line through which power passes via the uninterruptible power supply 70. The first power supply path 81 is electrically connected to the control device 60 and the auxiliary equipment system 130 so as to be able to supply power.

[0047] The second power supply system 90 supplies power from the secondary battery 50 to the control device 60 via a second power supply route 91 that is different from the first power supply route 81. In this example, the second power supply system 90 not only supplies power from the secondary battery 50 to the control device 60 via the second power supply route 91, but also supplies power from the secondary battery 50 to at least a portion of the auxiliary equipment system 130 via the second power supply route 91. In the example shown in Figure 1, the second power supply system 90 supplies power to the fuel system 131 and the purge system 132 of the auxiliary equipment system 130. The second power supply system 90 supplies the power discharged from the secondary battery 50. If the fuel cell 40 is generating power, the second power supply system 90 may supply the power output from the fuel cell 40 to the control device 60 via the second power supply route 91, or to at least a portion of the auxiliary equipment system 130 via the second power supply route 91.

[0048] The second power supply system 90 includes, for example, a DC / AC converter 92 and a second power supply path 91. The DC / AC converter 92 converts DC power supplied from the secondary battery 50 or fuel cell 40 via the DC bus 12 into AC power and outputs the converted AC power to the second power supply path 91. The second power supply path 91 is a power supply line through which the DC power supplied from the secondary battery 50 or fuel cell 40 via the DC bus 12 passes, and is a different path from the first power supply path 81. The second power supply path 91 is electrically connected to the control device 60 and at least a portion of the auxiliary equipment system 130 (in this example, the fuel system 131 and the purge system 132) so as to be able to supply power.

[0049] As described above, the power supply system 101 according to the first embodiment includes a first power supply system 80 that supplies power to the control device 60 and the auxiliary equipment system 130 via a first power supply path 81 that passes through the uninterruptible power supply 70. By including the first power supply system 80, the power supply system 101 can supply power to the control device 60 and the auxiliary equipment system 130 via the first power supply path 81 even when the power supply from the AC bus 11 is stopped due to the switch 3 being turned off or the inverter 20 being stopped. As a result, even if the switch 3 is turned off due to an abnormality such as a power outage in the power system 1, the control device 60 is powered by the first power supply system 80 and can control the power supply system 101 (for example, the inverter 20 can be controlled in self-sustaining operation mode). Alternatively, even if the power supply system 101 is stopped and the switch 3 is turned off, the control device 60 and the auxiliary equipment system 130 are powered by the first power supply system 80, so the control device 60 can start the power supply system 101 using the auxiliary equipment system 130.

[0050] Furthermore, the power supply system 101 according to the first embodiment includes a second power supply system 90 that supplies power from the secondary battery 50 to the control device 60 via a second power supply route 91 that is different from the first power supply route 81 that passes through the uninterruptible power supply 70. The second power supply route 91 is a route that does not pass through the uninterruptible power supply 70. By including the second power supply system 90, the power supply system 101 can supply power from the secondary battery 50 to the control device 60 via the second power supply route 91 even when the first power supply system 80 is unable to supply power to the control device 60 via the first power supply route 81, thereby ensuring that power can be supplied to the control device 60. As a result, even when the first power supply system 80 is unable to supply power to the control device 60 via the first power supply route 81, the control device 60 is powered by the second power supply system 90, so the control of the power supply system 101 (for example, control of the inverter 20 in independent operation mode) can be started or operation can continue.

[0051] A state in which the first power supply system 80 cannot supply power to the control device 60 via the first power supply path 81 may be referred to below as an abnormality in the first power supply system 80. Examples of abnormalities in the first power supply system 80 include an abnormality in the uninterruptible power supply 70 and a break in the first power supply path 81. Examples of abnormalities in the uninterruptible power supply 70 include a failure of the uninterruptible power supply 70 and depletion of the power stored in the uninterruptible power supply 70 (a drop in the stored voltage to below a predetermined value).

[0052] Even if switch 3 is off due to a power outage or other abnormality in power system 1, and there is an abnormality in the first power supply system 80, the control device 60 is powered by the second power supply system 90. Therefore, the control device 60 can start or continue controlling the power supply system 101 (for example, controlling the inverter 20 in independent operation mode).

[0053] Even when the power supply system 101 is stopped, switch 3 is off, and there is a malfunction in the first power supply system 80, the control device 60 and the auxiliary equipment system 130 are powered by the second power supply system 90. Therefore, the control device 60 can start the power supply system 101 using the auxiliary equipment system 130.

[0054] The power supply system 101 may include a switching device 110 that is electrically connected to the first power supply system 80, the second power supply system 90, and the control device 60. The switching device 110 switches whether the first power supply system 80 supplies power to the control device 60 or the second power supply system 90 supplies power to the control device 60. In other words, the switching device 110 selects either the first power supply system 80 or the second power supply system 90 as the system that supplies power to the control device 60. By selecting the first power supply system 80 as the system that supplies power to the control device 60, the power supply from the second power supply system 90 is stopped while the first power supply system 80 is supplying power to the control device 60, thus suppressing the discharge of the secondary battery 50. Suppressing the discharge of the secondary battery 50 contributes to energy saving.

[0055] The switching device 110 switches the power supply system to the control device 60 to the second power supply system 90 when there is an abnormality in the first power supply system 80. This ensures that power to the control device 60 is quickly secured by the second power supply system 90 when there is an abnormality in the first power supply system 80. For example, if an abnormality in the first power supply system 80 is detected by at least one of the control device 60 and the voltage detection device, the switching device 110 switches the power supply system to the control device 60 to the second power supply system 90 based on a switching command from at least one of the control device 60 and the voltage detection device. The control device 60 detects an abnormality in the first power supply system 80, for example, by detecting an error signal indicating an abnormality in the uninterruptible power supply 70. The voltage detection device detects an abnormality in the first power supply system 80, for example, by detecting an abnormal voltage value in the first power supply system 80.

[0056] The switching device 110 may switch the power supply system to the control device 60 to the first power supply system 80 when the first power supply system 80 returns from an abnormal state to a normal state.

[0057] In the example shown in Figure 1, the switching device 110 includes changeover switches 111, 112, and 113. Changeover switch 111 is a component that switches whether the first power supply system 80 supplies power to the control device 60 or the second power supply system 90 supplies power to the control device 60. Changeover switch 112 is a component that switches whether the first power supply system 80 supplies power to the fuel system 131 or the second power supply system 90 supplies power to the fuel system 131. Changeover switch 113 is a component that switches whether the first power supply system 80 supplies power to the purge system 132 or the second power supply system 90 supplies power to the purge system 132. Changeover switches 111, 112, and 113 each operate in response to a switching command from at least one of the control device 60 and the voltage detection device.

[0058] For example, when an abnormality in the first power supply system 80 is detected by at least one of the control device 60 and the voltage detection device, the changeover switch 111 switches the system supplying power to the control device 60 to the second power supply system 90 in response to a switching command from at least one of the control device 60 and the voltage detection device. For example, when an abnormality in the first power supply system 80 is detected by at least one of the control device 60 and the voltage detection device, the changeover switch 112 switches the system supplying power to the fuel system 131 to the second power supply system 90 in response to a switching command from at least one of the control device 60 and the voltage detection device. For example, when an abnormality in the first power supply system 80 is detected by at least one of the control device 60 and the voltage detection device, the changeover switch 113 switches the system supplying power to the purge system 132 to the second power supply system 90 in response to a switching command from at least one of the control device 60 and the voltage detection device. Therefore, in the event of an abnormality in the first power supply system 80, power to be supplied to the control device 60, fuel system 131, and purge system 132 is quickly secured by the second power supply system 90.

[0059] The changeover switch 111 may switch the power supply system to the control device 60 to the first power supply system 80 when the first power supply system 80 returns to a normal state from an abnormal state. The changeover switch 112 may switch the power supply system to the fuel system 131 to the first power supply system 80 when the first power supply system 80 returns to a normal state from an abnormal state. The changeover switch 113 may switch the power supply system to the purge system 132 to the first power supply system 80 when the first power supply system 80 returns to a normal state from an abnormal state.

[0060] The second power supply system 90 includes a DC / AC converter 92 as a power conversion device that converts power from the secondary battery 50 into power to be supplied to the control device 60. The DC / AC converter 92 converts the DC power from the secondary battery 50 into AC power, thereby supplying AC drive power to the control device 60 and the auxiliary equipment system 130 via the second power supply path 91.

[0061] The control device 60 stops the DC / AC converter 92 when the power supply system to the control device 60 is the first power supply system 80, and operates the DC / AC converter 92 when the power supply system to the control device 60 is the second power supply system 90. As a result, the conversion operation of the DC / AC converter 92 is stopped while the control device 60 is being powered by the first power supply system 80, so that the discharge of the secondary battery 50 is suppressed.

[0062] Figure 2 is a flowchart showing an example of a control method for the power supply system 101. The control method shown in Figure 2 is executed by the control device 60.

[0063] In step S11, the control device 60 determines whether or not an abnormality has occurred in power system 1 based on the detection results of the voltage of power system 1. If an abnormality in power system 1 is detected, the control device 60 turns off switch 3 (step S13). As a result, the power supply system 101 is disconnected from the power lines 2 of power system 1.

[0064] In step S15, the control device 60 determines whether the conditions for independent operation are met. If the conditions for independent operation are met, the control device 60 controls the inverter 20 in independent operation mode (step S17). As a result, the electricity generated by the fuel cell 40 is supplied to the load 4.

[0065] On the other hand, if the conditions for independent operation are not met, the control device 60 executes a process (shutdown process) to stop the operating power supply system 101. This reduces unnecessary power consumption. In step S19, the control device 60 simultaneously or sequentially stops the operation of the auxiliary equipment system 130 and the fuel cell 40. After the fuel cell 40 and the auxiliary equipment system 130 are stopped, the control device 60 stops the uninterruptible power supply 70 (step S21). This reduces the power consumption of the uninterruptible power supply 70 compared to when the uninterruptible power supply 70 continues to operate.

[0066] In step S23, the control device 60 determines whether the startup conditions for performing a startup process (startup process) to start the power supply system 101, which is in a stopped state, are met. If the startup conditions are not met, the control device 60 continues to keep the power supply system 101 in a stopped state. On the other hand, if the startup conditions are met, the control device 60 executes the startup process. The startup conditions may include a blackout start condition.

[0067] If the startup conditions are met, the control device 60 restarts the stopped uninterruptible power supply 70 during the startup process (step S25). Once the uninterruptible power supply 70 is restarted, the auxiliary system 130 becomes operational. After the uninterruptible power supply 70 is restarted, the control device 60 restarts the auxiliary system 130 (step S27). By restarting the auxiliary system 130, the control device 60 restarts the fuel cell 40 (step S29).

[0068] In step S31, the control device 60 determines whether the power system 1 has recovered from its abnormality based on the detection results of the voltage of the power system 1. If the power system 1 has not recovered (if the abnormality persists), the control device 60 controls the inverter 20 in self-sustaining operation mode so that power is supplied to the load 4 (step S17). On the other hand, if the power system 1 has recovered, the control device 60 does not control the inverter 20 in self-sustaining operation mode (step S32) and turns on switch 3 (step S33). As a result, the power supply system 101 is connected to the power system 1.

[0069] Here, in step S27, the control device 60 may restart multiple systems included in the stopped auxiliary system 130 according to a predetermined priority order. For example, the control device 60 may restart the stopped fuel system 131 without starting at least one of the stopped purge system 132 and the stopped cooler 133. At least one of the stopped purge system 132 and the stopped cooler 133 is a different system from the fuel system 131 among the multiple systems included in the stopped auxiliary system 130. By restarting the high-priority fuel system 131, fuel such as hydrogen can be supplied to the fuel cell 40 quickly. By not starting at least one of the stopped purge system 132 and the stopped cooler 133, the power consumption of the uninterruptible power supply 70 can be reduced.

[0070] In step S27, the control device 60 may decide whether or not to start up other systems from among the multiple systems included in the stopped auxiliary system 130, which are different from the fuel system 131, according to the power supply capacity of the uninterruptible power supply 70. The power supply capacity of the uninterruptible power supply 70 is determined, for example, by the backup time or stored voltage of the uninterruptible power supply 70. The longer the backup time or the higher the stored voltage of the uninterruptible power supply 70, the higher the power supply capacity of the uninterruptible power supply 70. Therefore, the control device 60 may restart other systems different from the fuel system 131 according to priority, according to the power supply capacity of the uninterruptible power supply 70. This makes it possible to restart auxiliary systems that are suitable for the power supply capacity of the uninterruptible power supply 70.

[0071] Figure 3 shows an example configuration of a power supply system according to the second embodiment. In the second embodiment, the description of the configuration, operation, and effects similar to those of the first embodiment will be omitted by referring to the above description. The power supply system 102 according to the second embodiment shown in Figure 3 differs from the power supply system 101 according to the first embodiment in the first power supply system 80, the second power supply system 90, and the switching device 120.

[0072] The first power supply system 80 supplies power to the control device 60 and the auxiliary equipment system 130 via a first power supply path 81 that passes through the uninterruptible power supply 70. In this example, the first power supply system 80 includes an AC / DC converter 82. The AC / DC converter 82 converts the AC power supplied via the first power supply path 81 that passes through the uninterruptible power supply 70 into DC power, and outputs the converted DC power to the control device 60 and the fuel system 131. In this example, the AC / DC converter 82 outputs the converted DC power to the control device 60 and the fuel system 131 via a switching device 120.

[0073] The second power supply system 90 supplies power from the secondary battery 50 to the control device 60 via a second power supply route 91 that is different from the first power supply route 81. In this example, the second power supply system 90 supplies power to the fuel system 131 of the auxiliary equipment system 130.

[0074] The second power supply system 90 includes a DC / DC converter 93. The DC / DC converter 93 converts the DC power supplied from the secondary battery 50 or fuel cell 40 via the DC bus 12 into DC power of a different voltage value (specifically, step-down conversion), and outputs the converted DC power to the control device 60 and the fuel system 131. In this example, the DC / DC converter 93 outputs the converted DC power to the control device 60 and the fuel system 131 via a switching device 120.

[0075] The auxiliary equipment system 130 includes a first auxiliary equipment system that can receive power from the first power supply system 80 and the second power supply system 90, and a second auxiliary equipment system that can receive power from the first power supply system 80 but not from the second power supply system 90. In the example shown in Figure 3, the auxiliary equipment system 130 includes a fuel system 131 as the first auxiliary equipment system, and a purge system 132 and a cooler 133 as the second auxiliary equipment system.

[0076] The power supply system 102 according to the second embodiment includes a second power supply system 90 that supplies power from the secondary battery 50 to the control device 60 via a second power supply route 91 that is different from the first power supply route 81 that passes through the uninterruptible power supply 70. The second power supply route 91 is a route that does not pass through the uninterruptible power supply 70. By including the second power supply system 90, the power supply system 102 can supply power from the secondary battery 50 to the control device 60 via the second power supply route 91 even when the first power supply system 80 is unable to supply power to the control device 60 via the first power supply route 81, thereby ensuring that power can be supplied to the control device 60. As a result, even when the first power supply system 80 is unable to supply power to the control device 60 via the first power supply route 81, the control device 60 is powered by the second power supply system 90, so the control of the power supply system 102 (for example, control of the inverter 20 in independent operation mode) can be started or operation can continue.

[0077] The power supply system 102 may include a switching device 120 that is electrically connected to the first power supply system 80, the second power supply system 90, and the control device 60. The switching device 120 switches whether the first power supply system 80 supplies power to the control device 60 or the second power supply system 90 supplies power to the control device 60. In other words, the switching device 120 selects either the first power supply system 80 or the second power supply system 90 as the system that supplies power to the control device 60. By selecting the first power supply system 80 as the system that supplies power to the control device 60, the power supply from the second power supply system 90 is stopped while the first power supply system 80 is supplying power to the control device 60, thus suppressing the discharge of the secondary battery 50. Suppressing the discharge of the secondary battery 50 contributes to energy saving.

[0078] The switching device 120 switches the power supply system to the control device 60 to the second power supply system 90 when the first power supply system 80 malfunctions. This ensures that power to the control device 60 is quickly secured by the second power supply system 90 when the first power supply system 80 malfunctions. For example, the switching device 120 includes a wired OR 121 that switches whether the first power supply system 80 or the second power supply system 90 supplies power to the control device 60. The wired OR 121 is implemented, for example, by a diode OR circuit.

[0079] The switching device 120 automatically switches the power supply system to the control device 60 to the second power supply system 90 if the output voltage of the AC / DC converter 82 falls below the output voltage of the DC / DC converter 93 due to an abnormality in the first power supply system 80, etc. The switching device 120 automatically switches the power supply system to the control device 60 back to the first power supply system 80 if the output voltage of the AC / DC converter 82 rises above the output voltage of the DC / DC converter 93 due to recovery from an abnormality in the first power supply system 80, etc. The switching device 120 can automatically switch the power supply system to the control device 60 to the first power supply system 80 or the second power supply system 90 using the wired OR 121, depending on the relative magnitudes of the output voltages of the AC / DC converter 82 and the DC / DC converter 93.

[0080] As described above, embodiments have been explained, but these embodiments are presented as examples only, and the present invention is not limited by these embodiments. The above embodiments can be implemented in various other forms, and various combinations, omissions, substitutions, and modifications are possible without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims of the invention and its equivalents. [Explanation of symbols]

[0081] 1 Power system 2 electric wire 3 switches 4 load 11 AC busbar 12 DC bus 20 Inverse converter 30 Transformers 40 Fuel Cell 50 Secondary battery 60 Control device 70 Uninterruptible power supply 80. First Power Supply System 81. First power supply route 82 AC / DC Converters 90 Second Power Supply System 91 Second power supply route 92 DC / AC Converter 93 DC / DC Converter 101,102 Power Systems 110 Switching device 111, 112, 113 toggle switch 120 Switching device 121 Wired Or 130 Auxiliary Equipment System 131 Fuel system 132 Purge System 133 Cooler 140 Auxiliary equipment

Claims

1. A power supply system connected to power grid lines via a switch, An AC bus connected to the aforementioned wire via the aforementioned switch, An inverse converter electrically connected to the aforementioned AC bus, A fuel cell connected to the aforementioned inverse converter via a DC bus, A secondary battery electrically connected to the DC bus, A control device for controlling the power supply system, An uninterruptible power supply electrically connected to the aforementioned AC bus, A first power supply system that supplies power to the control device via a first power supply path passing through the aforementioned uninterruptible power supply, A power supply system comprising: a second power supply system that supplies power from the secondary battery to the control device via a second power supply path different from the first power supply path.

2. The system includes a switching device that is electrically connected to the first power supply system, the second power supply system, and the control device. The power supply system according to claim 1, wherein the switching device switches whether the first power supply system supplies power to the control device or the second power supply system supplies power to the control device.

3. The power supply system according to claim 2, wherein the switching device switches the power supply system to the control device to the second power supply system when the first power supply system is abnormal.

4. The power supply system according to claim 3, wherein the abnormality of the first power supply system includes an abnormality of the uninterruptible power supply.

5. The power supply system according to any one of claims 2 to 4, wherein the switching device includes a changeover switch that switches whether the first power supply system supplies power to the control device or the second power supply system supplies power to the control device.

6. The power supply system according to any one of claims 2 to 4, wherein the switching device includes a wired OR that switches whether the first power supply system supplies power to the control device or the second power supply system supplies power to the control device.

7. The power supply system according to any one of claims 1 to 4, wherein the second power supply system includes a power conversion device that converts power from the secondary battery into power supplied to the control device.

8. The power supply system according to claim 7, wherein the power converter stops when the power supply system to the control device is the first power supply system, and operates when the power supply system to the control device is the second power supply system.

9. The power supply system according to any one of claims 1 to 4, comprising an auxiliary system for operating the fuel cell, which can receive power from the first power supply system.

10. The power supply system according to claim 9, wherein the auxiliary equipment system includes a first auxiliary equipment system that can receive power from the first power supply system and power from the second power supply system.

11. The power supply system according to claim 10, wherein the first auxiliary system includes a fuel system for supplying hydrogen to the fuel cell.

12. The power supply system according to claim 11, wherein the first auxiliary system includes a purge system that supplies an inert gas to the fuel system.

13. The power supply system according to claim 10, wherein the auxiliary equipment system includes a second auxiliary equipment system that can receive power from the first power supply system but cannot receive power from the second power supply system.

14. The power supply system according to claim 13, wherein the second auxiliary system includes a cooler for cooling the fuel cell.

15. The power supply system according to claim 9, wherein the uninterruptible power supply unit stops after the fuel cell and the auxiliary equipment system have stopped when the switch is off.

16. The auxiliary system includes a fuel system that supplies hydrogen to the fuel cell and other systems different from the fuel system. The power supply system according to claim 15, wherein, when the switch is off, the control device starts the uninterruptible power supply which is in a stopped state, and then starts the fuel system which is in a stopped state without starting the other systems which are in a stopped state.

17. The power supply system according to claim 16, wherein the control device determines whether or not to start the other stopped systems according to the power supply capacity of the uninterruptible power supply.

18. The power supply system according to any one of claims 1 to 4, wherein when the switch is off, the power obtained from the fuel cell by the autonomous operation of the inverter is supplied to the load.

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