Power System

Abstract

To secure power to be supplied to a control device when power cannot be supplied to the control device via a power supply path passing through an uninterruptible power supply. [Solution] A power supply system connected to an electric wire of a power grid via a switch, the power supply system comprising: an AC bus connected to the electric wire 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 that controls 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 that passes 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 power supply systems. [Background technology]

[0002] A power generation system is known that, in the event of a power outage in the commercial power system, is disconnected from the commercial power system and supplies power only to an isolated load system. This power generation system includes an AC current path connected to the commercial power system via a switch, a power conditioner connected to the AC current path, a power generation device connected to the power conditioner via a DC current path, a first storage battery connected to the DC current path, a control device that controls the power generation system, and a second storage battery connected to the AC current path. The second storage battery is an uninterruptible power supply that continues to supply power to the control device even in the event of a power loss. The control device can receive power from the second storage battery (uninterruptible power supply) in the event of a power outage in the power system, and therefore can perform control operations to maintain a state in which power can be supplied to the power conditioner (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2017 / 163625 Summary of the Invention [Problem to be solved by the invention]

[0004] However, with conventional technology, if the uninterruptible power supply cannot supply power to the control device due to an abnormality in the uninterruptible power supply during a power outage in the power grid, it becomes difficult for the control device to continue control.

[0005] The present disclosure provides a power supply system that can ensure power supply to a control device when power cannot be supplied to the control device via a power supply path that passes through an uninterruptible power supply. [Means for solving the problem]

[0006] As one aspect of the present disclosure, A power supply system connected to an electric power grid via a switch, an AC bus connected to the electric line 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 that controls 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 that passes through the uninterruptible power supply; The power supply system 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 the present disclosure, it is possible to ensure power to be supplied to a control device when power cannot be supplied to the control device via a power supply path that passes through an uninterruptible power supply. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a diagram illustrating an example of the configuration of a power supply system according to a first embodiment. [Figure 2] 10 is a flowchart illustrating an example of a control method for a power supply system. [Figure 3] FIG. 10 is a diagram illustrating an example of the configuration of a power supply system according to a second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, an embodiment will be described with reference to the drawings.

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

[0011] When the power grid 1 is operating normally, the power supply system 101 is interconnected with the power grid 1 via the switch 3 which is in the on state. When the power supply system 101 is interconnected with the power grid 1, the power supply system 101 receives power from the power grid 1 or supplies power to the power grid 1.

[0012] On the other hand, in the event of an abnormality such as a power outage in the power grid 1, the power supply system 101 is disconnected from the electric wire 2 of the power grid 1 by a switch 3. In a state in which the power supply system 101 is disconnected from the electric wire 2 of the power grid 1 by the switch 3, the power supply system 101 supplies electric power obtained from, for example, the fuel cell 40 or the secondary battery 50 to the load 4 through independent operation, or stops its own operation.

[0013] The power system 1 transmits AC power output from a power supply system 101 or a power generation facility (not shown). The power system 1 includes an electric wire 2 and a switch 3. The electric wire 2 transmits AC power. Specific examples of the electric wire 2 include a transmission line or a distribution line. The switch 3 is provided between the electric wire 2 and the power supply system 101, and connects or disconnects the electric wire 2 and the power supply system 101. The switch 3 may be a component of the power supply system 101. Specific examples of the switch 3 include a system breaker.

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

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

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

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

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

[0019] When the power system 1 is operating normally, the inverter 20 is connected to the power line 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 20 is disconnected from the power line 2 of the power system 1 by a switch 3. When the inverter 20 is disconnected from the power line 2 by the switch 3, the inverter 20 performs an independent operation, for example, by reverse-converting the power obtained from the fuel cell 40 or the secondary battery 50 via the DC bus 12 and supplying the power to the load 4, or it stops its own operation.

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

[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 the load 4 via the AC bus 11.

[0022] In FIG. 1 , the inverter 20 includes a plurality of inverters (four inverters 20a, 20b, 20c, and 20d in this example) connected in parallel between the AC bus 11 and the DC bus 12. However, the inverter 20 may be a single inverter electrically connected between the AC bus 11 and the DC bus 12. In FIG. 1 , the transformer 30 includes a plurality of transformers (four transformers 30a, 30b, 30c, and 30d in this example) connected in parallel between the AC bus 11 and the DC bus 12. However, the transformer 30 may be a single transformer electrically connected between the AC bus 11 and the DC bus 12. A single series circuit, or a plurality of series circuits each including an inverter 20 and a transformer 30, may be provided in parallel between the AC bus 11 and the DC bus 12.

[0023] The fuel cell 40 is connected to the inverter 20 via the DC bus 12. In FIG. 1, the fuel cell 40 includes a plurality of fuel cells (four fuel cells 40a, 40b, 40c, and 40d in this example) 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 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 the fuel system 131 and oxygen contained in air supplied from the air supply system. The fuel cell stack has a stack structure in which a plurality of cells are stacked. The fuel cell stack is, for example, a polymer electrolyte fuel cell (PEFC). However, the fuel cell stack may also be another type of fuel cell, such as a phosphoric acid 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 an 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 the fuel cell stack in generating electricity. The auxiliary equipment may include at least one of a fuel pipe, an air pipe, an air filter, an exhaust pipe, a heat exchanger, etc. The fuel pipe is a pipe that supplies hydrogen supplied from the fuel system 131 to the fuel electrode of the fuel cell stack. The air pipe is a pipe that supplies air supplied from the air supply system to the air electrode of the fuel cell stack. The air filter removes impurities from the air supplied from the air supply system. The air purified by the air filter is supplied to the air compressor via the air pipe. The exhaust pipe discharges exhaust gas generated in the fuel cell stack into the exhaust system. The heat exchanger cools the coolant used to cool the fuel cell stack by exchanging heat with a cold 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 supply 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 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 be a plurality of secondary batteries connected in parallel to the DC bus 12. The secondary batteries 50 may include a plurality of 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 system 130. The control device 60 is, for example, a PLC (Programmable Logic Controller).

[0031] The control device 60 includes electronic circuits such as a central processing unit (CPU), a field programmable gate array (FPGA), or an application specific integrated circuit (ASIC). The control device 60 may be a computer having a memory and a processor. The control device 60 executes various control operations described in this specification by executing programs such as instruction codes stored in the memory, or by being a circuit designed for a specific 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, etc. The control device 60 may also detect the presence or absence of an abnormality in the power system 1 using other known detection methods. For example, when 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 in the on state, the control device 60 switches the switch 3 from on to off. For example, when 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 in the off state, the control device 60 switches the switch 3 from off to on.

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

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

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

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

[0037] The uninterruptible power supply 70 may convert the AC power supplied from the AC bus 11 into AC power of a predetermined voltage and frequency, and supply AC drive power to the control device 60 and the auxiliary system 130 via the first power supply path 81. This allows the uninterruptible power supply 70 to operate the control device 60 and the auxiliary system 130 directly using 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 into DC and outputs it to a DC link, a storage unit connected to the DC link, and an inverter unit that converts the DC of the DC link into 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 is supplied with power from the first power supply system 80. The auxiliary system 130 includes a first auxiliary system that can receive power from the first power supply system 80 and from the second power supply system 90, and a second auxiliary system that can receive power from the first power supply system 80 but cannot receive power from the second power supply system 90. In the example shown in Fig. 1 , the auxiliary system 130 includes a fuel system 131 and a purge system 132 as the first auxiliary system, and a 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 operates using power 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 the inert gas such as nitrogen to the fuel pipe of the fuel system 131, and a purge valve provided in the purge pipe. The purge valve operates using 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, the inert gas such as nitrogen is supplied to the fuel pipe of the fuel system 131, and when the purge valve is closed, the supply of the inert gas such as nitrogen to the fuel pipe is stopped.

[0042] The cooler 133 is a device for cooling the fuel cell 40. The cooler 133 has, for example, a cold source for cooling a coolant for cooling the fuel cell stack in the fuel cell 40. Examples of the cooler 133 include an air-cooled cooler, an open-type cooling tower, and a closed-type cooling tower. The cooler 133 is not limited to these. The cooler 133 operates using power supplied from the first power supply system 80, but in this example, it is not supplied with 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 is supplied with 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 auxiliary systems other than these auxiliary systems (fuel system 131, purge system 132, and cooler 133). Examples of the other auxiliary systems include an air intake 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 can be supplied with power from the first power supply system 80 and the second power supply system 90, or a second auxiliary system that can be supplied with 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 device 140 that cannot receive power from the first power supply system 80 but can receive power directly from the AC bus 11. The auxiliary device 140 is an auxiliary device that is not included in the auxiliary system 130 and operates using power supplied from the AC bus 11. The auxiliary device 140 is a device that operates when the fuel cell 40 starts up, but it does not necessarily have to operate when the fuel cell 40 starts up, and it does not necessarily have to receive power (backup) from the first power supply system 80. An example of the auxiliary device 140 is a fan that generates an airflow that passes through the cooler 133. If the auxiliary system 130 does not include at least one of an air intake system that supplies air to the fuel cell 40 and an exhaust system that discharges exhaust gas from the fuel cell 40, the auxiliary device 140 may be at least one of these systems. For example, if the cooler 133 is not included in the auxiliary system 130, the auxiliary device 140 may be the cooler 133. The auxiliary device 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 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 that passes through the uninterruptible power supply 70 to the control device 60 and the auxiliary system 130. 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 system 130 so as to be able to supply power to them.

[0047] The second power feeding system 90 feeds power from the secondary battery 50 to the control device 60 via a second power feeding path 91 different from the first power feeding path 81. In this example, the second power feeding system 90 not only feeds power from the secondary battery 50 to the control device 60 via the second power feeding path 91, but also feeds power from the secondary battery 50 to at least a part of the auxiliary system 130 via the second power feeding path 91. In the example shown in FIG. 1 , the second power feeding system 90 feeds power to a fuel system 131 and a purge system 132 of the auxiliary system 130. The second power feeding system 90 supplies power discharged from the secondary battery 50. When the fuel cell 40 is generating power, the second power feeding system 90 may feed the power output from the fuel cell 40 to the control device 60 via the second power feeding path 91, or may feed power to at least a part of the auxiliary system 130 via the second power feeding path 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 the 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 the fuel cell 40 via the DC bus 12 passes, and is a path different 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 part of the auxiliary system 130 (in this example, the fuel system 131 and the purge system 132) so as to be able to supply power to them.

[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 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 system 130 via the first power supply path 81 even when the switch 3 is turned off or the inverter 20 is stopped, thereby stopping the power supply from the AC bus 11. As a result, even when 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 supplied with power from the first power supply system 80, and therefore can control the power supply system 101 (for example, can control the inverter 20 in an isolated operation mode). Alternatively, even when the power supply system 101 is stopped and the switch 3 is off, the control device 60 and the auxiliary system 130 are supplied with power from the first power supply system 80, and therefore the control device 60 can start up the power supply system 101 using the auxiliary system 130.

[0050] 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 path 91 that is different from the first power supply path 81 that passes through the uninterruptible power supply 70. The second power supply path 91 is a path 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 path 91 even when the first power supply system 80 cannot supply power to the control device 60 via the first power supply path 81, thereby ensuring power to be supplied to the control device 60. As a result, even when the first power supply system 80 cannot supply power to the control device 60 via the first power supply path 81, the control device 60 is supplied with power from the second power supply system 90, and therefore control of the power supply system 101 (e.g., control of the inverter 20 in the isolated operation mode) can be started or continued.

[0051] Hereinafter, 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 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 a loss of power stored in the uninterruptible power supply 70 (a drop in the stored voltage below a predetermined value).

[0052] Even if the switch 3 is off due to an abnormality such as a power outage in the power system 1 and an abnormality occurs in the first power supply system 80, the control device 60 is supplied with power from the second power supply system 90. Therefore, the control device 60 can start or continue to control the power supply system 101 (for example, control the inverter 20 in the isolated operation mode).

[0053] Even when the power supply system 101 is stopped, the switch 3 is off, and there is an abnormality in the first power supply system 80, the control device 60 and the auxiliary system 130 are supplied with power by the second power supply system 90. Therefore, the control device 60 can start up the power supply system 101 using the auxiliary system 130.

[0054] The power supply system 101 may include a switching device 110 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 between whether the first power supply system 80 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. When the switching device 110 selects the first power supply system 80 as the system that supplies power to the control device 60, power supply from the second power supply system 90 is stopped while power is being supplied to the control device 60 by the first power supply system 80, thereby suppressing discharge of the secondary battery 50. Suppressing discharge of the secondary battery 50 contributes to energy conservation.

[0055] The switching device 110 switches the system supplying power to the control device 60 to the second power supply system 90 when an abnormality occurs in the first power supply system 80. As a result, when an abnormality occurs in the first power supply system 80, power to be supplied to the control device 60 is quickly secured by the second power supply system 90. 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 switching device 110 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. The control device 60 detects the 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 the abnormality in the first power supply system 80, for example, by detecting an abnormal value of the voltage of the first power supply system 80.

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

[0057] 1, the switching device 110 includes changeover switches 111, 112, and 113. The changeover switch 111 is a component that switches whether the first power feeding system 80 feeds power to the control device 60 or the second power feeding system 90 feeds power to the control device 60. The changeover switch 112 is a component that switches whether the first power feeding system 80 feeds power to the fuel system 131 or the second power feeding system 90 feeds power to the fuel system 131. The changeover switch 113 is a component that switches whether the first power feeding system 80 feeds power to the purge system 132 or the second power feeding system 90 feeds power to the purge system 132. The changeover switches 111, 112, and 113 each perform a switching operation in response to a changeover 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 changeover 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 changeover 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 changeover command from at least one of the control device 60 and the voltage detection device. Therefore, when an abnormality occurs in the first power supply system 80, the power supplied to the control device 60, the fuel system 131, and the purge system 132 is quickly ensured by the second power supply system 90.

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

[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 DC power from the secondary battery 50 into AC power, thereby enabling AC drive power to be supplied to the control device 60 and the auxiliary system 130 via the second power supply path 91.

[0061] The control device 60 stops the DC / AC converter 92 when the system supplying power to the control device 60 is the first power supply system 80, and operates the DC / AC converter 92 when the system supplying power to the control device 60 is the second power supply system 90. As a result, the conversion operation of the DC / AC converter 92 stops while the first power supply system 80 is supplying power to the control device 60, thereby suppressing discharge of the secondary battery 50.

[0062] 2 is a flowchart showing an example of a control method for power supply system 101. The control method shown in FIG.

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

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

[0065] On the other hand, if the conditions for implementing independent operation are not met, the control device 60 executes processing (shutdown processing) to shut down the power supply system 101 in operation. This reduces unnecessary power consumption. In step S19, the control device 60 shuts down the operation of the auxiliary system 130 and the fuel cell 40 simultaneously or sequentially. After shutting down the fuel cell 40 and the auxiliary system 130, the control device 60 shuts down 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 or not a startup condition is met for performing processing (startup processing) to start up the power supply system 101 that is in a stopped state. If the startup condition is not met, the control device 60 continues the stopped state of the power supply system 101. On the other hand, if the startup condition is met, the control device 60 executes the startup processing. The startup condition may include a blackout start condition.

[0067] If the start-up conditions are met, the control device 60 restarts the uninterruptible power supply 70, which is in a stopped state, in the start-up process (step S25). When the uninterruptible power supply 70 restarts, the auxiliary system 130 becomes operable. After restarting the uninterruptible power supply 70, 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 the abnormality based on the detection result of the voltage of the power system 1, etc. If the power system 1 has not recovered (if the abnormality continues), the control device 60 controls the inverter 20 in the isolated 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 the isolated operation mode (step S32) and turns on the switch 3 (step S33). This allows the power supply system 101 to be connected to the power system 1.

[0069] Here, in step S27, the control device 60 may restart the multiple systems included in the stopped auxiliary system 130 in accordance with a predetermined priority. 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 system different from the fuel system 131 among the multiple systems included in the stopped auxiliary system 130. By restarting the fuel system 131 with a high priority, fuel such as hydrogen can be quickly supplied to the fuel cell 40. By not starting at least one of the stopped purge system 132 and the stopped cooler 133, power consumption of the uninterruptible power supply 70 can be reduced.

[0070] In step S27, the control device 60 may determine whether to start up a system other than the fuel system 131 among the multiple systems included in the stopped auxiliary system 130, depending on 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 available backup time or stored voltage of the uninterruptible power supply 70. The longer the available backup time of the uninterruptible power supply 70 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 the system other than the fuel system 131 in order of priority depending on the power supply capacity of the uninterruptible power supply 70. This allows the auxiliary system that is suitable for the power supply capacity of the uninterruptible power supply 70 to be restarted.

[0071] Fig. 3 is a diagram showing an example of the configuration of a power supply system according to a second embodiment. In the second embodiment, the description of the configuration, actions, and effects similar to those of the first embodiment will be omitted by referencing the above description. The power supply system 102 according to the second embodiment shown in Fig. 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 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 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 the switching device 120.

[0073] The second power feeding system 90 feeds power from the secondary battery 50 to the control device 60 via a second power feeding path 91 different from the first power feeding path 81. In this example, the second power feeding system 90 feeds power to a fuel system 131 of the auxiliary system 130.

[0074] The second power supply system 90 includes a DC / DC converter 93. The DC / DC converter 93 converts DC power supplied from the secondary battery 50 or the fuel cell 40 via the DC bus 12 into DC power with 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 the switching device 120.

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

[0076] A 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 path 91 that is different from the first power supply path 81 that passes through the uninterruptible power supply 70. The second power supply path 91 is a path 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 path 91 even when the first power supply system 80 cannot supply power to the control device 60 via the first power supply path 81, thereby ensuring power to be supplied to the control device 60. As a result, even when the first power supply system 80 cannot supply power to the control device 60 via the first power supply path 81, the control device 60 is supplied with power from the second power supply system 90, and therefore, control of the power supply system 102 (e.g., control of the inverter 20 in the isolated operation mode) can be started or continued.

[0077] The power supply system 102 may include a switching device 120 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 between whether the first power supply system 80 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. When the switching device 120 selects the first power supply system 80 as the system that supplies power to the control device 60, power supply from the second power supply system 90 is stopped while power is being supplied to the control device 60 by the first power supply system 80, thereby suppressing discharge of the secondary battery 50. Suppressing discharge of the secondary battery 50 contributes to energy conservation.

[0078] The switching device 120 switches the system that supplies power to the control device 60 to the second power supply system 90 when an abnormality occurs in the first power supply system 80. This allows the second power supply system 90 to quickly ensure power to be supplied to the control device 60 when an abnormality occurs in the first power supply system 80. 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 realized by, for example, a diode OR circuit.

[0079] When the output voltage of the AC / DC converter 82 falls below the output voltage of the DC / DC converter 93 due to, for example, an abnormality occurring in the first power supply system 80, the switching device 120 automatically switches the system supplying power to the control device 60 to the second power supply system 90. When the output voltage of the AC / DC converter 82 rises above the output voltage of the DC / DC converter 93 due, for example, to recovery from the abnormality in the first power supply system 80, the switching device 120 automatically switches the system supplying power to the control device 60 to the first power supply system 80. The switching device 120 can automatically switch the system supplying power to the control device 60 between the first power supply system 80 and the second power supply system 90 by a wired OR 121, depending on the magnitude relationship between the output voltage of the AC / DC converter 82 and the output voltage of the DC / DC converter 93.

[0080] Although the embodiments have been described above, they are presented as examples and the present invention is not limited to the above embodiments. The above embodiments can be implemented in various other forms, and various combinations, omissions, substitutions, modifications, etc. can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, and are also included in the scope of the invention and its equivalents as set forth in the claims. [Explanation of symbols]

[0081] 1 Power system 2 electric wire 3 Switch 4. Load 11 AC busbar 12 DC bus 20 Reverse conversion device 30 Transformer 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 converter 90 Second Power Supply System 91 Second power supply route 92 DC / AC converter 93 DC / DC converter 101,102 Power supply system 110 Switching Device 111,112,113 Changeover switch 120 Switching Device 121 Wired Or 130 Auxiliary Systems 131 Fuel system 132 Purge System 133 Cooler 140 Auxiliary Machinery

Claims

1. A power supply system connected to an electric power grid via a switch, an AC bus connected to the electric line 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 that controls 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 that passes through the uninterruptible power supply; a second power supply system that supplies power from the secondary battery to the control device through a second power supply path different from the first power supply path; an auxiliary system for operating the fuel cell, which receives power from the first power supply system; When the switch is off, the uninterruptible power supply shuts down after the fuel cell and the auxiliary system shut down.

2. a switching device 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 between the first power supply system and the second power supply system, which supplies power to the control device.

3. The power supply system according to claim 2 , wherein the switching device switches the system that supplies power to the control device to the second power supply system when an abnormality occurs in the first power supply system.

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

5. The power supply system according to claim 2 , wherein the switching device includes a changeover switch for switching between the first power supply system and the second power supply system to supply power to the control device.

6. 5. The power supply system according to claim 2, wherein the switching device includes a wired-OR that switches whether the first power supply system or the second power supply system supplies power to the control device.

7. The power supply system according to claim 1 , wherein the second power supply system includes a power converter that converts power from the secondary battery into power to be supplied to the control device.

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

9. A power supply system as described in any one of claims 1 to 4, wherein when the switch is off, the control device starts up the uninterruptible power supply device that is in a stopped state, and then starts up the auxiliary system that is in a stopped state.

10. The power supply system according to claim 1 , wherein the auxiliary system includes a first auxiliary 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 that supplies hydrogen to the fuel cell.

12. The power supply system according to claim 11 , wherein the first accessory 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 system includes a second auxiliary system that can receive power from the first power supply system but cannot receive power from the second power supply system.

14. 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 described in Claim 9, wherein when the switch is off, the control device starts up the uninterruptible power supply device that is in a stopped state, and then starts up multiple systems included in the auxiliary system that is in a stopped state in sequence.

16. the auxiliary system includes a fuel system that supplies hydrogen to the fuel cell and another system different from the fuel system, 5. The power supply system according to claim 1, wherein, when the switch is off, the control device starts up the uninterruptible power supply that is in a stopped state, and then starts up the fuel system that is in a stopped state without starting up the other systems that are in a stopped state.

17. 17. The power supply system according to claim 16, wherein the control device determines whether or not to start up the other system that is in a stopped state, depending on the power supply capacity of the uninterruptible power supply device.

18. 5. The power supply system according to claim 1, wherein when the switch is off, the power obtained from the fuel cell by the independent operation of the inverter is supplied to the load.

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