Power supply system and mobile object

Abstract

To provide a power supply system which suppresses occurrence of excess current even when difference occurs between output voltage of a first power storage device and output voltage of a second power storage device.SOLUTION: A power supply system 10 comprises: a first switch 34a provided on first wiring 28a of a power supply circuit; a second switch 36a provided on second wiring 30a of the power supply circuit; a third switch 40a provided on third wiring 38a, which bypasses the first switch; a fourth switch 46a provided on fourth wiring 44a, which is connected with the third wiring and the second wiring; and resistors provided in at least two parts of a first part 84a on the third wiring, a second part 86a on the fourth wiring and a third part 88a on the third wiring.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] Patent Document 1 listed below discloses a power supply system including a high-voltage battery and a motor generator. Three relays, a resistor (pre-charge resistor), a capacitor (smoothing capacitor), and a step-down converter are interposed between the high-voltage battery and the motor generator. In this power supply system, the capacitor can be pre-charged via the resistor by controlling the on / off of the three relays. In addition, in this power supply system, the charge stored in the capacitor can be discharged via the resistor by controlling the on / off of the three relays. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-141958 Summary of the Invention [Problem to be solved by the invention]

[0004] There is a need for better power supply systems and vehicles.

[0005] The present invention aims to solve the above-mentioned problems. [Means for solving the problem]

[0006] A first aspect of the present disclosure is a power supply system having a power supply circuit that supplies power from a power storage device to a load device, the power supply system including: a first wiring that is one of a positive wiring and a negative wiring provided in the power supply circuit; a first switch that is provided on the first wiring and switches between a connection state that connects the power storage device and the load device and a disconnection state that disconnects the power storage device and the load device; a second wiring that is the other of the positive wiring and the negative wiring; a second switch that is provided on the second wiring and switches between a connection state that connects the power storage device and the load device and a disconnection state that disconnects the power storage device and the load device; a third wiring that bypasses the first switch; a fourth wiring connected to the third wiring at a first node closer to the load device than the third switch and connected to the second wiring at a second node closer to the power storage device than the second switch; a fourth switch provided on the fourth wiring and switching between a connection state connecting the third wiring and the second wiring and a cut-off state cutting off the third wiring and the second wiring; and resistors arranged in at least two positions among a first position of the third wiring located between the power storage device and the first node, a second position on the fourth wiring, and a third position of the third wiring located between the first node and the load device.

[0007] A second aspect of the present disclosure is a power supply system having a power supply circuit that supplies power from a power storage device to a load device, the power supply system including: a first wiring that is one of a positive wiring and a negative wiring provided in the power supply circuit; a first switch that is provided on the first wiring and switches between a connection state that connects the power storage device and the load device and a disconnection state that disconnects the power storage device and the load device; a second wiring that is the other of the positive wiring and the negative wiring; a second switch that is provided on the second wiring and switches between a connection state that connects the power storage device and the load device and a disconnection state that disconnects the power storage device and the load device; a third wiring that bypasses the first switch; The power supply system includes: a third switch that switches between a connection state that connects the power storage device and the load device and a disconnection state that disconnects the power storage device and the load device; a first resistor that is provided on the third wiring and connected in series with the third switch; a fourth wiring that is connected to the first wiring at a third node that is closer to the load device than the first switch and that is connected to the second wiring at a fourth node that is closer to the power storage device than the second switch; a fourth switch that is provided on the fourth wiring and switches between a connection state that connects the third wiring and the second wiring and a disconnection state that disconnects the third wiring and the second wiring; and a second resistor that is provided on the fourth wiring and connected in series with the fourth switch.

[0008] A third aspect of the present disclosure is a mobile object including the power supply system according to the first aspect. [Effects of the Invention]

[0009] The present invention can provide a better power supply system and a mobile object. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a schematic diagram of a power supply system according to the first embodiment. [Figure 2] FIG. 2 is a control block diagram of the control device in the first embodiment. [Figure 3] FIG. 3 is a flowchart showing the operation of the power supply system in the first embodiment. [Figure 4] FIG. 4 is a diagram showing the operation of the power supply system in the system startup preparation process in the first embodiment. [Figure 5] FIG. 5 is a diagram showing the operation of the power supply system in the system operation process in the first embodiment. [Figure 6] FIG. 6 is a diagram illustrating the operation of the power supply system in the system shutdown process in the first embodiment. [Figure 7] FIG. 7 is a process flow of the discharge necessity determination process in the first embodiment. [Figure 8] FIG. 8 is a diagram showing the operation of the power supply system in the power storage device discharging process in the first embodiment. [Figure 9] FIG. 9 is a diagram illustrating the operation of the power supply system of the comparative example. [Figure 10] FIG. 10 is a diagram illustrating the operation of the power supply system of the comparative example. [Figure 11] FIG. 11 is a diagram illustrating the operation of the power supply system of the comparative example. [Figure 12] 12A and 12B are time charts showing time versus voltage and current, respectively, for a comparative example. [Figure 13] FIG. 13 is a diagram showing the state of the power supply system when the fourth switch malfunctions and goes into a connected state (ON) during the system startup preparation process. [Figure 14] FIG. 14 is a diagram showing the state of the power supply system when the fourth switch malfunctions and goes into a connected state (ON) during the system activation process. [Figure 15] FIG. 15 is a diagram showing the state of the power supply system when the third switch malfunctions and goes into a connected state (ON) during the discharge process of the power storage device. [Figure 16] FIG. 16 is a schematic diagram of a moving object. [Figure 17]FIG. 17 is a schematic diagram of a power supply system according to the second embodiment. [Figure 18] FIG. 18 is a schematic diagram of a power supply system according to the third embodiment. [Figure 19] FIG. 19 is a schematic diagram of a power supply system according to the fourth embodiment. [Figure 20] FIG. 20 is a schematic diagram of a power supply system according to the fifth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] In a power supply system that supplies power from a power generation device to a first load device and a second load device, in order to respond to cases where relatively large amounts of power are requested from each of the first load device and the second load device, a first storage battery device may be connected in parallel to the power generation device, and a second storage battery device may be connected in parallel to the power generation device.

[0012] When a relatively large amount of power is requested from a first load device, power is supplied to the first load device from the power generation device and the first power storage device. When a relatively large amount of power is requested from a second load device, power is supplied to the second load device from the power generation device and the second power storage device. However, when the difference between the output voltage of the first power storage device and the output voltage of the second power storage device is relatively large, an overcurrent may flow in the power supply system.

[0013] The power supply system of the present disclosure can suppress the occurrence of an overcurrent in the power supply system even when a difference occurs between the output voltage of the first power storage device and the output voltage of the second power storage device.

[0014] [First embodiment] [Power supply system configuration] 1 is a schematic diagram of a power supply system 10 according to this embodiment. The power supply system 10 includes a first power supply circuit 12a and a second power supply circuit 12b. The first power supply circuit 12a supplies DC power output from a power generation device 14 to a first load device 16a. The second power supply circuit 12b supplies DC power output from the power generation device 14 to a second load device 16b.

[0015] The power generation device 14 has an engine, a generator, and a power control unit (not shown). The engine drives the generator, which generates three-phase AC power. The power control unit converts the three-phase AC power into DC power. The power generation device 14 has a smoothing capacitor 18. When the power supply system 10 is started up, the smoothing capacitor 18 is charged (pre-charged). When the power supply system 10 is shut down, the smoothing capacitor 18 is discharged.

[0016] The power generation device 14 may include various elements such as various sensors, fuses, relays, breakers, diodes, transistors, resistors, and coils.

[0017] The first load device 16a and the second load device 16b each have an inverter and an electric motor (not shown). The inverter converts input DC power into three-phase AC power. The electric motor is driven by the three-phase AC power. The first load device 16a has a smoothing capacitor 20a. The second load device 16b has a smoothing capacitor 20b. When the power supply system 10 is started up, the smoothing capacitors 20a and 20b are first charged (pre-charged). When the power supply system 10 is shut down, the smoothing capacitors 20a and 20b are discharged.

[0018] The first load device 16a and the second load device 16b may include various elements such as various sensors, fuses, relays, breakers, diodes, transistors, resistors, coils, and capacitors.

[0019] The power supply system 10 includes interruption devices 22a and 22b. The interruption device 22a can disconnect the power generation device 14 from the first power supply circuit 12a. The interruption device 22b can disconnect the power generation device 14 from the second power supply circuit 12b.

[0020] The first power supply circuit 12a and the second power supply circuit 12b may include elements other than those described above, such as switches, sensors, fuses, diodes, resistors, coils, and capacitors.

[0021] The circuit breaker 22a includes a pair of switches (not shown). One switch is provided on the positive wiring connecting the power generation device 14 and the first power supply circuit 12a. The other switch is provided on the negative wiring connecting the power generation device 14 and the first power supply circuit 12a. The switch of the circuit breaker 22a is, for example, a switch, a relay, a contactor, a breaker, a semiconductor switch, or the like.

[0022] The circuit breaker 22b includes a pair of switches (not shown). One switch is provided on the positive wiring connecting the power generation device 14 and the second power supply circuit 12b. The other switch is provided on the negative wiring connecting the power generation device 14 and the second power supply circuit 12b. The switch of the circuit breaker 22b is, for example, a switch, a relay, a contactor, a breaker, a semiconductor switch, or the like.

[0023] The power supply system 10 includes a third power supply circuit 26a and a fourth power supply circuit 26b. The third power supply circuit 26a supplies power from the first power storage device 24a to the first load device 16a. The fourth power supply circuit 26b supplies power from the second power storage device 24b to the second load device 16b.

[0024] The first power storage device 24a is connected to the first power supply circuit 12a via a third power supply circuit 26a in parallel with the power generation device 14. The DC power output from the first power storage device 24a is supplied to the first load device 16a. The second power storage device 24b is connected to the second power supply circuit 12b via a fourth power supply circuit 26b in parallel with the power generation device 14. The DC power output from the second power storage device 24b is supplied to the second load device 16b.

[0025] The first power storage device 24a and the second power storage device 24b include, for example, lithium ion batteries. The first power storage device 24a and the second power storage device 24b may include secondary batteries other than lithium ion batteries. The first power storage device 24a and the second power storage device 24b may include large-capacity capacitors.

[0026] The third power supply circuit 26a includes a first wiring 28a, a second wiring 30a, a third wiring 38a, and a fourth wiring 44a. The third power supply circuit 26a also includes a first switch 34a, a second switch 36a, a third switch 40a, and a fourth switch 46a.

[0027] The first wiring 28a is a positive wiring and connects the positive terminal of the first power storage device 24a to the positive wiring of the first power supply circuit 12a. A first switch 34a is provided on the first wiring 28a. The first switch 34a can switch between a connection state in which the first power storage device 24a and the first load device 16a are connected and a disconnection state in which the first power storage device 24a and the first load device 16a are disconnected. The first switch 34a is, for example, a switch, a relay, a contactor, a breaker, a semiconductor switch, or the like.

[0028] The second wiring 30a is a negative wiring and connects the negative terminal of the first power storage device 24a to the negative wiring of the first power supply circuit 12a. A second switch 36a is provided on the second wiring 30a. The second switch 36a can switch between a connection state in which the first power storage device 24a and the first load device 16a are connected and a disconnection state in which the first power storage device 24a and the first load device 16a are disconnected. The second switch 36a is, for example, a switch, a relay, a contactor, a breaker, a semiconductor switch, or the like.

[0029] One end of the third wiring 38a is connected to the first wiring 28a between the first power storage device 24a and the first switch 34a. The other end of the third wiring 38a is connected to the first wiring 28a between the first switch 34a and the first load device 16a. That is, the third wiring 38a bypasses the first switch 34a. The third switch 40a is provided on the third wiring 38a and can switch between a connection state that connects the first power storage device 24a and the first load device 16a and a disconnection state that disconnects the first power storage device 24a and the first load device 16a. The third switch 40a is, for example, a switch, a relay, a contactor, a breaker, a semiconductor switch, or the like.

[0030] One end of the fourth wiring 44a is connected to the third wiring 38a at a first node 80a, and the other end of the fourth wiring 44a is connected to the second wiring 30a at a second node 82a. The first node 80a is located on the third wiring 38a. The first node 80a is located closer to the first load device 16a than the third switch 40a. The second node 82a is located on the second wiring 30a. The second node 82a is located closer to the first power storage device 24a than the second switch 36a. The fourth switch 46a is provided on the fourth wiring 44a and can switch between a connection state that connects the third wiring 38a and the second wiring 30a and a disconnection state that disconnects the third wiring 38a and the second wiring 30a. The fourth switch 46a is, for example, a switch, a relay, a contactor, a breaker, a semiconductor switch, or the like.

[0031] A first resistor 39a is disposed in a first portion 84a of the third wiring 38a between the first power storage device 24a and the first node 80a. The first resistor 39a is provided at a position closer to the first node 80a than the third switch 40a. The positions of the first resistor 39a and the third switch 40a may be interchanged.

[0032] The second resistor 41a is disposed at a second portion 86a on the fourth wiring 44a. The second resistor 41a is provided at a position closer to the first node 80a than the fourth switch 46a. The positions of the second resistor 41a and the fourth switch 46a may be interchanged.

[0033] The third resistor 42a is disposed in a third portion 88a of the third wiring 38a between the first node 80a and the first load device 16a.

[0034] The resistance value (R1) of the first resistor 39a, the resistance value (R2) of the second resistor 41a, and the resistance value (R3) of the third resistor 42a may be the same or different. When the resistance value (R1) of the first resistor 39a, the resistance value (R2) of the second resistor 41a, and the resistance value (R3) of the third resistor 42a are set to the same value, the resistance value (R1+R3) in the closed circuit formed when the smoothing capacitor 18 of the power generation device 14 and the smoothing capacitor 20a of the first load device 16a are charged (precharged) is equal to the resistance value (R2+R3) in the closed circuit formed when the smoothing capacitor 18 of the power generation device 14 and the smoothing capacitor 20a of the first load device 16a are discharged.

[0035] The third power supply circuit 26a includes a voltage sensor 48a and a current sensor 50a. The voltage sensor 48a detects the terminal voltage (output voltage) of the first power storage device 24a. The positive terminal of the voltage sensor 48a is connected to the first wiring 28a between the positive terminal of the first power storage device 24a and the first switch 34a. The negative terminal of the voltage sensor 48a is connected to the second wiring 30a between the negative terminal of the first power storage device 24a and the second switch 36a. The current sensor 50a is provided on the second wiring 30a at a location between the negative terminal of the first power storage device 24a and the second node 82a.

[0036] The fourth power supply circuit 26b includes a first wiring 28b, a second wiring 30b, a third wiring 38b, and a fourth wiring 44b. The fourth power supply circuit 26b also includes a first switch 34b, a second switch 36b, a third switch 40b, and a fourth switch 46b.

[0037] The first wiring 28b is a positive wiring and connects the positive terminal of the second power storage device 24b to the positive wiring of the second power supply circuit 12b. A first switch 34b is provided on the first wiring 28b. The first switch 34b can switch between a connection state in which the second power storage device 24b and the second load device 16b are connected and a disconnection state in which the second power storage device 24b and the second load device 16b are disconnected. The first switch 34b is, for example, a switch, a relay, a contactor, a breaker, a semiconductor switch, or the like.

[0038] The second wiring 30b is a negative wiring and connects the negative terminal of the second power storage device 24b to the negative wiring of the second power supply circuit 12b. A second switch 36b is provided on the second wiring 30b. The second switch 36b can switch between a connection state in which the second power storage device 24b and the second load device 16b are connected and a disconnection state in which the second power storage device 24b and the second load device 16b are disconnected. The second switch 36b is, for example, a switch, a relay, a contactor, a breaker, a semiconductor switch, or the like.

[0039] One end of the third wiring 38b is connected to the first wiring 28b between the second power storage device 24b and the first switch 34b. The other end of the third wiring 38b is connected to the first wiring 28b between the first switch 34b and the second load device 16b. That is, the third wiring 38b bypasses the first switch 34b. The third switch 40b is provided on the third wiring 38b and can switch between a connection state that connects the second power storage device 24b and the second load device 16b and a disconnection state that disconnects the second power storage device 24b and the second load device 16b. The third switch 40b is, for example, a switch, a relay, a contactor, a breaker, a semiconductor switch, or the like.

[0040] One end of the fourth wiring 44b is connected to the third wiring 38b at a first node 80b, and the other end of the fourth wiring 44b is connected to the second wiring 30b at a second node 82b. The first node 80b is located on the third wiring 38b. The first node 80b is located closer to the second load device 16b than the third switch 40b. The second node 82b is located on the second wiring 30b. The second node 82b is located closer to the second power storage device 24b than the second switch 36b. The fourth switch 46b is provided on the fourth wiring 44b and can switch between a connection state that connects the third wiring 38b and the second wiring 30b and a disconnection state that disconnects the third wiring 38b and the second wiring 30b. The fourth switch 46b is, for example, a switch, a relay, a contactor, a breaker, a semiconductor switch, or the like.

[0041] A first resistor 39b is disposed in a first portion 84b of the third wiring 38b between the second power storage device 24b and the first node 80b. The first resistor 39b is provided at a position closer to the first node 80b than the third switch 40b. The positions of the first resistor 39b and the third switch 40b may be interchanged.

[0042] The second resistor 41b is disposed at a second portion 86b on the fourth wiring 44b. The second resistor 41b is provided at a position closer to the first node 80b than the fourth switch 46b. The positions of the second resistor 41b and the fourth switch 46b may be interchanged.

[0043] The third resistor 42b is disposed in a third portion 88b of the third wiring 38b between the first node 80b and the second load device 16b.

[0044] The resistance value (R1) of the first resistor 39b, the resistance value (R2) of the second resistor 41b, and the resistance value (R3) of the third resistor 42b may be the same or different. When the resistance value (R1) of the first resistor 39b, the resistance value (R2) of the second resistor 41b, and the resistance value (R3) of the third resistor 42b are set to the same value, the resistance value (R1+R3) in the closed circuit formed when the smoothing capacitor 18 of the power generation device 14 and the smoothing capacitor 20b of the second load device 16b are charged becomes equal to the resistance value (R2+R3) in the closed circuit formed when the smoothing capacitor 18 of the power generation device 14 and the smoothing capacitor 20b of the second load device 16b are discharged.

[0045] In the present disclosure, the resistance values of the first resistors 39a and 39b are denoted as R1, but the resistance values of the first resistors 39a and 39b may be different. Similarly, the resistance values of the second resistors 41a and 41b are denoted as R2, but the resistance values of the second resistors 41a and 41b may be different. Furthermore, the resistance values of the third resistors 42a and 42b are denoted as R3, but the resistance values of the third resistors 42a and 42b may be different.

[0046] The fourth power supply circuit 26b includes a voltage sensor 48b and a current sensor 50b. The voltage sensor 48b detects the terminal voltage (output voltage) of the second power storage device 24b. The positive terminal of the voltage sensor 48b is connected to the first wiring 28b between the positive terminal of the second power storage device 24b and the first switch 34b. The negative terminal of the voltage sensor 48b is connected to the second wiring 30b between the negative terminal of the second power storage device 24b and the second switch 36b. The current sensor 50b is provided on the second wiring 30b at a location between the negative terminal of the second power storage device 24b and the second node 82b.

[0047] [Control device configuration] The power supply system 10 includes a control device 54. Fig. 2 is a control block diagram of the control device 54 in this embodiment. The control device 54 acquires signals indicating voltage from voltage sensors 48a and 48b. The control device 54 acquires signals indicating current from current sensors 50a and 50b. The control device 54 controls each switch (each switch of the circuit breaker devices 22a and 22b, first switches 34a and 34b, second switches 36a and 36b, third switches 40a and 40b, and fourth switches 46a and 46b).

[0048] The control device 54 has a calculation unit 56 and a storage unit 58. The calculation unit 56 is, for example, a processor such as a central processing unit (CPU) or a graphics processing unit (GPU). The calculation unit 56 controls each device by executing a program stored in the storage unit 58. At least a part of the calculation unit 56 may be realized by an integrated circuit such as an application specific integrated circuit (ASIC) or a field-programmable gate array (FPGA). At least a part of the calculation unit 56 may be realized by an electronic circuit including discrete devices.

[0049] The calculation unit 56 functions as a control unit 60, an internal resistance value acquisition unit 61, and an estimation unit 62. The control unit 60 can selectively cause the power supply system 10 to execute a system startup preparation process, a system operation process, a system shutdown process, and a power storage device discharge process, which will be described later. Specifically, the control unit 60 can execute each process by controlling the connection state (ON) and disconnection state (OFF) of each switch provided in the power supply system 10. The internal resistance value acquisition unit 61 acquires the internal resistance values of the first power storage device 24a and the second power storage device 24b. The estimation unit 62 estimates the degradation state of the first power storage device 24a based on the internal resistance value of the first power storage device 24a. The estimation unit 62 estimates the degradation state of the second power storage device 24b based on the internal resistance value of the second power storage device 24b.

[0050] The storage unit 58 is configured by a volatile memory (not shown) and a non-volatile memory (not shown), which are computer-readable non-transitory storage media. The volatile memory is, for example, a random access memory (RAM). The non-volatile memory is, for example, a read-only memory (ROM), a flash memory, etc. Data, etc., are stored in the volatile memory. Programs, tables, maps, etc., are stored in the non-volatile memory. At least a part of the storage unit 58 may be provided in the processor, integrated circuit, etc. described above.

[0051] [Power supply system operation] 3 is a flowchart showing the operation of the power supply system 10 in this embodiment. The power supply system 10 can repeatedly perform a series of processes including a system startup preparation process (step S1), a system operation process (step S2), and a system shutdown process (step S3). Furthermore, the power supply system 10 can perform a power storage device discharge process (step S4) as needed between the system shutdown process and the next system startup preparation process. The operation of the power supply system 10 in each process will be described below.

[0052] In the following, the operation of the circuit breaker 22a in the first power supply circuit 12a and the operation of each of the first switch 34a, second switch 36a, third switch 40a, and fourth switch 46a in the third power supply circuit 26a in each process will be described. The operation of the circuit breaker 22b in the second power supply circuit 12b and the operation of each of the first switch 34b, second switch 36b, third switch 40b, and fourth switch 46b in the fourth power supply circuit 26b in each process will be the same as the operation of the circuit breaker 22a in the first power supply circuit 12a and the operation of each of the first switch 34a, second switch 36a, third switch 40a, and fourth switch 46a in the third power supply circuit 26a in each process, and therefore will not be described again.

[0053] [Power supply system operation during system startup preparation process] 4 is a diagram showing the operation of the power supply system 10 in the system startup preparation process in this embodiment. For example, when a user manually turns on a power switch (not shown), the control unit 60 starts up the power supply system 10. In the system startup preparation process, the control unit 60 controls each switch so that the smoothing capacitors 18 and 20a are precharged.

[0054] The control unit 60 sets the pair of switches of the circuit breaker 22a to the connected state (ON). The control unit 60 also controls the switches of the third power supply circuit 26a as follows: The control unit 60 sets the first switch 34a to the disconnected state (OFF), the second switch 36a to the connected state (ON), the third switch 40a to the connected state (ON), and the fourth switch 46a to the disconnected state (OFF).

[0055] As a result, a closed circuit is formed from the first power storage device 24a via the third switch 40a, the first resistor 39a, the third resistor 42a, the circuit breaker 22a, the smoothing capacitor 18, and the second switch 36a, and returns to the first power storage device 24a. Also, a closed circuit is formed from the first power storage device 24a via the third switch 40a, the first resistor 39a, the third resistor 42a, the smoothing capacitor 20a, and the second switch 36a, and returns to the first power storage device 24a.

[0056] In this case, current flows along the path indicated by the arrows in Fig. 4. DC power is supplied to the smoothing capacitor 18 from the first power storage device 24a via the first resistor 39a and the third resistor 42a. As a result, electric charge is accumulated in the smoothing capacitor 18, and the smoothing capacitor 18 is charged. Similarly, DC power is supplied to the smoothing capacitor 20a from the first power storage device 24a via the first resistor 39a and the third resistor 42a. Electric charge is accumulated in the smoothing capacitor 20a, and the smoothing capacitor 20a is charged. When the smoothing capacitors 18 and 20a reach a predetermined voltage, the system startup preparation process is completed.

[0057] [Power supply system operation during system activation process] 5 is a diagram showing the operation of the power supply system 10 in the system activation process according to this embodiment. After the system startup preparation process is completed, the control unit 60 controls each switch to supply DC power to the first load device 16a.

[0058] The control unit 60 sets the pair of switches of the circuit breaker 22a to a connected state (ON). The control unit 60 also controls the switches of the third power supply circuit 26a as follows: The control unit 60 sets the first switch 34a to a connected state (ON), the second switch 36a to a connected state (ON), the third switch 40a to a disconnected state (OFF), and the fourth switch 46a to a disconnected state (OFF).

[0059] In this state, the power generation device 14 is started using power supplied from at least one of the first power storage device 24a and the second power storage device 24b. This completes the startup of the power supply system 10. After the startup of the power supply system 10 is completed, DC power is supplied from the power generation device 14 to the first load device 16a. Alternatively, after the startup of the power supply system 10 is completed, DC power is supplied from the power generation device 14 and the first power storage device 24a to the first load device 16a.

[0060] If an abnormality occurs in the power generation device 14 during the system operation process, the control unit 60 switches the pair of switches of the circuit breaker 22a to the circuit breaker state (OFF). In this case, DC power is supplied to the first load device 16a from the first power storage device 24a. This allows the supply of power to the first load device 16a to continue even if an abnormality occurs in the power generation device 14.

[0061] If an abnormality occurs in the first load device 16a during the system operation process, the control unit 60 switches the pair of switches of the cutoff device 22a to the cutoff state (OFF). This allows the second load device 16b to continue operating even if an abnormality occurs in the first load device 16a.

[0062] [Power supply system operation during system shutdown process] 6 is a diagram showing the operation of the power supply system 10 in the system shutdown process in this embodiment. When a user turns off a manual power switch or the like, the control unit 60 shuts down the power supply system 10. The control unit 60 controls each switch so that the smoothing capacitors 18 and 20a are discharged.

[0063] The control unit 60 sets the pair of switches of the circuit breaker 22a to a connected state (ON). The control unit 60 also controls the switches of the third power supply circuit 26a as follows: The control unit 60 sets the first switch 34a to a disconnected state (OFF), the second switch 36a to a connected state (ON), the third switch 40a to a disconnected state (OFF), and the fourth switch 46a to a connected state (ON).

[0064] As a result, a closed circuit is formed that runs from the smoothing capacitor 18 through the breaker device 22a, the third resistor 42a, the second resistor 41a, the fourth switch 46a, the second switch 36a, and the breaker device 22a back to the smoothing capacitor 18. Also, a closed circuit is formed that runs from the smoothing capacitor 20a through the smoothing capacitor 20a, the third resistor 42a, the second resistor 41a, the fourth switch 46a, and the second switch 36a back to the smoothing capacitor 20a.

[0065] In this case, the current flows through the path indicated by the arrow in Fig. 6. This causes the charge stored in the smoothing capacitor 18 to be discharged. Also, the charge stored in the smoothing capacitor 20a is discharged.

[0066] [Power supply system operation during storage device discharge process] Fig. 7 is a processing flow of the discharge necessity determination process in this embodiment. Between the system shutdown process and the system startup preparation process, the control unit 60 performs the discharge necessity determination process shown in Fig. 7. For example, the control unit 60 may perform the discharge necessity determination process periodically, may perform the discharge necessity determination process at a predetermined timing, or may perform the discharge necessity determination process in response to a request from a user. The discharge necessity determination process is a process for determining whether or not to perform the power storage device discharge process described below before the next system startup preparation process is performed.

[0067] In step S11, the control unit 60 acquires information about the terminal voltages of the first power storage device 24a and the second power storage device 24b based on the detection results of the voltage sensor 48a and the voltage sensor 48b.

[0068] In step S12, the control unit 60 compares whether the difference between the terminal voltage of the first power storage device 24a and the terminal voltage of the second power storage device 24b acquired in step S11 is greater than a voltage threshold value. The voltage threshold value is a value for determining whether an overcurrent occurs in the circuit of the power supply system 10. It is desirable that the voltage threshold value be a relatively small value. This overcurrent will be described later. The voltage threshold value is stored in advance in the storage unit 58.

[0069] If the difference between the terminal voltage of the first power storage device 24a and the terminal voltage of the second power storage device 24b is greater than the voltage threshold (step S12: YES), the process proceeds to step S13. On the other hand, if the difference between the terminal voltage of the first power storage device 24a and the terminal voltage of the second power storage device 24b is equal to or less than the voltage threshold (step S12: NO), the discharge necessity determination process shown in Fig. 7 ends. In this case, it is not necessary to perform the power storage device discharge process until the next system startup preparation process.

[0070] When the process proceeds from step S12 to step S13, control unit 60 executes the power storage device discharging process. In this case, control unit 60 continues to execute the power storage device discharging process, which will be described next, until the difference between the terminal voltage of first power storage device 24a and the terminal voltage of second power storage device 24b becomes equal to or less than the voltage threshold value.

[0071] 8 is a diagram showing the operation of the power supply system 10 in the power storage device discharging process in this embodiment. As described above, the control unit 60 performs the power storage device discharging process until the difference between the terminal voltage of the first power storage device 24a and the terminal voltage of the second power storage device 24b becomes equal to or less than the voltage threshold. Note that, below, as an example, a case will be described in which the terminal voltage of the first power storage device 24a is higher than the terminal voltage of the second power storage device 24b.

[0072] The control unit 60 sets the pair of switches of the circuit breaker 22a to a disconnected state (OFF). The control unit 60 also controls the switches of the third power supply circuit 26a as follows: The control unit 60 sets the first switch 34a to a connected state (ON), the second switch 36a to a disconnected state (OFF), the third switch 40a to a disconnected state (OFF), and the fourth switch 46a to a connected state (ON). This forms a closed circuit that runs from the first power storage device 24a, through the first switch 34a, the third resistor 42a, and the second resistor 41a, and returns to the first power storage device 24a.

[0073] As a result, current flows along the path indicated by the arrows in Figure 8. The power of the first power storage device 24a is consumed by the second resistor 41a and the third resistor 42a. In this state, power is not supplied from the first power storage device 24a to the first load device 16a. The control unit 60 switches the first switch 34a and the fourth switch 46a to the cut-off state (OFF) when the difference between the terminal voltage of the first power storage device 24a and the terminal voltage of the second power storage device 24b becomes equal to or less than the voltage threshold value.

[0074] [Processing for estimating the deterioration state of the power storage device] The internal resistance value acquisition unit 61 acquires the internal resistance value of the first power storage device 24a. The estimation unit 62 estimates the degradation state of the first power storage device 24a based on the acquired internal resistance value. The degradation state of the first power storage device 24a is also referred to as SOH (State Of Health).

[0075] The internal resistance value acquisition unit 61 acquires the internal resistance value (r) of the first power storage device 24a, for example, by the following equation (1).

[0076] r = (Vocv-Vccv) / i (1) Vocv: Terminal voltage of the storage device in a non-discharged state Vccv: Terminal voltage of the storage device during discharge i: current during discharge r: Internal resistance of the storage device

[0077] The internal resistance value acquiring unit 61 acquires the terminal voltage (Vccv) of the first power storage device 24a based on the detection result of the voltage sensor 48a during the power storage device discharging process for the first power storage device 24a. The internal resistance value acquiring unit 61 acquires the terminal voltage (Vocv) of the first power storage device 24a based on the detection result of the voltage sensor 48a before or after the power storage device discharging process for the first power storage device 24a is executed. The internal resistance value acquiring unit 61 acquires the current (i) based on the detection result of the current sensor 50a during the power storage device discharging process for the first power storage device 24a.

[0078] The estimation unit 62 estimates the SOH of the first power storage device 24a based on the internal resistance value (r) acquired by the internal resistance value acquisition unit 61 and the internal resistance value of the first power storage device 24a before deterioration that is stored in advance in the storage unit 58. The estimation unit 62 may store the estimation result in the storage unit 58, or may display the result on a display device (not shown).

[0079] The resistance values of the second resistor 41a and the third resistor 42a are constant. Therefore, the current (i) during the discharge process of the power storage device can be considered constant within a time period during which changes in the SOH can be ignored. In other words, the internal resistance (r) of the first power storage device 24a calculated by the above formula (1) can be considered constant within a time period during which changes in the SOH can be ignored. Therefore, according to this embodiment, a highly reliable SOH can be obtained.

[0080] [Comparison with comparative examples] In this embodiment, the third power supply circuit 26a is provided with a fourth wiring 44a and a fourth switch 46a. According to this embodiment, the first power storage device 24a can be discharged without supplying power to the first load device 16a. Similarly, in this embodiment, the fourth power supply circuit 26b is provided with a fourth wiring 44b and a fourth switch 46b. According to this embodiment, the second power storage device 24b can be discharged without supplying power to the second load device 16b.

[0081] To facilitate understanding of the effects achieved by this embodiment, a comparative example will be described. Here, a power supply system 100 of the comparative example will be described using FIGS. 9 to 11, 12A, and 12B. FIGS. 9 to 11 are diagrams showing the operation of the power supply system 100 of the comparative example. FIG. 12A is a timing chart showing time-voltage in the comparative example. FIG. 12B is a timing chart showing time-current in the comparative example. The power supply system 100 of the comparative example has the same configuration as the power supply system 10 of this embodiment, except that it does not include the fourth wiring 44a, 44b, the fourth switches 46a, 46b, the first resistors 39a, 39b, and the second resistors 41a, 41b.

[0082] The following describes the operating state of the power supply system 100 from the start of the system startup preparation process (precharge) to immediately after the start of the system operation process. At the start of the system startup preparation process, it is assumed that the terminal voltage of the first power storage device 24a is E1 and the terminal voltage of the second power storage device 24b is E2. E1>E2 and E1-E2 is greater than the voltage threshold.

[0083] 12A and 12B, the system startup preparation process is started at time t1. In the system startup preparation process, in order to charge the smoothing capacitor 18 of the power generation device 14 and the smoothing capacitor 20a of the first load device 16a, as shown in FIG. 9, a pair of switches of the circuit breaker 22a are set to the connected state (ON), the first switch 34a is set to the disconnected state (OFF), the second switch 36a is set to the connected state (ON), and the third switch 40a is set to the connected state (ON). In addition, in the system startup preparation process, in order to charge the smoothing capacitor 18 of the power generation device 14 and the smoothing capacitor 20b of the second load device 16b, a pair of switches of the circuit breaker 22b are set to the connected state (ON), the first switch 34b is set to the disconnected state (OFF), the second switch 36b is set to the connected state (ON), and the third switch 40b is set to the connected state (ON).

[0084] As a result, as shown in FIG. 12B, a current (i1) flows from the first power storage device 24a to the power generation device 14 and the first load device 16a. Similarly, a current (i2) flows from the second power storage device 24b to the power generation device 14 and the second load device 16b. Electric charge is gradually stored in the smoothing capacitors 18 and 20a, 20b, and as shown in FIG. 12A, the voltages (Vc) of the smoothing capacitors 18 and 20a, 20b gradually increase. At time t2 in FIGS. 12A and 12B, the voltages (Vc) of the smoothing capacitors 18 and 20a, 20b reach the same voltage as the terminal voltage (E2) of the second power storage device 24b.

[0085] After the voltage (Vc) of the smoothing capacitor 18 and the smoothing capacitors 20a, 20b reaches the same voltage as the terminal voltage (E2) of the second power storage device 24b, a current (i1) flows from the first power storage device 24a to the power generation device 14 and the first load device 16a, and a current (i1) flows from the first power storage device 24a to the second power storage device 24b, as shown in Fig. 10. That is, the first power storage device 24a charges the smoothing capacitor 18 and the smoothing capacitors 20a, 20b, and charges the second power storage device 24b.

[0086] If the first power storage device 24a continues to charge the smoothing capacitor 18 and the smoothing capacitors 20a and 20b and the second power storage device 24b, the voltage (Vc) of the smoothing capacitor 18 and the smoothing capacitors 20a and 20b and the terminal voltage (E2) of the second power storage device 24b will become equal to the terminal voltage (E1) of the first power storage device 24a. However, because the charging speed of the second power storage device 24b is relatively slow, it takes a long time for the voltage (Vc) of the smoothing capacitor 18 and the smoothing capacitors 20a and 20b and the terminal voltage (E2) of the second power storage device 24b to become equal to the terminal voltage (E1) of the first power storage device 24a.

[0087] 12A and 12B, which is a time before E1=E2, the system activation process is started. When the system activation process is started, as shown in FIG. 11, the pair of switches of the circuit breaker 22a are set to the connected state (ON), the first switch 34a is set to the connected state (ON), the second switch 36a is set to the connected state (ON), and the third switch 40a is set to the disconnected state (OFF). Also, when the system activation process is started, the pair of switches of the circuit breaker 22b are set to the connected state (ON), the first switch 34b is set to the connected state (ON), the second switch 36b is set to the connected state (ON), and the third switch 40b is set to the disconnected state (OFF).

[0088] In this case, the first power storage device 24a and the second power storage device 24b are connected without a resistor, and an overcurrent occurs as shown in Fig. 12B. At this time, as shown in Fig. 12A, the terminal voltage (E2) of the second power storage device 24b rises sharply to the same voltage as the terminal voltage (E1) of the first power storage device 24a.

[0089] As described above, in the power supply system 100 of the comparative example, if the system operation process is started when E1>E2, there is a risk of an overcurrent occurring throughout the entire circuit of the power supply system 100. In contrast, in the present embodiment, if E1>E2 at the time of the system shutdown process, it is possible to discharge the first power storage device 24a without supplying power to the first load device 16a until the next system startup preparation process. Therefore, according to this embodiment, the system startup preparation process and the system operation process are not started when E1>E2. Therefore, according to this embodiment, it is possible to suppress an overcurrent caused by E1>E2.

[0090] [Prevents overcurrent from occurring when the fourth switch malfunctions] When the fourth switches 46a and 46b malfunction, the power supply system 10 of this embodiment can suppress the occurrence of an overcurrent in the power supply system 10.

[0091] FIG. 13 is a diagram showing the state of the power supply system 10 when the fourth switches 46a and 46b malfunction and enter the connected state (ON) during the system startup preparation process.

[0092] If the fourth switch 46a malfunctions and switches to the connected state (ON) during the system startup preparation process (FIG. 4), a closed circuit is formed from the first power storage device 24a via the third switch 40a, the first resistor 39a, the second resistor 41a, and the fourth switch 46a, returning to the first power storage device 24a, as shown by the dashed arrow in FIG. 13. In this case, because the first resistor 39a and the second resistor 41a are included in the closed circuit, a short circuit does not occur between the positive and negative terminals of the first power storage device 24a. Therefore, even if the fourth switch 46a malfunctions and switches to the connected state (ON) during the system startup preparation process, an overcurrent does not flow in the power supply system 10, and loss of the first power storage device 24a can be prevented.

[0093] If the fourth switch 46b malfunctions and switches to the connected state (ON) during the system startup preparation process (FIG. 4), a closed circuit is formed from the second power storage device 24b via the third switch 40b, the first resistor 39b, the second resistor 41b, and the fourth switch 46b, returning to the second power storage device 24b, as shown by the dashed arrow in FIG. 13. In this case, because the first resistor 39b and the second resistor 41b are included in the closed circuit, a short circuit does not occur between the positive and negative terminals of the second power storage device 24b. Therefore, even if the fourth switch 46b malfunctions and switches to the connected state (ON) during the system startup preparation process, an overcurrent does not flow in the power supply system 10, and loss of the second power storage device 24b can be prevented.

[0094] FIG. 14 is a diagram showing the state of the power supply system 10 when the fourth switches 46a and 46b malfunction and enter the connected state (ON) during the system activation process.

[0095] If the fourth switch 46a malfunctions and switches to the connected state (ON) during the system activation process (FIG. 5), a closed circuit is formed from the first power storage device 24a via the first switch 34a, the third resistor 42a, the second resistor 41a, and the fourth switch 46a, returning to the first power storage device 24a, as shown by the dashed arrow in FIG. 14. In this case, because the second resistor 41a and the third resistor 42a are included in the closed circuit, a short circuit does not occur between the positive and negative terminals of the first power storage device 24a. Therefore, even if the fourth switch 46a malfunctions and switches to the connected state (ON) during the system activation process, an overcurrent does not flow in the power supply system 10, and loss of the first power storage device 24a can be prevented.

[0096] If the fourth switch 46b malfunctions and switches to the connected state (ON) during the system activation process (FIG. 5), a closed circuit is formed that runs from the second power storage device 24b through the first switch 34b, the third resistor 42b, the second resistor 41b, and the fourth switch 46b, returning to the second power storage device 24b, as shown by the dashed arrow in FIG. 14. In this case, because the second resistor 41b and the third resistor 42b are included in the closed circuit, a short circuit does not occur between the positive and negative terminals of the second power storage device 24b. Therefore, even if the fourth switch 46b malfunctions and switches to the connected state (ON) during the system activation process, an overcurrent does not flow in the power supply system 10, and loss of the second power storage device 24b can be prevented.

[0097] [Prevents overcurrent from occurring when the third switch malfunctions] When the third switches 40a and 40b malfunction, the power supply system 10 of this embodiment can suppress the occurrence of an overcurrent in the power supply system 10.

[0098] FIG. 15 is a diagram showing the state of power supply system 10 when third switch 40a malfunctions and enters the connected state (ON) during the discharge process of the power storage device.

[0099] If the third switch 40a malfunctions and switches to the connected state (ON) during the power storage device discharge process (FIG. 8), a closed circuit is formed from the first power storage device 24a via the third switch 40a, the first resistor 39a, the second resistor 41a, and the fourth switch 46a, returning to the first power storage device 24a, as shown by the dashed arrow in FIG. 15. In this case, because the first resistor 39a and the second resistor 41a are included in the closed circuit, a short circuit does not occur between the positive and negative terminals of the first power storage device 24a. Therefore, even if the third switch 40a malfunctions and switches to the connected state (ON) during the power storage device discharge process, an overcurrent does not flow in the power supply system 10, and loss of the first power storage device 24a can be suppressed.

[0100] If the third switch 40b malfunctions and switches to a connected state (ON) (not shown) during the power storage device discharge process ( FIG. 8 ), a closed circuit is formed that runs from the second power storage device 24b through the third switch 40b, the first resistor 39b, the second resistor 41b, and the fourth switch 46b, and returns to the second power storage device 24b. In this case, the first resistor 39b and the second resistor 41b are included in the closed circuit, so that the positive and negative terminals of the second power storage device 24b are not short-circuited. Therefore, even if the third switch 40b malfunctions and switches to a connected state (ON) during the power storage device discharge process, an overcurrent does not flow in the power supply system 10, and loss of the second power storage device 24b can be prevented.

[0101] [Example of power supply system use] FIG. 16 is a schematic diagram of a mobile body 64. The power supply system 10 can be mounted on the mobile body 64. The mobile body 64 is, for example, an electric vertical take-off and landing aircraft (eVTOL aircraft). The mobile body 64 includes eight VTOL rotors 66. The VTOL rotors 66 generate upward thrust for the airframe 68. The mobile body 64 includes eight electric motors 70. Each electric motor 70 drives one VTOL rotor 66. The mobile body 64 has two cruise rotors 72. The cruise rotor 72 generates forward thrust for the airframe 68. The mobile body 64 includes four electric motors 74. Each electric motor 74 drives one cruise rotor 72.

[0102] Each of the first load device 16a and the second load device 16b may include at least one of a plurality of electric motors 70 and a plurality of electric motors 74. In addition to the electric motors 70 and 74, each of the first load device 16a and the second load device 16b may include a low-voltage drive device.

[0103] The mobile object 64 is not limited to an aircraft, but may be a ship, an automobile, a train, etc. Furthermore, the power supply system 10 may be used in facilities, factories, etc. in addition to the mobile object 64.

[0104] Second Embodiment 17 is a schematic diagram of a power supply system 10 according to the present embodiment. The power supply system 10 according to the present embodiment differs from the power supply system 10 according to the first embodiment in that the power supply system 10 according to the present embodiment does not have the second resistors 41a and 41b that are provided in the power supply system 10 according to the first embodiment. The other configurations of the power supply system 10 according to the present embodiment are the same as those of the power supply system 10 according to the first embodiment.

[0105] The resistance value (R1) of the first resistor 39a and the resistance value (R3) of the third resistor 42a may be the same or different. The resistance value (R1+R3) in the closed circuit formed when the smoothing capacitor 18 of the power generation device 14 and the smoothing capacitor 20a of the first load device 16a are charged (precharged) is greater than the resistance value (R3) in the closed circuit formed when the smoothing capacitor 18 of the power generation device 14 and the smoothing capacitor 20a of the first load device 16a are discharged.

[0106] Similarly, the resistance value (R1) of the first resistor 39b and the resistance value (R3) of the third resistor 42b may be the same or different. The resistance value (R1+R3) in the closed circuit formed when the smoothing capacitor 18 of the power generation device 14 and the smoothing capacitor 20b of the second load device 16b are charged (precharged) is greater than the resistance value (R3) in the closed circuit formed when the smoothing capacitor 18 of the power generation device 14 and the smoothing capacitor 20b of the first load device 16a are discharged.

[0107] Third Embodiment 18 is a schematic diagram of a power supply system 10 according to the present embodiment. The power supply system 10 according to the present embodiment differs from the power supply system 10 according to the first embodiment in that it does not have the first resistors 39a and 39b that are provided in the power supply system 10 according to the first embodiment. The other configurations of the power supply system 10 according to the present embodiment are the same as those of the power supply system 10 according to the first embodiment.

[0108] The resistance value (R2) of the second resistor 41a and the resistance value (R3) of the third resistor 42a may be the same or different. The resistance value (R3) in the closed circuit formed when the smoothing capacitor 18 of the power generation device 14 and the smoothing capacitor 20a of the first load device 16a are charged (precharged) is smaller than the resistance value (R2+R3) in the closed circuit formed when the smoothing capacitor 18 of the power generation device 14 and the smoothing capacitor 20a of the first load device 16a are discharged.

[0109] Similarly, the resistance value (R2) of the second resistor 41b and the resistance value (R3) of the third resistor 42b may be the same or different. The resistance value (R3) in the closed circuit formed when the smoothing capacitor 18 of the power generation device 14 and the smoothing capacitor 20b of the second load device 16b are charged (precharged) is smaller than the resistance value (R2+R3) in the closed circuit formed when the smoothing capacitor 18 of the power generation device 14 and the smoothing capacitor 20b of the second load device 16b are discharged.

[0110] [Fourth embodiment] 19 is a schematic diagram of a power supply system 10 according to the present embodiment. The power supply system 10 according to the present embodiment differs from the power supply system 10 according to the first embodiment in that it does not have the third resistors 42a and 42b that are provided in the power supply system 10 according to the first embodiment. The other configurations of the power supply system 10 according to the present embodiment are the same as those of the power supply system 10 according to the first embodiment.

[0111] The resistance value (R1) of the first resistor 39a and the resistance value (R2) of the second resistor 41a may be the same or different. The resistance value is R1 in the closed circuit formed when the smoothing capacitor 18 of the power generation device 14 and the smoothing capacitor 20a of the first load device 16a are charged (precharged), and the resistance value is R2 in the closed circuit formed when the smoothing capacitor 18 of the power generation device 14 and the smoothing capacitor 20a of the first load device 16a are discharged.

[0112] Similarly, the resistance value (R1) of the first resistor 39b and the resistance value (R2) of the second resistor 41b may be the same or different. The resistance value is R1 in the closed circuit formed when the smoothing capacitor 18 of the power generation device 14 and the smoothing capacitor 20b of the second load device 16b are charged (precharged), and the resistance value is R2 in the closed circuit formed when the smoothing capacitor 18 of the power generation device 14 and the smoothing capacitor 20b of the second load device 16b are discharged.

[0113] Fifth Embodiment 20 is a schematic diagram of a power supply system 10 according to the present embodiment. The power supply system 10 according to the present embodiment differs from the power supply system 10 according to the first embodiment in that it does not have the third resistors 42a and 42b that are provided in the power supply system 10 according to the first embodiment. Furthermore, the positions at which the fourth wirings 44a and 44b are connected in the power supply system 10 according to the present embodiment differ from the positions at which the fourth wirings 44a and 44b are connected in the power supply system 10 according to the first embodiment. The other configurations of the power supply system 10 according to the present embodiment are the same as those of the power supply system 10 according to the first embodiment.

[0114] One end of the fourth wiring 44a is connected to the first wiring 28a at a third node 90a, and the other end of the fourth wiring 44a is connected to the second wiring 30a at a fourth node 92a. The third node 90a is located on the first wiring 28a. The third node 90a is located at a position closer to the first load device 16a than the first switch 34a. The fourth node 92a is located on the second wiring 30a. The fourth node 92a is located at a position closer to the first power storage device 24a than the second switch 36a.

[0115] One end of the fourth wiring 44b is connected to the first wiring 28b at a third node 90b, and the other end of the fourth wiring 44b is connected to the second wiring 30b at a fourth node 92b. The third node 90b is located on the first wiring 28b. The third node 90b is located at a position closer to the second load device 16b than the first switch 34b. The fourth node 92b is located on the second wiring 30b. The fourth node 92b is located at a position closer to the second power storage device 24b than the second switch 36b.

[0116] The resistance value (R1) of the first resistor 39a and the resistance value (R2) of the second resistor 41a may be the same or different. The resistance value is R1 in the closed circuit formed when the smoothing capacitor 18 of the power generation device 14 and the smoothing capacitor 20a of the first load device 16a are charged (precharged), and the resistance value is R2 in the closed circuit formed when the smoothing capacitor 18 of the power generation device 14 and the smoothing capacitor 20a of the first load device 16a are discharged.

[0117] Similarly, the resistance value (R1) of the first resistor 39b and the resistance value (R2) of the second resistor 41b may be the same or different. The resistance value is R1 in the closed circuit formed when the smoothing capacitor 18 of the power generation device 14 and the smoothing capacitor 20b of the second load device 16b are charged (precharged), and the resistance value is R2 in the closed circuit formed when the smoothing capacitor 18 of the power generation device 14 and the smoothing capacitor 20b of the second load device 16b are discharged.

[0118] The circuit of the power supply system 10 of this embodiment (FIG. 20) and the circuit of the power supply system 10 of the fourth embodiment (FIG. 19) are electrically equivalent circuits.

[0119] The following additional notes are further disclosed regarding the above embodiment.

[0120] (Appendix 1) A power supply system (10) of the present disclosure is a power supply system having a power supply circuit that supplies power from an electricity storage device (24a) to a load device (16a), the power supply system including: a first wiring (28a) that is one of a positive wiring and a negative wiring provided in the power supply circuit; a first switch (34a) that is provided on the first wiring and that switches between a connection state that connects the electricity storage device and the load device and a disconnection state that disconnects the electricity storage device and the load device; a second wiring (30a) that is the other of the positive wiring and the negative wiring; a second switch (36a) that is provided on the second wiring and that switches between a connection state that connects the electricity storage device and the load device and a disconnection state that disconnects the electricity storage device and the load device; a third wiring (38a) that bypasses the first switch; and a third wiring (38a) that is provided on the third wiring and that switches between a connection state that connects the electricity storage device and the load device and a disconnection state that disconnects the electricity storage device and the load device. a third switch (40a) that switches between a connected state that connects the third wiring and the second wiring and a cut-off state that cuts off the connection between the power storage device and the load device; a fourth wiring (44a) that is connected to the third wiring at a first node (80a) that is closer to the load device than the third switch and that is connected to the second wiring at a second node (82a) that is closer to the power storage device than the second switch; a fourth switch (46a) that is provided on the fourth wiring and that switches between a connected state that connects the third wiring and the second wiring and a cut-off state that cuts off the connection between the third wiring and the second wiring; and resistors that are arranged in at least two of a first portion (84a) that is a portion of the third wiring located between the power storage device and the first node, a second portion (86a) that is a portion of the fourth wiring, and a third portion (88a) that is a portion of the third wiring located between the first node and the load device. As a result, even if the fourth switch malfunctions and the second wiring and the third wiring are connected via the fourth wiring while the load device is being charged (pre-charged), an overcurrent will not flow in the power supply system, and the loss of the storage device can be prevented.

[0121] (Appendix 2) In the power supply system described in Supplementary Note 1, the resistors may be arranged in three locations: the first location, the second location, and the third location. This prevents an overcurrent from flowing in the power supply system, and prevents the loss of the power storage device, even if the second wiring and the third wiring are connected by the fourth wiring due to a malfunction of the fourth switch while the load device is being charged (pre-charged).

[0122] (Appendix 3) In the power supply system described in Supplementary Note 1, the resistors may be disposed in two locations, the first location and the second location. This prevents an overcurrent from flowing in the power supply system and prevents the loss of the power storage device even if the second wiring and the third wiring are connected by the fourth wiring due to a malfunction of the fourth switch while the load device is being charged (pre-charged).

[0123] (Appendix 4) In the power supply system described in Supplementary Note 1, the resistors may be disposed in two locations, the second location and the third location. This prevents an overcurrent from flowing in the power supply system and prevents the loss of the power storage device even if the second wiring and the third wiring are connected by the fourth wiring due to a malfunction of the fourth switch while the load device is being charged (pre-charged).

[0124] (Appendix 5) In the power supply system described in Supplementary Note 1, the resistors may be disposed in two locations, the first location and the third location. This prevents an overcurrent from flowing in the power supply system and prevents the loss of the power storage device even if the second wiring and the third wiring are connected by the fourth wiring due to a malfunction of the fourth switch while the load device is being charged (pre-charged).

[0125] (Appendix 6) The power supply system of the present disclosure is a power supply system having a power supply circuit that supplies power from a power storage device to a load device, the power supply system including: a first wiring that is one of a positive wiring and a negative wiring provided in the power supply circuit; a first switch that is provided on the first wiring and switches between a connection state that connects the power storage device and the load device and a cut-off state that cuts off the connection between the power storage device and the load device; a second wiring that is the other of the positive wiring and the negative wiring; a second switch that is provided on the second wiring and switches between a connection state that connects the power storage device and the load device and a cut-off state that cuts off the connection between the power storage device and the load device; a third wiring that bypasses the first switch; a third switch that switches between a connection state that connects the power storage device and the load device and a disconnection state that disconnects the power storage device and the load device, a first resistor (39a) that is provided on the third wiring and connected in series with the third switch, a fourth wiring that is connected to the first wiring at a third node (90a) that is closer to the load device than the first switch and that is connected to the second wiring at a fourth node (92a) that is closer to the power storage device than the second switch, a fourth switch that is provided on the fourth wiring and switches between a connection state that connects the third wiring and the second wiring and a disconnection state that disconnects the third wiring and the second wiring, and a second resistor (41a) that is provided on the fourth wiring and connected in series with the fourth switch. Thus, even if the fourth switch malfunctions and the first wiring and the second wiring are connected by the fourth wiring while the load device is being charged (pre-charged), an overcurrent does not flow in the power supply system, and loss of the power storage device can be suppressed.

[0126] (Appendix 7) In the power supply system according to any one of Supplementary Notes 1 to 6, the load device may have a smoothing capacitor (20a), and when charging the smoothing capacitor, the first switch may be in the disconnected state, the second switch may be in the connected state, the third switch may be in the connected state, and the fourth switch may be in the disconnected state. This allows the smoothing capacitor of the load device to be charged.

[0127] (Appendix 8) In the power supply system according to any one of Supplementary Notes 1 to 6, when power is supplied from the power storage device to the load device, the first switch may be in the connected state, the second switch may be in the connected state, the third switch may be in the disconnected state, and the fourth switch may be in the disconnected state, thereby enabling power to be supplied from the power storage device to the load device.

[0128] (Appendix 9) In the power supply system according to any one of Supplementary Notes 1 to 6, the load device may have a smoothing capacitor, and when discharging the smoothing capacitor, the first switch may be set to the disconnected state, the second switch may be set to the connected state, the third switch may be set to the disconnected state, and the fourth switch may be set to the connected state. This allows the smoothing capacitor of the load device to be discharged.

[0129] (Appendix 10) In the power supply system according to any one of Supplementary Notes 1 to 6, when discharging the power storage device, the first switch may be set to the connected state, the second switch may be set to the disconnected state, the third switch may be set to the disconnected state, and the fourth switch may be set to the connected state, thereby enabling the power storage device to be discharged.

[0130] (Appendix 11) The power supply system described in Supplementary Note 9 may further include an internal resistance value acquisition unit (61) that acquires an internal resistance value of the power storage device based on a terminal voltage of the power storage device in a non-discharging state, the terminal voltage of the power storage device during discharging, and a current of the power storage device during discharging. This makes it possible to estimate a degree of deterioration of the power storage device.

[0131] (Appendix 12) A mobile object (64) of the present disclosure includes the power supply system according to any one of Supplementary Notes 1 to 6. This prevents an overcurrent from flowing in the power supply system of the mobile object, thereby preventing the loss of the power storage device.

[0132] Although the present disclosure has been described in detail, the present disclosure is not limited to the individual embodiments described above. Various additions, substitutions, modifications, partial deletions, etc. are possible in these embodiments without departing from the gist of the present disclosure or the spirit of the present disclosure derived from the content of the claims and their equivalents. These embodiments can also be implemented in combination. For example, in the above-described embodiments, the order of each operation and the order of each process are shown as examples and are not limited to these. The same applies when numerical values or mathematical expressions are used in the description of the above-described embodiments. [Explanation of symbols]

[0133] 10... Power supply system 16a... First load device (load device) 16b... second load device (load device) 20a, 20b... smoothing capacitor 24a...First power storage device (power storage device) 24b...Second power storage device (power storage device) 26a…Third power supply circuit (power supply circuit) 26b...Fourth power supply circuit (power supply circuit) 28a, 28b... First wiring 30a, 30b... Second wiring 34a, 34b...first switch 36a, 36b...second switch 38a, 38b...Third wiring 39a, 39b...First resistor 40a, 40b...Third switches 41a, 41b...Second resistors 44a, 44b...Fourth wiring 46a, 46b...Fourth switch 61...Internal resistance value acquisition unit 64...Moving body 80a, 80b...first node 82a, 82b...second node 84a, 84b...1st part 86a, 86b...2nd part 88a, 88b...Third part 90a, 90b...Third node 92a, 92b...4th Node

Claims

1. A power supply system having a power supply circuit that supplies power from a power storage device to a load device, a first wiring that is one of a positive wiring and a negative wiring provided in the power supply circuit; a first switch provided on the first wiring and configured to switch between a connection state in which the power storage device and the load device are connected and a disconnection state in which the power storage device and the load device are disconnected; a second wiring that is the other of the positive wiring and the negative wiring; a second switch provided on the second wiring and configured to switch between a connection state in which the power storage device and the load device are connected and a disconnection state in which the power storage device and the load device are disconnected; a third wiring that bypasses the first switch; a third switch provided on the third wiring and configured to switch between a connection state in which the power storage device and the load device are connected and a disconnection state in which the power storage device and the load device are disconnected; a fourth wiring connected to the third wiring at a first node closer to the load device than the third switch and connected to the second wiring at a second node closer to the power storage device than the second switch; a fourth switch provided on the fourth wiring and configured to switch between a connection state in which the third wiring and the second wiring are connected and a disconnection state in which the third wiring and the second wiring are disconnected; resistors arranged in at least two of a first portion of the third wiring that is located between the power storage device and the first node, a second portion of the fourth wiring that is located on the third wiring, and a third portion of the third wiring that is located between the first node and the load device; A power supply system comprising:

2. 2. The power supply system according to claim 1, A power supply system, wherein the resistors are arranged at three locations: the first location, the second location, and the third location.

3. 2. The power supply system according to claim 1, A power supply system, wherein the resistor is disposed at two locations, the first location and the second location.

4. 2. The power supply system according to claim 1, A power supply system, wherein the resistor is disposed at two locations, the second location and the third location.

5. 2. The power supply system according to claim 1, A power supply system, wherein the resistor is disposed at two locations, the first location and the third location.

6. A power supply system having a power supply circuit that supplies power from a power storage device to a load device, a first wiring that is one of a positive wiring and a negative wiring provided in the power supply circuit; a first switch provided on the first wiring and configured to switch between a connection state in which the power storage device and the load device are connected and a disconnection state in which the power storage device and the load device are disconnected; A second wiring that is the other of the positive wiring and the negative wiring; a second switch provided on the second wiring and configured to switch between a connection state in which the power storage device and the load device are connected and a disconnection state in which the power storage device and the load device are disconnected; a third wiring that bypasses the first switch; a third switch provided on the third wiring and configured to switch between a connection state in which the power storage device and the load device are connected and a disconnection state in which the power storage device and the load device are disconnected; a first resistor provided on the third wiring and connected in series with the third switch; a fourth wiring connected to the first wiring at a third node closer to the load device than the first switch and connected to the second wiring at a fourth node closer to the power storage device than the second switch; a fourth switch provided on the fourth wiring and configured to switch between a connection state in which the third wiring and the second wiring are connected and a disconnection state in which the third wiring and the second wiring are disconnected; a second resistor provided on the fourth wiring and connected in series with the fourth switch; A power supply system comprising:

7. The power supply system according to any one of claims 1 to 6, the load device has a smoothing capacitor; When charging the smoothing capacitor, the power supply system sets the first switch to the disconnected state, the second switch to the connected state, the third switch to the connected state, and the fourth switch to the disconnected state.

8. The power supply system according to any one of claims 1 to 6, When power is supplied from the power storage device to the load device, the first switch is set to the connected state, the second switch is set to the connected state, the third switch is set to the disconnected state, and the fourth switch is set to the disconnected state.

9. The power supply system according to any one of claims 1 to 6, the load device has a smoothing capacitor; When discharging the smoothing capacitor, the first switch is set to the disconnected state, the second switch is set to the connected state, the third switch is set to the disconnected state, and the fourth switch is set to the connected state.

10. The power supply system according to any one of claims 1 to 6, When discharging the power storage device, the first switch is set to the connected state, the second switch is set to the disconnected state, the third switch is set to the disconnected state, and the fourth switch is set to the connected state.

11. 10. The power supply system according to claim 9, The power supply system further includes an internal resistance value acquisition unit that acquires an internal resistance value of the power storage device based on a terminal voltage of the power storage device in a non-discharging state, the terminal voltage of the power storage device during discharging, and a current of the power storage device during discharging.

12. A mobile object comprising the power supply system according to any one of claims 1 to 6.

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