Power supply system and method for controlling power supply system

Abstract

To provide a better power supply system and a method for controlling the power supply system.SOLUTION: When a terminal voltage of a first power storage device 24a is higher than a terminal voltage of a second power storage device 24b, a power supply system 10 electrically disconnects a power generation device 14 from a first load device 16a, electrically disconnects the power generation device from the first power storage device, charges a smoothing capacitor 20a of the first load device with power supplied from the first power storage device, electrically connects the power generation device to a second load device 16b, and electrically connects the power generation device to the second power storage device, and charges a smoothing capacitor 18 of the power generation device and a smoothing capacitor 20b of the second load device with power supplied from the second power storage device.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a power supply system and a method for controlling the power supply system.

Background Art

[0002] Patent Document 1 below discloses a power supply system including a high-voltage battery and a motor generator. Between the high-voltage battery and the motor generator, three relays, a resistor (precharge resistor), a capacitor (smoothing capacitor), and a step-down converter are interposed. In this power supply system, by controlling the on and off of the three relays, the capacitor can be precharged through the resistor. Also, in this power supply system, by controlling the on and off of the three relays, the charge accumulated in the capacitor can be discharged through the resistor.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] A better power supply system and a method for controlling the power supply system are desired.

[0005] The present invention aims to solve the above-described problems.

Means for Solving the Problems

[0006] A first aspect of the present disclosure includes a first load device having a smoothing capacitor, a second load device having a smoothing capacitor, a power generation device having a smoothing capacitor and supplying power to the first load device and the second load device, a first power storage device connected in parallel with the power generation device and supplying power to the first load device, a second power storage device connected in parallel with the power generation device and supplying power to the second load device, a first switching device that electrically connects between the power generation device and the first load device and also electrically connects between the power generation device and the first power storage device, and a second switching device that electrically connects between the power generation device and the second load device and also electrically connects between the power generation device and the second power storage device, and switches between a first state of electrically connecting between the power generation device and the first load device and also electrically connecting between the power generation device and the first power storage device, and a second state of electrically disconnecting between the power generation device and the first load device and also electrically disconnecting between the power generation device and the first power storage device, and a third switching device that electrically connects between the power generation device and the second load device and also electrically connects between the power generation device and the second power storage device, and a fourth switching device that electrically disconnects between the power generation device and the second load device and also electrically disconnects between the power generation device and the second power storage device, a voltage acquisition unit that acquires a first voltage that is a terminal voltage of the first power storage device and a second voltage that is a terminal voltage of the second power storage device, and a control unit that controls the first switching device and the second switching device. When the first voltage is higher than the second voltage, the control unit sets the first switching device to the second state and the second switching device to the third state, charges the smoothing capacitor of the first load device with the power supplied from the first power storage device, and charges the smoothing capacitor of the power generation device and the smoothing capacitor of the second load device with the power supplied from the second power storage device.

[0007] A second aspect of the present disclosure includes a first load device having a smoothing capacitor, a second load device having a smoothing capacitor, a power generation device having a smoothing capacitor and supplying power to the first load device and the second load device, a first power storage device connected in parallel with the power generation device and supplying power to the first load device, a second power storage device connected in parallel with the power generation device and supplying power to the second load device, a first switching device that electrically connects between the power generation device and the first load device and also electrically connects between the power generation device and the first power storage device, and switches between a first state of electrically connecting between the power generation device and the first load device and also electrically connecting between the power generation device and the first power storage device, and a second state of electrically disconnecting between the power generation device and the first load device and also electrically disconnecting between the power generation device and the first power storage device, and a second switching device that electrically connects between the power generation device and the second load device and also electrically connects between the power generation device and the second power storage device, and switches between a third state of electrically connecting between the power generation device and the second load device and also electrically connecting between the power generation device and the second power storage device, and a fourth state of electrically disconnecting between the power generation device and the second load device and also electrically disconnecting between the power generation device and the second power storage device. A control method for a power supply system includes a voltage acquisition step of acquiring a first voltage that is a terminal voltage of the first power storage device and a second voltage that is a terminal voltage of the second power storage device, and when the first voltage is higher than the second voltage, setting the first switching device to the second state and setting the second switching device to the third state, charging the smoothing capacitor of the first load device with the power supplied from the first power storage device, and charging the smoothing capacitor of the power generation device and the smoothing capacitor of the second load device with the power supplied from the second power storage device.

Advantages of the Invention

[0008] The present invention can provide a better power supply system and a control method for the power supply system.

Brief Description of the Drawings

[0009]

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[0010] In a power supply system that supplies power from a power generation device to a first load device and a second load device, a first power storage device may be connected in parallel with the power generation device, and a second power storage device may be connected in parallel with the power generation device. Thereby, when a relatively large amount of power is required from the first load device, power is supplied to the first load device from the power generation device and the first power storage device. Also, when a relatively large amount of power is required from the 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, there is a risk of overcurrent flowing in the power supply system.

[0011] The power supply system and the control method of the power supply system of the present disclosure can suppress the occurrence of 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.

[0012] [One Embodiment] [Configuration of Power Supply System] FIG. 1 is a schematic diagram of a power supply system 10 according to the present 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 the power generation device 14 to the first load device 16a. The second power supply circuit 12b supplies DC power output from the power generation device 14 to the second load device 16b. The first power supply circuit 12a and the second power supply circuit 12b may include elements such as switches, sensors, fuses, diodes, resistors, coils, and capacitors.

[0013] The power generation device 14 includes an engine, a generator, and a power control unit (not shown). The generator is driven by the engine, and the generator 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, the smoothing capacitor 18 is charged (pre-charged). Also, when the power supply system 10 is shut down, the smoothing capacitor 18 is discharged. The power generation device 14 may have various elements such as sensors, fuses, relays, breakers, diodes, transistors, resistors, and coils.

[0014] The first load device 16a and the second load device 16b include an inverter and an electric motor (not shown). The inverter converts the 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, the smoothing capacitor 20a and the smoothing capacitor 20b are first charged (pre-charged). Also, when the power supply system 10 is shut down, the smoothing capacitor 20a and the smoothing capacitor 20b are discharged. The first load device 16a and the second load device 16b may have various elements such as sensors, fuses, relays, breakers, diodes, transistors, resistors, coils, and capacitors.

[0015] The power supply system 10 includes a third power supply circuit 22a and a fourth power supply circuit 22b. The third power supply circuit 22a supplies the DC power output from the first power storage device 24a to the first load device 16a. The fourth power supply circuit 22b supplies the DC power output from the second power storage device 24b to the second load device 16b. The third power supply circuit 22a and the fourth power supply circuit 22b may have elements such as switches, sensors, fuses, diodes, resistors, coils, and capacitors.

[0016] The first power storage device 24a is connected in parallel with the power generation device 14. The second power storage device 24b is connected in parallel with the power generation device 14. The first power storage device 24a and the second power storage device 24b have, for example, a lithium-ion battery. The first power storage device 24a and the second power storage device 24b may have a secondary battery other than a lithium-ion battery. The first power storage device 24a and the second power storage device 24b may have a large-capacity capacitor.

[0017] The power supply system 10 includes a cutoff device 28a and a cutoff device 28b. FIG. 2 is a schematic diagram of the cutoff device 28a and the cutoff device 28b of the present embodiment.

[0018] The cutoff device 28a includes a switch 32a and a switch 34a. The switch 32a is provided in the positive electrode wiring connecting the power generation device 14 and the first power supply circuit 12a. The switch 34a is provided in the negative electrode wiring connecting the power generation device 14 and the first power supply circuit 12a. The switch 32a and the switch 34a are, for example, a switch, a relay, a contactor, a breaker, a semiconductor switch, or the like.

[0019] When both the switch 32a and the switch 34a are in the connected state (ON), the cutoff device 28a connects the power generation device 14 to the first power supply circuit 12a. When both the switch 32a and the switch 34a are in the cutoff state (OFF), the cutoff device 28a cuts off the power generation device 14 from the first power supply circuit 12a. Note that, by turning one of the switch 32a and the switch 34a to OFF, the cutoff device 28a may cut off the power generation device 14 from the first power supply circuit 12a.

[0020] Hereinafter, when both the switch 32a and the switch 34a are in the connected state (ON), the cutoff device 28a may be described as being in the connected state (ON). Also, when both the switch 32a and the switch 34a are in the cutoff state (OFF), the cutoff device 28a may be described as being in the cutoff state (OFF).

[0021] The cutoff device 28b includes a switch 32b and a switch 34b. The switch 32b is provided in the positive electrode wiring connecting the power generation device 14 and the second power supply circuit 12b. The switch 34b is provided in the negative electrode wiring connecting the power generation device 14 and the second power supply circuit 12b. The switch 32b and the switch 34b are, for example, a switch, a relay, a contact, a breaker, a semiconductor switch, or the like.

[0022] When both the switch 32b and the switch 34b are in the connected state (ON), the cutoff device 28b connects the power generation device 14 to the second power supply circuit 12b. When both the switch 32b and the switch 34b are in the cutoff state (OFF), the cutoff device 28b cuts off the power generation device 14 from the second power supply circuit 12b. Note that even if one of the switch 32b and the switch 34b is turned OFF and the cutoff device 28b cuts off the power generation device 14 from the second power supply circuit 12b, it may be acceptable.

[0023] Hereinafter, when both the switch 32b and the switch 34b are in the connected state (ON), it may be described that the cutoff device 28b is in the connected state (ON). Also, when both the switch 32b and the switch 34b are in the cutoff state (OFF), it may be described that the cutoff device 28b is in the cutoff state (OFF).

[0024] The power supply system 10 includes a backflow prevention device 36a and a backflow prevention device 36b. FIG. 3 is a schematic diagram of the backflow prevention device 36a and the backflow prevention device 36b.

[0025] The backflow prevention device 36a has a diode 38a and a transistor 40a. The diode 38a is provided in the positive electrode wiring connecting the power generation device 14 and the first power supply circuit 12a. The transistor 40a is provided in parallel with the diode 38a. Note that the diode 38a may be provided in the negative electrode wiring connecting the power generation device 14 and the first power supply circuit 12a.

[0026] When the value obtained by subtracting the potential of the first power supply circuit 12a side (cathode) of the diode 38a from the potential of the power generation device 14 side (anode) of the diode 38a (hereinafter referred to as the potential difference) is less than the forward voltage, the diode 38a hardly conducts current. When the potential difference is equal to or higher than the forward voltage, the diode 38a conducts current. The forward voltage is relatively low. Therefore, hereinafter, it will be described that the diode 38a conducts current when the potential of the anode is higher than the potential of the cathode. Also, it will be described that the diode 38a does not conduct current when the potential of the anode is lower than the potential of the cathode.

[0027] When the transistor 40a is in the cutoff state (OFF), when the terminal voltage of the power generation device 14 is higher than the terminal voltage of the first load device 16a, the power generation device 14 is connected to the first power supply circuit 12a by the diode 38a. When the transistor 40a is in the cutoff state (OFF), when the terminal voltage of the power generation device 14 is lower than the terminal voltage of the first load device 16a, the power generation device 14 is disconnected from the first power supply circuit 12a by the diode 38a.

[0028] When the transistor 40a is in the connected state (ON), regardless of the relationship between the terminal voltage of the power generation device 14 and the terminal voltage of the first load device 16a, the power generation device 14 is connected to the first power supply circuit 12a.

[0029] Hereinafter, when the transistor 40a is in the connected state (ON), it may be described that the reverse current prevention device 36a is in the reverse current permission state. Also, when the transistor 40a is in the cutoff state (OFF), it may be described that the reverse current prevention device 36a is in the reverse current prohibition state. Instead of the transistor 40a, for example, a relay, a contactor, a breaker, etc. may be used.

[0030] The backflow prevention device 36b includes a diode 38b and a transistor 40b. The diode 38b is provided on the positive electrode wiring connecting the power generation device 14 and the second power supply circuit 12b. The transistor 40b is provided in parallel with the diode 38b. Note that the diode 38b may be provided on the negative electrode wiring connecting the power generation device 14 and the second power supply circuit 12b.

[0031] When the value obtained by subtracting the potential of the second power supply circuit 12b side (cathode) of the diode 38b from the potential of the power generation device 14 side (anode) of the diode 38b (hereinafter referred to as the potential difference) is less than the forward voltage, the diode 38b hardly conducts current. When the potential difference is greater than or equal to the forward voltage, the diode 38b conducts current. The forward voltage is relatively low. Therefore, hereinafter, it will be described that the diode 38b conducts current when the potential of the anode is higher than the potential of the cathode. Also, hereinafter, it will be described that the diode 38b does not conduct current when the potential of the anode is lower than the potential of the cathode.

[0032] When the transistor 40b is in the cut-off state (OFF), when the terminal voltage of the power generation device 14 is higher than the terminal voltage of the second load device 16b, the power generation device 14 is connected to the second power supply circuit 12b by the diode 38b. When the transistor 40b is in the cut-off state (OFF), when the terminal voltage of the power generation device 14 is less than or equal to the terminal voltage of the second load device 16b, the power generation device 14 is disconnected from the second power supply circuit 12b by the diode 38b.

[0033] When the transistor 40b is in the connected state (ON), the power generation device 14 is connected to the second power supply circuit 12b regardless of the relationship between the terminal voltage of the power generation device 14 and the terminal voltage of the second load device 16b.

[0034] Hereinafter, when the transistor 40b is in the connected state (ON), it may be described that the backflow prevention device 36b is in the backflow permission state. Also, when the transistor 40b is in the cut-off state (OFF), it may be described that the backflow prevention device 36b is in the backflow prohibition state. Instead of the transistor 40b, for example, a relay, a contactor, a breaker, etc. may be used.

[0035] The first switching device 42a is constituted by the cutoff device 28a and the backflow prevention device 36a. The first switching device 42a may have a configuration other than the cutoff device 28a and the backflow prevention device 36a.

[0036] When the cutoff device 28a is in the connected state (ON) and the backflow prevention device 36a is in the backflow permission state, the first switching device 42a electrically connects between the power generation device 14 and the first load device 16a.

[0037] When the cutoff device 28a is in the connected state (ON) and the backflow prevention device 36a is in the backflow prohibition state, when the terminal voltage of the power generation device 14 is higher than the terminal voltage of the first load device 16a, the first switching device 42a electrically connects between the power generation device 14 and the first load device 16a.

[0038] When the cutoff device 28a is in the connected state (ON) and the backflow prevention device 36a is in the backflow prohibition state, when the terminal voltage of the power generation device 14 is lower than the terminal voltage of the first load device 16a, the first switching device 42a electrically disconnects between the power generation device 14 and the first load device 16a.

[0039] When the cutoff device 28a is in the cut-off state (OFF), regardless of the state of the backflow prevention device 36a, the first switching device 42a electrically disconnects between the power generation device 14 and the first load device 16a.

[0040] When the first power storage device 24a is connected to the third power supply circuit 22a, when the power generation device 14 and the first load device 16a are electrically connected, the power generation device 14 and the first power storage device 24a will also be electrically connected. Further, even when the first power storage device 24a is connected to the third power supply circuit 22a, when the power generation device 14 and the first load device 16a are electrically disconnected, the power generation device 14 and the first power storage device 24a will also be electrically disconnected.

[0041] Hereinafter, the state in which the first switching device 42a electrically connects the power generation device 14 and the first load device 16a and also electrically connects the power generation device 14 and the first power storage device 24a may be described as the first state. Further, the state in which the first switching device 42a electrically disconnects the power generation device 14 and the first load device 16a and also electrically disconnects the power generation device 14 and the first power storage device 24a may be described as the second state.

[0042] The second switching device 42b is constituted by the cutoff device 28b and the backflow prevention device 36b. The second switching device 42b may have a configuration other than the cutoff device 28b and the backflow prevention device 36b.

[0043] When the cutoff device 28b is in the connected state (ON) and the backflow prevention device 36b is in the backflow permission state, the second switching device 42b electrically connects the power generation device 14 and the second load device 16b.

[0044] When the cutoff device 28b is in the connected state (ON) and the backflow prevention device 36b is in the backflow prohibition state, when the terminal voltage of the power generation device 14 is higher than the terminal voltage of the second load device 16b, the second switching device 42b electrically connects the power generation device 14 and the second load device 16b.

[0045] When the cutoff device 28b is in the connected state (ON) and the backflow prevention device 36b is in the backflow prohibition state, when the terminal voltage of the power generation device 14 is lower than the terminal voltage of the second load device 16b, the second switching device 42b electrically cuts off between the power generation device 14 and the second load device 16b.

[0046] When the cutoff device 28b is in the cutoff state (OFF), regardless of the state of the backflow prevention device 36b, the second switching device 42b electrically cuts off between the power generation device 14 and the second load device 16b.

[0047] In addition, when the second power storage device 24b is connected to the fourth power supply circuit 22b, when the power generation device 14 and the second load device 16b are electrically connected, the power generation device 14 and the second power storage device 24b are also electrically connected. Also, even when the second power storage device 24b is connected to the fourth power supply circuit 22b, when the power generation device 14 and the second load device 16b are electrically cut off, the power generation device 14 and the second power storage device 24b are also electrically cut off.

[0048] Hereinafter, the state in which the second switching device 42b electrically connects between the power generation device 14 and the second load device 16b and also electrically connects between the power generation device 14 and the second power storage device 24b may be described as the third state. Also, the state in which the second switching device 42b electrically cuts off between the power generation device 14 and the second load device 16b and also electrically cuts off between the power generation device 14 and the second power storage device 24b may be described as the fourth state.

[0049] The power supply system 10 includes a third switching device 44a. The third switching device 44a has a switch 46a, a switch 48a, a switch 50a, and a precharge resistor 52a. The switch 46a is provided in the positive electrode wiring connecting the first power storage device 24a and the third power supply circuit 22a. The switch 48a is provided in the negative electrode wiring connecting the first power storage device 24a and the third power supply circuit 22a. The switch 50a is provided in a precharge circuit 54a that bypasses the switch 46a. A precharge resistor 52a is provided in series with the switch 50a in the precharge circuit 54a. The switch 46a, the switch 48a, and the switch 50a are, for example, switches, relays, contactors, breakers, semiconductor switches, or the like.

[0050] When the switch 46a is in the connected state (ON), the switch 48a is in the connected state (ON), and the switch 50a is in the disconnected state (OFF), the third switching device 44a connects the first power storage device 24a to the third power supply circuit 22a without passing through the precharge resistor 52a.

[0051] When the switch 46a is in the disconnected state (OFF), the switch 48a is in the connected state (ON), and the switch 50a is in the connected state (ON), the third switching device 44a connects the first power storage device 24a to the third power supply circuit 22a via the precharge resistor 52a.

[0052] When the switch 46a is in the off state, the switch 48a is in the off state, and the switch 50a is in the off state, the third switching device 44a disconnects the first power storage device 24a from the third power supply circuit 22a. Note that the third switching device 44a may disconnect the first power storage device 24a from the third power supply circuit 22a with the switch 46a in the on state, the switch 48a in the off state, and the switch 50a in the on state. Also, the third switching device 44a may disconnect the first power storage device 24a from the third power supply circuit 22a with the switch 46a in the off state, the switch 48a in the off state, and the switch 50a in the on state. Further, the third switching device 44a may disconnect the first power storage device 24a from the third power supply circuit 22a with the switch 46a in the on state, the switch 48a in the off state, and the switch 50a in the off state. Additionally, the third switching device 44a may disconnect the first power storage device 24a from the third power supply circuit 22a with the switch 46a in the off state, the switch 48a in the on state, and the switch 50a in the off state.

[0053] The power supply system 10 includes a fourth switching device 44b. The fourth switching device 44b has a switch 46b, a switch 48b, a switch 50b, and a precharge resistor 52b. The switch 46b is provided in the positive electrode wiring connecting the second power storage device 24b and the fourth power supply circuit 22b. The switch 48b is provided in the negative electrode wiring connecting the second power storage device 24b and the fourth power supply circuit 22b. The switch 50b is provided in a precharge circuit 54b that bypasses the switch 46b. A precharge resistor 52b is provided in series with the switch 50b in the precharge circuit 54b. The switch 46b, the switch 48b, and the switch 50b are, for example, switches, relays, contactors, breakers, semiconductor switches, etc.

[0054] When the switch 46b is in the connected state (ON), the switch 48b is in the connected state (ON), and the switch 50b is in the disconnected state (OFF), the fourth switching device 44b connects the second power storage device 24b to the fourth power supply circuit 22b without passing through the precharge resistor 52b.

[0055] When the switch 46b is in the disconnected state (OFF), the switch 48b is in the connected state (ON), and the switch 50b is in the connected state (ON), the fourth switching device 44b connects the second power storage device 24b to the fourth power supply circuit 22b via the precharge resistor 52b.

[0056] When the switch 46b is in the disconnected state (OFF), the switch 48b is in the disconnected state (OFF), and the switch 50b is in the disconnected state (OFF), the fourth switching device 44b disconnects the second power storage device 24b from the fourth power supply circuit 22b. Incidentally, the fourth switching device 44b may disconnect the second power storage device 24b from the fourth power supply circuit 22b with the switch 46b in the connected state (ON), the switch 48b in the disconnected state (OFF), and the switch 50b in the connected state (ON). Also, the fourth switching device 44b may disconnect the second power storage device 24b from the fourth power supply circuit 22b with the switch 46b in the disconnected state (OFF), the switch 48b in the disconnected state (OFF), and the switch 50b in the connected state (ON). Further, the fourth switching device 44b may disconnect the second power storage device 24b from the fourth power supply circuit 22b with the switch 46b in the connected state (ON), the switch 48b in the disconnected state (OFF), and the switch 50b in the disconnected state (OFF). Additionally, the fourth switching device 44b may disconnect the second power storage device 24b from the fourth power supply circuit 22b with the switch 46b in the disconnected state (OFF), the switch 48b in the connected state (ON), and the switch 50b in the disconnected state (OFF).

[0057] The power supply system 10 includes a voltage sensor 56a and a voltage sensor 56b. The voltage sensor 56a detects the terminal voltage (output voltage) of the first power storage device 24a. The voltage sensor 56b detects the terminal voltage (output voltage) of the second power storage device 24b. Hereinafter, the terminal voltage of the first power storage device 24a may be referred to as the first voltage. Also, the terminal voltage of the second power storage device 24b may be referred to as the second voltage.

[0058] [Configuration of the control device] The power supply system 10 includes a control device 58. FIG. 4 is a control block diagram of the control device 58 in the present embodiment.

[0059] The control device 58 has an arithmetic unit 60 and a storage unit 62. The arithmetic unit 60 is a processor such as a CPU (Central Processing Unit) or a GPU (Graphics Processing Unit), for example. The arithmetic unit 60 controls each device by executing a program stored in the storage unit 62. At least a part of the arithmetic unit 60 may be realized by an integrated circuit such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field-Programmable Gate Array). At least a part of the arithmetic unit 60 may be realized by an electronic circuit including discrete devices.

[0060] The arithmetic unit 60 functions as a voltage acquisition unit 64 and a control unit 66. The voltage acquisition unit 64 acquires the terminal voltage (output voltage) of the first power storage device 24a from the voltage sensor 56a. The voltage acquisition unit 64 acquires the terminal voltage (output voltage) of the second power storage device 24b from the voltage sensor 56b. The control unit 66 controls each of the power generation device 14, the first switching device 42a, the second switching device 42b, the third switching device 44a, and the fourth switching device 44b.

[0061] The storage unit 62 is composed of 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 RAM (Random Access Memory) or the like. The non-volatile memory is, for example, a ROM (Read Only Memory), a flash memory, or the like. Data and the like are stored, for example, in the volatile memory. Programs, tables, maps, and the like are stored, for example, in the non-volatile memory. At least a part of the storage unit 62 may be provided in the above-described processor, integrated circuit, or the like.

[0062] [Operation of the Power Supply System] The first load device 16a and the second load device 16b are driven by the electric power supplied from the power generation device 14. When the generated electric power of the power generation device 14 is not sufficient for the required electric power of the first load device 16a, electric power is supplied from the first power storage device 24a to the first load device 16a. Similarly, when the generated electric power of the power generation device 14 is not sufficient for the required electric power of the second load device 16b, electric power is supplied from the second power storage device 24b to the second load device 16b.

[0063] During the driving of the first load device 16a and the second load device 16b, a difference may occur between the power consumption of the first power storage device 24a by the first load device 16a and the power consumption of the second power storage device 24b by the second load device 16b. In this case, a difference may occur between the remaining amount of the first power storage device 24a and the remaining amount of the second power storage device 24b. Therefore, when the power supply system 10 is stopped, the terminal voltage (Vbat1) of the first power storage device 24a and the terminal voltage (Vbat2) of the second power storage device 24b may be different.

[0064] FIG. 5A is a voltage time chart of the power supply system 10 at startup in the present embodiment. FIG. 5B is a current time chart of the power supply system 10 at startup in the present embodiment. FIGS. 6 to 14 are diagrams showing the state of the power supply system 10 in the present embodiment.

[0065] Hereinafter, the operation of the power supply system 10 at startup will be described with reference to FIGS. 5A, 5B, 6 to 14. At the start of startup of the power supply system 10, it is assumed that the terminal voltage (Vbat1) of the first power storage device 24a is higher than the terminal voltage (Vbat2) of the second power storage device 24b.

[0066] (Power supply system at stop) FIG. 6 is a diagram showing the state of the power supply system 10 at stop (time point t0). When stopping the power supply system 10, the control unit 66 sets the cutoff device 28a to the cutoff state (OFF) and sets the backflow prevention device 36a to the backflow prohibition state. As a result, the power generation device 14 is disconnected from the first power supply circuit 12a. Also, the cutoff device 28b is set to the cutoff state (OFF) and the backflow prevention device 36b is set to the backflow prohibition state. As a result, the power generation device 14 is disconnected from the second power supply circuit 12b.

[0067] Furthermore, when stopping the power supply system 10, the control unit 66 sets the switch 46a to the cutoff state (OFF), sets the switch 48a to the cutoff state (OFF), and sets the switch 50a to the cutoff state (OFF). As a result, the first power storage device 24a is disconnected from the third power supply circuit 22a. Also, the control unit 66 sets the switch 46b to the cutoff state (OFF), sets the switch 48b to the cutoff state (OFF), and sets the switch 50b to the cutoff state (OFF). As a result, the second power storage device 24b is disconnected from the fourth power supply circuit 22b.

[0068] (Power supply system at start of startup) FIG. 7 is a diagram showing the state of the power supply system 10 at the start of startup (time point t1). At the start of startup of the power supply system 10, the control unit 66 sets the cutoff device 28a to the connected state (ON) and sets the cutoff device 28b to the connected state (ON).

[0069] (Power supply system at start of charging the smoothing capacitor of the first load device) FIG. 8 is a diagram showing the state of the power supply system 10 at the start of charging (time t2) of the smoothing capacitor 20a of the first load device 16a. When charging the smoothing capacitor 20a, the control unit 66 turns on the switch 48a and turns on the switch 50a. As a result, the first load device 16a is connected to the first power storage device 24a via the precharge resistor 52a. Therefore, the smoothing capacitor 20a is charged by the power of the first power storage device 24a without an overcurrent flowing through the power supply system 10.

[0070] As shown in FIG. 5B, a current (Ibat1) flows from the first power storage device 24a to the first load device 16a. Charge is gradually stored in the smoothing capacitor 20a, and as shown in FIG. 5A, the terminal voltage (Vload1) of the first load device 16a gradually increases. At time t3, the terminal voltage (Vload1) of the first load device 16a reaches the same voltage as the terminal voltage (Vbat1) of the first power storage device 24a, and the charging of the smoothing capacitor 20a is completed.

[0071] At this time, the reverse current prevention device 36a is in a reverse current prohibition state. Therefore, power is not supplied from the first power storage device 24a to the power generation device 14 and the second load device 16b, and the smoothing capacitor 18 of the power generation device 14 and the smoothing capacitor 20b of the second load device 16b are not charged.

[0072] (Power supply system when charging of smoothing capacitor of first load device is completed) FIG. 9 is a diagram showing the state of the power supply system 10 at the completion of charging (time t3) of the smoothing capacitor 20a of the first load device 16a. When the charging of the smoothing capacitor 20a is completed, the control unit 66 turns on the switch 46a. Thereafter, the control unit 66 turns off the switch 50a.

[0073] (Power supply system at start of charging of smoothing capacitor of power generation device and smoothing capacitor of second load device) FIG. 10 is a diagram showing the state of the power supply system 10 at the start of charging (time t4) of the smoothing capacitor 18 of the power generation device 14 and the smoothing capacitor 20b of the second load device 16b. When charging the smoothing capacitor 18 and the smoothing capacitor 20b, the control unit 66 sets the reverse current prevention device 36b to the reverse current permission state. Thereafter, the control unit 66 turns on the switch 48b and turns on the switch 50b.

[0074] As a result, the power generation device 14 is connected to the second power storage device 24b via the precharge resistor 52b. Therefore, the smoothing capacitor 18 is charged by the power of the second power storage device 24b without an overcurrent flowing through the power supply system 10. Further, the second load device 16b is connected to the second power storage device 24b via the precharge resistor 52b. Therefore, the smoothing capacitor 20b is charged by the power of the second power storage device 24b without an overcurrent flowing through the power supply system 10.

[0075] As shown in FIG. 5B, a current (Ibat2) flows from the second power storage device 24b to the power generation device 14 and the second load device 16b. Charges are gradually stored in the smoothing capacitor 18 and the smoothing capacitor 20b, and as shown in FIG. 5A, the terminal voltage (Vtg) of the power generation device 14 and the terminal voltage (Vload2) of the second load device 16b gradually increase. At time t5, the terminal voltage (Vtg) of the power generation device 14 and the terminal voltage (Vload2) of the second load device 16b reach the same voltage as the terminal voltage (Vbat2) of the second power storage device 24b, and the charging of the smoothing capacitor 18 and the smoothing capacitor 20b is completed.

[0076] At this time, the reverse current prevention device 36a is in the reverse current prohibition state. Therefore, the power of the first power storage device 24a is not supplied to the power generation device 14 and the second load device 16b.

[0077] (Power supply system when charging of smoothing capacitor of power generation device and smoothing capacitor of second load device is completed) FIG. 11 is a diagram showing the state of the power supply system 10 when the smoothing capacitors 18 of the power generation device 14 and the smoothing capacitor 20b of the second load device 16b are fully charged (time point t5). When the charging of the smoothing capacitor 18 and the smoothing capacitor 20b is completed, the control unit 66 turns on the switch 46b. Thereafter, the control unit 66 turns off the switch 50b.

[0078] At this time, the backflow prevention device 36a is in a backflow prohibition state. Therefore, the power of the first power storage device 24a is not supplied to the power generation device 14 and the second load device 16b.

[0079] (Power supply system at the start of the power generation device) FIG. 12 is a diagram showing the state of the power supply system 10 when the power generation device 14 is started (time point t6). When starting the power generation device 14, the control unit 66 makes the power generation device 14 perform a power running operation with the power of the second power storage device 24b, and after the rotational speed of the rotor of the power generation device 14 rises to a sufficient rotational speed, the engine of the power generation device 14 is ignited.

[0080] As shown in FIG. 5B, a current (Ibat2) flows from the second power storage device 24b to the power generation device 14. The power of the second power storage device 24b is consumed by the power running operation of the power generation device 14, and the terminal voltage (Vbat2) of the second power storage device 24b decreases. As the terminal voltage (Vbat2) of the second power storage device 24b decreases, the terminal voltage (Vtg) of the power generation device 14 and the terminal voltage (Vload2) of the second load device 16b also decrease.

[0081] At this time, the backflow prevention device 36a is in a backflow prohibition state. Therefore, the power of the first power storage device 24a is not supplied to the power generation device 14 and the second load device 16b.

[0082] (Power supply system at the start of power generation of the power generation device) FIG. 13 is a diagram showing the state of the power supply system 10 at the start of power generation (time point t7) of the power generation device 14. When the power generation device 14 rotates independently and starts power generation, the smoothing capacitor 20b and the second power storage device 24b of the second load device 16b are charged by the power of the power generation device 14. After the power generation device 14 starts power generation, the control unit 66 sets the reverse current prevention device 36b to the reverse current prohibition state.

[0083] As shown in FIG. 5B, a current (Ibat2) flows from the power generation device 14 to the second power storage device 24b. The second power storage device 24b is charged by the power of the power generation device 14, and as shown in FIG. 5A, the terminal voltage (Vbat2) of the second power storage device 24b gradually increases. As the terminal voltage (Vbat2) of the second power storage device 24b increases, the terminal voltage (Vtg) of the power generation device 14 and the terminal voltage (Vload2) of the second load device 16b also increase.

[0084] At this time, the reverse current prevention device 36a is in the reverse current prohibition state. Therefore, the power of the first power storage device 24a is not supplied to the power generation device 14 and the second load device 16b. Also, the terminal voltage (Vtg) of the power generation device 14 is lower than the terminal voltage (Vbat1) of the first power storage device 24a and the terminal voltage (Vload1) of the first load device 16a. Therefore, no power is supplied from the power generation device 14 to the first power storage device 24a and the first load device 16a.

[0085] (Power supply system when the terminal voltage of the first power storage device is equal to the terminal voltage of the second power storage device)

[0086] FIG. 14 is a diagram showing the state of the power supply system 10 when the terminal voltage (Vbat1) of the first power storage device 24a becomes equal to the terminal voltage (Vbat2) of the second power storage device 24b (time point t8). When the terminal voltage (Vbat1) of the first power storage device 24a becomes equal to the terminal voltage (Vbat2) of the second power storage device 24b, the smoothing capacitor 20a and the first power storage device 24a of the first load device 16a are charged by the power of the power generation device 14.

[0087] Actually, the diode 38a of the backflow prevention device 36a in the first switching device 42a conducts current when the potential difference between the anode potential and the cathode potential is equal to or higher than the forward voltage. Therefore, in the above case, the terminal voltage (Vtg) of the power generation device 14 is higher than the terminal voltage (Vbat1) of the first power storage device 24a. That is, when the terminal voltage (Vtg) of the power generation device 14 is higher than the terminal voltage (Vbat1) of the first power storage device 24a, the first switching device 42a allows power to be supplied from the power generation device 14 to the first power storage device 24a.

[0088] Also, when the terminal voltage (Vbat1) of the first power storage device 24a and the terminal voltage (Vbat2) of the second power storage device 24b become equal, the smoothing capacitor 20b of the second load device 16b and the second power storage device 24b are charged by the power of the power generation device 14.

[0089] Actually, the diode 38b of the backflow prevention device 36b in the second switching device 42b conducts current when the potential difference between the anode potential and the cathode potential is equal to or higher than the forward voltage. Therefore, in the above case, the terminal voltage (Vtg) of the power generation device 14 is higher than the terminal voltage (Vbat2) of the second power storage device 24b. That is, when the terminal voltage (Vtg) of the power generation device 14 is higher than the terminal voltage (Vbat2) of the second power storage device 24b, the second switching device 42b allows power to be supplied from the power generation device 14 to the second power storage device 24b.

[0090] As shown in FIG. 5B, a current (Ibat2) flows from the power generation device 14 to the second power storage device 24b. Also, a current (Ibat1) flows from the power generation device 14 to the first power storage device 24a. Both the first power storage device 24a and the second power storage device 24b are charged by the power of the power generation device 14, and as shown in FIG. 5A, the terminal voltage (Vbat1) of the first power storage device 24a and the terminal voltage (Vbat2) of the second power storage device 24b rise in unison.

[0091] [Startup Process of Power Supply System] FIG. 15 is a flowchart showing the startup process of the power supply system 10 performed in the control device 58.

[0092] In step S1, the control unit 66 determines whether the terminal voltage (Vbat1) of the first power storage device 24a is equal to the terminal voltage (Vbat2) of the second power storage device 24b.

[0093] In step S1, when it is determined that the terminal voltage (Vbat1) of the first power storage device 24a is equal to the terminal voltage (Vbat2) of the second power storage device 24b (step S1: YES), the process proceeds to step S2.

[0094] In step S2, the control unit 66 sets the cutoff device 28a to the connected state (ON) and sets the backflow prevention device 36a to the backflow permission state. As a result, the power generation device 14 is connected to the first power supply circuit 12a. Also, the control unit 66 sets the cutoff device 28b to the connected state (ON) and sets the backflow prevention device 36b to the backflow permission state. As a result, the power generation device 14 is connected to the second power supply circuit 12b.

[0095] The control unit 66 sets the switch 48a to the connected state (ON) and sets the switch 50a to the connected state (ON). As a result, the first power storage device 24a is connected to the third power supply circuit 22a via the pre-charge resistor 52a. Also, the control unit 66 sets the switch 48b to the connected state (ON) and sets the switch 50b to the connected state (ON). As a result, the second power storage device 24b is connected to the fourth power supply circuit 22b via the pre-charge resistor 52b.

[0096] At this time, the smoothing capacitor 18 of the power generation device 14 is charged by the power of the first power storage device 24a and the power of the second power storage device 24b. Also, the smoothing capacitor 20a of the first load device 16a is charged by the power of the first power storage device 24a. Further, the smoothing capacitor 20b of the second load device 16b is charged by the power of the second power storage device 24b. When the charging of the smoothing capacitor 18, the smoothing capacitor 20a, and the smoothing capacitor 20b is completed, the process proceeds to step S3.

[0097] In step S3, the control unit 66 turns on the switch 46a and turns off the switch 50a. As a result, the first power storage device 24a is connected to the third power supply circuit 22a without passing through the pre-charge resistor 52a. Also, the control unit 66 turns on the switch 46b and turns off the switch 50b. As a result, the second power storage device 24b is connected to the fourth power supply circuit 22b without passing through the pre-charge resistor 52b.

[0098] The control unit 66 starts the power generation device 14 using the power of the first power storage device 24a and the power of the second power storage device 24b. When the power generation device 14 starts generating power, the process proceeds to step S4.

[0099] In step S4, the control unit 66 sets the backflow prevention device 36a to the backflow prohibition state. Also, the control unit 66 sets the backflow prevention device 36b to the backflow prohibition state. The first power storage device 24a and the second power storage device 24b are charged by the power of the power generation device 14. Then, the startup process of the power supply system 10 is terminated.

[0100] In step S1, if it is determined that the terminal voltage (Vbat1) of the first power storage device 24a is not equal to the terminal voltage (Vbat2) of the second power storage device 24b (step S1: NO), the process proceeds to step S5.

[0101] In step S5, the control unit 66 determines whether the terminal voltage (Vbat1) of the first power storage device 24a is higher than the terminal voltage (Vbat2) of the second power storage device 24b.

[0102] In step S5, if it is determined that the terminal voltage (Vbat1) of the first power storage device 24a is higher than the terminal voltage (Vbat2) of the second power storage device 24b (step S5: YES), the process proceeds to step S6.

[0103] In step S6, the control unit 66 turns on the cutoff device 28a. Also, the control unit 66 turns on the cutoff device 28b. Further, the control unit 66 turns on the switch 48a and turns on the switch 50a. As a result, the first power storage device 24a is connected to the third power supply circuit 22a via the precharge resistor 52a. Therefore, the smoothing capacitor 20a of the first load device 16a is charged by the power of the first power storage device 24a. When the charging of the smoothing capacitor 20a is completed, the control unit 66 turns on the switch 46a and turns off the switch 50a. As a result, the first power storage device 24a is connected to the third power supply circuit 22a without passing through the precharge resistor 52a. Then, the process proceeds to step S7.

[0104] In step S7, the control unit 66 sets the backflow prevention device 36b to the backflow permission state. As a result, the power generation device 14 is connected to the second power supply circuit 12b. The control unit 66 turns on the switch 48b and turns on the switch 50b. As a result, the second power storage device 24b is connected to the fourth power supply circuit 22b via the precharge resistor 52b.

[0105] At this time, the smoothing capacitor 18 of the power generation device 14 is charged by the power of the second power storage device 24b. Also, the smoothing capacitor 20b of the second load device 16b is charged by the power of the second power storage device 24b. When the charging of the smoothing capacitor 18 and the smoothing capacitor 20b is completed, the control unit 66 turns on the switch 46b and turns off the switch 50b. As a result, the second power storage device 24b is connected to the fourth power supply circuit 22b without passing through the precharge resistor 52b. Then, the process proceeds to step S8. Note that the order of the processes in step S6 and step S7 may be swapped.

[0106] In step S8, the control unit 66 starts the power generation device 14 using the power of the second power storage device 24b. When the power generation device 14 starts generating power, the process proceeds to step S9.

[0107] In step S9, the control unit 66 sets the backflow prevention device 36b to the backflow prohibition state. The second power storage device 24b is charged by the power of the power generation device 14. After the terminal voltage (Vbat2) of the second power storage device 24b becomes the same as the terminal voltage (Vbat1) of the first power storage device 24a, both the first power storage device 24a and the second power storage device 24b are charged by the power of the power generation device 14. Thereafter, the startup process of the power supply system 10 is terminated.

[0108] In step S10, the control unit 66 sets the cutoff device 28a to the connected state (ON). Also, the control unit 66 sets the cutoff device 28b to the connected state (ON). Further, the control unit 66 sets the switch 48b to the connected state (ON) and sets the switch 50b to the connected state (ON). As a result, the second power storage device 24b is connected to the fourth power supply circuit 22b via the precharge resistor 52b. Therefore, the smoothing capacitor 20b of the second load device 16b is charged by the power of the second power storage device 24b. When the charging of the smoothing capacitor 20b is completed, the control unit 66 sets the switch 46b to the connected state (ON) and sets the switch 50b to the cutoff state (OFF). As a result, the second power storage device 24b is connected to the fourth power supply circuit 22b without passing through the precharge resistor 52b. Thereafter, the process proceeds to step S11.

[0109] In step S11, the control unit 66 sets the backflow prevention device 36a to the backflow permission state. As a result, the power generation device 14 is connected to the first power supply circuit 12a. The control unit 66 sets the switch 48a to the connected state (ON) and sets the switch 50a to the connected state (ON). As a result, the first power storage device 24a is connected to the third power supply circuit 22a via the precharge resistor 52a.

[0110] At this time, the smoothing capacitor 18 of the power generation device 14 is charged by the power of the first power storage device 24a. Also, the smoothing capacitor 20a of the first load device 16a is charged by the power of the first power storage device 24a. When the charging of the smoothing capacitor 18 and the smoothing capacitor 20a is completed, the control unit 66 turns on the switch 46a and turns off the switch 50a. As a result, the first power storage device 24a is connected to the third power supply circuit 22a without passing through the precharge resistor 52a. Then, the process proceeds to step S12. Note that the order of the processes in step S10 and step S11 may be swapped.

[0111] In step S12, the control unit 66 starts the power generation device 14 by the power of the first power storage device 24a. When the power generation device 14 starts generating power, the process proceeds to step S13.

[0112] In step S13, the control unit 66 sets the backflow prevention device 36a to the backflow prohibition state.

[0113] The first power storage device 24a is charged by the power of the power generation device 14. After the terminal voltage (Vbat1) of the first power storage device 24a becomes the same as the terminal voltage (Vbat2) of the second power storage device 24b, both the first power storage device 24a and the second power storage device 24b are charged by the power of the power generation device 14. Then, the startup process of the power supply system 10 is terminated.

[0114] [Comparison with the comparative example] In the present embodiment, even when there is a difference between the terminal voltage (Vbat1) of the first power storage device 24a and the terminal voltage (Vbat2) of the second power storage device 24b, the power supply system 10 can be started without generating an overcurrent in the power supply system 10.

[0115] To facilitate understanding of the effects achieved by this embodiment, a comparative example will be described. FIG. 16A is a time chart of the voltage in the power supply system 100 at startup in the comparative example. FIG. 16B is a time chart of the current in the power supply system 100 at startup in the comparative example. FIGS. 17 to 19 are diagrams showing the state of the power supply system 100 of 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 backflow prevention devices 36a and 36b.

[0116] Hereinafter, the state of the power supply system 100 at startup will be described with reference to FIGS. 16A, 16B, and FIGS. 17 to 19. At the start of startup of the power supply system 100, it is assumed that the terminal voltage (Vbat1) of the first power storage device 24a is higher than the terminal voltage (Vbat2) of the second power storage device 24b.

[0117] FIG. 17 is a diagram showing the state of the power supply system 100 at the start of charging (time point t11) of the smoothing capacitor 18 of the power generation device 14, the smoothing capacitor 20a of the first load device 16a, and the smoothing capacitor 20b of the second load device 16b. When charging the smoothing capacitor 18, the blocking device 28a is set to the connected state (ON), and the blocking device 28b is set to the connected state (ON). Also, the switch 46a is set to the blocking state (OFF), the switch 48a is set to the connected state (ON), and the switch 50a is set to the connected state (ON). Further, the switch 46b is set to the blocking state (OFF), the switch 48b is set to the connected state (ON), and the switch 50b is set to the connected state (ON).

[0118] As a result, the power generation device 14 is connected to the first power storage device 24a via the precharge resistor 52a. Also, the power generation device 14 is connected to the second power storage device 24b via the precharge resistor 52b. Therefore, the smoothing capacitor 18 is charged by the power of the first power storage device 24a and the second power storage device 24b.

[0119] The first load device 16a is connected to the first power storage device 24a via the pre-charge resistor 52a. Therefore, the smoothing capacitor 20a is charged by the power of the first power storage device 24a. The second load device 16b is connected to the second power storage device 24b via the pre-charge resistor 52b. Therefore, the smoothing capacitor 20b is charged by the power of the second power storage device 24b.

[0120] At this time, as shown in FIG. 16B, a current (Ibat1) flows from the first power storage device 24a to the power generation device 14 and the first load device 16a. Similarly, a current (Ibat2) flows from the second power storage device 24b to the power generation device 14 and the second load device 16b. Electric charges are gradually stored in the smoothing capacitor 18, the smoothing capacitor 20a, and the smoothing capacitor 20b. As a result, as shown in FIG. 16A, the terminal voltage (Vtg) of the power generation device 14, the terminal voltage (Vload1) of the first load device 16a, and the terminal voltage (Vload2) of the second load device 16b gradually increase. At time t12, the terminal voltage (Vtg) of the power generation device 14, the terminal voltage (Vload1) of the first load device 16a, and the terminal voltage (Vload2) of the second load device 16b reach the same voltage as the terminal voltage (Vbat2) of the second power storage device 24b.

[0121] After time t12, as shown in FIG. 18, a current (Ibat1) flows from the first power storage device 24a to the power generation device 14, the first load device 16a, the second load device 16b, and the second power storage device 24b. That is, by the power of the first power storage device 24a, the smoothing capacitor 18, the smoothing capacitor 20a, and the smoothing capacitor 20b are charged, and the second power storage device 24b is charged.

[0122] If the charging by the power of the first power storage device 24a continues, the terminal voltage (Vtg) of the power generation device 14, the terminal voltage (Vload1) of the first load device 16a, the terminal voltage (Vload2) of the second load device 16b, and the terminal voltage (Vbat2) of the second power storage device 24b will become equal to the terminal voltage (Vbat1) of the first power storage device 24a. However, since the charging speed of the second power storage device 24b is relatively slow, it takes a long time for the terminal voltage (Vtg) of the power generation device 14, the terminal voltage (Vload1) of the first load device 16a, the terminal voltage (Vload2) of the second load device 16b, and the terminal voltage (Vbat2) of the second power storage device 24b to become equal to the terminal voltage (Vbat1) of the first power storage device 24a.

[0123] At time t13 before Vbat1 = Vbat2, as shown in FIG. 19, it is assumed that the third switching device 44a connects the first power storage device 24a to the third power supply circuit 22a without passing through the pre-charge resistor 52a. Also, at time t13, it is assumed that the fourth switching device 44b connects the second power storage device 24b to the fourth power supply circuit 22b without passing through the pre-charge resistor 52b.

[0124] In this case, the first power storage device 24a will be connected to the power generation device 14, the first load device 16a, the second load device 16b, and the second power storage device 24b without passing through a resistor. Therefore, as shown in FIG. 16B, an overcurrent will occur. At this time, as shown in FIG. 16A, the terminal voltage (Vbat2) of the second power storage device 24b rapidly rises to the same voltage as the terminal voltage (Vbat1) of the first power storage device 24a (time t14).

[0125] As described above, in the comparative example, when there is a difference between the terminal voltage (Vbat1) of the first power storage device 24a and the terminal voltage (Vbat2) of the second power storage device 24b, there is a risk of overcurrent occurring in the power supply system 10 when driving the power supply system 10. On the other hand, in the present embodiment, even when there is a difference between the terminal voltage (Vbat1) of the first power storage device 24a and the terminal voltage (Vbat2) of the second power storage device 24b, the power supply system 10 can be started without generating an overcurrent in the power supply system 10.

[0126] [Examples of Use of Power Supply System] FIG. 20 is a schematic diagram of the mobile body 70. The power supply system 10 can be mounted on the mobile body 70. The mobile body 70 is, for example, an electric vertical takeoff and landing aircraft (eVTOL aircraft). The mobile body 70 includes eight VTOL rotors 72. The VTOL rotors 72 generate an upward thrust with respect to the airframe 74. The mobile body 70 includes eight electric motors 76. One electric motor 76 drives one VTOL rotor 72. The mobile body 70 has two cruise rotors 78. The cruise rotors 78 generate a forward thrust with respect to the airframe 74. The mobile body 70 includes four electric motors 80. Two electric motors 80 drive one cruise rotor 78.

[0127] Each of the first load device 16a and the second load device 16b may include at least one of the plurality of electric motors 76 and the plurality of electric motors 80. Each of the first load device 16a and the second load device 16b may include a low-voltage drive device in addition to the electric motor 76 and the electric motor 80.

[0128] The mobile body 70 is not limited to an aircraft, and may be a ship, an automobile, a train, or the like. Further, the power supply system 10 may be used in a facility, a factory, or the like in addition to the mobile body 70.

[0129] Regarding the above embodiment, the following additional remarks are further disclosed.

[0130] (Additional Remark 1) The power supply system (10) of the present disclosure includes a first load device (16a) having a smoothing capacitor (20a), a second load device (16b) having a smoothing capacitor (20b), a power generation device (14) having a smoothing capacitor (18) and supplying power to the first load device and the second load device, a first power storage device (24a) connected in parallel with the power generation device and supplying power to the first load device, a second power storage device (24b) connected in parallel with the power generation device and supplying power to the second load device, a first switching device (42a) that electrically connects between the power generation device and the first load device and also electrically connects between the power generation device and the first power storage device, and a second switching device (42b) that electrically connects between the power generation device and the second load device and also electrically connects between the power generation device and the second power storage device, and a voltage acquisition unit (64) that acquires a first voltage which is the terminal voltage of the first power storage device and a second voltage which is the terminal voltage of the second power storage device, and a control unit (66) that controls the first switching device and the second switching device. The power supply system is configured such that when the first voltage is higher than the second voltage, the control unit sets the first switching device to the second state and the second switching device to the third state, charges the smoothing capacitor of the first load device with the power supplied from the first power storage device, and charges the smoothing capacitor of the power generation device and the smoothing capacitor of the second load device with the power supplied from the second power storage device. Thereby, the power supply system can be started without generating an overcurrent in the power supply system.

[0131] (Appendix 2) In the power supply system described in Supplementary Note 1, when the charging of the smoothing capacitor of the power generation device is completed, the control unit may start the power generation device with the power supplied from the second power storage device. Thereby, the power generation device can be started.

[0132] (Supplementary Note 3) In the power supply system described in Supplementary Note 2, when the start-up of the power generation device is completed, the control unit may charge the second power storage device with the power supplied from the power generation device. Thereby, the second power storage device can be charged with the power generated by the power generation device.

[0133] (Supplementary Note 4) In the power supply system described in Supplementary Note 1, when the first switching device is in the second state, the first switching device may allow the supply of power from the power generation device to the first power storage device when the terminal voltage of the power generation device is higher than the first voltage. Thereby, the first power storage device can be charged with the power generated by the power generation device.

[0134] (Supplementary Note 5) In the power supply system described in Supplementary Note 1, a third switching device (44a) that switches between a state in which the first power storage device and the first load device are electrically connected via a first pre-charge resistor (52a) and a state in which the first power storage device and the first load device are electrically connected without passing through the first pre-charge resistor; and a fourth switching device (44b) that switches between a state in which the second power storage device and the second load device are electrically connected via a second pre-charge resistor (52b) and a state in which the second power storage device and the second load device are electrically connected without passing through the second pre-charge resistor. When charging the smoothing capacitor of the first load device with the power supplied from the first power storage device, the control unit sets the third switching device to a state in which the first power storage device and the first load device are electrically connected via the first pre-charge resistor. When driving the first load device with the power supplied from the first power storage device, the control unit sets the third switching device to a state in which the first power storage device and the first load device are electrically connected without passing through the first pre-charge resistor. When charging the smoothing capacitor of the second load device with the power supplied from the second power storage device, the control unit sets the fourth switching device to a state in which the second power storage device and the second load device are electrically connected via the second pre-charge resistor. When driving the second load device with the power supplied from the second power storage device, the control unit may set the fourth switching device to a state in which the second power storage device and the second load device are electrically connected without passing through the second pre-charge resistor. Thereby, the smoothing capacitor of the first load device can be charged without generating an overcurrent in the power supply system. Also, the smoothing capacitor of the second load device can be charged without generating an overcurrent in the power supply system.

[0135] (Supplementary Note 6) The control method of the power supply system of the present disclosure includes a first load device having a smoothing capacitor, a second load device having a smoothing capacitor, a power generation device having a smoothing capacitor and supplying power to the first load device and the second load device, a first power storage device connected in parallel with the power generation device and supplying power to the first load device, a second power storage device connected in parallel with the power generation device and supplying power to the second load device, a first switching device that electrically connects between the power generation device and the first load device and electrically connects between the power generation device and the first power storage device, and a second switching device that electrically connects between the power generation device and the second load device and electrically connects between the power generation device and the second power storage device, and switches between a first state of electrically connecting between the power generation device and the first load device and electrically connecting between the power generation device and the first power storage device, and a second state of electrically disconnecting between the power generation device and the first load device and electrically disconnecting between the power generation device and the first power storage device, and a third state of electrically connecting between the power generation device and the second load device and electrically connecting between the power generation device and the second power storage device, and a fourth state of electrically disconnecting between the power generation device and the second load device and electrically disconnecting between the power generation device and the second power storage device. The control method of the power supply system includes a voltage acquisition step of acquiring a first voltage that is a terminal voltage of the first power storage device and a second voltage that is a terminal voltage of the second power storage device, and when the first voltage is higher than the second voltage, setting the first switching device to the second state and the second switching device to the third state, charging the smoothing capacitor of the first load device with the power supplied from the first power storage device, and charging the smoothing capacitor of the power generation device and the smoothing capacitor of the second load device with the power supplied from the second power storage device. This enables the power supply system to be started without generating an overcurrent in the power supply system.

[0136] Although the present disclosure has been described in detail, the present disclosure is not limited to the individual embodiments described above. These embodiments can be variously added, replaced, changed, partially deleted, etc., without departing from the gist of the present disclosure or without departing from the spirit of the present disclosure derived from the content described in the claims and its equivalents. Also, these embodiments can 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 an example and are not limited thereto. The same applies when numerical values or mathematical formulas are used in the description of the above-described embodiments.

Explanation of Signs

[0137] 10…Power supply system 14…Power generation device 16a…First load device 16b…Second load device 18…Smoothing capacitor 20a…Smoothing capacitor 20b…Smoothing capacitor 24a…First power storage device 24b…Second power storage device 42a…First switching device 42b…Second switching device 44a…Third switching device 44b…Fourth switching device 52a…Precharge resistor (first precharge resistor) 52b…Precharge resistor (second precharge resistor) 64…Voltage acquisition unit 66…Control unit

Claims

1. A first load device having a smoothing capacitor; A second load device having a smoothing capacitor; A power generation device having a smoothing capacitor and supplying power to the first load device and the second load device; A first power storage device connected in parallel with the power generation device and supplying power to the first load device; A second power storage device connected in parallel with the power generation device and supplying power to the second load device; A first switching device that electrically connects between the power generation device and the first load device and also electrically connects between the power generation device and the first power storage device, and switches between a first state of electrically connecting between the power generation device and the first load device and also electrically connecting between the power generation device and the first power storage device, and a second state of electrically disconnecting between the power generation device and the first load device and also electrically disconnecting between the power generation device and the first power storage device; A second switching device that electrically connects between the power generation device and the second load device and also electrically connects between the power generation device and the second power storage device, and switches between a third state of electrically connecting between the power generation device and the second load device and also electrically connecting between the power generation device and the second power storage device, and a fourth state of electrically disconnecting between the power generation device and the second load device and also electrically disconnecting between the power generation device and the second power storage device; A voltage acquisition unit that acquires a first voltage that is the terminal voltage of the first power storage device and a second voltage that is the terminal voltage of the second power storage device; A control unit that controls the first switching device and the second switching device; A power supply system comprising: When the first voltage is higher than the second voltage, the control unit sets the first switching device to the second state and the second switching device to the third state, charges the smoothing capacitor of the first load device with the power supplied from the first power storage device, and charges the smoothing capacitor of the power generation device and the smoothing capacitor of the second load device with the power supplied from the second power storage device. A power supply system.

2. In the power supply system according to claim 1, When the charging of the smoothing capacitor of the power generation device is completed, the control unit starts the power generation device with the power supplied from the second power storage device. A power supply system.

3. In the power supply system according to claim 2, When the start of the power generation device is completed, the control unit charges the second power storage device with the power supplied from the power generation device. A power supply system.

4. In the power supply system according to claim 1, When the first switching device is in the second state, the first switching device allows power supply from the power generation device to the first energy storage device when the terminal voltage of the power generation device is higher than the first voltage. A power supply system.

5. In the power supply system according to claim 1, A third switching device that switches between a state in which the first energy storage device and the first load device are electrically connected via a first precharge resistor and a state in which the first energy storage device and the first load device are electrically connected without passing through the first precharge resistor; A fourth switching device that switches between a state in which the second energy storage device and the second load device are electrically connected via a second precharge resistor and a state in which the second energy storage device and the second load device are electrically connected without passing through the second precharge resistor; further comprising When charging the smoothing capacitor of the first load device with the power supplied from the first energy storage device, the control unit sets the third switching device to a state in which the first energy storage device and the first load device are electrically connected via the first precharge resistor. When driving the first load device with the power supplied from the first energy storage device, the control unit sets the third switching device to a state in which the first energy storage device and the first load device are electrically connected without passing through the first precharge resistor. When charging the smoothing capacitor of the second load device with the power supplied from the second energy storage device, the control unit sets the fourth switching device to a state in which the second energy storage device and the second load device are electrically connected via the second precharge resistor. When driving the second load device with the power supplied from the second energy storage device, the control unit sets the fourth switching device to a state in which the second energy storage device and the second load device are electrically connected without passing through the second precharge resistor. A power supply system.

6. A first load device having a smoothing capacitor; A second load device having a smoothing capacitor; A power generation device having a smoothing capacitor and supplying power to the first load device and the second load device; A first energy storage device connected in parallel with the power generation device and supplying power to the first load device; A second energy storage device connected in parallel with the power generation device and supplying power to the second load device; A first switching device that electrically connects between the power generation device and the first load device and also electrically connects between the power generation device and the first power storage device, and switches between a first state of electrically connecting between the power generation device and the first load device and electrically connecting between the power generation device and the first power storage device, and a second state of electrically disconnecting between the power generation device and the first load device and electrically disconnecting between the power generation device and the first power storage device; A second switching device that electrically connects between the power generation device and the second load device and also electrically connects between the power generation device and the second power storage device, and switches between a third state of electrically connecting between the power generation device and the second load device and electrically connecting between the power generation device and the second power storage device, and a fourth state of electrically disconnecting between the power generation device and the second load device and electrically disconnecting between the power generation device and the second power storage device; A control method for a power supply system comprising: A voltage acquisition step of acquiring a first voltage which is the terminal voltage of the first power storage device and a second voltage which is the terminal voltage of the second power storage device; When the first voltage is higher than the second voltage, setting the first switching device to the second state and the second switching device to the third state, charging the smoothing capacitor of the first load device with the power supplied from the first power storage device, and charging the smoothing capacitor of the power generation device and the smoothing capacitor of the second load device with the power supplied from the second power storage device, a pre-charge step; A control method for a power supply system having the above.

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