Control devices, power supply systems, aircraft, control methods and programs

Abstract

The present invention provides a control device, a power supply system, an aircraft, a control method, and a program for suitably managing power. [Solution] In the power supply system, the control device 80 includes a first control unit that controls the power conversion unit 44a so that power is supplied from the generator 42a to at least one of the energy storage device 64a and the first load device 36a, and a determination unit that determines the remaining capacity of the energy storage device 64a. The first control unit performs remaining capacity reduction control to reduce the remaining capacity of the energy storage device 64a by controlling the power conversion unit 44a so that power is supplied from the energy storage device 64a to the generator 42a, in response to the determination unit determining that the remaining capacity of the energy storage device 64a has become greater than or equal to a first threshold.

Description

Technical Field

[0001] The present disclosure relates to a control device, a power supply system, an aircraft, a control method, and a program.

Background Art

[0002] Japanese Patent No. 6557321 discloses an aircraft equipped with a generator driven by an engine.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] It is desirable to suitably perform power management.

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

Means for Solving the Problems

[0006] A first aspect of the present disclosure is a control device that controls a first power generation device including an engine, a generator, and a power conversion unit, the control device including: a first control unit that can control the power conversion unit so that power is supplied from the generator to at least one of a power storage device and a first load device; and a determination unit that determines a remaining capacity of the power storage device, wherein the first control unit can execute remaining capacity reduction control for reducing the remaining capacity of the power storage device by controlling the power conversion unit so that power is supplied from the power storage device to the generator in response to the determination unit determining that the remaining capacity of the power storage device has become equal to or greater than a first threshold value.

[0007] A second aspect of the present disclosure is a power supply system comprising a control device according to the first aspect, the system comprising: a first power supply circuit capable of supplying power output from a first power generator to a first load device; a second power supply circuit capable of supplying power output from a second power generator to a second load device; and a connection circuit equipped with a connection device capable of connecting the first power supply circuit and the second power supply circuit, wherein the energy storage device is connected in parallel with the first power generator to the first power supply circuit, and the first control unit is capable of performing the remaining capacity reduction control and performing control of supplying power from the energy storage device to the second power generator via the connection circuit.

[0008] A third aspect of the present disclosure is an aircraft comprising a control device according to the first aspect, wherein the first control unit can perform the remaining capacity reduction control before transitioning from cruising to descent.

[0009] A fourth aspect of the present disclosure is a control method for controlling a first power generation device comprising an engine, a generator, and a power conversion unit, comprising: a control step of controlling the power conversion unit so that power is supplied from the generator to at least one of a power storage device and a first load device; and a determination step of determining the remaining capacity of the power storage device, wherein the control step can perform remaining capacity reduction control to reduce the remaining capacity of the power storage device by controlling the power conversion unit so that power is supplied from the power storage device to the generator, in response to the determination step determining that the remaining capacity of the power storage device has become equal to or greater than a first threshold.

[0010] A fifth aspect of this disclosure is a program for causing a computer to execute the control method according to the fourth aspect. [Effects of the Invention]

[0011] According to this disclosure, power can be managed effectively. [Brief explanation of the drawing]

[0012] [Figure 1]Figure 1 is a schematic diagram of the moving object. [Figure 2] Figure 2 is a schematic diagram of a power supply system according to one embodiment. [Figure 3] Figure 3 is a schematic diagram showing an example of a first power generation device in one embodiment. [Figure 4] Figure 4 is a schematic diagram showing an example of a first energy storage device in one embodiment. [Figure 5] Figure 5 is a schematic diagram showing an example of a backflow prevention device in one embodiment. [Figure 6] Figure 6 is a control block diagram of a control device in one embodiment. [Figure 7] Figure 7 shows the operation of a power supply system in a regenerative state in one embodiment. [Figure 8] Figure 8 shows the operation of a power supply system in the powered state in one embodiment. [Figure 9] Figure 9 is a flowchart of the power management process. [Figure 10] Figure 10A is a time chart showing the power generated and supplied from the first power generator to the first load device, and the power consumed by the first load device. Figure 10B is a time chart showing the charging and discharging power of the first energy storage device. Figure 10C is a time chart showing the state of charge (SOC) of the first energy storage device. [Figure 11] Figure 11 shows the operation of the power supply system in a powered state in another use case of one embodiment. [Modes for carrying out the invention]

[0013] This disclosure reduces the remaining capacity of the energy storage device in advance, before surplus power is generated by the generator producing more power than necessary. According to this disclosure, when surplus power is actually generated, the generated surplus power can be received by the energy storage device.

[0014] [Mobile Unit 10] FIG. 1 is a schematic diagram of the mobile body 10. The mobile body 10 in one embodiment is an electric vertical take-off and landing aircraft (eVTOL aircraft). The mobile body 10 includes eight VTOL rotors 12. The VTOL rotors 12 generate thrust upward with respect to the airframe 14. The mobile body 10 includes eight electric motors 16. One electric motor 16 drives one VTOL rotor 12. The mobile body 10 has two cruise rotors 18. The cruise rotors 18 generate thrust forward with respect to the airframe 14. The mobile body 10 includes four electric motors 20. Two electric motors 20 drive one cruise rotor 18. The mobile body 10 includes a power supply system 30 described later. The mobile body 10 is not limited to an aircraft and may be a ship, an automobile, a train, or the like.

[0015] [Configuration of Power Supply System 30] FIG. 2 is a schematic diagram of the power supply system 30 in one embodiment. As shown in FIG. 2, the power supply system 30 includes a first power supply circuit 32a, a second power supply circuit 32b, a third power supply circuit 32c, and a fourth power supply circuit 32d. The first power supply circuit 32a supplies the DC power output from the first power generation device 34a to the first load device 36a. The second power supply circuit 32b supplies the DC power output from the second power generation device 34b to the second load device 36b. The third power supply circuit 32c supplies the DC power output from the first power generation device 34a to the third load device 36c. The fourth power supply circuit 32d supplies the DC power output from the second power generation device 34b to the fourth load device 36d.

[0016] The power supply system 30 includes a first power generation device 34a and a second power generation device 34b. The first power generation device 34a has a first fuel supply device 38a, a first engine 40a, a first generator 42a, and a first power conversion device (power conversion unit) 44a. The second power generation device 34b has a second fuel supply device 38b, a second engine 40b, a second generator 42b, and a second power conversion device 44b. The first fuel supply device 38a and the second fuel supply device 38b include electronically controlled injectors. The first fuel supply device 38a supplies fuel to the first engine 40a. The second fuel supply device 38b supplies fuel to the second engine 40b. The first engine 40a and the second engine 40b are, for example, gas turbine engines. Note that the first engine 40a and the second engine 40b may be other engines such as reciprocating engines. The first generator 42a and the second generator 42b are motor generators that can also function as motors. The first power conversion device 44a and the second power conversion device 44b can perform power conversion from three-phase AC power to DC power and power conversion from DC power to three-phase AC power.

[0017] FIG. 3 is a schematic diagram showing an example of the first power generation device 34a in one embodiment. The configuration of the second power generation device 34b is the same as that of the first power generation device 34a. As shown in FIG. 3, the first power conversion device 44a provided in the first power generation device 34a has power element units 46U, 46V, 46W corresponding to each of the three-phase voltages output from the first generator 42a, and a smoothing capacitor 48. The configurations of the power element units 46V and 46W are the same as that of the power element unit 46U.

[0018] The power element section 46U has an upper arm 50 and a lower arm 52. The upper arm 50 has switching elements 54 (54Uu, 54Vu, 54Wu) and diodes 56 (56Uu, 56Vu, 56Wu). The lower arm 52 has switching elements 54 (54Ud, 54Vd, 54Wd) and diodes 56 (56Ud, 56Vd, 56Wd). For example, in the power element section 46U, switching elements 54Uu and 54Ud are connected in series with each other. That is, the first end of switching element 54Uu is connected to the positive terminal wiring of the first power converter 44a. The second end of switching element 54Uu is connected to the first end of switching element 54Ud. The second end of switching element 54Ud is connected to the negative terminal wiring of the first power converter 44a. The second end of switching element 54Uu and the first end of switching element 54Ud are connected to the terminals of the first phase (e.g., U phase) of the first generator 42a. The anode of diode 56Uu is connected to the second end of switching element 54Uu. The cathode of diode 56Uu is connected to the first end of switching element 54Uu. The anode of diode 56Ud is connected to the second end of switching element 54Ud. The cathode of diode 56Ud is connected to the first end of switching element 54Ud.

[0019] In power element section 46V, the second end of switching element 54Vu and the first end of switching element 54Vd are connected to the terminals of the second phase (e.g., V phase) of the first generator 42a. In power element section 46W, the second end of switching element 54Wu and the first end of switching element 54Wd are connected to the terminals of the third phase (e.g., W phase) of the first generator 42a.

[0020] Each switching element 54 is a semiconductor switch such as a MOSFET (Metal Oxide Semiconductor Field Effect Transistor) or an IGBT (Insulated Gate Bipolar Transistor).

[0021] The first power converter 44a and the second power converter 44b have bidirectional power conversion functions. The first power converter 44a and the second power converter 44b are capable of regenerative operation and power operation under the control of the control device 80. Specifically, the control device 80 switches the on state and off state of multiple switching elements 54 in each power element section 46U, 46V, and 46W. During power operation, the magnitude and period of the three-phase AC power are adjusted by adjusting the on time of each power element section 46U, 46V, and 46W.

[0022] During regeneration, the first generator 42a is driven by the first engine 40a to generate three-phase AC power. The first power converter 44a converts the three-phase AC power output from the first generator 42a into DC power. Similarly, during regeneration, the second generator 42b is driven by the second engine 40b to generate three-phase AC power. The second power converter 44b converts the three-phase AC power output from the second generator 42b into DC power.

[0023] During powering, the first power converter 44a converts the DC power supplied from the first energy storage device 64a (or other energy storage device) into three-phase AC power. The first generator 42a functions as an electric motor that drives the first engine 40a when supplied with three-phase AC power from the first power converter 44a. Similarly, during powering, the second power converter 44b converts the DC power supplied from the second energy storage device 64b (or other energy storage device) into three-phase AC power. The second generator 42b functions as an electric motor that drives the second engine 40b when supplied with three-phase AC power from the second power converter 44b.

[0024] The first power converter 44a and the second power converter 44b may have various sensors such as voltage sensors and current sensors, as well as various elements such as fuses, relays, circuit breakers, diodes, transistors, resistors, coils, and capacitors.

[0025] As shown in Figure 2, the power supply system 30 comprises a first load device 36a, a second load device 36b, a third load device 36c, and a fourth load device 36d. Each of the first load device 36a, the second load device 36b, the third load device 36c, and the fourth load device 36d comprises two electric motors 16 and one electric motor 20. An inverter is connected to each of the two electric motors 16 and the electric motor 20. The inverter converts the input DC power into three-phase AC power, and the electric motors 16 (or electric motor 20) are driven by the three-phase AC power. The first load device 36a, the second load device 36b, the third load device 36c, and the fourth load device 36d may have a DC / DC power converter and a low-voltage drive device (not shown). The DC / DC power converter reduces the voltage of the input DC power, and the low-voltage drive device is driven by the DC power.

[0026] The first load device 36a, second load device 36b, third load device 36c, and fourth load device 36d may have various sensors such as voltage sensors and current sensors, fuses, relays, circuit breakers, diodes, transistors, resistors, coils, and capacitors. Multiple first load devices 36a may be connected in parallel to each other in the first power supply circuit 32a. Multiple second load devices 36b may be connected in parallel to each other in the second power supply circuit 32b. Multiple third load devices 36c may be connected in parallel to each other in the third power supply circuit 32c. Multiple fourth load devices 36d may be connected in parallel to each other in the fourth power supply circuit 32d.

[0027] The power supply system 30 includes a first connection circuit 58a and a second connection circuit 58b. The first connection circuit 58a is equipped with a first connection device 60a. The second connection circuit 58b is equipped with a second connection device 60b.

[0028] The first connection device 60a can connect the first power supply circuit 32a and the second power supply circuit 32b. The first connection device 60a switches between a state in which the first power supply circuit 32a and the second power supply circuit 32b are connected and a state in which the first power supply circuit 32a and the second power supply circuit 32b are disconnected by a contactor (not shown).

[0029] Similarly, the second connection device 60b can connect the third power supply circuit 32c and the fourth power supply circuit 32d. The second connection device 60b switches between a state in which the third power supply circuit 32c and the fourth power supply circuit 32d are connected and a state in which the third power supply circuit 32c and the fourth power supply circuit 32d are disconnected by a contactor (not shown).

[0030] The first connection device 60a and the second connection device 60b may have relays instead of contactors. The first connection device 60a and the second connection device 60b may have circuit breakers instead of contactors. The first connection device 60a and the second connection device 60b may have semiconductor switches instead of contactors.

[0031] Normally, the first power supply circuit 32a and the second power supply circuit 32b are disconnected. This prevents an abnormality in one of the power supply circuits from affecting the other. For example, if an overcurrent occurs in one of the power supply circuits, it prevents the overcurrent from flowing to the other.

[0032] Similarly, the third power supply circuit 32c and the fourth power supply circuit 32d are normally disconnected. This prevents an abnormality in one of the third power supply circuit 32c and the fourth power supply circuit 32d from affecting the other. For example, if an overcurrent occurs in one of the third power supply circuit 32c and the fourth power supply circuit 32d, it prevents the overcurrent from flowing to the other.

[0033] If a malfunction occurs in the power supply from the first power generator 34a to the first power supply circuit 32a, the first connection device 60a connects the first power supply circuit 32a and the second power supply circuit 32b. As a result, power is supplied from the second power supply circuit 32b to the first power supply circuit 32a.

[0034] If a problem occurs in the power supply from the first power generator 34a to the third power supply circuit 32c, the second connection device 60b connects the third power supply circuit 32c and the fourth power supply circuit 32d. As a result, power is supplied from the fourth power supply circuit 32d to the third power supply circuit 32c.

[0035] If a malfunction occurs in the power supply from the second power generator 34b to the second power supply circuit 32b, the first connection device 60a connects the first power supply circuit 32a and the second power supply circuit 32b. This allows power to be supplied from the first power supply circuit 32a to the second power supply circuit 32b.

[0036] If a malfunction occurs in the power supply from the second power generator 34b to the fourth power supply circuit 32d, the second connection device 60b connects the third power supply circuit 32c and the fourth power supply circuit 32d. This allows power to be supplied from the third power supply circuit 32c to the fourth power supply circuit 32d.

[0037] The power supply system 30 is equipped with circuit breakers 62a to 62d. Circuit breaker 62a can disconnect the first power generator 34a from the first power supply circuit 32a and the first connection circuit 58a. Circuit breaker 62b can disconnect the second power generator 34b from the second power supply circuit 32b and the first connection circuit 58a. Circuit breaker 62c can disconnect the first power generator 34a from the third power supply circuit 32c and the second connection circuit 58b. Circuit breaker 62d can disconnect the second power generator 34b from the fourth power supply circuit 32d and the second connection circuit 58b.

[0038] The circuit breaker 62a, using a contactor (not shown), switches between a state in which the first power generator 34a is disconnected from the first power supply circuit 32a and the first connection circuit 58a, and a state in which the first power generator 34a is connected to the first power supply circuit 32a and the first connection circuit 58a. Similarly, the circuit breaker 62b, using a contactor (not shown), switches between a state in which the second power generator 34b is disconnected from the second power supply circuit 32b and the first connection circuit 58a, and a state in which the second power generator 34b is connected to the second power supply circuit 32b and the first connection circuit 58a.

[0039] Furthermore, the circuit breaker 62c switches between a state in which the first power generator 34a is disconnected from the third power supply circuit 32c and the second connection circuit 58b, and a state in which the first power generator 34a is connected to the third power supply circuit 32c and the second connection circuit 58b, using a contactor (not shown). Similarly, the circuit breaker 62d switches between a state in which the second power generator 34b is disconnected from the fourth power supply circuit 32d and the second connection circuit 58b, and a state in which the second power generator 34b is connected to the fourth power supply circuit 32d and the second connection circuit 58b, using a contactor (not shown).

[0040] The circuit breakers 62a to 62d may have relays instead of contactors. The circuit breakers 62a to 62d may have circuit breakers instead of contactors. The circuit breakers 62a to 62d may have semiconductor switches instead of contactors.

[0041] The power supply system 30 includes a first energy storage device 64a, a second energy storage device 64b, a third energy storage device 64c, and a fourth energy storage device 64d. The first energy storage device 64a is connected in parallel to the first power supply circuit 32a with respect to the first power generator 34a. The second energy storage device 64b is connected in parallel to the second power supply circuit 32b with respect to the second power generator 34b. The third energy storage device 64c is connected in parallel to the third power supply circuit 32c with respect to the first power generator 34a. The fourth energy storage device 64d is connected in parallel to the fourth power supply circuit 32d with respect to the second power generator 34b.

[0042] Figure 4 is a schematic diagram showing an example of a first energy storage device 64a in one embodiment. As shown in Figure 4, the configurations of the second energy storage device 64b, the third energy storage device 64c, and the fourth energy storage device 64d are the same as those of the first energy storage device 64a. The first energy storage device 64a has a battery 66. The battery 66 may be, for example, a lithium-ion battery or another type of battery. The first energy storage device 64a, the second energy storage device 64b, the third energy storage device 64c, and the fourth energy storage device 64d may have a large-capacity capacitor instead of a battery 66.

[0043] The first energy storage device 64a includes a voltage sensor 68 and a current sensor 70. The voltage sensor 68 is connected to the positive terminal and the negative terminal of the battery 66. The voltage sensor 68 measures the potential difference between the terminals of the battery 66. The current sensor 70 is provided on the positive wiring connected to the positive terminal of the battery 66 or on the negative wiring connected to the negative terminal of the battery 66. The current sensor 70 measures the current flowing through the positive wiring or the negative wiring.

[0044] The first energy storage device 64a, the second energy storage device 64b, the third energy storage device 64c, and the fourth energy storage device 64d may also have various other elements such as sensors, fuses, relays, circuit breakers, diodes, transistors, resistors, coils, and capacitors.

[0045] As shown in Figure 2, the power supply system 30 is equipped with circuit breakers 72a to 72d. Circuit breaker 72a can disconnect the first energy storage device 64a from the first power supply circuit 32a and the first load device 36a. Circuit breaker 72b can disconnect the second energy storage device 64b from the second power supply circuit 32b and the second load device 36b. Circuit breaker 72c can disconnect the third energy storage device 64c from the third power supply circuit 32c and the third load device 36c. Circuit breaker 72d can disconnect the fourth energy storage device 64d from the fourth power supply circuit 32d and the fourth load device 36d.

[0046] The circuit breaker 72a switches between a state in which the first energy storage device 64a is disconnected from the first power supply circuit 32a and the first load device 36a, and a state in which the first energy storage device 64a is connected to the first power supply circuit 32a and the first load device 36a, using a contactor (not shown). Similarly, the circuit breaker 72b switches between a state in which the second energy storage device 64b is disconnected from the second power supply circuit 32b and the second load device 36b, and a state in which the second energy storage device 64b is connected to the second power supply circuit 32b and the second load device 36b, using a contactor (not shown).

[0047] Furthermore, the circuit breaker 72c switches between a state in which the third energy storage device 64c is disconnected from the third power supply circuit 32c and the third load device 36c, and a state in which the third energy storage device 64c is connected to the third power supply circuit 32c and the third load device 36c, using a contactor (not shown). Similarly, the circuit breaker 72d switches between a state in which the fourth energy storage device 64d is disconnected from the fourth power supply circuit 32d and the fourth load device 36d, and a state in which the fourth energy storage device 64d is connected to the fourth power supply circuit 32d and the fourth load device 36d, using a contactor (not shown).

[0048] The circuit breakers 72a to 72d may have relays instead of contactors. The circuit breakers 72a to 72d may have circuit breakers instead of contactors. The circuit breakers 72a to 72d may have semiconductor switches instead of contactors.

[0049] The power supply system 30 is equipped with reverse current prevention devices 74a to 74d. Reverse current prevention device 74a restricts the supply of power from the first energy storage device 64a to the first power supply circuit 32a and the first power generator 34a. Reverse current prevention device 74b restricts the supply of power from the second energy storage device 64b to the second power supply circuit 32b and the second power generator 34b. Reverse current prevention device 74c restricts the supply of power from the third energy storage device 64c to the third power supply circuit 32c and the first power generator 34a. Reverse current prevention device 74d restricts the supply of power from the fourth energy storage device 64d to the fourth power supply circuit 32d and the second power generator 34b.

[0050] Figure 5 is a schematic diagram showing an example of a reverse current prevention device 74a in one embodiment. As shown in Figure 5, the configurations of reverse current prevention devices 74b to 74d are the same as the configuration of reverse current prevention device 74a. Reverse current prevention device 74a includes, for example, a diode 76 and a transistor 78.

[0051] Diode 76 is installed in the positive terminal wiring. When the anode voltage is lower than the cathode voltage, diode 76 conducts almost no current. When the anode voltage becomes higher than the forward voltage relative to the cathode voltage, current flows through diode 76. As a result, power is supplied from the first power generator 34a to the first load device 36a and the first energy storage device 64a via diode 76.

[0052] Transistor 78 is provided by bypassing diode 76. When current flows from the base to the emitter of transistor 78, current flows from the collector to the emitter. This enables power to be supplied from the first energy storage device 64a to the first connection circuit 58a via the first power supply circuit 32a. Diode 76 may be provided in the negative terminal wiring. Alternatively, diode 76 may be provided in both the positive terminal wiring and the negative terminal wiring.

[0053] Furthermore, the reverse current prevention device 74a may be provided with a diode 76, but not with a transistor 78. The reverse current prevention device 74a may also include a switching device such as a contactor. The contactor is provided on at least one of the positive and negative terminal wirings.

[0054] In addition to the configuration described above, the power supply system 30 may also include various sensors such as voltage sensors and current sensors, as well as elements such as fuses, resistors, coils, and capacitors.

[0055] Figure 6 is a control block diagram of the control device 80 in one embodiment. The power supply system 30 includes the control device 80. The control device 80 controls the first power converter 44a, the second power converter 44b, the first connection device 60a, the second connection device 60b, the circuit breakers 62a to 62d, the circuit breakers 72a to 72d, and the reverse current prevention devices 74a to 74d.

[0056] The control device 80 includes an arithmetic unit 82 and a storage unit 84. The arithmetic unit 82 is a processor such as a CPU (Central Processing Unit) or a GPU (Graphics Processing Unit). The arithmetic unit 82 includes a flight process determination unit 86, a State of Operation (SOC) determination unit 88, a first control unit 90, and a second control unit 92. The flight process determination unit 86, SOC determination unit 88, first control unit 90, and second control unit 92 are realized by the execution of a program stored in the storage unit 84 in the arithmetic unit 82. At least a portion of the flight process determination unit 86, SOC determination unit 88, first control unit 90, and second control unit 92 may be realized by an integrated circuit such as an ASIC (Application Specific Integrated Circuit) or FPGA (Field-Programmable Gate Array). At least a portion of the flight process determination unit 86, SOC determination unit 88, first control unit 90, and second control unit 92 may be realized by an electronic circuit including discrete devices.

[0057] The storage unit 84 is a computer-readable, non-transient, tangible storage medium. The storage unit 84 is composed of volatile memory (not shown) and non-volatile memory (not shown). The volatile memory is, for example, RAM (Random Access Memory). The non-volatile memory is, for example, ROM (Read Only Memory), flash memory, etc. Data is stored in the volatile memory, for example. Programs, tables, maps, etc. are stored in the non-volatile memory, for example. At least a part of the storage unit 84 may be provided in the processor, integrated circuit, etc. mentioned above.

[0058] The flight process determination unit 86 determines which of the entire flight process the mobile body 10 is currently in. The flight process of the mobile body 10 includes a takeoff process, a cruising process, and a landing process. The takeoff process includes a vertical takeoff process in which the mobile body 10 ascends almost vertically upward, and an ascent process in which the mobile body 10 ascends to cruising altitude while accelerating horizontally. A first stop process (hovering) may also be included between the vertical takeoff process and the ascent process. The landing process includes a descent process in which the mobile body 10 descends from cruising altitude to a predetermined altitude while decelerating horizontally, and a vertical landing process in which the mobile body 10 descends almost vertically downward. A second stop process (hovering) may also be included between the descent process and the vertical landing process. The flight process determination unit 86 obtains information indicating the current flight process (referred to as flight information) from, for example, the flight controller 94, which comprehensively manages the control of the mobile body 10.

[0059] The SOC determination unit 88 determines the remaining capacity of each energy storage device (first energy storage device 64a to fourth energy storage device 64d). In this specification, the remaining capacity of an energy storage device is also referred to as SOC (State of Charge). The SOC determination unit 88 periodically determines the SOC of an energy storage device by, for example, a current integration method based on the current value detected by the current sensor 70. In this specification, the latest (current) SOC determined by the SOC determination unit 88 is referred to as SOC_L.

[0060] The first control unit 90 performs switching control of each switching element 54 provided in the first power converter 44a and each switching element 54 provided in the second power converter 44b. The first control unit 90 can control multiple switching elements 54 with switching patterns corresponding to regeneration and powering, respectively. The first control unit 90 also performs switching control (on / off control) of each transistor 78 of the first connection device 60a, the second connection device 60b, the circuit breakers 62a to 62d, the circuit breakers 72a to 72d, and the reverse current prevention devices 74a to 74d.

[0061] The second control unit 92 can limit the amount of fuel supplied to the first engine 40a and the second engine 40b by controlling the injectors provided in the first fuel supply device 38a and the injectors provided in the second fuel supply device 38b.

[0062] [Operation of the regenerative power supply system 30] Figure 7 shows the operation of the power supply system 30 in a regenerative state in one embodiment. Figure 7 shows the operation of the power supply system 30 under normal conditions. The arrows shown in Figure 7 indicate the power supply path.

[0063] As shown in Figure 7, the first power generator 34a is connected to the first power supply circuit 32a by the circuit breaker 62a, and the first power generator 34a is connected to the third power supply circuit 32c by the circuit breaker 62c. As a result, the three-phase AC power output from the first generator 42a is converted to DC power in the first power converter 44a and supplied to the first load device 36a and the third load device 36c.

[0064] The circuit breaker 62b connects the second generator 34b to the second power supply circuit 32b, and the circuit breaker 62d connects the second generator 34b to the fourth power supply circuit 32d. As a result, the three-phase AC power output from the second generator 42b is converted to DC power in the second power converter 44b and supplied to the second load device 36b and the fourth load device 36d.

[0065] The circuit breaker 72a connects the first energy storage device 64a to the first load device 36a. As a result, the DC power output from the first energy storage device 64a is supplied to the first load device 36a. The circuit breaker 72b connects the second energy storage device 64b to the second load device 36b. As a result, the DC power output from the second energy storage device 64b is supplied to the second load device 36b. The circuit breaker 72c connects the third energy storage device 64c to the third load device 36c. As a result, the DC power output from the third energy storage device 64c is supplied to the third load device 36c. The circuit breaker 72d connects the fourth energy storage device 64d to the fourth load device 36d. As a result, the DC power output from the fourth energy storage device 64d is supplied to the fourth load device 36d.

[0066] Under normal conditions, the first connection device 60a disconnects the first power supply circuit 32a and the second power supply circuit 32b, and the second connection device 60b disconnects the third power supply circuit 32c and the fourth power supply circuit 32d.

[0067] In the event of a malfunction in the first power generator 34a or the second power generator 34b, the first power supply circuit 32a and the second power supply circuit 32b may be connected by the first connection device 60a. Similarly, in the event of a malfunction in the first power generator 34a or the second power generator 34b, the third power supply circuit 32c and the fourth power supply circuit 32d may be connected by the second connection device 60b. As a result, the three-phase AC power output from the first generator 42a can be converted to DC power in the first power converter 44a and supplied to the second load device 36b and the fourth load device 36d. Alternatively, the three-phase AC power output from the second generator 42b can be converted to DC power in the second power converter 44b and supplied to the first load device 36a and the third load device 36c.

[0068] [Operation of the power supply system 30 in the powered state] Figure 8 shows the operation of the power supply system 30 in the powered state in one embodiment. The arrows in Figure 8 indicate the power supply path.

[0069] The first control unit 90 of the control device 80 transmits an ON signal to the transistors 78 provided in each of the reverse current prevention devices 74a and 74c. This causes current to flow from the base to the emitter of each transistor 78, and current to flow from the collector to the emitter. If the potential of the first energy storage device 64a is higher than the potential of the first power generation device 34a, the DC power output from the first energy storage device 64a is converted into three-phase AC power in the first power converter 44a and supplied to the first generator 42a. The DC power output from the first energy storage device 64a is also supplied to the first load device 36a. If the potential of the third energy storage device 64c is higher than the potential of the first power generation device 34a, the DC power output from the third energy storage device 64c is converted into three-phase AC power in the first power converter 44a and supplied to the first generator 42a. The DC power output from the third energy storage device 64c is also supplied to the third load device 36c.

[0070] The first control unit 90 of the control device 80 transmits an ON signal to the transistors 78 provided in each of the reverse current prevention devices 74b and 74d. This causes current to flow from the base to the emitter of each transistor 78, and current to flow from the collector to the emitter. If the potential of the second energy storage device 64b is higher than the potential of the second power generation device 34b, the DC power output from the second energy storage device 64b is converted into three-phase AC power in the second power converter 44b and supplied to the second generator 42b. The DC power output from the second energy storage device 64b is also supplied to the second load device 36b. If the potential of the fourth energy storage device 64d is higher than the potential of the second power generation device 34b, the DC power output from the fourth energy storage device 64d is converted into three-phase AC power in the second power converter 44b and supplied to the second generator 42b. The DC power output from the fourth energy storage device 64d is also supplied to the fourth load device 36d.

[0071] [Power Management Processing] Figure 9 is a flowchart of the power management process. Here, we will explain the process of managing the power generated by the first power generator 34a and the charging and discharging power of the first energy storage device 64a.

[0072] In step S1, the flight path determination unit 86 determines the current flight path of the mobile object 10 based on the flight information acquired from the flight controller 94. The timing of the processing from step S2 onward is predetermined. The processing from step S2 onward is performed at a predetermined stage immediately preceding the descent stage of the cruising stage. If the current flight path is a predetermined stage in the cruising stage (step S1: YES), the process proceeds to step S2. On the other hand, if the current flight path is not a predetermined stage in the cruising stage (step S1: NO), the determination in step S1 is performed again.

[0073] When the process moves from step S1 to step S2, the first control unit 90 determines whether the first power generator 34a is generating power or not. If the first power generator 34a is generating power (step S2: YES), the process moves to step S3. On the other hand, if the first power generator 34a is not generating power (step S2: NO), the power management process ends.

[0074] When the process moves from step S2 to step S3, the SOC determination unit 88 compares SOC_L, which is the current SOC of the first energy storage device 64a, with SOC_th (first threshold). SOC_th is, for example, the upper threshold of the recommended range (acceptable range, etc.) of SOC. Note that SOC_th is not limited to this and can be set arbitrarily. SOC_th is stored in advance in the storage unit 84. If SOC_L ≤ SOC_th (step S3: YES), the process moves to step S4. In this case, since the SOC of the first energy storage device 64a is relatively low, the first energy storage device 64a can accept the surplus power generated by the first power generator 34a. On the other hand, if SOC_L > SOC_th (step S3: NO), the process moves to step S5. In this case, because the State of Charge (SOC) of the first energy storage device 64a is high, the first energy storage device 64a cannot accept the surplus power generated by the first power generation device 34a.

[0075] When the process moves from step S3 to step S4, the first control unit 90 and the second control unit 92 perform control to put the power supply system 30 into a regenerative state. For example, the first control unit 90 controls each part of the power supply system 30 so that it is in the state shown in Figure 7. At this time, the first control unit 90 controls each switching element 54 provided in the first power converter 44a so that DC power is supplied from the first generator 42a to at least one of the first energy storage device 64a and the first load device 36a. The second control unit 92 also controls the first fuel supply device 38a so that the first engine 40a maintains a rotational speed above the target value. With this, the power management process is completed.

[0076] When the system moves from step S3 to step S5, the first control unit 90 executes SOC reduction control (remaining capacity reduction control) to reduce the SOC of the first energy storage device 64a. Specifically, the first control unit 90 executes the processes of steps S5, S6, and S8.

[0077] In step S5, the first control unit 90 calculates (estimates) the amount of surplus power generated during the descent process. During the descent process, the mobile body 10 glides. While the mobile body 10 is gliding, the electric motors 16 and 20 provided on the first load device 36a stop. On the other hand, even while the mobile body 10 is gliding, the first engine 40a is operating. Therefore, the power generated by the first power generator 34a becomes surplus power. The surplus power is mainly supplied to the first energy storage device 64a. The first control unit 90 calculates the amount of surplus power generated during the gliding process. For example, the first control unit 90 calculates the amount of surplus power (the amount of power generated by the first engine 40a) based on information such as the time required for the descent process and the rotational speed of the first engine 40a during the descent process.

[0078] In step S6, the first control unit 90 calculates SOC_tar (second threshold). SOC_tar is the target value of the SOC of the first energy storage device 64a in SOC reduction control. The first control unit 90 calculates SOC_tar based on the surplus power amount calculated in step S5 and SOC_th.

[0079] In step S7, the second control unit 92 restricts the operation of the first engine 40a. The second control unit 92 restricts the fuel supplied to the first engine 40a by controlling the first fuel supply device 38a. The rotational speed of the first engine 40a after fuel restriction becomes lower than the rotational speed of the first engine 40a in the regenerative state.

[0080] In step S8, the first control unit 90 performs control to bring the power supply system 30 into a powered state. For example, the first control unit 90 controls each part of the power supply system 30 so that it is in the state shown in Figure 8. At this time, the first control unit 90 controls each switching element 54 provided in the first power converter 44a so that power is supplied from the first energy storage device 64a to the first generator 42a.

[0081] In step S9, the SOC determination unit 88 compares SOC_L, which is the current SOC of the first energy storage device 64a, with SOC_tar, which is the target value of the SOC of the first energy storage device 64a. If SOC_L ≤ SOC_tar (step S9: YES), the process proceeds to step S10. In this case, the SOC of the first energy storage device 64a has been reduced to a state where it can accept the amount of surplus power estimated to be generated by the end of the descent process. On the other hand, if SOC_L > SOC_tar (step S9: NO), the determination in step S9 is performed again.

[0082] In step S10, the second control unit 92 releases the operating restriction on the first engine 40a. The second control unit 92 increases the amount of fuel supplied to the first engine 40a. As a result, the rotational speed of the first engine 40a increases.

[0083] In step S11, the first control unit 90 performs control so that the power supply system 30 enters a regenerative state. For example, the first control unit 90 controls each part of the power supply system 30 so that it enters the state shown in Figure 7. At this time, the first control unit 90 controls each switching element 54 provided in the first power converter 44a so that DC power is supplied from the first generator 42a to at least one of the first energy storage device 64a and the first load device 36a. With this, the power management process is completed.

[0084] [Comparison between cases where SOC reduction control is implemented and cases where SOC reduction control is not implemented] Figure 10A is a time chart showing the power generated and supplied from the first power generator 34a to the first load device 36a, and the power consumed by the first load device 36a. Figure 10B is a time chart showing the charging and discharging power of the first energy storage device 64a. Figure 10C is a time chart showing the state of charge (SOC) of the first energy storage device 64a.

[0085] In Figures 10A to 10C, the flight path of the mobile object 10 from time t0 to time t1 is the cruising path. The flight path of the mobile object 10 from time t1 to time t2 is the descent path. The flight path of the mobile object 10 from time t2 to time t3 is the vertical landing path.

[0086] If SOC reduction control is not performed, the following situation occurs. At time t1, which is the timing of the transition from the cruising phase to the descent phase, the mobile body 10 begins gliding. At this time, the power consumption of the electric motors 16 and 20 of the first load device 36a becomes zero. Consequently, the power generation of the first engine 40a is suppressed. However, the first generator 34a continues to generate power until the power generation of the first engine 40a is reduced to the target value. The power generated by the first generator 34a becomes surplus power. The surplus power is supplied to the first energy storage device 64a. When the surplus power is supplied to the first energy storage device 64a while its SOC is close to SOC_th, the SOC of the first energy storage device 64a exceeds SOC_th. As a result, the first energy storage device 64a becomes overcharged.

[0087] On the other hand, when SOC reduction control is performed, overcharging of the first energy storage device 64a can be suppressed as follows. At time t01 during the cruising process (a predetermined period), the first control unit 90 starts SOC reduction control. That is, the first control unit 90 transitions the state of the power supply system 30 from the regenerative state to the powering state. Then, as shown by the dashed line in Figure 10B, the first energy storage device 64a discharges. At this time, DC power is supplied from the first energy storage device 64a to the first generator 42a and the first load device 36a. As a result, as shown by the dashed line in Figure 10C, the SOC of the first energy storage device 64a is reduced.

[0088] After time t01 but before time t1, the first control unit 90 terminates the SOC reduction control. That is, the first control unit 90 transitions the state of the power supply system 30 from the powering state to the regenerative state. At this point, the SOC of the first energy storage device 64a has been sufficiently reduced. Therefore, even if the power generated by the first power generator 34a (surplus power) is supplied to the first energy storage device 64a after time t1, the SOC of the first energy storage device 64a will not exceed SOC_th.

[0089] In this embodiment, the first control unit 90 reduces the State of Charge (SOC) of the first energy storage device 64a in advance, before surplus power is generated by the first generator 42a generating more power than necessary. According to this embodiment, when surplus power is generated, the generated surplus power can be received by the first energy storage device 64a.

[0090] Furthermore, in this embodiment, when the first control unit 90 reduces the State of Charge (SOC) of the first energy storage device 64a, it supplies power from the first energy storage device 64a to the first generator 42a, thereby operating the first generator 42a as an electric motor. According to this embodiment, even if the fuel supplied to the first engine 40a is reduced, engine stall of the first engine 40a can be suppressed.

[0091] [Other usage examples] Figure 11 shows the operation of the power supply system 30 in the powered state in another use case of one embodiment. The arrows shown in Figure 11 indicate the power supply path.

[0092] As shown in Figure 11, when the power supply system 30 is in the powering state, the first control unit 90 may connect the first connection device 60a. This allows the first energy storage device 64a to supply power to the second generator 42b via the first connection circuit 58a. Alternatively, the second energy storage device 64b can supply power to the first generator 42a via the first connection circuit 58a.

[0093] The first energy storage device 64a can rapidly reduce its State of Charge (SOC) by supplying power to the first generator 42a and the second generator 42b. Similarly, the second energy storage device 64b can rapidly reduce its SOC by supplying power to the first generator 42a and the second generator 42b.

[0094] As shown in Figure 11, when the power supply system 30 is in the powering state, the first control unit 90 may connect the second connection device 60b. This allows the third energy storage device 64c to supply power to the second generator 42b via the second connection circuit 58b. Alternatively, the fourth energy storage device 64d can supply power to the first generator 42a via the second connection circuit 58b.

[0095] The State of Charge (SOC) of the third energy storage device 64c can be rapidly reduced by supplying power to the first generator 42a and the second generator 42b. Similarly, the State of Charge (SOC) of the fourth energy storage device 64d can be rapidly reduced by supplying power to the first generator 42a and the second generator 42b.

[0096] [Note] The following additional information is disclosed regarding the above embodiments.

[0097] (Note 1) The control device (80) of the present disclosure is a control device for controlling a first power generation device (34a) comprising an engine (40a), a generator (42a), and a power conversion unit (44a), and comprises a first control unit (90) capable of controlling the power conversion unit so that power is supplied from the generator to at least one of a power storage device (64a) and a first load device (36a), and a determination unit (88) for determining the remaining capacity (SOC_L) of the power storage device, wherein the first control unit can perform remaining capacity reduction control to reduce the remaining capacity of the power storage device by controlling the power conversion unit so that power is supplied from the power storage device to the generator, in response to the determination unit determining that the remaining capacity of the power storage device has become equal to or greater than a first threshold (SOC_th).

[0098] With the above configuration, if surplus power is generated, the surplus power can be received by the first energy storage device.

[0099] With the above configuration, even if the amount of fuel supplied to the engine is reduced, engine stalling can be suppressed.

[0100] (Note 2) In the control device described in Appendix 1, the first control unit may terminate the remaining capacity reduction control after starting the remaining capacity reduction control, in response to the determination unit determining that the remaining capacity of the first power generation device has fallen below a second threshold (SOC_tar) which is smaller than the first threshold.

[0101] (Note 3) In the control device described in Appendix 1, a second control unit (92) is provided to control a fuel supply device (38a) that supplies fuel to the engine, and when the first control unit is performing the remaining capacity reduction control, the second control unit may limit the amount of fuel supplied to the engine.

[0102] (Note 4) In the control device described in Appendix 3, the first control unit may terminate the remaining capacity reduction control after starting the remaining capacity reduction control, in response to the determination unit determining that the remaining capacity of the first power generator has fallen to a second threshold less than or equal to the first threshold, and the second control unit may release the restriction on the amount of fuel supplied to the engine when the first control unit terminates the remaining capacity reduction control.

[0103] (Note 5) In the control device described in Appendix 1, the first control unit may convert the DC power output from the energy storage device into three-phase AC power by controlling the on / off state of a plurality of switching elements (54) connected in series with each other in each arm of the three-phase arm provided in the power conversion unit, and may also adjust the three-phase AC power and supply it to the generator.

[0104] (Note 6) The power supply system (30) of this disclosure is a power supply system equipped with the control device described in Appendix 1, comprising: a first power supply circuit (32a) capable of supplying power output from the first power generator to the first load device; a second power supply circuit (32b) capable of supplying power output from the second power generator (34b) to the second load device (36b); and a connection circuit (58a) equipped with a connection device (60a) capable of connecting the first power supply circuit and the second power supply circuit, wherein the energy storage device is connected in parallel with the first power generator to the first power supply circuit, and the first control unit is capable of performing the remaining capacity reduction control and is capable of performing control to supply power from the energy storage device to the second power generator via the connection circuit.

[0105] According to the above configuration, the remaining capacity of the energy storage device can be reduced rapidly.

[0106] (Note 7) The aircraft of this disclosure is an aircraft (10) equipped with a control device as described in any one of appendices 1 to 5, wherein the first control unit can perform the remaining capacity reduction control before transitioning from cruising to descent.

[0107] (Note 8) The control method of the present disclosure is a control method for controlling a first power generation device comprising an engine, a generator, and a power conversion unit, comprising: a control step of controlling the power conversion unit so that power is supplied from the generator to at least one of a power storage device and a first load device; and a determination step of determining the remaining capacity of the power storage device, wherein the control step can perform remaining capacity reduction control to reduce the remaining capacity of the power storage device by controlling the power conversion unit so that power is supplied from the power storage device to the generator, in response to the determination step determining that the remaining capacity of the power storage device has become equal to or greater than a first threshold.

[0108] (Note 9) The program of this disclosure can cause a computer to execute the control method described in Appendix 8.

[0109] While this disclosure has been described in detail, it is not limited to the individual embodiments described above. These embodiments can be added, replaced, modified, partially deleted, etc., in any way that does not depart from the gist of this disclosure or from the spirit of this disclosure derived from the claims and their equivalents. These embodiments can also be implemented in combination. For example, the order of operations and processes in the embodiments described above are given as examples only and are not limited thereto. The same applies when numerical values ​​or mathematical formulas are used in the description of the embodiments described above. [Explanation of Symbols]

[0110] 10…Mobile vehicles (aircraft) 30…Power supply systems 32a...First power supply circuit 32b...Second power supply circuit 34a...First power generator 34b...Second power generator 36a...First load device 36b...Second load device 38a...First fuel supply device (fuel supply device) 40a...First engine (engine) 42a...First generator (generator) 44a...First power converter (power converter unit) 58a...First connection circuit (connection circuit) 60a...First connection device (connection device) 64a...First energy storage device (energy storage device) 80...Control device 88...SOC determination unit (determination unit) 90...First control unit 92...Second control unit

Claims

1. A control device for controlling a first power generation device comprising an engine, a generator, and a power conversion unit, A first control unit capable of controlling the power conversion unit so that power is supplied from the generator to at least one of the energy storage device and the first load device, A determination unit for determining the remaining capacity of the energy storage device, Equipped with, The first control unit is a control device that can perform remaining capacity reduction control to reduce the remaining capacity of the energy storage device by controlling the power conversion unit so that power is supplied from the energy storage device to the generator, in response to the determination unit determining that the remaining capacity of the energy storage device has become equal to or greater than a first threshold.

2. In the control device according to claim 1, The first control unit terminates the remaining capacity reduction control after starting the remaining capacity reduction control, in accordance with the determination unit's determination that the remaining capacity of the first power generation device has fallen below a second threshold, which is smaller than the first threshold.

3. In the control device according to claim 1, The system includes a second control unit that controls a fuel supply device that supplies fuel to the engine, A control device in which, when the first control unit is performing the remaining capacity reduction control, the second control unit limits the amount of fuel supplied to the engine.

4. In the control device according to claim 3, The first control unit terminates the remaining capacity reduction control after starting the remaining capacity reduction control, in response to the determination unit determining that the remaining capacity of the first power generation device has fallen below a second threshold, which is smaller than the first threshold. The second control unit is a control device that enables the first control unit to terminate the remaining capacity reduction control and to release the restriction on the amount of fuel supplied to the engine.

5. In the control device according to claim 1, The first control unit is a control device that converts DC power output from the energy storage device into three-phase AC power by controlling the on / off state of a plurality of switching elements connected in series with each arm of the three-phase arm provided in the power conversion unit, and also adjusts the three-phase AC power and supplies it to the generator.

6. A power supply system comprising the control device described in claim 1, A first power supply circuit capable of supplying power output from the first power generator to the first load device, A second power supply circuit capable of supplying power output from the second power generator to the second load device, A connection circuit equipped with a connection device capable of connecting the first power supply circuit and the second power supply circuit, Equipped with, The energy storage device is connected in parallel with the first power generation device to the first power supply circuit. A power supply system in which the first control unit can perform the remaining capacity reduction control and can also perform control to supply power from the energy storage device to the second power generation device via the connection circuit.

7. An aircraft equipped with a control device according to any one of claims 1 to 5, The first control unit is capable of performing the remaining capacity reduction control before transitioning from cruising to descent in an aircraft.

8. A control method for controlling a first power generation device comprising an engine, a generator, and a power conversion unit, A control step of controlling the power conversion unit so that power is supplied from the generator to at least one of the energy storage device and the first load device, A determination step for determining the remaining capacity of the energy storage device, Equipped with, A control method in which, in the control step, a remaining capacity reduction control is performed to reduce the remaining capacity of the energy storage device by controlling the power conversion unit so that power is supplied from the energy storage device to the generator, in accordance with the determination in the determination step that the remaining capacity of the energy storage device has become equal to or greater than a first threshold.

9. A program for causing a computer to execute the control method described in claim 8.

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