Power supply system for vertical take-off and landing aircraft

Abstract

To provide a power supply system of a vertical take-off and landing aircraft including VTOL rotors.SOLUTION: A controller (a control unit 64) of a power supply system 30 of a vertical take-off and landing aircraft is configured to: after lift is generated by wings (a front wing and a rear wing), perform stop control of controlling electric power supplied to a motor 40 so that rotation of a VTOL rotor 20 continues to stop; temporarily cancel the stop control in response to a temperature of any one switching element detected by a temperature detection unit (a temperature sensor 58) becoming equal to or higher than a temperature threshold during the stop control; and resume the stop control after the stop control has been temporarily canceled.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a power supply system for a vertical take-off and landing aircraft with a VTOL rotor. [Background technology]

[0002] In recent years, vertical take-off and landing aircraft, so-called VTOL aircraft, have been developed. Some types of VTOL aircraft are equipped with multiple VTOL rotors and one or more cruise rotors. The VTOL rotor generates vertical thrust. The VTOL rotor is mainly used in the take-off and landing process of the VTOL aircraft. The cruise rotor generates horizontal thrust. The cruise rotor is mainly used in the cruising process of the VTOL aircraft.

[0003] Each blade of a VTOL rotor experiences air resistance while the VTOL aircraft is cruising. In other words, the VTOL rotor generates drag while the VTOL aircraft is cruising. It is preferable to reduce the drag caused by the VTOL rotor while the VTOL aircraft is cruising. Patent Document 1 discloses a technique for reducing drag by stopping the rotation of each VTOL rotor while the VTOL aircraft is cruising. This technique stops the rotation of the VTOL rotor using a mechanical stopping mechanism. However, the mechanical stopping mechanism increases the weight of the VTOL aircraft. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Application No. 2015-147574 Summary of the Invention [Problem to be solved by the invention]

[0005] The rotation of the VTOL rotor can also be stopped by power control performed by the controller. The VTOL rotor is connected to the rotating shaft of the motor. An inverter device is interposed between the motor and the power source. The controller can stop the rotation of the VTOL rotor by controlling the switching elements of the inverter device to control the power supplied to the motor. This technology does not increase the weight of the VTOL aircraft. However, this technology causes power to be concentrated in some switching elements, which causes the switching elements to heat up. This may damage the switching elements or shorten their lifespan.

[0006] The present invention aims to solve the above-mentioned problems. [Means for solving the problem]

[0007] An aspect of the present invention is a power supply system for a vertical take-off and landing aircraft comprising: a VTOL rotor that generates vertical thrust; a motor that rotates the VTOL rotor; a power source; an inverter device that supplies polyphase AC power from the power source to the motor using a plurality of switching elements; and a controller that controls the plurality of switching elements to control the power supplied to the motor, further comprising a temperature detection unit that detects the temperature of each of the switching elements; the controller performs stop control to control the power supplied to the motor so that the rotation of the VTOL rotor continues to stop after lift is generated by the wings; and during the stop control, the controller temporarily releases the stop control in response to the temperature of any one of the switching elements detected by the temperature detection unit becoming equal to or higher than a temperature threshold, and resumes the stop control after the stop control is temporarily released. [Effects of the Invention]

[0008] According to the present invention, it is possible to avoid various problems caused by heat, such as a shortened lifespan or damage to switching elements, and as a result, it is possible to realize or maintain stop control. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a top view of a vertical take-off and landing aircraft. [Figure 2] FIG. 2 is a block diagram of a power supply system for a vertical take-off and landing aircraft. [Figure 3] FIG. 3 is a top view of a stationary VTOL rotor. [Figure 4] FIG. 4 is a flowchart of the stop processing according to the first embodiment. [Figure 5] Fig. 5A is a graph showing the change over time in torque generated in the VTOL rotor by the motor. Fig. 5B is a graph showing the change over time in the electrical angle of the motor. Fig. 5C is a graph showing the change over time in three-phase (U, V, W) current flowing through the motor. Fig. 5D is a graph showing the change over time in temperature of the switching elements that pass the three-phase (U, V, W) current flowing through the motor. [Figure 6] FIG. 6 is a flowchart of the stop processing according to the second embodiment. [Figure 7] FIG. 7 is a flowchart of the stop processing according to the third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] [1 Configuration of vertical take-off and landing aircraft 10] 1 is a top view of a vertical take-off and landing aircraft 10. Hereinafter, the vertical take-off and landing aircraft 10 will also be referred to as a VTOL aircraft 10. The VTOL aircraft 10 is, for example, an electric vertical take-off and landing aircraft, a so-called eVTOL aircraft. The VTOL aircraft 10 includes a fuselage 12, a front wing 14, a rear wing 16, two booms 18, eight VTOL rotors 20, and two cruise rotors 22.

[0011] The VTOL aircraft 10 shown in Figure 1 is one example of an aircraft that uses the present invention. The present invention can be used for any aircraft that stops multiple VTOL rotors 20 in a state where lift is generated by fixed wings as the aircraft moves forward.

[0012] The front wings 14 are connected to the front of the fuselage 12. The rear wings 16 are connected to the rear of the fuselage 12. The front wings 14 and the rear wings 16 generate lift as the VTOL aircraft 10 moves forward.

[0013] Of the two booms 18, the boom 18R is disposed on the right side of the fuselage 12. Of the two booms 18, the boom 18L is disposed on the left side of the fuselage 12. Each boom 18 extends in the front-to-rear direction.

[0014] Four motors 40 (FIG. 2) are arranged on the boom 18L in sequence toward the rear. Similarly, four motors 40 are arranged on the boom 18R in sequence toward the rear. The rotation shaft of each motor 40 is connected to the VTOL rotor 20 corresponding to the motor 40. One or more gears may be interposed between the rotation shaft of the motor 40 and the VTOL rotor 20. The axis of the VTOL rotor 20 is approximately parallel to the vertical direction. Alternatively, the axis of the VTOL rotor 20 may be inclined at a predetermined angle relative to the vertical direction. Each VTOL rotor 20 is controlled to rotate so as to generate vertical thrust during a vertical takeoff process, a transition process from takeoff and climb to cruise, a transition process from cruise to descent and landing, a vertical landing process, and a hovering flight process. Each VTOL rotor 20 generates vertical thrust through the rotation of its propeller.

[0015] Two motors 40 (FIG. 2) are arranged side by side on the fuselage 12. The rotation shaft of each motor 40 is connected to the corresponding cruise rotor 22. Multiple gears may be interposed between the rotation shaft of the motor 40 and the cruise rotor 22. The axis of the cruise rotor 22 is approximately parallel to the horizontal direction. Each cruise rotor 22 is controlled to rotate so as to generate horizontal thrust during the cruise phase, the transition from takeoff and climb to cruise, and the transition from cruise to descent and landing. Each cruise rotor 22 generates horizontal thrust through the rotation of its propeller.

[0016] [2. Configuration of the power supply system 30] The VTOL aircraft 10 has a power supply system 30 shown in Fig. 2. Fig. 2 is a block diagram of the power supply system 30 of the vertical take-off and landing aircraft 10. The power supply system 30 includes a power storage device 32, a power generation device 34, a converter device 36, an inverter device 38, a motor 40, a sensor group 42, and a control device 44. In Fig. 2, solid arrows indicate power supply lines, and dashed lines indicate signal lines. Note that although the present specification describes a power supply system 30 that includes the power generation device 34, the power supply system 30 does not necessarily have to include the power generation device 34.

[0017] One inverter device 38 and one motor 40 are provided for each rotor (VTOL rotor 20 or cruise rotor 22). Meanwhile, one power storage device 32, one power generation device 34, and one converter device 36 are provided for each of a plurality of rotors (VTOL rotors 20 or cruise rotors 22). In other words, the power storage device 32, the power generation device 34, and the converter device 36 are shared by a plurality of power supply systems 30. For example, the same power storage device 32 may be provided for a pair of VTOL rotors 20 that cancel each other's torques.

[0018] The power storage device 32 has, for example, a high-voltage battery. The power generation device 34 has a generator. The rotating shaft of the generator is connected to the rotating shaft of, for example, a gas turbine engine. The converter device 36 has a converter circuit. One converter device 36 is provided for one power generation device 34. Primary terminals of the converter circuit are connected to the power generation device 34. Secondary terminals of the converter circuit are connected to the power storage device 32 and the inverter device 38. The converter device 36 can convert AC power output from the power generation device 34 into DC power and output it to the power storage device 32 and the inverter device 38. The converter device 36 can also transform the voltage of the power output from the power generation device 34 and output it to the power storage device 32 and the inverter device 38.

[0019] The inverter device 38 has, for example, a three-phase inverter circuit. The inverter circuit has a plurality of switching elements. A primary terminal of the inverter circuit is connected to the power storage device 32 and the converter device 36. A secondary terminal of the inverter circuit is connected to the motor 40. The inverter device 38 can convert DC power output from at least one of the power storage device 32 and the converter device 36 into AC power and output it to the motor 40.

[0020] The motor 40 is, for example, a three-phase motor. As described above, the rotating shaft of the motor 40 is connected to the hub of one of the rotors (the VTOL rotor 20 or the cruise rotor 22) directly or via one or more gears.

[0021] The sensor group 42 includes sensors provided in the VTOL aircraft 10. For example, the sensor group 42 includes multiple temperature sensors 58, one angle sensor 60, and multiple current sensors 62. One temperature sensor 58 is provided for each switching element of the inverter device 38. The temperature sensor 58 detects the temperature of the switching element (switch temperature). Note that instead of the temperature sensor 58, a control unit 64 (described later) may estimate the temperature of each switch based on a current value or the like. The angle sensor 60 detects the rotation angle of the VTOL rotor 20. Each current sensor 62 detects one phase of current supplied to the motor 40. Each sensor outputs a signal indicating the detected information to the control device 44.

[0022] The control device 44 controls the power supply system 30. The control device 44 may be, for example, a flight controller for the VTOL aircraft 10, or may be a slave controller managed by the flight controller. The control device 44 has a control unit 64, a memory unit 66, and a driver 68.

[0023] The control unit 64 has a processing circuit. The processing circuit may be a processor such as a CPU. The processing circuit may be an integrated circuit such as an ASIC or an FPGA. The processor can perform various processes by executing programs stored in the storage unit 66. At least some of the processes may be performed by electronic circuits including discrete devices.

[0024] The control unit 64 outputs a control signal to the driver 68 to control each motor 40. This allows the control unit 64 to supply power to each motor 40 and also to stop the supply of power to each motor 40. The control unit 64 can stop the rotation of the VTOL rotor 20 by controlling the inverter device 38. The control of the inverter device 38 performed by the control unit 64 to stop the rotation of the VTOL rotor 20 is referred to as stop control. Furthermore, the control unit 64 may fix the rotation angle of the VTOL rotor 20 to a predetermined angle. Furthermore, the control unit 64 can change the torque of the motor 40 by controlling the inverter device 38.

[0025] The storage unit 66 has a volatile memory and a non-volatile memory. Examples of the volatile memory include RAM. The volatile memory is used as a working memory for the processor. The volatile memory temporarily stores data required for processing or calculation. Examples of the non-volatile memory include ROM and flash memory. The non-volatile memory is used as a storage memory. The non-volatile memory stores programs, tables, maps, etc. At least a part of the storage unit 66 may be provided in the processor, integrated circuit, etc. as described above.

[0026] The nonvolatile memory stores the relationship between the amount of change in the rotation angle of the VTOL rotor 20 and the amount of change in the electrical angle of the motor 40. The amount of change in the rotation angle of the VTOL rotor 20 and the amount of change in the electrical angle of the motor 40 are determined according to the number of magnetic poles of the motor 40. Furthermore, if a gear is interposed between the VTOL rotor 20 and the motor 40, the amount of change in the rotation angle of the VTOL rotor 20 and the amount of change in the electrical angle of the motor 40 are determined according to the gear ratio.

[0027] The driver 68 has a gate driver circuit. The driver 68 outputs an on / off signal to each switching element of the inverter circuit of the inverter device 38 in response to a control signal output from the control unit 64. Furthermore, if the converter device 36 has switching elements, the driver 68 outputs an on / off signal to each switching element of the converter device 36.

[0028] [3. Status of Blade 70 during Stop Control] FIG. 3 is a top view of the VTOL rotor 20 at rest. As shown in FIG. 3, the control unit 64 stops the VTOL rotor 20 in a state where one blade 70 extends generally straight forward. The air resistance experienced by the blade 70 varies depending on the shape, size, etc. of the blade 70. In this specification, it is assumed that the attitude shown in FIG. 3 minimizes the total value of the air resistance experienced by each blade 70. In other words, the attitude shown in FIG. 3 can minimize the drag caused by the VTOL rotor 20.

[0029] Note that FIG. 3 shows the VTOL rotor 20 having three blades 70. However, the number of blades 70 is irrelevant. Regardless of the number of blades 70, the drag caused by the VTOL rotor 20 can be minimized by stopping the VTOL rotor 20 with one blade 70 extending generally straight forward. Note that the drag can be minimized if the angle of the blade 70 with respect to the fore-and-aft direction is within 0°±a°. a° is determined by the shape of the blade 70, etc. In this specification, the angle range of 0°±a° is referred to as the "stop angle range."

[0030] The memory unit 66 stores, as a predetermined angle range, a rotation angle range of the VTOL rotor 20 in which the angle of the blades 70 is within the stop angle range. It is preferable that the control unit 64 fixes the rotation angle of the VTOL rotor 20 within the predetermined angle range when the VTOL aircraft 10 is in a cruising state.

[0031] [4. Stop processing performed by the control unit 64] [4-1 First Embodiment] Figure 4 is a flowchart of the stop processing of the first embodiment. After the VTOL aircraft 10 transitions from the takeoff process to the cruising process, the control unit 64 executes the processing shown in Figure 4 at predetermined time intervals. For example, when the VTOL aircraft 10 is moving forward at a predetermined speed or higher, the wings (front wings 14 and rear wings 16) generate sufficient lift. For this reason, after operating the cruise rotor 22, the control unit 64 may stop the rotation of each VTOL rotor 20 in response to the forward speed reaching a predetermined speed or higher.

[0032] In step S1, the control unit 64 performs stop control. Here, the control unit 64 controls the inverter device 38 to stop the VTOL rotor 20, and supplies power to the motor 40. The power storage device 32 or the power generation device 34 supplies appropriate power to the inverter device 38. The inverter device 38 supplies power to the motor 40 through the switching element that is turned on. This allows the motor 40 and the VTOL rotor 20 to maintain a stopped state. When the processing of step S1 is completed, the processing proceeds to step S2.

[0033] In step S2, the control unit 64 compares the switch temperatures detected by each temperature sensor 58 with the temperature threshold value. The temperature threshold value is pre-stored in the memory unit 66. If any switch temperature is equal to or higher than the temperature threshold value (step S2: YES), the process proceeds to step S3. On the other hand, if all switch temperatures are lower than the temperature threshold value (step S2: NO), the stop process ends at this timing. In this case, the control unit 64 continues the stop control. As a result, the motor 40 and the VTOL rotor 20 remain stopped.

[0034] When the process proceeds from step S2 to step S3, the control unit 64 temporarily cancels the stop control. For example, the control unit 64 turns off each switching element of the inverter device 38 to temporarily stop the power supply to the motor 40. The time for which the power supply is stopped can be set arbitrarily. Note that the control unit 64 may reduce the torque of the motor 40 instead of stopping the power supply. When the process of step S3 ends, the process proceeds to step S4.

[0035] In step S4, the control unit 64 resumes the stop control. If the power was stopped in step S3, the control unit 64 resumes the power supply to the motor 40 to stop the VTOL rotor 20. If the torque was reduced in step S3, the control unit 64 increases the torque. When the processing of step S4 ends, the stop processing ends for the time being.

[0036] As shown in Figure 5A, the torque of motor 40 temporarily decreases when stop control is temporarily released and recovers when stop control is resumed. As shown in Figure 5B, the electrical angle (the phase of the current in motor 40) changes when stop control is temporarily released and resumed. As shown in Figure 5C, the current values ​​of the three-phase currents (U phase, V phase, W phase) change when stop control is temporarily released and resumed. As shown in Figure 5D, the temperature of the hottest switching element among the switching elements through which the three-phase (U phase, V phase, W phase) current flows decreases after stop control is temporarily released.

[0037] 5A, the torque of motor 40 is set to zero due to the temporary release of stop control. However, control unit 64 does not have to set the torque of motor 40 to zero. For example, control unit 64 may control motor 40 so that the torque of motor 40 is reduced relative to the external force acting on the propeller of VTOL rotor 20.

[0038] In the first embodiment, when one of the switching elements of the inverter device 38 reaches or exceeds the temperature threshold, the process of step 3 is performed. For example, the control unit 64 temporarily stops the power supply to the motor 40. This switches the heated switching element to an off state. This reduces the temperature of the switching element. Alternatively, the control unit 64 reduces the torque of the motor 40. This changes the phase of the three-phase current supplied to the motor 40. This changes the conduction state of the heated switching element, and the temperature of the switching element decreases. Therefore, according to the first embodiment, damage to the switching element can be prevented. As a result, according to the first embodiment, the life of the switching element can be extended.

[0039] [4-2 Second embodiment] Fig. 6 is a flowchart of the stop processing of the second embodiment. The second embodiment is an application example of the first embodiment. The processing of steps S11 to S13 and step S15 shown in Fig. 6 is the same as the processing of steps S1 to S4 shown in Fig. 4. Below, the explanation of steps S11 to S13 and step S15 will be omitted, and only step S14 will be explained.

[0040] In step S13, the power supply to the motor 40 is stopped. As a result, no torque is applied to the VTOL rotor 20 by the motor 40. In this state, the VTOL rotor 20 can be rotated by an external force.

[0041] In step S14, the control unit 64 determines whether the rotation angle of the VTOL rotor 20 detected by the angle sensor 60 is within a predetermined angle range. As described above, the predetermined angle range is pre-stored in the storage unit 66. If the rotation angle of the VTOL rotor 20 is within the predetermined angle range (step S14: YES), the processing proceeds to step S15. In this case, the control unit 64 resumes stop control. On the other hand, if the rotation angle of the VTOL rotor 20 is not within the predetermined angle range (step S14: NO), the control unit 64 continues the determination in step S14.

[0042] In step S14, the control unit 64 may gradually increase the torque of the motor 40 when the rotation angle of the VTOL rotor 20 falls within the stop angle range ±b°.

[0043] According to the second embodiment, as in the first embodiment, damage to the switching elements can be prevented. As a result, according to the second embodiment, the life of the switching elements can be extended. Furthermore, according to the second embodiment, any one of the blades 70 of the VTOL rotor 20 can be reliably stopped within the stopping angle range.

[0044] [4-3 Third Embodiment] FIG. 7 is a flowchart of the stop processing of the third embodiment. The third embodiment is an application example of the second embodiment. In the second embodiment described above, an external force rotates the VTOL rotor 20. In the third embodiment, the motor 40 rotates the VTOL rotor 20. The processing of steps S21 to S24 and step S26 shown in FIG. 7 is the same as the processing of steps S11 to S15 shown in FIG. 6. Below, the description of steps S21 to S24 and step S26 will be omitted, and only step S25 will be described.

[0045] In step S24, if the rotation angle of the VTOL rotor 20 is not within the predetermined angle range (step S24: NO), the process proceeds to step S25. In step S25, the control unit 64 supplies power to the motor 40 to rotate the VTOL rotor 20. The control unit 64 switches on and off each switching element of the inverter device 38 to supply power to the motor 40. The motor 40 rotates in response to the power supply. The VTOL rotor 20 rotates in response to the rotation of the motor 40. The control unit 64 continues the process of step S25 until the rotation angle of the VTOL rotor 20 falls within the predetermined angle range (step S24: NO).

[0046] According to the third embodiment, as in the first and second embodiments, damage to the switching elements can be prevented. As a result, according to the third embodiment, the life of the switching elements can be extended. Furthermore, according to the third embodiment, any of the blades 70 of the VTOL rotor 20 can be reliably stopped within the stop angle range. Furthermore, according to the third embodiment, any of the blades 70 of the VTOL rotor 20 can be quickly rotated to the stop angle range. As a result, drag can be minimized.

[0047] Note that the control unit 64 may control the rotation direction of the VTOL rotor 20 in step 25. The motor 40 is capable of rotating in two directions, the forward direction and the reverse direction. For example, the control unit 64 acquires the latest rotation angle of the VTOL rotor 20. The control unit 64 compares the angle difference from the latest rotation angle in the forward direction to a predetermined angle range with the angle difference from the latest rotation angle in the reverse direction to a predetermined angle range. The control unit 64 selects the direction with the smaller angle difference and rotates the motor 40. This allows one of the blades 70 of the VTOL rotor 20 to rotate to the stop angle range more quickly. As a result, drag can be minimized.

[0048] The third embodiment can be modified. In the embodiment described above, the control unit 64 determines the rotation direction of the VTOL rotor 20 based on the rotation angle. Alternatively, the control unit 64 may determine the rotation direction of the VTOL rotor 20 based on the power consumption of the motor 40. For example, the control unit 64 calculates the power consumption when the VTOL rotor 20 is rotated in two directions based on the current values ​​detected by each current sensor 62. The control unit 64 may supply power to the motor 40 so as to rotate the VTOL rotor 20 in a rotation direction that reduces the power consumption of the motor 40.

[0049] [5 Inventions Obtained from the Embodiments] The invention that can be understood from the above embodiment will be described below.

[0050] An aspect of the present invention is a power supply system (30) for a vertical take-off and landing aircraft (10) comprising: a VTOL rotor (20) that generates vertical thrust; a motor (40) that rotates the VTOL rotor; a power source (32, 34); an inverter device (38) that supplies polyphase AC power from the power source to the motor using a plurality of switching elements; and a controller (64) that controls the plurality of switching elements to control the power supplied to the motor, further comprising a temperature detection unit (58) that detects the temperature of each of the switching elements, and the controller performs stop control to control the power supplied to the motor so that the rotation of the VTOL rotor continues to stop after lift is generated by the wings (14, 16), and temporarily releases the stop control in response to the temperature of any one of the switching elements detected by the temperature detection unit becoming equal to or higher than a temperature threshold during the stop control, and resumes the stop control after the stop control is temporarily released.

[0051] In the above configuration, the stop control is temporarily released. By releasing the stop control, the temperature of the heated switching element drops. Therefore, with the above configuration, damage to the switching element can be prevented. As a result, with the above configuration, the life of the switching element caused by heat generation can be extended.

[0052] In the above aspect, the controller may temporarily cancel the stop control by temporarily stopping the power supplied to the motor.

[0053] According to the above configuration, the temperature of the heated switching element is reduced by turning off the heated switching element. Therefore, according to the above configuration, damage to the switching element can be prevented. As a result, according to the above configuration, the life of the switching element caused by heat generation can be extended.

[0054] In the above aspect, the controller may temporarily cancel the stop control by reducing the torque of the motor to a value lower than that before the temperature of the switching element becomes equal to or higher than the temperature threshold value.

[0055] According to the above configuration, the torque of the motor is reduced, which causes the balance between the external force and the torque to be lost. This causes the motor to rotate, changing the phase of the current supplied to the motor. This then reduces the temperature of the heated switching element. Therefore, according to the above configuration, damage to the switching element can be prevented. As a result, according to the above configuration, the life of the switching element caused by heat generation can be extended.

[0056] In the above aspect, the controller may further include an angle detection unit (60) that detects a rotation angle of the VTOL rotor, and after the stop control is temporarily released, the controller may resume the stop control in response to the rotation angle detected by the angle detection unit falling within a predetermined angle range.

[0057] According to the above configuration, any one of the blades of the VTOL rotor can be reliably stopped within the stopping angle range.

[0058] In the above aspect, the controller may further include an angle detection unit that detects a rotation angle of the VTOL rotor, and after temporarily releasing the stop control, the controller may supply power to the motor to rotate the VTOL rotor, and resume the stop control when the rotation angle detected by the angle detection unit falls within a predetermined angle range.

[0059] According to the above configuration, any one of the blades of the VTOL rotor can be reliably stopped within the stop angle range. Also, according to the above configuration, any one of the blades of the VTOL rotor can be quickly rotated to the stop angle range.

[0060] In the above aspect, the controller may supply power to the motor so as to rotate the VTOL rotor in a rotation direction that has a smaller angle from the latest rotation angle of the VTOL rotor to the predetermined angle range, out of two rotation directions of the VTOL rotor.

[0061] According to the above configuration, any one of the blades of the VTOL rotor can be rotated and moved to the stop angle range more quickly.

[0062] In the above aspect, the controller may supply power to the motor so as to rotate the VTOL rotor in one of two rotation directions of the VTOL rotor in which the power consumption of the motor is smaller.

[0063] The present invention is not limited to the above disclosure, and various configurations can be adopted without departing from the gist of the present invention. [Explanation of symbols]

[0064] 10...VTOL aircraft (vertical takeoff and landing aircraft) 14...Forewing (wing) 16...Rear wing (wing) 20...VTOL rotor 30... Power supply system 32... Power storage device (power source) 34... Power generation device (power supply) 38... Inverter device 40...Motor 58...Temperature sensor (temperature detection unit) 60...Angle sensor (angle detection unit) 64...Control unit (controller)

Claims

1. a VTOL rotor that generates vertical thrust; a motor that rotates the VTOL rotor; Power supply and an inverter device that supplies polyphase AC power from the power supply to the motor using a plurality of switching elements; a controller that controls the plurality of switching elements to control the power supplied to the motor; A power supply system for a vertical take-off and landing aircraft, comprising: a temperature detection unit that detects the temperature of each of the switching elements; The controller performing stop control to control the power supplied to the motor so that the rotation of the VTOL rotor continues to stop after lift is generated by the wings; temporarily canceling the stop control in response to a temperature of any one of the switching elements detected by the temperature detection unit becoming equal to or higher than a temperature threshold during the stop control; and a power supply system for a vertical take-off and landing aircraft, the power supply system resuming the stop control after the stop control is temporarily released.

2. 2. The power supply system for a vertical take-off and landing aircraft according to claim 1, The controller temporarily releases the stop control by temporarily suspending the power supplied to the motor.

3. 2. The power supply system for a vertical take-off and landing aircraft according to claim 1, The power supply system for a vertical take-off and landing aircraft, wherein the controller temporarily releases the stop control by reducing the torque of the motor to a value lower than that before the temperature of the switching element became equal to or higher than the temperature threshold.

4. A power supply system for a vertical take-off and landing aircraft according to any one of claims 1 to 3, An angle detection unit that detects a rotation angle of the VTOL rotor is further provided, a power supply system for a vertical take-off and landing aircraft, wherein the controller resumes the stop control in response to the rotation angle detected by the angle detection unit falling within a predetermined angle range after the stop control is temporarily released.

5. 2. The power supply system for a vertical take-off and landing aircraft according to claim 1, An angle detection unit that detects a rotation angle of the VTOL rotor is further provided, The controller After the stop control is temporarily released, power is supplied to the motor so as to rotate the VTOL rotor; a power supply system for a vertical take-off and landing aircraft, the power supply system restarting the stop control when the rotation angle detected by the angle detection unit falls within a predetermined angle range;

6. 6. The power supply system for a vertical take-off and landing aircraft according to claim 5, The controller supplies power to the motor so as to rotate the VTOL rotor in one of two rotation directions of the VTOL rotor, the rotation direction having a smaller angle from the latest rotation angle of the VTOL rotor within the specified angle range.

7. 6. The power supply system for a vertical take-off and landing aircraft according to claim 5, The controller supplies power to the motor so as to rotate the VTOL rotor in one of two rotation directions of the VTOL rotor that consumes less power.

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