Motor controller and flight control system

Abstract

To provide a motor controller capable of quickly dissolving an excessive rotation state of a propeller.SOLUTION: An inverter control unit as a motor controller comprises a positive torque control unit (step S10), a negative torque control unit (steps S41, S44), and an excessive rotation detection unit (step S20). Of rotation torque of a motor, torque for accelerating or keeping rotation in a positive direction for flying is taken as positive torque and torque for decelerating the rotation in the positive direction is taken as negative torque. The positive torque control unit controls the motor in a positive torque mode for exerting the positive torque. The negative torque control unit controls the motor in a negative torque mode for exerting the negative torque. The excessive rotation detection unit detects excessive rotation of a propeller or the motor. When excessive rotation is being detected by the excessive rotation detection unit, control in the negative torque mode is executed by the negative torque control unit.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The disclosure in this specification relates to a motor control device and a flight control system applied to an electric aircraft. [Background technology]

[0002] Patent Document 1 describes an electric aircraft that flies by rotating a propeller with an electric motor. In this type of aircraft, the supply of power to the motor is controlled by a motor control device. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-79869 Summary of the Invention [Problem to be solved by the invention]

[0004] If the propeller goes into an overspeed state, the motor may generate electricity. As a result, the voltage applied to the electrical components that make up the control device may exceed their withstand voltage, raising concerns that this could lead to component failure. Therefore, it is desirable to quickly eliminate the propeller overspeed state. Furthermore, it is also desirable to quickly eliminate the propeller overspeed state in order to stabilize the aircraft's attitude control as quickly as possible.

[0005] However, simply stopping the power supply to the motor by the motor control device will not quickly resolve the over-speed condition because the propeller will continue to rotate due to inertia. In particular, if a strong wind is blowing in the direction that is causing the propeller to rotate, it will take an extremely long time to resolve the over-speed condition.

[0006] One disclosed object is to provide a motor control device and a flight control system that can quickly resolve a propeller overspeed condition. [Means for solving the problem]

[0007] In order to achieve the above object, a motor control device according to one aspect of the present disclosure includes: A motor control device applied to an electric aircraft (10) having a passenger compartment or a luggage compartment in a fuselage, which flies with a propeller (20) rotated by an electric motor (61), Among the rotational torques of the motor, a torque for accelerating or maintaining the rotation in the positive direction for flight is defined as a positive torque, and a torque for decelerating the rotation in the positive direction is defined as a negative torque. a positive torque control unit (S10) that controls the motor in a positive torque mode to generate positive torque; a negative torque control unit (S41, S44) that controls the motor in a negative torque mode to generate a negative torque; an over-rotation detection unit (S20) that detects over-rotation of the propeller or motor, When the overspeed detection unit detects an overspeed, the negative torque control unit executes control in the negative torque mode.

[0008] According to the motor control device disclosed herein, when overspeed is detected, a negative torque is generated in the motor to slow down the rotation in the positive direction, thereby enabling the motor to be quickly decelerated and ultimately the propeller overspeed state to be quickly resolved.

[0009] In order to achieve the above object, a flight control system according to one aspect of the present disclosure includes: a motor control device (82) adapted to an electric aircraft (10) having a passenger compartment or a luggage compartment in a fuselage, which flies with a propeller (20) rotated by an electric motor (61), and which controls the driving of the motor; A flight control system including a flight control device (40) that issues a control command to a motor control device, Among the rotational torques of the motor, a torque for accelerating or maintaining the rotation in the positive direction for flight is defined as a positive torque, and a torque for decelerating the rotation in the positive direction is defined as a negative torque. The motor control device a positive torque control unit (S10) that controls the motor in a positive torque mode to generate positive torque; a negative torque control unit (S41, S44) that controls the motor in a negative torque mode to generate a negative torque; an over-rotation detection unit (S20) that detects over-rotation of the propeller or motor, When the overspeed detection unit detects overspeed, overspeed protection control including at least deceleration control in the negative torque mode is executed.

[0010] According to the flight control system disclosed herein, when an overspeed condition is detected, a negative torque is generated in the motor to slow down the positive rotation, thereby enabling the motor to be quickly decelerated and ultimately the propeller overspeed condition to be quickly resolved.

[0011] The reference numbers in parentheses above merely indicate an example of the correspondence with specific configurations in the embodiments described below, and do not in any way limit the technical scope. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a diagram showing the configuration of an eVTOL in a first embodiment. [Figure 2] Block diagram showing the electrical configuration of the EPU. [Figure 3] 4 is a flowchart showing a procedure of stop control according to the first embodiment. [Figure 4] 10 is a flowchart showing a procedure of stop control according to a second embodiment. [Figure 5] 10 is a flowchart showing a procedure of stop control according to a third embodiment. [Figure 6] 10 is a flowchart showing a procedure for lock control according to the third embodiment. [Figure 7] FIG. 2 is a schematic diagram showing the configuration of a locking device in a locked state. [Figure 8] FIG. 2 is a schematic diagram showing the configuration of a locking device in an unlocked state. [Figure 9] 10 is a flowchart showing a procedure for lock control according to a fourth embodiment. [Figure 10] 10 is a flowchart showing a procedure for lock control according to a fifth embodiment. [Figure 11] 13 is a flowchart showing a control procedure in a sixth embodiment. [Figure 12] FIG. 20 is a block diagram showing the electrical configuration of an EPU according to a seventh embodiment. [Figure 13] 13 is a flowchart showing a control procedure in the seventh embodiment. [Figure 14] FIG. 13 is a block diagram showing the electrical configuration of an EPU according to an eighth embodiment. [Figure 15] 13 is a flowchart showing a control procedure in the eighth embodiment. [Figure 16] 13 is a flowchart showing a control procedure in the ninth embodiment. [Figure 17] 20 is a flowchart showing a control procedure in the tenth embodiment. [Figure 18] 20 is a flowchart showing a control procedure in the eleventh embodiment. [Figure 19] 22 is a flowchart showing a control procedure in the twelfth embodiment. [Figure 20] 23 is a flowchart showing the procedure of a function test in the thirteenth embodiment. [Figure 21] 23 is a time chart showing an example of a change in rotation speed when a function test is performed in the thirteenth embodiment. [Figure 22] 23 is a flowchart showing a procedure for testing the function of the overspeed protection control, which is included in the function test in the thirteenth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, several embodiments for carrying out the present disclosure will be described with reference to the drawings. In each embodiment, parts corresponding to matters described in the preceding embodiment will be assigned the same reference numerals, and duplicate descriptions may be omitted. In each embodiment, when only a part of the configuration is described, other previously described embodiments may be applied to the other parts of the configuration. In addition to combinations of parts that are specifically specified as being combinable in each embodiment, it is also possible to partially combine embodiments even if not specified, as long as there is no particular problem with the combination.

[0014] (First embodiment) The flight system 30 shown in FIG. 1 is mounted on an eVTOL 10, which is an electric aircraft. The eVTOL 10 is an electric vertical take-off and landing aircraft, and is capable of taking off and landing vertically. eVTOL is an abbreviation for electric Vertical Take-Off and Landing aircraft. The eVTOL 10 is a manned aircraft that carries a crew member. The flight system 30 is a system that drives the eVTOL 10 to fly, and includes a battery 31, a distributor 32, an FCU 40, and an EPU 50.

[0015] The eVTOL 10 has an airframe 11 and a propeller 20. The airframe 11 has an airframe main body 12 and wings 13. The airframe main body 12 is the fuselage of the airframe 11 and has a shape that extends, for example, in the front-to-rear direction. The airframe main body 12 has a passenger compartment for passengers. The wings 13 extend from the airframe main body 12 and multiple wings 13 are provided on the airframe main body 12. The wings 13 are fixed wings. The multiple wings 13 include main wings, a tail, etc.

[0016] A plurality of propellers 20 are provided on the airframe 11. The eVTOL 10 is a multicopter having at least three propellers 20. For example, at least four propellers 20 are provided on the airframe 11. The propellers 20 are provided on each of the airframe body 12 and the wings 13. The propellers 20 rotate around a propeller axis. The propeller axis is, for example, the center line of the propeller 20. The propellers 20 can generate thrust and lift for the eVTOL 10. The propellers 20 correspond to rotating wings. The propellers 20 are sometimes referred to as rotors.

[0017] The propeller 20 has blades 21, a boss 22, and a propeller shaft 23. A plurality of blades 21 are arranged in the circumferential direction of the propeller axis. The boss 22 connects the plurality of blades 21. The blades 21 extend from the boss 22 in the radial direction of the propeller axis. The propeller shaft 23 is the rotation axis of the propeller 20, and extends from the boss 22 along the propeller axis.

[0018] The eVTOL 10 is a tilt rotor aircraft. In the eVTOL 10, the propeller 20 can be tilted. That is, the tilt angle of the propeller 20 is adjustable. For example, when the eVTOL 10 ascends, the orientation of the propeller 20 is set so that the propeller axis extends in the vertical direction. In this case, the propeller 20 functions as a lift propeller for generating lift in the eVTOL 10. When the eVTOL 10 moves forward, the orientation of the propeller 20 is set so that the propeller axis extends in the longitudinal direction. In this case, the propeller 20 functions as a cruise propeller for generating thrust in the eVTOL 10.

[0019] The battery 31 is electrically connected to the plurality of EPUs 50. The battery 31 is a power supply unit that supplies power to the EPUs 50 and corresponds to a power supply unit. The battery 31 is a DC voltage source that applies a DC voltage to the EPUs 50. The battery 31 has a rechargeable secondary battery. Examples of such secondary batteries include a lithium ion battery and a nickel-metal hydride battery. Note that a fuel cell, a generator, or the like may be used as the power supply unit in addition to or instead of the battery 31.

[0020] The distributor 32 is electrically connected to the battery 31 and the plurality of EPUs 50. The distributor 32 distributes the power from the battery 31 to the plurality of EPUs 50. The power distributed by the distributor 32 to the EPUs 50 is drive power for driving the EPUs 50.

[0021] The EPU 50 is a device that propels the eVTOL 10 by driving and rotating the propellers 20, and corresponds to an electric propulsion device. EPU is an abbreviation for Electric Propulsion Unit. An EPU 50 is provided individually for each of the multiple propellers 20. The EPUs 50 are arranged on the propellers 20 along the propeller axes. All of the multiple EPUs 50 are fixed to the airframe 11. The EPUs 50 support the propellers 20 so that they can rotate. The EPUs 50 are connected to the propellers 20. The propellers 20 are fixed to the airframe 11 via the EPUs 50.

[0022] The EPU 50 has a motor device 60 and an inverter device 80. In the EPU 50, the motor device 60 and the inverter device 80 are arranged side by side along the motor axis Cm. The motor device 60 has a motor 61 and a motor housing. The motor housing accommodates the motor 61. The motor 61 is a rotating electric machine, and is a multi-phase AC motor. The motor 61 is, for example, a three-phase motor.

[0023] As shown in Fig. 2, the motor 61 has a stator 63, a rotor 64, and a motor shaft 65. The stator 63 is a stator, and the rotor 64 is a rotor. The motor shaft 65 is fixed to the rotor 64 and rotates together with the rotor 64. The motor 61 is an axial gap type rotating electric machine. In the motor 61, the stator 63 and the rotor 64 are aligned along the motor axis Cm.

[0024] The motor axis Cm is the rotation axis of the rotor 64. The rotor 64 rotates around the motor axis Cm. The motor axis Cm is, for example, the center line of the rotor 64. The motor axis Cm is also the center line of the motor 61 and the motor shaft 65. When the rotation of the rotor 64 is referred to as the rotation of the motor 61, the motor 61 rotates around the motor axis Cm.

[0025] The stator 63 has a motor coil that forms an armature. The motor coil in this embodiment has two three-phase individual coils. When power is supplied to both individual coils, the motor coil functions as a six-phase coil, and the motor 61 operates as a six-phase motor. When power is supplied to only one individual coil, the motor coil functions as a three-phase coil, and the motor 61 operates as a three-phase motor.

[0026] The two individual coils are referred to as a first coil 63a and a second coil 63b, respectively. The first coil 63a and the second coil 63b, each of which is a three-phase coil, are wound around a single common stator 63. The first coil 63a and the second coil 63b are arranged to be aligned in the circumferential direction of rotation of the motor 61. For example, a plurality of coil portions forming the first coil 63a and a plurality of coil portions forming the second coil 63b are arranged alternately in the circumferential direction.

[0027] The individual coils are not limited to three phases, and the number of individual coils is not limited to two. In other words, the motor 61 has a structure including m individual coils of n phases, and has m×n phase coils, where m and n are natural numbers. When power is supplied to m individual coils, the motor 61 operates as an m×n phase motor. The motor 61 can be driven by supplying power to at least one individual coil. For example, when power is supplied to one individual coil, the motor 61 operates as a 1×n phase motor.

[0028] The inverter device 80 is a control device that drives the motor 61. The inverter device 80 has an inverter 81, an inverter control unit 82, and an inverter housing. The inverter housing is a case that houses the inverter 81 and the inverter control unit 82. The inverter 81 drives the motor 61 by converting the power supplied to the motor 61.

[0029] The inverter 81 is configured to include a plurality of electronic components such as switching elements and capacitor elements. In the inverter 81, these electronic components are mounted on a circuit board or the like. The inverter control unit 82 controls the motor 61 by controlling the inverter 81. The inverter control unit 82 is configured to include a plurality of electronic components such as a microcomputer, a processor 83 (described later), and a memory 84. In the inverter control unit 82, these electronic components are mounted on a circuit board or the like. The inverter device 80 controls the power supplied to the motor coil. In the inverter device 80, one inverter 81 and one inverter control unit 82 form one inverter module.

[0030] The EPU 50 has a first inverter device 80A and a second inverter device 80B as the inverter device 80. The first inverter device 80A has a first inverter 81A as the inverter 81 and a first inverter control unit 82A as the inverter control unit 82. The second inverter device 80B has a second inverter 81B as the inverter 81 and a second inverter control unit 82B as the inverter control unit 82. The first inverter control unit 82A controls the power supplied to the first coil 63a as motor control. The second inverter control unit 82B controls the power supplied to the second coil 63b as motor control.

[0031] In the EPU 50, when both the first inverter control unit 82A and the second inverter control unit 82B perform motor control, the motor 61 is driven as a six-phase motor. When only one of the first inverter control unit 82A and the second inverter control unit 82B performs motor control, the motor 61 is driven as a three-phase motor. The FCU 40 controls the inverter control units 82A and 82B to switch between six-phase drive and three-phase drive of the motor 61. In other words, each of the two inverter control units can independently control the motor 61.

[0032] In FIG. 2, the processor 41 is shown as PRO, the memory 42 as MEM, and the program 43 as PG. The motor 61 is shown as eMOT, the first coil 63a as CL1, the second coil 63b as CL2, the first rotor 64a as Rot1, and the second rotor 64b as Rot2. The first inverter device 80A is shown as MCUA, the first inverter 81A as INVA, and the first inverter control unit 82A as ICDA. The second inverter device 80B is shown as MCUB, the second inverter 81B as INVB, and the second inverter control unit 82B as ICDB. In the inverter control units 82A and 82B, the processor 83 is shown as PRO, the memory 84 as MEM, and the program 85 as PG. MCU is an abbreviation for Motor Control Unit.

[0033] The EPU 50 has an EPU shaft 51 and a gear 53. The EPU shaft 51 connects the motor 61 and the propeller 20. For example, the EPU shaft 51 connects the motor shaft 65 and the propeller shaft 23 via the gear 53. The EPU shaft 51 rotates around the motor axis Cm. The EPU shaft 51 and the propeller 20 are aligned in the axial direction along the motor axis Cm. For example, the EPU shaft 51, the boss 22, and the propeller shaft 23 are aligned in the axial direction. The motor axis Cm coincides with the propeller axis.

[0034] The gear 53 mechanically connects the motor shaft 65 and the EPU shaft 51. The gear 53 transmits the rotation of the motor shaft 65 to the EPU shaft 51. The gear 53 is provided, for example, between the propeller 20 and the motor 61 in the axial direction AD. The gear 53 has a reducer.

[0035] The EPU 50 has a propeller rotation sensor 52, a first motor rotation sensor 52a, and a second motor rotation sensor 52b. These rotation sensors include, for example, an encoder, a resolver, and the like.

[0036] The propeller rotation sensor 52 is provided on the EPU shaft 51. The propeller rotation sensor 52 detects the number of rotations per predetermined time of the propeller 20, that is, the propeller rotation speed. For example, the propeller rotation sensor 52 is provided on the gear 53. The propeller rotation sensor 52 outputs a signal of the detection result to the first inverter control unit 82A and the second inverter control unit 82B.

[0037] The first motor rotation sensor 52a detects the number of rotations per predetermined time of the motor shaft 65, i.e., the motor rotation speed. The second motor rotation sensor 52b detects the number of rotations per predetermined time of the motor shaft 65, i.e., the motor rotation speed. The first motor rotation sensor 52a outputs a signal of the detection result to the first inverter 81A. The second motor rotation sensor 52b outputs a signal of the detection result to the second inverter 81B.

[0038] FCU 40 is an abbreviation for Flight Control Unit, and is a flight control device that controls the flight system 30. The FCU 40 mainly controls the inverter control unit 82 to control the drive states of the multiple EPUs 50, and ultimately the drive states of the multiple propellers 20. In other words, the FCU 40 performs flight control for flying the eVTOL 10. The FCU 40 is mainly configured as a computer. This computer has a processor 41, a memory 42, an input / output interface, a bus connecting these, and the like. The FCU 40 executes various processes, such as flight control processes for flight control, by having the processor 41 execute a control program 43 stored in the memory 42.

[0039] The processor 41 is hardware for arithmetic processing coupled to the memory 42. The processor 41 executes various processes such as flight control processing by accessing the memory 42. The memory 42 is a storage medium that stores a control program 43 and the like. For example, the memory 42 is a non-transitory tangible storage medium that non-temporarily stores computer-readable programs and data. The non-transitory tangible storage medium as the memory 42 is a non-transitory tangible storage medium, and is realized by a semiconductor memory, a magnetic disk, or the like.

[0040] The inverter control unit 82 controls the rotation of the propeller 20 by controlling the motor 61. The inverter control unit 82 performs propulsion control to propel the eVTOL 10. The inverter control unit 82 performs propulsion control using the detection results of various sensors such as the propeller rotation sensor 52, command signals from the FCU 40, and the like. The inverter control unit 82 is mainly composed of a computer. This computer has a processor 83, a memory 84, an input / output interface, a bus connecting these, and the like. The inverter control unit 82 executes various processes such as propulsion control processing for performing propulsion control by having the processor 83 execute a program 85 stored in the memory 84.

[0041] The processor 83 is hardware for arithmetic processing coupled to the memory 84. The processor 83 executes various processes such as flight control processing by accessing the memory 84. The memory 84 is a storage medium that stores a program 85 and the like. For example, the memory 84 is a non-transitory tangible storage medium that non-temporarily stores computer-readable programs and data. The non-transitory tangible storage medium as the memory 84 is a non-transitory tangible storage medium, and is realized by a semiconductor memory, a magnetic disk, or the like.

[0042] As described above, the inverter device 80 includes the first inverter device 80A and the second inverter device 80B. With this, even if the first inverter device 80A fails and is unable to supply power to the first coil 63a, the second inverter device 80B can supply power to the second coil 63b. This allows the motor 61 to continue to be driven, and the propeller 20 to continue to rotate. In other words, the inverter device 80 has redundancy.

[0043] However, if a fault in the first inverter device 80A results in excessive power being supplied to the first coil 63a, it may cause the motor shaft 65 to over-rotate. When the motor shaft 65 enters an over-rotation state, the motor device may generate electricity. As a result, there is a concern that the voltage applied to the electrical components constituting the inverter device 80 may exceed their withstand voltage, causing the electrical components to fail. For example, a voltage exceeding the withstand voltage may be applied to electrical components such as switching elements and capacitor elements, causing them to fail. Therefore, it is desirable to quickly resolve the over-rotation state of the motor shaft 65.

[0044] Moreover, excessive rotation of the motor shaft 65 leads to excessive rotation of the EPU shaft 51 and the propeller 20. A sudden gust of wind may also cause the propeller 20 to over-rotate. If the propeller 20 falls into an over-rotation state, it becomes difficult to achieve an optimal flight attitude for the eVTOL 10. Therefore, it is desirable to quickly resolve the propeller over-rotation state.

[0045] The inverter device 80 can control the motor rotation to decelerate in a negative torque mode described below. Such deceleration can quickly resolve the above-mentioned motor over-speed and propeller over-speed. In the following description, of the motor rotational torque exerted by the power supply, torque for accelerating or maintaining the rotation in the positive direction for flight is called positive torque, and torque for decelerating the rotation in the positive direction is called negative torque. The positive torque mode is a mode in which current supply is controlled to exert positive torque. The negative torque mode is a mode in which current supply is controlled to exert negative torque.

[0046] The control in the negative torque mode may be regenerative control, which will be described below, or non-regenerative control. Regenerative control is control that operates the inverter 81 to cause the motor 61 to generate electricity. With regenerative control, the rotational energy of the propeller is converted into electrical energy, thereby slowing down the propeller rotation. Non-regenerative control is control that operates the inverter 81 to cause the motor 61 to exert negative torque without generating electricity. With non-regenerative control, the rotational energy of the propeller is converted into thermal energy, thereby slowing down the propeller rotation. Specific examples of non-regenerative control include d-axis current control and zero-phase current control.

[0047] Non-regenerative control allows negative torque to be generated without applying a high voltage to the battery 31, thereby suppressing deterioration of the battery 31. Regenerative control allows negative torque to be generated more quickly than non-regenerative control, so propeller overspeed can be eliminated in a short time.

[0048] The control procedure achieved by processor 83 executing program 85 will be described below with reference to Fig. 3. Note that memory 84 storing program 85 and processor 83 are provided in inverter control unit 82. This inverter control unit 82 corresponds to the "motor control device." In other words, first inverter control unit 82A and second inverter control unit 82B correspond to the "motor control device."

[0049] 3, the first inverter unit 80A (MCUA) controls the energization of the first coil 63a in the positive torque mode. The second inverter unit 80B (MCUB) controls the energization of the second coil 63b in the positive torque mode. Specifically, the MCUA and MCUB execute energization control in the positive torque mode so as to output the requested torque commanded from the FCU 40 to the EPU 50.

[0050] In the next step S20, at least one of the MCUA and MCUB determines whether over-rotation has been detected. Specifically, the MCUA determines whether the motor rotation speed exceeds a first threshold based on the detection signal output from the first motor rotation sensor 52a. The MCUB determines whether the motor rotation speed exceeds the first threshold based on the detection signal output from the second motor rotation sensor 52b. If at least one of the MCUs determines that the first threshold has been exceeded, it determines that over-rotation has been detected.

[0051] If over-rotation is detected by one of the MCUA and MCUB but not the other, it may be determined that over-rotation has not occurred, taking into consideration the possibility that one of the rotation sensors may have made an erroneous detection. In other words, it may be determined that over-rotation has occurred on the condition that over-rotation has been detected by both the MCUA and MCUB. Note that the MCU may detect over-rotation based on the propeller rotation speed instead of the motor rotation speed.

[0052] In the subsequent step S30, the current Ia output from the first inverter 81A to the first coil 63a and the current Ib output from the second inverter 81B to the second coil 63b are measured. Specifically, as shown in Fig. 2, the first inverter device 80A has a first current sensor 86A, and the second inverter device 80B has a second current sensor 86B.

[0053] The first current sensor 86A outputs a detection signal corresponding to the current Ia output from the first inverter 81A to the motor 61 to the MCUA. The MCUA calculates the magnitude of the current Ia output from the first inverter 81A based on the detection signal output from the first current sensor 86A. The second current sensor 86B outputs a detection signal corresponding to the current Ib output from the second inverter 81B to the motor 61 to the MCUB. The MCUB calculates the magnitude of the current Ib output from the second inverter 81B based on the detection signal output from the second current sensor 86B.

[0054] In the following step S31, the currents Ia and Ib measured in step S30 are compared in magnitude. If it is determined that the current Ia from the MCUA is smaller than the current Ib from the MCUB, the processes of steps S41 and S42 are executed. In step S41, the MCUA executes energization control in negative torque mode. In step S42, the MCUB executes control in stop mode. In stop mode, the MCUB stops energization of the second coil 63b.

[0055] If it is determined in step S31 that the current Ia from the MCUA is greater than the current Ib from the MCUB, the processes of steps S43 and S44 are executed. In step S43, the MCUA executes control in the stop mode. In the stop mode, the MCUA stops the energization of the first coil 63a. In step S44, the MCUB executes energization control in the negative torque mode.

[0056] The inverter control unit 82 when executing the processing of step S10 corresponds to a positive torque control unit that controls the motor 61 in positive torque mode. The inverter control unit 82 when executing the processing of steps S41 and S44 corresponds to a negative torque control unit that controls the motor 61 in negative torque mode. The inverter control unit 82 when executing the processing of steps S42 and S43 corresponds to a stop control unit that stops the supply of current to the motor 61. The inverter control unit 82 when executing the processing of step S20 corresponds to an over-rotation detection unit that detects over-rotation of the motor shaft 65. The inverter control unit 82 corresponds to a motor control device, and can be said to include a positive torque control unit, a negative torque control unit, a stop control unit, and an over-rotation detection unit.

[0057] <Operation and effect of the first embodiment> In this embodiment, when overspeed is detected in step S20, control is executed in the negative torque mode in step S41 or step S44. Therefore, when overspeed is detected, negative torque is generated in the motor 61. This allows the motor 61 to be quickly decelerated, and ultimately the overspeed state of the propeller 20 to be quickly resolved.

[0058] Furthermore, in this embodiment, multiple inverter devices 80 are provided for one motor 61. The positive torque control unit and the negative torque control unit can independently control the energization state of each of the multiple coils 63a, 63b provided in the motor 61. When overspeed is detected, control in the positive torque mode is prohibited, and at least one of the multiple coils is controlled in the negative torque mode. In this way, even if one inverter device 80 fails and is no longer able to execute the negative torque mode, the other inverter devices 80 can execute the negative torque mode. This ensures redundancy in the negative torque mode, which quickly resolves overspeed.

[0059] Furthermore, in this embodiment, when overspeed is detected in step S20, one coil is controlled in negative torque mode, and the remaining coils are stopped by the stop control unit. For example, one of the first coil 63a and the second coil 63b is controlled in negative torque mode, and power supply to the other coil is stopped. In this way, because only one MCU executes the negative torque mode, cooperative control that would be required when multiple MCUs execute the negative torque mode is not necessary, and control can be simplified.

[0060] Here, overspeed refers to a state in which excessive positive torque is applied to the propeller 20. The excessive positive torque application may be caused by a malfunction of one of the MCUs, causing a large current to flow. The MCU that was passing the maximum current when the overspeed was detected is likely to have malfunctioned and may be the cause of the overspeed. In light of this, in this embodiment, when overspeed is detected in step S20, the stop control unit stops the power supply to the coil that was passing the maximum current. For example, the power supply is stopped for the coil that was passing the largest current when the overspeed was detected, out of the first coil 63a and the second coil 63b. This reduces the risk of the overspeed recurring. Stopping one of the MCUs also reduces energy consumption and simplifies control.

[0061] (Second embodiment) In the first embodiment, when overspeed is detected in step S20, power supply to one coil is controlled in negative torque mode, and power supply to the remaining coils is stopped. In contrast, in this embodiment, when overspeed is detected, power supply to all coils is controlled in negative torque mode. Specifically, in this embodiment, the processing from step S30 onwards in FIG. 3 according to the first embodiment is changed to step S40 in FIG. 4. In step S40 in FIG. 4, both the MCUA and the MCUB execute energization control in negative torque mode.

[0062] Here, an abnormality in one of the multiple MCUs may be the cause of the overspeed. In consideration of this, in this embodiment, all MCUs are made to execute the negative torque mode, and all coils are controlled in the negative torque mode. Therefore, even if an abnormality occurs in one of the MCUs, negative torque can be reliably generated. This improves the reliability of quickly decelerating the motor 61 when overspeed occurs.

[0063] (Third embodiment) In the control flow of FIG. 5 showing this embodiment, the processes of steps S50, S51, S52, S60, and S61 are added to the control flow of FIG.

[0064] In step S50, after one of the two MCUs executes the negative torque mode and the other executes the stop mode, it is determined whether the overspeed has been resolved. For example, if the motor rotation speed is less than the first threshold value in the detection signals from both the first motor rotation sensor 52a and the second motor rotation sensor 52b, it is determined that the overspeed has been resolved.

[0065] If it is determined in step S50 that the overspeed has been resolved, the next step S51 determines whether there is a continuation request to continue driving the propeller 20. The continuation request is one of the command signals transmitted from the FCU 40 to the inverter device 80.

[0066] If it is possible to continue driving the propeller while preventing overspeed, continuing the drive would prevent an increase in the load on the other propellers 20, i.e., the load on the other EPUs 50. However, the occurrence of overspeed may indicate that some kind of abnormality has occurred in the MCU. Therefore, even if the overspeed is resolved, it is not necessarily possible to control the propeller drive appropriately. Therefore, if priority is given to avoiding the use of an MCU that may be abnormal for control, the FCU 40 will not issue a request to continue driving the propeller. On the other hand, if priority is given to reducing the load on the other EPUs 50, the FCU 40 will issue a request to continue driving the propeller.

[0067] If it is determined that a continuation request has been made, the process of the next step S52 is executed, and if it is determined that a continuation request has not been made, the process of step S60 is executed. In step S52, the MCU that was executing the negative torque mode in step S41 or step S44 is changed to the positive torque mode. Note that the MCU that was executing the stop mode in step S42 or step S43 continues in the stop mode.

[0068] In step S60, it is determined whether or not there is a lock request to lock the propeller 20 in a non-rotatable state. The lock request is one of the command signals transmitted from the FCU 40 to the inverter device 80. If it is determined that there is no lock request, the process of the next step S601 is executed, and if it is determined that there is a lock request, the process of FIG. 6 is executed.

[0069] In step S601, the MCUs that were in the negative torque mode in step S41 or step S44 are changed to the stop mode. Note that the MCUs that were in the stop mode in step S42 or step S43 continue to be in the stop mode. Therefore, all MCUs are in the stop mode.

[0070] Next, the lock control processing procedure will be described with reference to Figure 6. First, in step S61, it is determined whether the motor rotation speed has been sufficiently decelerated to a predetermined low rotation speed. Specifically, it is determined whether the motor rotation speed is equal to or lower than a second threshold value based on the detection signal output from the first motor rotation speed sensor 52a or the second motor rotation speed sensor 52b. The second threshold value is set to a value lower than the first threshold value used for overspeed detection in step S20. Note that instead of confirming that the rotation speed has been reduced based on the motor rotation speed, the MCU may also confirm the reduction in rotation speed based on the propeller rotation speed.

[0071] In other words, in step S61, negative torque continues to be applied until the rotation speed reaches a predetermined low level even after the overspeed is resolved. The rotation speed is usually measured using the propeller rotation sensor 52 or the motor rotation sensors 52a and 52b. However, if the rotation sensor is not used, for example, when an abnormality occurs in the rotation sensor, it may be possible to estimate whether the rotation speed has reached a low level based on the negative current generated during the negative torque mode. The negative current is a current that flows in the charging direction.

[0072] If it is determined in step S61 that the rotation speed has fallen to or below a predetermined low speed, a target lock position is calculated in the following step S62. The target lock position is a target rotation angle at which the propeller 20 is locked. In the following step S63, the MCU, which has initiated execution of the negative torque mode in step S41 or step S44, switches to the following feedback control. In this feedback control, the state of energization to the first coil 63a or the second coil 63b is feedback-controlled so that the actual propeller rotation position (actual propeller position) stops at the target lock position calculated in step S62. The actual propeller position is calculated based on a signal detected by the propeller rotation sensor 52.

[0073] Here, the MCU in negative torque mode is less likely to have an abnormality than the MCU in stop mode. Therefore, the feedback control of step S63 is performed using the MCU in negative torque mode, which is less likely to have an abnormality. The MCU in stop mode, which is more likely to have an abnormality, is not used in the feedback control of step S63. The feedback control of step S63 may be performed by switching between positive torque and negative torque as appropriate, or by continuously applying a constant negative torque.

[0074] In the next step S64, it is determined whether the actual propeller position has stopped near the target lock position. For example, if the actual propeller position has stopped at an angle less than plus or minus 5 degrees from the target lock position, it is determined that the propeller has stopped near the target lock position. If it is determined that the propeller has stopped near the target lock position, in the next step S70, it is determined that electrical locking has been completed and this fact is stored.

[0075] In the next step S71, the MCU, which was executing feedback control in step S63, switches to lock maintenance control. Lock maintenance control is control that causes the motor to exert a braking force so that the propeller 20 does not move from the locked position using electrical force. Lock maintenance control may be open control that generates torque to inhibit rotation of the propeller 20, or may be feedback control relative to a target position.

[0076] If it is determined in step S64 that the propeller 20 has not stopped near the target lock position, then in step S65 it is determined whether a predetermined time has elapsed since the lock request was made. If it is determined that the predetermined time has elapsed, then in step S66 it is determined that locking has failed and this fact is stored. Then in step S67, all MCUs are changed to stop mode. In short, if the propeller 20 cannot be locked even after a sufficient amount of time has elapsed, all MCUs are stopped because continuing lock control would waste energy.

[0077] However, if the system is simply switched to stop mode when overspeed occurs, the propeller 20 will continue to rotate due to wind or other factors, which will increase air resistance during flight. Therefore, if the propeller 20 is not to be driven continuously, it is desirable to lock the propeller 20 at a position where flight resistance is small. In consideration of this, in this embodiment, if there is no request to continue driving, an attempt is made to lock the propeller 20 first, and if locking is not possible, all MCUs are stopped.

[0078] The inverter control unit 82 when executing the processes of steps S63 and S71 corresponds to a lock control unit that locks the propeller 20 so that it cannot rotate. In particular, the inverter control unit 82 when executing the process of step S63 corresponds to a feedback control unit that, after decelerating to a predetermined rotation speed in negative torque mode, feedback controls the power supply to the motor so that the actual propeller position is stopped near the target rotation position. Furthermore, the inverter control unit 82 when executing the process of step S71 corresponds to an electric lock control unit that, after stopping the propeller 20 near the target rotation position, controls the power supply to the motor in a lock mode in which a braking torque is exerted to prevent the propeller 20 from rotating.

[0079] As described above, in this embodiment, if a request to continue driving the propeller 20 is made after overspeed is detected, at least one of the coils 63a, 63b is controlled in the positive torque mode. This reduces the load on the other EPUs 50 compared to when all ECUs are placed in the stop mode and the EPU 50 is stopped. On the other hand, if there is no request to continue driving, i.e., when a stop request is made, power supply to all coils is stopped after the overspeed is resolved. Specifically, motor drive is stopped by lock control, or all MCUs are placed in the stop mode in step S601 and motor drive is stopped. This improves the reliability of preventing overspeed from recurring.

[0080] Furthermore, in this embodiment, the coil through which the maximum current was flowing when the overspeed was detected is prohibited from being controlled in positive torque mode after the overspeed is resolved, even if a continuation request is made. In other words, in step S63, the MCU in negative torque mode is switched to feedback mode, but the MCU in stop mode remains in stop mode. The MCU through which the largest current was flowing is more likely to be the cause of the overspeed than the other MCUs. Therefore, in this embodiment, the MCU that controls the coil through which the maximum current was flowing is prohibited from being controlled in positive torque mode, thereby reducing the risk of the overspeed recurring.

[0081] Furthermore, in this embodiment, if a lock request is made after overspeed is detected, the lock control unit executes control after the overspeed is resolved. This locks the propeller 20 after the overspeed is resolved, thereby improving the reliability of preventing the recurrence of overspeed.

[0082] Furthermore, in this embodiment, the lock control unit includes a feedback control unit and an electric lock control unit. The feedback control unit performs feedback control of the power supply to the motor so that the actual propeller position is stopped near the target rotation position after decelerating to a predetermined rotation speed in the negative torque mode. The electric lock control unit controls the power supply to the motor in a lock mode in which a braking torque is exerted to prevent the propeller 20 from rotating after stopping the propeller near the target rotation position. In other words, the propeller 20 is locked electrically by energizing the coil. Therefore, locking can be achieved without providing a mechanical locking mechanism. Note that while the negative torque mode is a mode in which rotation in the positive direction is decelerated, the electric lock mode is a mode in which rotation in both the positive and negative directions is prevented.

[0083] (Fourth embodiment) The EPU 50 according to this embodiment has a locking device 100 shown in FIGS. 7 and 8. The locking device 100 is capable of locking the propeller 20. The locking device 100 is capable of transitioning between a locked state and an unlocked state. When in the locked state, the locking device 100 restricts the rotation of the propeller 20, thereby locking the propeller 20 in a non-rotatable state. When in the locked state, the locking device 100 holds the propeller 20 at a predetermined lock angle. Note that the lock angle may have a predetermined angle range.

[0084] When the locking device 100 is in the unlocked state, it does not lock the propeller 20. When the locking device 100 is in the unlocked state, it does not restrict the rotation of the propeller 20 and allows the rotation of the propeller 20. The unlocked state is a state in which the propeller 20 is unlocked.

[0085] The inverter control unit 82 controls the locking device 100. The inverter control unit 82 can transition the locking device 100 between a locked state and an unlocked state. The FCU 40 outputs a command signal to the inverter control unit 82 to control the operation of the locking device 100 via the inverter control unit 82. The FCU 40 individually controls the locking device 100 for each of the multiple EPUs 50.

[0086] The FCU 40 outputs a lock command to the inverter control unit 82 according to the flight state of the eVTOL 10. For example, when the eVTOL 10 lifts for vertical takeoff or the like, the FCU 40 controls flight so that the propellers 20 functioning as lift propellers are driven to rotate by the motors 61. In this case, the FCU 40 commands the locking device 100 to lock the propellers 20 that do not function as lift propellers.

[0087] For example, the FCU 40 locks the propellers 20 that do not function as lift propellers in a state in which they extend along the pitch axis of the airframe main body 12 (the vertical direction on the paper in FIG. 1). For these propellers 20, the rotation angle in a state in which they extend along the pitch axis is the locked angle. Locking the propellers 20 in this manner makes it possible to avoid inconveniences such as airflow turbulence caused by the propellers 20 that do not function as lift propellers when the eVTOL 10 is lifting.

[0088] When the eVTOL 10 is cruising, the FCU 40 drives and rotates the propeller 20 that functions as a cruising propeller using the motor 61. In this case, the FCU 40 locks the propeller 20 that does not function as a cruising propeller using the locking device 100.

[0089] For example, the FCU 40 locks the propellers 20 that do not function as cruise propellers in a state in which they extend along the roll axis of the airframe main body 12 (the left-right direction on the paper in FIG. 1 ). For these propellers 20, the rotation angle in the state in which they extend along the roll axis is the locked angle. Locking the propellers 20 in this manner can prevent inconveniences such as airflow turbulence caused by the propellers 20 that do not function as cruise propellers when the eVTOL 10 is cruising.

[0090] As shown in FIG. 7, the locking device 100 has a lock pin 101, a solenoid 110, a pressing force transmission unit 115, and a pressing unit 120. The lock pin 101 restricts rotation of the propeller 20 by being caught on the EPU shaft 51. In other words, the lock pin 101 is a locking member that can lock the propeller 20. The lock pin 101 corresponds to the restricting member. The circumferential direction CD shown in FIG. 7 corresponds to the rotation direction of the EPU shaft 51 and the propeller 20. The radial direction RD shown in FIG. 7 indicates the radial direction of the EPU shaft 51 and the propeller 20. The axial direction AD shown in FIG. 7 indicates the axial direction of the EPU shaft 51. The EPU axis and the motor axis Cm may be aligned or may be misaligned in the radial direction RD.

[0091] The lock pin 101 is movable between a locked position P11 and an unlocked position P12. When the lock pin 101 is in the locked position P11, it locks the propeller 20. When the lock pin 101 is in the locked position P11, it engages with the shaft groove 55 of the EPU shaft 51, thereby restricting the rotation of the propeller 20. When the lock pin 101 is in the unlocked position P12, it does not lock the propeller 20. When the lock pin 101 is in the unlocked position P12, it does not engage with the shaft groove 55, allowing the rotation of the propeller 20. The locked position P11 corresponds to the restricting position, and the unlocked position P12 corresponds to the allowing position.

[0092] The shaft groove 55 is provided in the EPU shaft 51. The shaft groove 55 is a groove-shaped recess provided in the shaft outer peripheral surface 51a. The shaft outer peripheral surface 51a is the outer peripheral surface of the EPU shaft 51. The shaft groove 55 opens radially outward. The shaft groove 55 extends, for example, in the axial direction AD along the shaft outer peripheral surface 51a. The shaft groove 55 is configured to engage with a portion of the lock pin 101. For example, the pin portion 103 of the lock pin 101 engages in the shaft groove 55. The lock pin 101 is engaged in the shaft groove 55. The pin portion 103 fits into the shaft groove 55, thereby holding the propeller 20 at the lock angle. Note that if a gap exists between the inner wall surface of the shaft groove 55 and the pin portion 103, the lock angle will be within a predetermined angle range.

[0093] The lock pin 101 has a pin base 102 and a pin portion 103. The pin base 102 is formed in a plate shape and extends, for example, along the shaft outer circumferential surface 51a. The pin portion 103 is a protrusion provided on the plate surface of the pin base 102. The pin portion 103 protrudes radially inward from the pin base 102.

[0094] The lock pin 101 is movable in the radial direction RD relative to the EPU shaft 51. The lock pin 101 can move between a locked position P11 and an unlocked position P12 by moving in the radial direction RD. The lock pin 101 moves from the unlocked position P12 to the locked position P11 by approaching the EPU shaft 51. The locked position P11 is the position where the pin portion 103 is caught in the shaft groove 55 and the rotation of the propeller 20 is locked. The unlocked position P12 is the position where the pin portion 103 is not caught in the shaft groove 55 and the rotation of the propeller 20 is not locked.

[0095] The pressing unit 120 is capable of locking the propeller 20 by mechanical energy. The pressing unit 120 is capable of moving the lock pin 101 from the unlocked position P12 to the locked position P11 by mechanical energy. The pressing unit 120 uses the restoring force of an elastic member as the mechanical energy.

[0096] The pressing unit 120 has a pressing member 121 and a pressing support portion 122. The pressing member 121 is configured to include an elastic member such as a spring. The pressing member 121 is elastically deformable as a whole. The pressing member 121 is in an elastically deformed state when the lock pin 101 is in the unlock position P12. The pressing member 121 urges the lock pin 101 from the unlock position P12 toward the locked position P11 by a mechanical pressing force F12 generated by the elastic deformation of the pressing member 121. The mechanical pressing force F12 is a restoring force of the pressing member 121. The mechanical pressing force F12 is a force due to mechanical energy generated in the pressing member 121. The pressing member 121 presses the lock pin 101 toward the EPU shaft 51 by the mechanical pressing force F12.

[0097] The pressing support portion 122 supports the pressing member 121 in a state in which the pressing member 121 is elastically deformable. The pressing support portion 122 is fixed to a motor housing of the EPU 50. Note that the pressing support portion 122 may be a part of the motor housing.

[0098] The solenoid 110 is capable of unlocking the propeller 20 using electrical energy. The solenoid 110 is capable of moving the lock pin 101 from a locked position P11 to an unlocked position P12 using electrical energy. The solenoid 110 uses power supplied to the solenoid 110 from the battery 31 as electrical energy. For example, the power of the battery 31 is supplied to the solenoid 110 via the inverter control unit 82.

[0099] The solenoid 110 has a solenoid coil 111 and a plunger 112. In the solenoid 110, the plunger 112 is displaced when the solenoid coil 111 is energized. For example, the plunger 112 is movable along the center line of the solenoid coil 111. The plunger 112 urges the lock pin 101 from the locked position P11 toward the unlocked position P12 by an electric pressing force F11 generated when the solenoid coil 111 is energized. The electric pressing force F11 is a force generated by the electromagnetic attractive force of the solenoid 110. This electromagnetic attractive force is a force generated when the solenoid 110 is excited. The excitation of the solenoid 110 is generated when the solenoid coil 111 is energized. The electric pressing force F11 is a force due to electric energy generated when the solenoid coil 111 is energized. The electrical pressing force F11 is greater than the mechanical pressing force F12.

[0100] A plurality of energizable current paths are connected to the solenoid 110. The plurality of energizable current paths include a first parallel path 130a and a second parallel path 130b. The parallel paths 130a and 130b electrically connect the inverter control unit 82 and the solenoid coil 111. The parallel paths 130a and 130b are formed by including electrical wiring such as communication lines. The first parallel path 130a and the second parallel path 130b are connected in parallel with each other. The inverter control unit 82 controls the energization of the solenoid coil 111 so that a signal current Is flows through one of the first parallel path 130a and the second parallel path 130b. The solenoid 110 generates an electric pressing force F11 when the signal current Is flows through the solenoid coil 111.

[0101] Note that, as long as a current such as the signal current Is flows through the solenoid coil 111, the solenoid coil 111 may be connected to the battery 31 so as to be electrically connected thereto without passing through the inverter control unit 82. For example, in a configuration in which the electrical connection between the battery 31 and the solenoid coil 111 is interrupted by a predetermined switch, the opening and closing of this switch may be controlled by the inverter control unit 82.

[0102] When the solenoid coil 111 is energized, the solenoid 110 drives the lock pin 101 to move from the locked position P11 to the unlocked position P12.

[0103] The pressing force transmission unit 115 transmits pressing forces F11 and F12 to the lock pin 101. For example, the mechanical pressing force F12 generated by the pressing unit 120 is applied to the lock pin 101 via the pressing force transmission unit 115. The mechanical pressing force F12 is also applied to the solenoid 110 via the pressing force transmission unit 115. In addition, the electrical pressing force F11 generated by the solenoid 110 is applied to the lock pin 101 via the pressing force transmission unit 115. The electrical pressing force F11 is also applied to the pressing unit 120 via the pressing force transmission unit 115.

[0104] The pressing force transmission unit 115 has a transmission plate unit 116 and a transmission shaft unit 117. The transmission plate unit 116 is rotatable around the transmission shaft unit 117 as a rotation axis. The transmission plate unit 116 rotates when pressing forces F11, F12 are applied to it. For example, the transmission plate unit 116 rotates to one side in the circumferential direction of the transmission shaft unit 117, thereby transmitting the mechanical pressing force F12 to the lock pin 101 and the solenoid 110. The transmission plate unit 116 rotates to the other side in the circumferential direction, thereby applying the electrical pressing force F11 to the lock pin 101 and the pressing unit 120.

[0105] Next, the operation of the locking device 100 will be described.

[0106] As shown in FIG. 7, the locking device 100 is in a locked state when the solenoid coil 111 is not energized. When the solenoid coil 111 is not energized, the solenoid 110 does not generate an electrical pressing force F11. That is, the plunger 112 does not urge the lock pin 101 toward the unlocked position P12. In this case, the pressing unit 120 holds the lock pin 101 at the locked position P11 by a mechanical pressing force F12. The mechanical pressing force F12 is a force capable of holding the lock pin 101 at the locked position P11. The mechanical pressing force F12 corresponds to a mechanical restricting force, and the pressing unit 120 corresponds to a mechanical restricting portion.

[0107] As shown in Figure 8, the locking device 100 transitions to an unlocked state when the solenoid coil 111 is energized. When the solenoid coil 111 is energized, the solenoid 110 generates an electrical pressing force F11. In this case, the plunger 112 moves the lock pin 101 from the locked position P11 to the unlocked position P12 against a mechanical pressing force F12 generated by the pressing unit 120. As the solenoid coil 111 continues to be energized, the plunger 112 holds the lock pin 101 in the unlocked position P12.

[0108] Next, lock control of the EPU 50 by the inverter control unit 82 will be described with reference to Fig. 9. In the control flow of Fig. 9, the processes of steps S70 and S71 shown in Fig. 6 are changed to processes of steps S80 to S86. In other words, the processes of steps S70 and S71 for electrical locking are changed to processes of steps S80 to S86 for mechanical locking.

[0109] If it is determined in step S64 that the lock pin 101 has stopped near the target lock position, then in step S80, the MCU used for the feedback control in step S63 executes mechanical lock control. In mechanical lock control, the solenoid coil 111 is de-energized, and the lock pin 101 is pressed down by a mechanical pressing force F12. As a result, the lock pin 101 fits into the shaft groove 55 and is locked.

[0110] In the next step S81, the MCU that executed the mechanical lock control generates an extremely weak torque in the motor. This torque may be either positive or negative. In the next step S82, it is determined whether the torque generated in step S81 has caused the propeller 20 to move. Specifically, if a predetermined or greater change occurs in the detection signal from the propeller rotation sensor 52, it is determined that the propeller 20 has moved. In short, the inverter control unit 82 confirms that the lock pin 101 has been fitted into the shaft groove 55 and properly locked by the processing of step S80, because the propeller 20 does not rotate even when an extremely weak torque is applied to the propeller 20.

[0111] If it is determined in step S82 that the propeller 20 is not moving, the process proceeds to step S83, where it is determined that the mechanical locking is complete and this information is stored. Then, in step S84, the MCU used for the feedback control in step S63 executes mechanical lock maintenance control. In the mechanical lock maintenance control, the solenoid coil 111 is kept de-energized.

[0112] If it is determined in step S82 that the propeller 20 has moved, then in step S85 it is determined that mechanical locking has failed and this fact is stored. Then, in step S86, the mechanical lock control is changed to electrical lock control. That is, the MCU used for the feedback control in step S63 executes the same processing as in FIG. 6. In short, mechanical lock control is executed first, and if it fails, the propeller 20 is locked using electrical lock control. If electrical locking also fails, the EPU 50 determines that an abnormality has occurred and stops all MCUs in step S67 of FIG. 6.

[0113] In the control flow of Figure 9, the locking control is switched to electrical locking control after one mechanical locking failure, but the locking control may be switched to electrical locking control after multiple mechanical locking attempts. Also, if the mechanical locking fails, all MCUs may be stopped without executing electrical locking control.

[0114] When executing the process of step S80, the inverter control unit 82 corresponds to a lock control unit that locks the propeller 20 in an unrotatable state, and also corresponds to a mechanical lock control unit. After decelerating to a predetermined rotation speed in negative torque mode, the mechanical lock control unit controls the power supply to the motor so that the locking device 100 is in a lockable position. Specifically, it controls the rotational position of the motor shaft 65 so that the lock pin 101 is in a position facing the shaft groove 55.

[0115] As described above, in this embodiment, the EPU 50 is equipped with the locking device 100 that mechanically locks the propeller 20 by inhibiting its rotation. The locking control unit provided in the inverter control unit 82 also has a mechanical locking control unit. The mechanical locking control unit controls the power supply to the motor so that the locking device 100 is in a lockable position after decelerating the rotational speed to a predetermined rotational speed in negative torque mode. This reduces the energy required to maintain the locked state compared to electrical locking, thereby enabling power savings.

[0116] (Fifth embodiment) In the control flow of FIG. 10 showing this embodiment, the processes of steps S62 to S64 and S80 to S82 in the control flow of FIG. 9 are changed to steps S80A, S81A, and S82A.

[0117] First, an outline of the control will be described. In the fourth embodiment shown in FIG. 9, first, feedback control is used to rotate the motor so that the lock pin 101 is positioned opposite the shaft groove 55. Then, mechanical lock control is executed to press down the lock pin 101, thereby fitting the lock pin 101 into the shaft groove 55 and completing the locking. In contrast, in the present embodiment shown in FIG. 10, feedback control is eliminated. Then, mechanical lock control is executed in a state where the lock pin 101 is not positioned opposite the shaft groove 55, and the lock pin 101 is pressed against the shaft outer circumferential surface 51a. In this state, the motor is rotated to fit the lock pin 101 into the shaft groove 55 and complete the locking.

[0118] Next, the control flow will be described in detail with reference to Figure 10. When it is determined in step S61 that the rotation speed has fallen below a predetermined low speed, in the next step S80A, the MCU used in the negative torque mode in steps S41 and S44 executes mechanical lock control. In mechanical lock control, the solenoid coil 111 is de-energized, and the lock pin 101 is pressed down by a mechanical pressing force F12. As a result, the lock pin 101 is pressed against the shaft outer peripheral surface 51a.

[0119] In the next step S81A, the MCU that executed the mechanical lock control generates an extremely weak torque in the motor. This torque may be either positive or negative, and the motor is rotated so that the lock pin 101 straddles the shaft groove 55. For example, the motor is rotated so that the EPU shaft 51 rotates at least one revolution but less than two revolutions.

[0120] In the next step S82A, it is determined whether the propeller 20 is stopped in the locked position. Specifically, if a change of a predetermined magnitude or more occurs in the detection signal from the propeller rotation sensor 52, it is determined that the propeller 20 is not stopped in the locked position. In short, the locking device 100 is first activated, and then the propeller 20 is rotated with a weak torque so as to cross the locked position, and when the rotation of the propeller 20 is stopped in the locked position, mechanical locking is completed.

[0121] As described above, according to this embodiment, the mechanical locking can be completed without requiring the feedback control relating to steps S62 to S64.

[0122] (Sixth embodiment) When there is a request to continue driving the propeller, the inverter control unit 82 according to this embodiment checks its operation before driving the propeller. An outline of this control is explained below. The motor is rotated with a weak torque (low rotation speed) that does not affect flight, and whether the MCU is normal or not is determined based on the motor's rotation state at that time. When multiple MCUs are used to rotate one propeller 20, the operation of each MCU is checked in order to accurately determine whether the MCU is normal or not. The propeller is then driven by an MCU that has been confirmed to be normal. If all MCUs are normal, the propeller is driven by all MCUs, thereby reducing the load on each MCU.

[0123] Next, the control flow will be described in detail with reference to Fig. 11. First, in step S51, which is the same as in Fig. 5, it is determined whether or not there is a continuation request to continue driving the propeller 20. If it is determined that there is no continuation request, then in step S95, the lock control shown in Fig. 6 and the like is executed. Alternatively, all MCUs are placed in stop mode as in step S601 in Fig. 5.

[0124] If it is determined in step S51 that a continuation request exists, then in step S90, the MCUA executes energization control of the first coil 63a in the mode for executing the above-mentioned operation check. The MCUB is set to stop mode. Then in step S91, it is determined whether the MCUA is normal. Specifically, if the execution of energization control in the operation check mode results in motor rotation or propeller rotation by an amount corresponding to the energization control, the MCUA is determined to be normal.

[0125] In the following step S92, the MCUB executes the energization control for the second coil 63b in the mode for executing the above-mentioned operation check. The MCUA is set to stop mode. In the following step S93, it is confirmed whether the MCUB is normal. In the following step S94, the MCU determined to be normal in steps S91 and S93 executes propeller drive corresponding to the continuation request. Note that the MCU determined to be abnormal is set to stop mode.

[0126] As described above, according to this embodiment, if a continuation request is made after the overspeed is resolved in negative torque mode, the system checks which MCU is normal. The MCU that is confirmed to be normal resumes propeller drive. This prevents the propeller from being driven by an MCU that is experiencing an abnormality, reducing the risk of an abnormality such as overspeed recurring.

[0127] (Seventh embodiment) As shown in FIG. 12, the eVTOL 10 according to this embodiment is equipped with multiple batteries 31. In FIG. 12, the first battery 31A is illustrated as BATA, and the second battery 31B is illustrated as BATB. The first battery 31A supplies power to MCUA, and the second battery 31B supplies power to MCUB. In this way, one battery 31 is assigned as a power supply source to one inverter device 80 that is the power supply destination. Furthermore, one inverter device 80 is assigned to one battery 31.

[0128] In this embodiment, we assume that after overspeed occurs, the overspeed is resolved by using negative torque mode, and then a request to continue propeller drive is made. If multiple MCUs are switched to positive torque mode in response to this request, if one battery runs out of charge first, the MCU connected to that battery will not be able to operate even if it is normal. Therefore, it is desirable to minimize SOC variations. In particular, the SOC of a specific battery may have decreased due to overspeed, which may result in large SOC variations at the time of the request to continue. Note that SOC is an abbreviation for State of Charge, and refers to the state of charge or charging rate.

[0129] In consideration of this point, in this embodiment, after a continuation request is received, the MCU is operated to check the SOC imbalance and suppress the imbalance. Specifically, the inverter control unit 82 executes the process shown in FIG. 13.

[0130] In the control flow of Fig. 13, first, in step S51, it is determined whether or not there is a continuation request to continue driving the propeller 20. If it is determined that there is no continuation request, then in step S95, the lock control shown in Fig. 6 and the like is executed. Alternatively, all MCUs are placed in stop mode as in step S601 of Fig. 5. If it is determined that there is a continuation request, then in steps S90 to S94, the same MCU operation check as in Fig. 11 is executed.

[0131] If it is determined in step S96 that both the MCUA and MCUB are normal as a result of the operation check, the following steps S971 and S972 determine whether there is a large difference in the SOC between the first battery 31A and the second battery 31B. If the SOC of the first battery 31A is lower than that of the second battery 31B by a predetermined amount or more, in step S981, the MCUA is controlled in the negative torque mode and the MCUB is controlled in the positive torque mode. If the SOC of the second battery 31B is lower than that of the first battery 31A by a predetermined amount or more, in step S982, the MCUA is controlled in the positive torque mode and the MCUB is controlled in the negative torque mode. If the difference between the SOCs is less than the predetermined amount, in step S983, both the MCUA and MCUB are controlled in the positive torque mode.

[0132] According to the control shown in FIG. 13, when the SOC of BATA is lower than that of BATB by a predetermined amount or more, as shown in FIG. 12, step S981 controls MCUA in the negative torque mode. As a result, BATA is charged and its SOC increases. Meanwhile, MCUB is controlled in the positive torque mode, so BATB is discharged and its SOC decreases. This suppresses SOC variations. Thereafter, when the SOC difference becomes less than the predetermined value, control switches to step S983, and both MCUA and MCUB are controlled in the positive torque mode. In other words, it is possible to reduce the chance that the first battery 31A will run out of charge immediately after a continuation request is issued.

[0133] (Eighth embodiment) In the present embodiment shown in FIG. 14 , one battery 31 supplies power to multiple EPUs 50. In this embodiment, the motor 61 that drives the first propeller 20A of the multiple propellers 20 is referred to as the first motor 61A, and the motor 61 that drives the second propeller 20B is referred to as the second motor 61B. Also in FIG. 14 , the first inverter device 80A associated with the first motor 61A is illustrated as MCUA1, and the second inverter device 80B associated with the second motor 61B is illustrated as MCUB1. Furthermore, in FIG. 14 , the first inverter device 80A associated with the first motor 61A is illustrated as MCUA2, and the second inverter device 80B associated with the second motor 61B is illustrated as MCUB2. The first battery 31A can distribute and supply power to MCUA1 and MCUA2. The second battery 31B can distribute and supply power to MCUB1 and MCUB2.

[0134] Here, the battery discharge rate, i.e., the current battery current, may vary depending on the state of the other EPUs 50. For example, in Figure 14, a scenario is assumed in which the second EPU overspeeds due to a failure in MCUB2, the overspeed is resolved by switching to negative torque mode, and then a request to continue propeller drive is made. If, in response to this request, MCUB2 is switched to stop mode while MCUA2 is switched to positive torque mode, the amount of discharge from BATA to MCUA2 increases by the amount that MCUB2 is stopped. As a result, there is a concern that the SOC of BATA will drop rapidly, resulting in a large difference with the SOC of BATB.

[0135] In consideration of this point, in this embodiment, the control flow shown in FIG. 15 places the MCU connected to the battery with the largest discharge amount in the negative torque mode. That is, MCUA1 is placed in the negative torque mode, and BATA is charged from MCUA1. This suppresses the increase in SOC variation. In the control flow of FIG. 15, the processes of steps S971, S972, S981, S982, and S983 in FIG. 13 are replaced by steps S991 and S992. In step S991, the control modes of all MCUs are selected so that the difference in discharge amount between the first battery 31A and the second battery 31B is minimized. In the following step S992, MCUA and MCUB are controlled in the selected control mode.

[0136] Specifically, the difference in the discharge amounts of the first battery 31A and the second battery 31B due to the EPUs other than the EPU 50 where the overspeed occurred is calculated from the operating states of the EPUs 50 other than the EPU 50 where the overspeed occurred. If the difference in the discharge amounts of the first battery 31A and the second battery 31B is small, the MCUs of the overspeed EPU are both set to the positive torque mode. If the difference in the discharge amounts is large, leaving it as is will increase the SOC variation, so the positive torque mode, negative torque mode, and stop mode of each MCU are selected to suppress the variation due to the other MCUs.

[0137] (Ninth embodiment) This embodiment is based on the premise that there are multiple motor rotation sensors 52a, 52b. The inverter control unit 82 according to this embodiment executes control in various modes, taking into consideration the possibility that an abnormality in one of the motor rotation sensors may be causing an erroneous detection of over-rotation. In the following description, the motor rotation sensor 52a will be referred to as rotation sensor A, and the motor rotation sensor 52b will be referred to as rotation sensor B.

[0138] If overspeed is actually occurring, both rotation sensors A and B should detect the overspeed. Therefore, in this embodiment, if both rotation sensors A and B detect overspeed, it is considered that overspeed is actually occurring.

[0139] There are cases where only one of the rotation sensors A and B detects over-rotation. For example, if only the rotation sensor A detects over-rotation, there are two possibilities: One is a case where the rotation sensor B is abnormal and an over-rotation has actually occurred. The other is a case where the rotation sensor A is simply abnormal and an over-rotation has not actually occurred, resulting in a false detection. The former case cannot occur unless an abnormality in the rotation sensor B and another abnormality, such as a sudden gust of wind, that is causing the over-rotation, occur simultaneously. Therefore, in this embodiment, if only one of the rotation sensors A and B detects over-rotation, it is assumed that an abnormality has occurred in that rotation sensor.

[0140] The mode is then changed as shown in FIG. 16 depending on whether the rotation sensor is abnormal or whether overspeed is actually occurring. In the control flow of FIG. 16, first, in step S10, the MCUA and MCUB execute energization control in positive torque mode. Next, in step S201, it is determined whether all rotation sensors have detected overspeed. If it is determined that all rotation sensors have detected overspeed, in the following step S211, it is determined that overspeed is actually occurring, rather than that there is an abnormality in the rotation sensor. In the following step S212, deceleration control is performed in negative torque mode, as in the various embodiments described above, to decelerate the motor rotation.

[0141] If it is determined in step S201 that none of the rotation sensors have detected over-rotation, it is determined in the following step S202 whether or not some of the rotation sensors have detected over-rotation. If it is determined that some of the rotation sensors have detected over-rotation, it is determined in the following step S221 that an abnormality has occurred in the rotation sensor that has detected over-rotation, and that over-rotation has not actually occurred. It is determined in the following step S222 whether or not the torque required by the EPU 50 can be output even if one of the MCUs is stopped.

[0142] If it is determined in step S222 that output is possible, then in step S223, the MCU corresponding to the rotation sensor deemed to have an abnormality is changed to stop mode. If it is determined in step S222 that output is not possible, then in step S224, both MCUs are controlled in positive torque mode using the detection signal from the normal rotation sensor. Note that in step S224, the MCU corresponding to the abnormal rotation sensor may also be controlled using the detection signal from propeller rotation sensor 52. Alternatively, the MCU corresponding to the abnormal rotation sensor may be controlled based on a control model.

[0143] (Tenth embodiment) When actual overspeed is detected by both rotation sensors A and B, the inverter control unit 82 according to this embodiment executes control in various modes, taking into consideration the cause of the overspeed.

[0144] 17, first, in step S10, MCUA and MCUB execute energization control in the positive torque mode. Next, if it is determined in step S201 that both rotation sensors A and B have detected overspeed, it is determined that overspeed has actually occurred.

[0145] If the difference in current between the MCUs is determined to be greater than a predetermined value in the next step S231, it is determined that the overspeed is caused by an abnormality in the MCU. Specifically, it is determined that the abnormality is occurring in the MCU through which the larger current is flowing. For example, if there is a discrepancy between the current sensor values ​​of MCUA and MCUB, it is assumed that there is an abnormality in at least one of the MCUs, which results in an inability to perform normal control and causes the overspeed. In other words, if both MCUs are normal and in the same control mode, there should be no discrepancy between the current sensor values.

[0146] If it is determined in step S231 that there is no discrepancy in the currents of the MCUs, and if it is determined in step S232 that both positive torque currents are smaller than the normal range, it is assumed that overspeed is occurring due to an external force. For example, if the propeller 20 is forcibly rotated due to an external factor such as a strong wind, feedback control should be performed to resolve the situation, and the current should decrease. However, it is considered that the overspeed has not yet been resolved.

[0147] If it is determined in step S231 that there is no deviation in the currents of the MCUs, and if it is determined in step S233 that both positive torque currents are larger than the normal range, there is a possibility that an abnormality has occurred in the MCU control command value output from the FCU 40. Since the multiple MCUs are independent of each other and it is extremely rare for an abnormality to occur in both at the same time, it is assumed that the overspeed is occurring because a common abnormal command value has been input to both MCUs.

[0148] If it is determined in step S231 that there is no deviation in the currents of the MCUs, and no abnormality is determined in either step S232 or S233, it is determined in step S244 that an overspeed of unknown cause has occurred.

[0149] If it is determined in step S201 that none of the rotation sensors have detected over-rotation, and if it is determined in step S202 that some of the rotation sensors have detected over-rotation, then in the following step S245, it is determined that an abnormality has occurred in the rotation sensor, as in step S221 of FIG. 16.

[0150] If the cause of the overspeed is identified in steps S241, S242, and S245, the motor rotation is decelerated in the following step S251 by controlling in the negative torque mode as in the various embodiments described above. If the cause of the overspeed is identified in step S243, the lock control shown in Fig. 6 and the like is executed in the following step S252 as in the previous step S95. Alternatively, all MCUs are put into stop mode as in step S601 of Fig. 5.

[0151] If the cause of over-rotation is identified in steps S241, S242, and S245, all MCUs may be set to stop mode or lock control mode in step S251 instead of controlling in negative torque mode in step S251.

[0152] (Eleventh embodiment) The ninth and tenth embodiments are based on the premise that one EPU 50 has multiple motor rotation sensors 52a, 52b. In contrast, this embodiment is based on the premise that one EPU 50 has one motor rotation sensor. In the control flow of FIG. 18 according to this embodiment, the processes of steps S201 and S244 in FIG. 17 are changed to steps S201A and S244A.

[0153] In the case where there is only one rotation sensor, if that rotation sensor does not detect overspeed, the determination of whether or not overspeed is actually occurring is not executed. Therefore, if overspeed is not detected in step S201A, the control of step S10 continues. On the other hand, even if overspeed is detected in step S201A, it is not possible to determine from that information alone whether overspeed is actually occurring or whether the overspeed is being falsely detected due to an abnormality in the rotation sensor. Therefore, in this embodiment, step S245 in FIG. 17 is omitted.

[0154] The processes of steps S241, S242, S243, etc., which estimate the location of the abnormality from the state of the current of each MCU, are the same as those in Fig. 17. However, in step S244A, which is executed when the MCU current is within the normal range, only one rotation sensor is considered to be abnormal, unlike step S244 in Fig. 17.

[0155] (Twelfth embodiment) In this embodiment, the inverter control unit 82 executes control assuming a case in which an over-speed detection is erroneously made when an over-speed detection does not actually occur, resulting in execution of deceleration control in negative torque mode. If an over-speed detection actually occurs, excessive output can be suppressed by executing deceleration control, and the vehicle attitude control of the eVTOL 10 should change toward stability. However, if deceleration control is executed in response to the above-described erroneous detection, the vehicle attitude control should change toward instability. Alternatively, the control amount of another EPU should fluctuate significantly to offset the influence of the deceleration control in response to the erroneous detection. Focusing on this point, in this embodiment, the state of vehicle attitude control after execution of deceleration control is used to estimate whether an over-speed detection actually occurs or whether there is an abnormality in the rotation sensor.

[0156] In the control flow of FIG. 19 according to this embodiment, the processes of steps S231 to S233 and S241 to S244 in FIG. 18 are changed to steps S251A, S251B, S251C, and S251D.

[0157] In the control flow of Figure 19, first, in step S10, the MCUA and MCUB execute energization control in positive torque mode. If overspeed is detected in the following step S201A, negative torque control similar to that in the various embodiments described above is executed in step S251 to decelerate motor rotation. Next, in step S251A, it is determined whether aircraft attitude control has become unstable. As described above, if aircraft attitude control has changed in an unstable direction or if other EPU control variables have fluctuated significantly, it is determined in step S251A that instability has occurred.

[0158] If it is determined in step S251A that instability has occurred, it is determined in the following step S251B that an abnormality has occurred in the rotation sensor. In other words, it is determined that the overspeed detected in the previous step S201A was due to a false detection. In the following step S252, locking control is executed, and if locking fails, all MCUs are put into stop mode.

[0159] In step S252, sensor values ​​other than the rotation sensor may be input to the control model, and propeller drive may be continued using model control. However, if stopping the propeller does not impede flight, the propeller may be locked instead of the control described above. When locking the propeller, the propeller rotation speed must be controlled to an extremely low rotation speed. However, because an abnormality has occurred in the rotation sensor, it is desirable to determine that the rotation speed is extremely low using the current value during negative torque mode.

[0160] If it is determined in step S251A that the engine is not unstable, it is determined in the following step S251C that an overspeed has actually occurred. In the following step S251D, the deceleration control in step S251 is continued.

[0161] (Thirteenth embodiment) The flight control system according to this embodiment includes an inverter control unit 82 (motor control device) and an FCU 40 (flight control device). Control commands output from the FCU 40 to the inverter control unit 82 include commands for flight mode and commands for function test mode. The flight mode is a mode used to control the EPU 50 in normal flight conditions. The function test mode is a mode used to check the operation of the EPU 50 while the eVTOL 10 is not flying and is placed on the ground.

[0162] When the FCU 40 commands the EPU 50 to execute various tests in the function test mode, the inverter control unit 82 of the EPU 50 that receives the command executes the process shown in FIG.

[0163] In step Sa10 shown in FIG. 20, power supply from the control power supply to the inverter control unit 82 is turned on. In the following step Sa11, the power supply state from the control power supply is checked. For example, it is checked whether the power supply state to the processor 83 and memory 84 is normal. It is also checked whether the power supply state to various sensors such as the propeller rotation sensor 52, motor rotation sensors 52a and 52b, voltage sensors, and current sensors is normal. In the following step Sa12, it is determined whether the check result in step Sa11 is normal. For example, if there is an abnormality such as a break or short circuit in the power supply path of the control power supply, or if various sensors are broken, it is determined that an abnormality has occurred in the control power supply system.

[0164] If the determination in step Sa12 is normal, the power supply from the drive power supply to the inverter 81 is turned on in the following step Sa13. In the following step Sa14, it is determined whether the voltage of the drive power supply is normal. If the determination in step Sa14 is normal, a function test in the function test mode is started in the following step Sa15. In the following step Sa16, the result of the function test is notified to the operator. If the determination in steps Sa12 and Sa14 is not normal but an abnormality is determined, the function test is stopped in step Sa17, and the details of the abnormality are notified to the operator in step Sa18.

[0165] When notifying the operator in steps Sa16 and Sa18, for example, the operator may be notified by displaying the abnormality details and test results on a display device mounted on the eVTOL 10. Alternatively, the operator may be notified using a test device connected to the FCU 40 or EPU 50. If an abnormality (including severe deterioration) that affects flight performance is detected, the next flight may be prohibited until the abnormality is resolved. Furthermore, if an abnormality or deterioration that does not affect the next flight is detected, a gradual notification may be given, such as displaying a warning but not prohibiting flight.

[0166] FIG. 21 is a time chart showing an example of changes in motor rotation speed when the above-mentioned functional test is performed. Note that the motor rotation speed refers to the number of times the motor shaft 65 rotates per unit time, and is synonymous with rotation speed. In the example shown in FIG. 21, first, during the first period T10, a test is performed to determine whether the feedback control that matches the actual rotation speed with the target rotation speed functions normally. In this test, the target rotation speed is changed in various patterns, and a test is performed to determine whether the actual rotation speed follows the change without delay. Furthermore, during the first period T10, it is confirmed that there are no abnormalities in the drive power supply or various sensors.

[0167] In the second period T20 following the first period T10, an operation check is performed to determine whether the overspeed protection control functions properly. In the example of Figure 21, the overspeed protection control whose operation is checked in the second period T20 includes the deceleration control, continuous drive control, and lock control, similar to the above-described embodiments. These deceleration control, continuous drive control, and lock control, which are expected to function properly in flight mode, are checked in order in the second period T20 of the function test mode.

[0168] The deceleration control is a control for decelerating the rotation of the propeller 20 in the negative torque mode when overspeed is detected. The continuous drive control is a control for continuing the rotation of the propeller 20 in the positive torque mode when a continuation request to continue driving the propeller 20 is output (command) from the FCU 40 after the overspeed is resolved. The lock control is a control for locking the propeller 20 in a non-rotatable state when a lock request is output (command) from the FCU 40 after the overspeed is resolved.

[0169] During the second period T20 in the function test mode, the FCU 40 outputs commands for simulation control and confirmation control to the EPU 50. Simulation control is a control that simulates an overspeed state using a judgment threshold Nth for the function test that is different from that used in flight mode. Confirmation control is a control that confirms whether overspeed protection control equivalent to that performed when overspeed is detected in flight mode can be performed normally. Confirmation control checks the operation of deceleration control, continuous drive control, and lock control.

[0170] <Simulated control> The dotted line in FIG. 21 indicates the judgment threshold Nth for determining whether the propeller 20 is in an overspeed state. The judgment threshold Nth in the first period T10 is the same value as the judgment threshold in flight mode. However, the judgment threshold Nth in the second period T20 is a dummy threshold for a functional test that is changed to a value lower than the judgment threshold in flight mode. The judgment threshold Nth in the first period T10 is set to a value sufficiently larger than the normal target rotation speed. In contrast, the dummy threshold is set to a value slightly larger than the normal target rotation speed. For example, the dummy threshold is set to a value less than half the judgment threshold Nth in the first period T10.

[0171] In the simulated control, at the start time ta of the second period T20, the dummy threshold is used and the rotation speed is intentionally increased. In other words, the feedback control that matches the actual rotation speed with the target rotation speed is stopped, and the actual rotation speed is increased while the target rotation speed is fixed within the normal range. This causes the actual rotation speed to exceed the dummy threshold, creating a simulated overspeed state. Note that after the actual rotation speed exceeds the dummy threshold, the stopped feedback control is resumed.

[0172] <Confirmation Control> After the simulated over-speed state is reached as described above, it is confirmed during the deceleration period T21 that the deceleration control is being executed normally. After the deceleration is completed normally during the deceleration period T21, it is confirmed during the continuous drive period T22 that the continuous drive control is being executed normally. After the feedback control is completed normally during the continuous drive period T22, it is confirmed during the lock period T23 that the lock control is being executed normally.

[0173] FIG. 22 shows the control procedure of the functional test mode executed by the inverter control unit 82. First, in step Sa20 of FIG. 22, it is determined whether or not the functional test mode is in progress. The functional test mode is started in step Sa15 of FIG. 20. In the following step Sa21, a judgment threshold for the functional test is set at the start time ta of the second period T20. That is, the judgment threshold Nth is changed to a dummy threshold. In the following step Sa22, increase control is executed to increase the actual rotation speed. In this increase control, feedback control is stopped while the target rotation speed and target torque are fixed within the normal range. As a result, the actual rotation speed exceeds the dummy threshold, creating a simulated overspeed state.

[0174] In the next step Sa23, it is determined whether the overspeed state is detected normally. If it is determined that the overspeed state is detected, in the next step Sa24, the control (deceleration control) that is executed when the overspeed state is detected is executed. In the next step Sa25, it is determined whether the overspeed state has been resolved based on whether the actual rotation speed has become smaller than the dummy threshold value.

[0175] If it is determined in step Sa25 that the overspeed has been resolved, it is assumed that deceleration control has been performed normally. Then, in the following step Sa26, a command signal for a continuation request to continue driving the propeller 20 is simulated. As a result, control that is performed when there is a continuation request (continuous drive control) is executed. In the following step Sa27, it is determined whether the propeller drive operation is normal. For example, it is determined whether the actual rotation speed follows changes in the target rotation speed without delay through feedback control, without falling into an overspeed state again.

[0176] If step Sa27 determines that the propeller is locked normally, it is assumed that the continuous drive control has been executed normally. Then, in the following step Sa28, a command signal for a lock request is generated simulated. As a result, the control that is executed when a lock request is made (lock control) is executed. In the following step Sa29, it is determined whether the propeller has been locked normally.

[0177] If the result of step Sa29 is normal, it is determined that the lock control has been executed normally. Then, in the following step Sa30, the operator is notified that the overspeed protection function is normal, in the same manner as in step Sa16.

[0178] If a simulated overspeed state cannot be created or if the deceleration control, continuous drive control, or lock control does not function normally, the function test is stopped in step Sa31. That is, if a negative determination is made in any of steps Sa23, Sa25, Sa27, and Sa29, the function test is stopped in step Sa31. In the following step Sa32, the operator is notified of the abnormality in the same manner as in step Sa18.

[0179] <Effects> The flight control system according to this embodiment includes an inverter control unit 82 and an FCU 40. The inverter control unit 82 includes the positive torque control unit, negative torque control unit, and overspeed detection unit described in the first embodiment. When the overspeed detection unit detects overspeed, overspeed protection control is executed, including at least deceleration control in negative torque mode. Therefore, similar to the first embodiment, when overspeed occurs, the motor 61 can be quickly decelerated by negative torque, and the overspeed state of the propeller 20 can be quickly resolved.

[0180] Furthermore, in this embodiment, the control commands from the FCU 40 include, in addition to commands in flight mode, commands in a function test mode that checks the operation of the EPU 50 while the eVTOL 10 is not flying but is on the ground. The commands in the function test mode include commands for simulation control and verification control. Simulation control is control that creates a simulated overspeed state using a judgment threshold for function testing that is different from that used in flight mode. Verification control is control that checks whether overspeed protection control equivalent to that performed when overspeed is detected in flight mode can be performed normally. This allows the operation of the overspeed protection control to be checked before flight, thereby preventing the overspeed protection control from malfunctioning during flight.

[0181] Furthermore, in this embodiment, in addition to checking the operation of the deceleration control, the operation of the continuous drive control is also checked after the overspeed is resolved. This allows the operation of the continuous drive control to be checked before flight, making it possible to prevent the continuous drive control from malfunctioning during flight.

[0182] Furthermore, in this embodiment, in the confirmation control, in addition to checking the operation of the deceleration control, the operation of the lock control is also checked after the overspeed is resolved. This allows the operation of the lock control to be checked before flight, making it possible to prevent the lock control from malfunctioning during flight.

[0183] Contrary to this embodiment, even if the target rotation speed is changed to a value higher than the dummy threshold while feedback control is being executed, it is possible to simulate an overspeed state. However, this results in an unlikely situation during flight, where an overspeed abnormality occurs even though the target rotation speed is being followed. In consideration of this, the simulation control of this embodiment simulates an overspeed state by stopping feedback control and increasing the actual rotation speed while fixing the target rotation speed within the normal range. This makes it possible to simulate a situation in which overspeed occurs even when the target rotation speed is within the normal range, allowing for a functional test that is closer to an actual overspeed state. This improves the reliability of pre-flight operation checks.

[0184] (Modification of the thirteenth embodiment) Various modifications of the thirteenth embodiment will be listed below.

[0185] In the thirteenth embodiment, the operation check is performed in the function test mode while the eVTOL 10 is not flying and is placed on the ground. In contrast, the operation check in the function test mode may be performed while the eVTOL 10 is flying. In this case, the EPU 50 is the target of the operation check when the eVTOL 10 is flying but does not require thrust from the propeller 20. For example, if different EPUs 50 are used for takeoff and cruising, there may be an EPU 50 that is not generating thrust depending on the flight situation. For such an EPU 50 that does not require thrust, the operation check in the function test mode may be performed during flight. However, even when the operation of an EPU 50 that does not require thrust is being checked in the function test mode, the EPU 50 that is generating thrust is maintained in normal flight mode.

[0186] In the example shown in FIG. 21, the determination threshold Nth is changed to a dummy threshold in the second period T20. Instead of changing the threshold in this way, a dummy rotation speed value may be provided. This also causes the dummy signal of the actual rotation speed to exceed the determination threshold Nth, thereby creating a simulated over-speed state. Furthermore, instead of changing the determination threshold Nth to a dummy threshold or changing the rotation speed to a dummy rotation speed, a dummy over-speed detection result may be provided. In other words, a dummy result signal indicating that the rotation speed has exceeded the determination threshold and an over-speed state has occurred may be output without determining whether or not it has exceeded the determination threshold. This can also be said to create a simulated over-speed state.

[0187] However, compared to providing a dummy rotation speed or a dummy signal of the overspeed detection result, changing to a dummy threshold value allows for a check of operation closer to the actual overspeed protection control in flight mode. Therefore, when creating a simulated overspeed state in the function test mode, it is desirable to change the judgment threshold value Nth to a dummy threshold value.

[0188] In the thirteenth embodiment, the overspeed protection control includes deceleration control, which is used to eliminate the overspeed state. However, it is not essential that the overspeed protection control includes deceleration control; the overspeed protection control may include at least one of deceleration control, stop control, and idling control, which may be used to eliminate the overspeed state.

[0189] That is, the stop control is control that stops the power supply to the motor 61. In this case, when a simulated overspeed is detected in the confirmation control, an operation check is performed to determine whether the power supply to the motor 61 is stopped normally. The idle operation control is control that drives the propeller 20 at a low rotation speed that does not cause the eVTOL 10 body, which is placed and stopped on the ground, to move. In this case, when a simulated overspeed is detected in the confirmation control, an operation check is performed to determine whether the propeller 20 switches to idle operation normally.

[0190] In the example of Fig. 21 according to the thirteenth embodiment, the operation check of the locking control is performed after the operation checks of the deceleration control and the continuous drive control. However, the operation check of the locking control may be performed after the operation check of the deceleration control without the operation check of the continuous drive control. In other words, an overspeed state is created by the simulation control, and then the operation check of the deceleration control and the locking control is performed. In this case, an overspeed state may be created separately from the simulation control and the verification control, and the operation check of the deceleration control and the continuous drive control may be performed.

[0191] The simulation control and verification control according to the thirteenth embodiment are preferably performed separately for each of the first inverter control unit 82A and the second inverter control unit 82B.

[0192] In the thirteenth embodiment, the feedback control executed in the flight mode and the function test mode is control for matching the actual rotation speed with the target rotation speed. Alternatively, the feedback control may be feedback control for matching the target torque with the actual torque. In this case, the feedback control that is stopped during the overspeed protection control in the second period T20 is torque-based feedback control. Even when torque-based feedback control is used, overspeed determination is performed based on the rotation speed. In other words, during the second period T20, the target torque remains within the normal range, feedback control is stopped, and the actual torque is increased. As a result, the rotation speed increases and exceeds the overspeed determination threshold. This allows overspeed determination and subsequent control operation to be confirmed.

[0193] (Other embodiments) The disclosure of this specification is not limited to the exemplified embodiments. The disclosure encompasses the exemplified embodiments and modifications thereto by those skilled in the art. For example, the disclosure is not limited to the combinations of parts and elements shown in the embodiments, and can be implemented in various modifications. The disclosure can be implemented in various combinations. The disclosure can have additional parts that can be added to the embodiments. The disclosure encompasses the omission of parts and elements from the embodiments. The disclosure encompasses the substitution or combination of parts and elements between one embodiment and another embodiment. The disclosed technical scope is not limited to the description of the embodiments. The disclosed technical scope is defined by the claims, and should be interpreted as including all modifications within the meaning and scope equivalent to the claims.

[0194] The EPU 50 according to each of the above embodiments has one motor device 60 and two MCUs, but may have one motor device 60 and three or more MCUs, or may have only one MCU. The EPU 50 according to each of the above embodiments may have both a mechanical locking device and an electrical locking device, or may have a configuration including either one of the devices, or may have a configuration including neither of the devices. In each of the above embodiments, the electric aircraft on which the EPU 50 is mounted may be an aircraft without fixed wings, or may be an unmanned aircraft.

[0195] As mentioned above, in each of the above embodiments, after overspeed detection, the MCU controls the aircraft to resolve the overspeed by entering stop mode, negative torque mode, or other modes. If this control changes the EPU output, the torque of the corresponding propeller changes, which could lead to a deterioration in the balance of the aircraft's attitude. Therefore, during the above control, it is desirable to change the EPU output corresponding to the other propeller so as to balance the aircraft's attitude.

[0196] The eVTOL 10 may be equipped with a mechanism for changing the pitch angle of the blades 21. In this case, the pitch angle may be changed after overspeed is detected. For example, it is desirable to change the pitch angle so that the torque required for rotation is increased, thereby promoting deceleration of the propeller. It is desirable to combine pitch control that changes the pitch angle in this way with negative torque mode to quickly resolve overspeed. Alternatively, if, even after overspeed is resolved, neither negative torque control nor propeller lock is possible due to an abnormality or other reason, the pitch angle may be controlled to minimize flight resistance, and then the MCU may be stopped.

[0197] In each of the above embodiments, the control content may be changed as follows depending on the degree of overspeed. For example, the inverter control unit 82 distinguishes between two levels of overspeed: severe overspeed and mild overspeed, and determines whether or not the overspeed has occurred. For example, severe overspeed is an overspeed that may cause damage to the shaft. For example, mild overspeed is an overspeed that does not cause damage but the rotation speed is outside the normal range. When severe overspeed occurs, it is desirable to prohibit further propeller drive and lock the propeller or stop all MCUs. As a specific example, when mild overspeed occurs, propeller drive may be permitted as needed after the overspeed is resolved.

[0198] In the seventh and eighth embodiments, a switching device capable of switching the connection combination between multiple MCUs and multiple batteries may be mounted on the eVTOL 10. In this case, when performing battery balance control to suppress SOC imbalance, SOC variation may be suppressed by switching the connection of an MCU in negative torque mode to a battery with a low SOC.

[0199] In each of the above embodiments, the power supply to the coil is stopped in the stop mode. However, in the stop mode, the power supply to the coil does not have to be completely stopped, and instead a minute current may be supplied to the coil. This minute current may be a current equivalent to that of idling. For example, a specific example of a minute current is a current sufficient to generate a positive torque smaller than the maximum static friction force required to start the propeller rotation.

[0200] In each of the above embodiments, the inverter control unit 82 is provided by a control system including at least one computer. The control system includes at least one processor that is hardware. If this processor is referred to as a hardware processor, the hardware processor can be provided by the following (i), (ii), or (iii).

[0201] (i) A hardware processor may be a hardware logic circuit. In this case, the computer is implemented by a digital circuit including a number of programmed logic units. The logic units may be, for example, gate circuits. The digital circuit may include a memory that stores at least one of a program and data. The computer may be implemented by an analog circuit. The computer may be implemented by a combination of a digital circuit and an analog circuit.

[0202] (ii) The hardware processor may be at least one processor core that executes a program stored in at least one memory. In this case, a computer is provided by at least one memory and at least one processor core. The processor core is referred to as a CPU, for example. The memory is also referred to as a storage medium. The memory is a non-transitory, tangible storage medium that non-temporarily stores "at least one of a program and data" that can be read by the processor.

[0203] (iii) The hardware processor may be a combination of the above (i) and (ii). (i) and (ii) may be located on different chips or on a common chip. That is, at least one of the means and functions provided by the inverter control unit 82 may be provided solely by hardware, solely by software, or a combination thereof.

[0204] (Disclosure of technical ideas) This specification discloses multiple technical ideas described in the following multiple clauses. Some clauses may be written in a multiple dependent form, with the subsequent clause referring to the preceding clause as an alternative. Furthermore, some clauses may be written in a multiple dependent form, referring to another multiple dependent clause. These multiple dependent clauses define multiple technical ideas.

[0205] (Technical thought 1) A motor control device applied to an electric aircraft (10) having a passenger compartment or a luggage compartment in a fuselage, which flies with a propeller (20) rotated by an electric motor (61), Among the rotational torques of the motor, a torque for accelerating or maintaining a rotation in a positive direction for flight is defined as a positive torque, and a torque for decelerating the rotation in the positive direction is defined as a negative torque; a positive torque control unit (S10) that controls the motor in a positive torque mode to exert the positive torque; a negative torque control unit (S41, S44) that controls the motor in a negative torque mode to exert the negative torque; an over-rotation detection unit (S20) that detects over-rotation of the propeller or the motor, When the overspeed detection unit detects the overspeed, the negative torque control unit executes control in the negative torque mode.

[0206] (Technical thought 2) the positive torque control unit and the negative torque control unit can independently control the energization state of each of a plurality of coils (63a, 63b) provided in the motor, A motor control device according to Technical Idea 1, wherein when the over-rotation is detected, control in the positive torque mode is prohibited, while at least one of the plurality of coils is controlled in the negative torque mode.

[0207] (Technical Thought 3) The motor control device according to Technical Idea 2, wherein when the over-rotation is detected, one of the coils is controlled in the negative torque mode, and the power supply to the remaining other coils is stopped.

[0208] (Technical Thought 4) The motor control device according to Technical Idea 3, wherein when the over-rotation is detected, the current flowing through the coil through which the maximum current has flowed is stopped.

[0209] (Technical Thought 5) The motor control device according to Technical Concept 2, wherein when the overspeed is detected, all of the coils are controlled in the negative torque mode.

[0210] (Technical Thought 6) A motor control device according to any one of technical ideas 2 to 5, wherein if there is a request to continue driving the propeller after the over-rotation is detected, at least one of the plurality of coils is controlled in the positive torque mode after the over-rotation is resolved.

[0211] (Technical Thought 7) The motor control device according to Technical Idea 6, wherein the coil through which the maximum current was flowing when the over-rotation was detected is prohibited from being controlled in the positive torque mode after the over-rotation is resolved, even if the continuation request is made.

[0212] (Technical Thought 8) A motor control device according to any one of technical ideas 2 to 7, wherein if there is a request to stop the propeller after the over-rotation is detected, the power supply to all of the coils is stopped after the over-rotation is resolved.

[0213] (Technical Thought 9) A lock control unit (S63, S71, S80) that locks the propeller in a non-rotatable state, A motor control device according to any one of technical ideas 1 to 8, wherein if a lock request is made after the over-rotation is detected, control by the lock control unit is executed after the over-rotation is resolved.

[0214] (Technical Thought 10) The lock control unit a feedback control unit (S63) that performs feedback control of power supply to the motor so that an actual rotation position of the propeller is stopped near a target rotation position after the rotation speed is reduced to a predetermined rotation speed in the negative torque mode; and an electric lock control unit (S71) that controls the supply of power to the motor in a lock mode that exerts a braking torque to prevent the propeller from rotating after stopping the motor near the target rotation position.

[0215] (Technical Thought 11) The lock control unit and a mechanical lock control unit (S80) that controls the supply of power to the motor so that a locking device (100) that mechanically locks the propeller by impeding its rotation is placed in a lockable position after the motor has been decelerated to a predetermined rotational speed in the negative torque mode.

[0216] (Technical Thought 12) The electric aircraft (10) is adapted to fly using a propeller (20) rotated by an electric motor (61), and has a passenger compartment or a luggage compartment in the fuselage. A motor control device (82) controls the drive of the motor. a flight control device (40) that gives control commands to the motor control device; A flight control system comprising: Among the rotational torques of the motor, a torque for accelerating or maintaining a rotation in a positive direction for flight is defined as a positive torque, and a torque for decelerating the rotation in the positive direction is defined as a negative torque; The motor control device includes: a positive torque control unit (S10) that controls the motor in a positive torque mode to exert the positive torque; a negative torque control unit (S41, S44) that controls the motor in a negative torque mode to exert the negative torque; an over-rotation detection unit (S20) that detects over-rotation of the propeller or the motor, When the overspeed detection unit detects the overspeed, an overspeed protection control including at least deceleration control in the negative torque mode is executed.

[0217] (Technical Thought 13) the control commands include a command in a flight mode that controls a normal flight state and a command in a function test mode that checks the operation of the motor control device while the electric aircraft is not flying and is placed on the ground; The commands in the functional test mode include: a command for simulated control to create a simulated over-rotation state using a judgment threshold or signal for a functional test different from that in the flight mode; A flight control system as described in Technical Idea 12, which includes a command for confirmation control to confirm whether the over-speed protection control equivalent to that performed when over-speed is detected in the flight mode can be performed normally.

[0218] (Technical Thought 14) The control commands include a command in a flight mode for controlling a normal flight state requiring the propeller thrust, and a command in a function test mode for performing an operation check on the motor control device during flight but when the propeller thrust is not required, The command for the functional test mode includes: a command for simulated control to create a simulated over-rotation state using a judgment threshold or signal for a functional test different from that in the flight mode; A flight control system as described in Technical Idea 12, which includes a command for confirmation control to confirm whether the over-speed protection control equivalent to that performed when over-speed is detected in the flight mode can be performed normally.

[0219] (Technical Thought 15) the motor control device executes lock control to lock the propeller in a non-rotatable state when a lock request is received in the flight mode; A flight control system as described in Technical Idea 13 or 14, wherein the overspeed protection control whose operation is confirmed by the confirmation control includes, in addition to the deceleration control, the lock control which is executed after the overspeed is resolved.

[0220] (Technical Thought 16) the motor control device, in the flight mode, when there is a request to continue driving the propeller after the overspeed is resolved, executes the continuous drive control in the positive torque mode; A flight control system described in any one of Technical Ideas 13 to 15, wherein the over-speed protection control whose operation is confirmed by the confirmation control includes, in addition to the deceleration control, the continuous drive control which is executed after the over-speed is resolved.

[0221] (Technical Thought 17) the motor control device executes stop control to stop power supply to the motor when there is a stop request to stop the propeller in the flight mode; A flight control system described in any one of Technical Ideas 13 to 16, wherein the over-speed protection control whose operation is confirmed by the confirmation control includes, in addition to the deceleration control, the stop control which is executed after the over-speed is resolved.

[0222] (Technical Thought 18) the motor control device performs feedback control of driving of the motor in the flight mode so that an actual rotation speed of the propeller or the motor matches a target rotation speed of the propeller or the motor; The flight control system described in any one of Technical Ideas 13 to 17, wherein the simulation control stops the feedback control and creates a simulated over-speed state by increasing the actual rotation speed while fixing the target rotation speed within a normal range.

[0223] (Technical philosophy A1) A motor control device applied to an electric aircraft (10) having a passenger compartment or a luggage compartment in a fuselage, which flies with a propeller (20) rotated by an electric motor (61), a first inverter control unit (82A) that converts DC power of a first battery (31A) into AC power and supplies the AC power to a first coil (63a) provided in the motor; a second inverter control unit (82B) that converts DC power of a second battery (31B) into AC power and supplies the AC power to a second coil (63b) provided in the motor; Equipped with Among the rotational torques of the motor, a torque for accelerating or maintaining a rotation in a positive direction for flight is defined as a positive torque, and a torque for decelerating the rotation in the positive direction is defined as a negative torque; each of the first inverter control unit and the second inverter control unit includes a positive torque control unit (S10) that controls the motor in a positive torque mode to generate the positive torque, and a negative torque control unit (S41, S44) that controls the motor in a negative torque mode to generate the negative torque; When the charging rate of the first battery is lower than the charging rate of the second battery by a predetermined amount or more, A motor control device wherein the second inverter control unit stops the energization of the second coil or executes the positive torque mode, and the first inverter control unit executes the negative torque mode so as to perform regenerative power generation in the first coil.

[0224] (Technical philosophy A2) the electric aircraft includes a plurality of the propellers, the motor that rotates a first propeller is a first motor (61A), and the motor that rotates a second propeller is a second motor (61B); the first battery is capable of distributing and supplying electric power to the first inverter control unit associated with the first motor and the first inverter control unit associated with the second motor; the second battery is capable of distributing and supplying electric power to the second inverter control unit associated with the first motor and the second inverter control unit associated with the second motor; When the amount of power supplied to the first coil associated with the second motor increases as a result of the second coil associated with the second motor being de-energized, the second inverter control unit associated with the first motor stops energization of the second coil or executes the positive torque mode; The motor control device according to Technical Idea A1, wherein the first inverter control unit associated with the first motor executes the negative torque mode so as to generate regenerative power in the first coil associated with the first motor.

[0225] According to the above-described technical concept A1, when the SOC of the first battery 31A is lower than the state of charge of the second battery 31B by a predetermined amount or more, the first battery 31A is charged by regenerative power generation in the first coil 63a. Meanwhile, the second battery 31B is discharged because power is consumed in the second coil 63b in the positive torque mode. Alternatively, the second coil 63b is deenergized. This reduces the SOC variation between the first battery 31A and the second battery 31B.

[0226] Here, there is a concern that, in a situation where the amount of power supplied to the first coil associated with the second motor increases as a result of de-energizing the second coil associated with the second motor, the SOC of the first battery 31A may fall significantly below the SOC of the second battery 31B. In consideration of this, in the above-described technical idea A2, in the above-described situation, the first inverter control unit associated with the first motor executes a negative torque mode to cause regenerative power generation in the first coil associated with the first motor. Therefore, the first battery 31A is charged by regenerative power generation in the first coil 63a associated with the first motor. Therefore, the SOC difference between the first battery 31A and the second battery 31B is suppressed.

[0227] It is also possible to combine technical idea A1 or technical idea A2 with at least one of technical ideas 1 to 11. For example, in technical idea 1 or technical idea A2, when propeller over-rotation is slowed down in negative torque mode, regenerative power generation may be performed in the negative torque mode to suppress SOC variations. [Explanation of symbols]

[0228] 10 eVTOL (electric aircraft), 100 locking device, 20 propeller, 40 FCU (flight control unit) 61 motor, 63a, 63b coils, 82 inverter control unit (motor control unit), S10 positive torque control unit, S20 over-speed detection unit, S41, S44 negative torque control unit, S63 lock control unit, S63 feedback control unit, S71 lock control unit, S71 electric lock control unit, S80 lock control unit, S80 mechanical lock control unit.

Claims

1. A motor control device applied to an electric aircraft (10) having a passenger compartment or a luggage compartment in a fuselage, which flies with a propeller (20) rotated by an electric motor (61), Among the rotational torques of the motor, a torque for accelerating or maintaining a rotation in a positive direction for flight is defined as a positive torque, and a torque for decelerating the rotation in the positive direction is defined as a negative torque; a positive torque control unit (S10) that controls the motor in a positive torque mode to exert the positive torque; a negative torque control unit (S41, S44) that controls the motor in a negative torque mode to exert the negative torque; an over-rotation detection unit (S20) that detects over-rotation of the propeller or the motor, When the overspeed detection unit detects the overspeed, the negative torque control unit executes control in the negative torque mode.

2. the positive torque control unit and the negative torque control unit can independently control the energization state of each of a plurality of coils (63 a, 63 b) provided in the motor, 2. The motor control device according to claim 1, wherein when the overspeed is detected, control in the positive torque mode is prohibited, and at least one of the plurality of coils is controlled in the negative torque mode.

3. 3. The motor control device according to claim 2, wherein when the overspeed is detected, one of the coils is controlled in the negative torque mode, and the other coils are de-energized.

4. 4. The motor control device according to claim 3, wherein when the overspeed is detected, the energization of the coil through which the maximum current has flowed is stopped.

5. 3. The motor control device according to claim 2, wherein when the overspeed is detected, all of the coils are controlled in the negative torque mode.

6. 6. The motor control device according to claim 2, wherein, when a request to continue driving the propeller is made after the over-rotation is detected, at least one of the plurality of coils is controlled in the positive torque mode after the over-rotation is resolved.

7. 7. The motor control device according to claim 6, wherein the coil through which the maximum current was flowing when the overspeed was detected is prohibited from being controlled in the positive torque mode after the overspeed is resolved, even if the continuation request is made.

8. 6. The motor control device according to claim 2, wherein, if there is a request to stop the propeller after the over-rotation is detected, the supply of current to all of the coils is stopped after the over-rotation is resolved.

9. A lock control unit (S63, S71, S80) that locks the propeller in a non-rotatable state, 6. The motor control device according to claim 1, wherein, when a lock request is made after the overspeed is detected, control by the lock control unit is executed after the overspeed is resolved.

10. The lock control unit a feedback control unit (S63) that performs feedback control of power supply to the motor so that an actual rotation position of the propeller is stopped near a target rotation position after the rotation speed is decelerated to a predetermined rotation speed in the negative torque mode; and an electric lock control unit (S71) that controls power supply to the motor in a lock mode in which a braking torque is exerted to prevent the propeller from rotating after the propeller has been stopped near the target rotation position.

11. The lock control unit a mechanical lock control unit (S80) that controls power supply to the motor so that a locking device (100) that mechanically locks the propeller by inhibiting rotation of the propeller is placed in a lockable position after the motor has been decelerated to a predetermined rotational speed in the negative torque mode.

12. a motor control device (82) applied to an electric aircraft (10) having a passenger compartment or a luggage compartment in a fuselage, which flies with a propeller (20) rotated by an electric motor (61), and which controls the drive of the motor; a flight control device (40) that gives control commands to the motor control device; A flight control system comprising: Among the rotational torques of the motor, a torque for accelerating or maintaining a rotation in a positive direction for flight is defined as a positive torque, and a torque for decelerating the rotation in the positive direction is defined as a negative torque; The motor control device includes: a positive torque control unit (S10) that controls the motor in a positive torque mode to exert the positive torque; a negative torque control unit (S41, S44) that controls the motor in a negative torque mode to exert the negative torque; an over-rotation detection unit (S20) that detects over-rotation of the propeller or the motor, When the overspeed detection unit detects the overspeed, an overspeed protection control including at least deceleration control in the negative torque mode is executed.

13. the control commands include a command in a flight mode that controls a normal flight state and a command in a function test mode that checks the operation of the motor control device while the electric aircraft is not flying and is placed on the ground; The commands in the functional test mode include: a command for simulated control to create a simulated over-rotation state using a judgment threshold or signal for a functional test different from that in the flight mode; 13. The flight control system according to claim 12, further comprising a command for confirmation control that confirms whether the overspeed protection control equivalent to that when overspeed is detected in the flight mode can be normally performed.

14. The control commands include a command in a flight mode for controlling a normal flight state requiring the propeller thrust, and a command in a function test mode for performing an operation check on the motor control device during flight but when the propeller thrust is not required, The command for the functional test mode includes: a command for simulated control to create a simulated over-rotation state using a judgment threshold or signal for a functional test different from that in the flight mode; 13. The flight control system according to claim 12, further comprising a command for confirmation control that confirms whether the overspeed protection control equivalent to that when overspeed is detected in the flight mode can be normally performed.

15. the motor control device executes lock control to lock the propeller in a non-rotatable state when a lock request is received in the flight mode; 15. The flight control system according to claim 13, wherein the overspeed protection control whose operation is confirmed by the confirmation control includes, in addition to the deceleration control, the lock control that is executed after the overspeed is resolved.

16. the motor control device executes the continuous drive control in the positive torque mode when there is a request to continue driving the propeller after the overspeed is resolved in the flight mode, 15. The flight control system according to claim 13, wherein the overspeed protection control whose operation is confirmed by the confirmation control includes, in addition to the deceleration control, the continuous drive control that is executed after the overspeed is resolved.

17. the motor control device executes stop control to stop power supply to the motor when there is a stop request to stop the propeller in the flight mode; 15. The flight control system according to claim 13, wherein the overspeed protection control whose operation is confirmed by the confirmation control includes, in addition to the deceleration control, the stop control that is executed after the overspeed is resolved.

18. the motor control device performs feedback control of driving of the motor in the flight mode so that an actual rotation speed of the propeller or the motor matches a target rotation speed of the propeller or the motor; 15. The flight control system according to claim 13, wherein the simulation control creates a simulated over-speed state by suspending the feedback control and increasing the actual rotation speed while fixing the target rotation speed within a normal range.

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