aircraft

Abstract

To provide an electric multi-rotor aircraft capable of ensuring thrust even when fragments are scattered by a rotor burst of an engine or generator.SOLUTION: An aircraft 10 includes: rotors 18 and 20, each driven by an electric motor 48; a PCU 42 that converts AC power output from a generator 40 into DC power; an inverter 50 that converts DC power supplied from the PCU 42 into AC power and outputs the AC power to the electric motor 48; a DC wire that connects the PCU 42 and the inverter 50; and an AC wire that connects the inverter 50 and the electric motor 48. The AC wire is disposed in a direction orthogonal to a direction in which rotation shafts of the generator 40 and a gas turbine 38 extend.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to aircraft. [Background technology]

[0002] Patent Document 1 below discloses an electric multi-rotor aircraft. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] US Patent Application Publication No. 2020 / 0115045 Summary of the Invention [Problem to be solved by the invention]

[0004] The electric multi-rotor aircraft disclosed in Patent Document 1 has multiple electric motors that drive multiple rotors. The electric motors are supplied with power from an electric energy source. The electric energy source includes an engine, a generator, a power storage device, and an energy management device.

[0005] If debris is scattered due to a rotor burst of the engine or generator, the scattered debris may damage the wiring connecting some of the electric motors to the electric energy source, causing a short circuit. In this case, power will not be supplied to the other electric motors, and thrust will not be secured.

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

[0007] One aspect of the present invention is an aircraft having a generator that generates electric power, an engine that drives the generator, an electric motor that operates on AC power, a rotor that is driven by the electric motor and generates thrust, a power control unit that converts the AC power output from the generator into DC power, an inverter that converts the DC power supplied from the power control unit into AC power and outputs the AC power to the electric motor, DC wiring that connects the power control unit and the inverter, and AC wiring that connects the inverter and the electric motor, wherein the AC wiring is arranged relative to the generator in a direction perpendicular to the direction in which a rotational shaft of the generator extends, or relative to the engine in a direction perpendicular to the direction in which a rotational shaft of the engine extends, and the DC wiring is not arranged. [Effects of the Invention]

[0008] According to the present invention, thrust can be ensured even if debris is scattered due to a rotor burst of the engine or generator. [Brief explanation of the drawings]

[0009] [Figure 1] Figure 1 is a schematic diagram of an aircraft. [Figure 2] FIG. 2 is a schematic diagram showing the configuration of the power supply system. [Figure 3] FIG. 3 is a diagram showing the wiring structure inside an aircraft. DETAILED DESCRIPTION OF THE INVENTION

[0010] [First embodiment] [Aircraft configuration] FIG. 1 is a schematic diagram of an aircraft 10. The aircraft 10 of this embodiment is an electric vertical take-off and landing aircraft (eVTOL aircraft). In the aircraft 10, a rotor is driven by an electric motor. In the aircraft 10, the rotor generates vertical thrust and horizontal thrust. The aircraft 10 is also a hybrid aircraft. The aircraft 10 has a generator and a battery as power sources for the electric motor. In the aircraft 10, power generated by the generator is supplied to the electric motor. When the power generated by the generator is insufficient to meet the required power, power stored in the battery is supplied to the electric motor.

[0011] The aircraft 10 has a fuselage 12. The fuselage 12 is provided with a cockpit, a cabin, etc. A pilot sits in the cockpit and pilots the aircraft 10. The cabin houses passengers, etc. The aircraft 10 may be piloted automatically.

[0012] The aircraft 10 has a front wing 14 and a rear wing 16. When the aircraft 10 moves forward, lift is generated on each of the front wing 14 and the rear wing 16.

[0013] The aircraft 10 has a boom 17L and a boom 17R. The boom 17L and the boom 17R are fixed to the front wing 14 and the rear wing 16. The boom 17L and the boom 17R extend in the fore-and-aft direction of the aircraft 10. The boom 17L is provided to the left of the center of gravity G of the fuselage 12, and the boom 17R is provided to the right of the center of gravity G of the fuselage 12.

[0014] The aircraft 10 has eight VTOL rotors 18. The eight VTOL rotors 18 are rotor 18La, rotor 18Lb, rotor 18Lc, rotor 18Ld, rotor 18Ra, rotor 18Rb, rotor 18Rc, and rotor 18Rd.

[0015] The rotors 18La, 18Lb, 18Lc, and 18Ld are attached to the boom 17L. The rotors 18Ra, 18Rb, 18Rc, and 18Rd are attached to the boom 17R.

[0016] The rotating shaft of each VTOL rotor 18 extends in the vertical direction of the airframe 12. The thrust of each VTOL rotor 18 is controlled by adjusting the rotor rotation speed and the blade pitch angle. Each VTOL rotor 18 is used during vertical takeoff, transition from vertical takeoff to cruising, transition from cruising to vertical landing, vertical landing, hovering in the air, etc. Each VTOL rotor 18 is also used during attitude control.

[0017] Lift thrust is generated by controlling the thrust of each VTOL rotor 18. Lift thrust refers to thrust in the vertical direction. Controlling the thrust of each VTOL rotor 18 causes a roll moment, a pitch moment, and a yaw moment to act on the airframe 12.

[0018] The aircraft 10 has two cruise rotors 20. The two cruise rotors 20 are rotor 20L and rotor 20R. Rotor 20L and rotor 20R are attached to the rear of the fuselage 12.

[0019] The rotating shaft of each cruise rotor 20 extends in the fore-and-aft direction of the airframe 12. The thrust of each cruise rotor 20 is controlled by adjusting the rotor rotation speed and blade pitch angle. Each cruise rotor 20 is used during transition from vertical takeoff to cruise, during cruise, and during transition from cruise to vertical landing, etc.

[0020] Cruise thrust is generated by controlling the thrust of each cruise rotor 20. Cruise thrust refers to thrust in the horizontal direction.

[0021] [Power supply system configuration] FIG. 2 is a schematic diagram showing the configuration of the power supply system 22. As shown in FIG.

[0022] The power supply system 22 includes a power supply circuit 24, two power generation units 26, and four batteries 28. The power supply system 22 supplies power to four drive modules 30. The two power generation units 26 refer to a first power generation unit 26a and a second power generation unit 26b. The four drive modules 30 refer to a first drive module 30a, a second drive module 30b, a third drive module 30c, and a fourth drive module 30d.

[0023] The power supply circuit 24 has a first power transmission line 32 and a second power transmission line 34. The first power transmission line 32 supplies power from the first power generation unit 26a to each of the first drive module 30a and the second drive module 30b. The second power transmission line 34 supplies power from the second power generation unit 26b to each of the third drive module 30c and the fourth drive module 30d. In this embodiment, the first power transmission line 32 and the second power transmission line 34 are not connected, but a circuit connecting the first power transmission line 32 and the second power transmission line 34 may be provided. In this case, the circuit may be provided with a contactor that switches between a state in which the first power transmission line 32 and the second power transmission line 34 are connected and a state in which the first power transmission line 32 and the second power transmission line 34 are disconnected.

[0024] Each drive module 30 is supplied with electric power stored in each battery 28 in addition to the electric power generated in each power generation unit 26 .

[0025] Each power generation unit 26 has a gas turbine 38, a generator 40, and a power control unit (hereinafter referred to as PCU) 42. The gas turbine 38 drives the generator 40, which then generates electricity. The PCU 42 converts AC power generated by the generator 40 into DC power and outputs it to the power supply circuit 24.

[0026] When starting the gas turbine 38, the PCU 42 converts the DC power supplied from the power supply circuit 24 into AC power and outputs it to the generator 40. The generator 40 operates using the power input from the PCU 42, and the generator 40 drives the gas turbine 38.

[0027] Each of the first drive module 30a and the third drive module 30c has two drive units 44 and one converter 46. Each of the second drive module 30b and the fourth drive module 30d has three drive units 44. Each drive unit 44 drives one of the VTOL rotors 18 or the cruise rotors 20.

[0028] Each drive unit 44 has an electric motor 48 and an inverter 50. The electric motor 48 is a three-phase motor. Each VTOL rotor 18 is connected to the output shaft of the corresponding electric motor 48. Each cruise rotor 20 is connected to the output shaft of the corresponding electric motor 48. The inverter 50 has a semiconductor switching element such as an IGBT (Insulated Gate Bipolar Transistor). The inverter 50 converts DC power supplied from the power supply circuit 24 into three-phase AC power and outputs it to the electric motor 48.

[0029] A controller (not shown) controls the semiconductor switching elements in the inverter 50. The controller is supplied with power from a low-voltage battery (not shown).

[0030] Converter 46 reduces the voltage of the DC power supplied from power supply circuit 24 and outputs it to a device that operates on DC power. An example of a device that operates on DC power is a cooling device that cools PCU 42, inverter 50, etc. The power whose voltage has been reduced by converter 46 may be supplied to the above-mentioned controller.

[0031] A battery 28 is connected to each drive module 30. The battery 28 is a high-voltage battery provided separately from the low-voltage battery described above. A circuit breaker 52 is provided between each battery 28 and each drive module 30. Each circuit breaker 52 has a contactor 52a, a contactor 52b, and a pre-charge circuit 52c. The contactor 52a is provided on the positive wiring connecting each battery 28 and each drive module 30. The contactor 52b is provided on the negative wiring connecting each battery 28 and each drive module 30. The pre-charge circuit 52c is provided in parallel with the contactor 52b. The pre-charge circuit 52c has a contactor 52d and a resistor 52e. A current sensor 54 is provided on the negative wiring connecting each battery 28 and each drive module 30.

[0032] Each interrupter device 52 switches between a conductive state and a cut-off state between each battery 28 and each drive module 30. The conductive state is a state in which the flow of current is not cut off by the interrupter device 52 and current flows. The cut-off state is a state in which the flow of current is cut off by the interrupter device 52.

[0033] Each interrupting device 52 may include only the contactor 52b and the precharge circuit 52c. The precharge circuit 52c may be provided in parallel with the contactor 52a. In this case, each interrupting device 52 may include only the contactor 52a and the precharge circuit 52c. Note that the power supply system 22 does not necessarily have to include the battery 28 and the interrupting device 52.

[0034] The power supply circuit 24 has a circuit breaker 56. The circuit breaker 56 is provided between the power generation unit 26 and the first power transmission line 32. The circuit breaker 56 has a contactor 56a and a contactor 56b. The contactor 56a is provided on the positive wiring connecting the power generation unit 26 and the first power transmission line 32. The contactor 56b is provided on the negative wiring connecting the power generation unit 26 and the first power transmission line 32. A current sensor 58 is provided between the contactor 56a and the first power transmission line 32. The circuit breaker 56 may have only one of the contactor 56a and the contactor 56b.

[0035] The circuit breaker 56 switches between a conductive state and a cut-off state between each power generating unit 26 and the first power transmission line 32 .

[0036] The power supply circuit 24 has two circuit breakers 60. Each circuit breaker 60 is provided between each drive module 30 and the first power transmission line 32. Each circuit breaker 60 has a contactor 60a and a contactor 60b. Each contactor 60a is provided on the positive wiring connecting each drive module 30 and the first power transmission line 32. Each contactor 60b is provided on the negative wiring connecting each drive module 30 and the first power transmission line 32. A current sensor 62 is provided between each contactor 60a and the first power transmission line 32.

[0037] Each interrupting device 60 may have only one of the contactor 60a and the contactor 60b. If the interrupting device 56 has only the contactor 56a, each interrupting device 60 preferably has only the contactor 60b. If the interrupting device 56 has only the contactor 56b, each interrupting device 60 preferably has only the contactor 60a.

[0038] Each of the circuit breakers 60 switches between a conductive state and a cut-off state between the corresponding drive module 30 and the first power transmission line 32 .

[0039] The power supply circuit 24 has a circuit breaker 64. The circuit breaker 64 is provided between the power generation unit 26 and the second power transmission line 34. The circuit breaker 64 has a contactor 64a and a contactor 64b. The contactor 64a is provided on the positive wiring connecting the power generation unit 26 and the second power transmission line 34. The contactor 64b is provided on the negative wiring connecting the power generation unit 26 and the second power transmission line 34. A current sensor 66 is provided between the contactor 64a and the second power transmission line 34. The circuit breaker 64 may have only one of the contactor 64a and the contactor 64b.

[0040] The circuit breaker 64 switches between a conductive state and a cut-off state between each power generating unit 26 and the second power transmission line 34 .

[0041] The power supply circuit 24 has two circuit breakers 68. Each circuit breaker 68 is provided between each drive module 30 and the second power transmission line 34. Each circuit breaker 68 has a contactor 68a and a contactor 68b. Each contactor 68a is provided on the positive wiring connecting the power generation unit 26 and the second power transmission line 34. Each contactor 68b is provided on the negative wiring connecting the power generation unit 26 and the second power transmission line 34. A current sensor 70 is provided between each contactor 68a and the second power transmission line 34.

[0042] Each interrupting device 68 may have only one of the contactor 68a and the contactor 68b. If the interrupting device 64 has only the contactor 64a, each interrupting device 68 preferably has only the contactor 68b. If the interrupting device 64 has only the contactor 64b, each interrupting device 68 preferably has only the contactor 68a.

[0043] Each of the breaker devices 68 switches between a conductive state and a cutoff state between each of the drive modules 30 and the second power transmission line 34 .

[0044] A diode 71 is provided between the contactor 60a of each breaker device 60 and the battery 28. The anode of each diode 71 is connected to the contactor 60a side, and the cathode is connected to the corresponding battery 28 side. Each diode 71 allows power to be supplied from the first power transmission line 32 to each battery 28. Each diode 71 prevents power from being supplied from each battery 28 to the first power transmission line 32. Each battery 28 is charged with power supplied from the first power generation unit 26a. Furthermore, if the first power transmission line 32 is short-circuited, the diode 71 prevents power from each battery 28 from flowing to the first power transmission line 32. As a result, even if the first power transmission line 32 is short-circuited, power can be supplied from each battery 28 to the drive unit 44 and the converter 46 in each drive module 30.

[0045] A transistor 72 is provided in parallel with each diode 71. When transistor 72 is on, diode 7 1 Electric power is supplied from each battery 28 to the first power transmission line 32, bypassing the main power line 10. The electric power supplied from each battery 28 operates the generator 40, and the gas turbine 38 can be started.

[0046] Furthermore, a diode 74 is provided between the contactor 68a of each breaker device 68 and the battery 28. The anode of each diode 74 is connected to the contactor 68a, and the cathode is connected to the corresponding battery 28. Each diode 74 allows power to be supplied from the second power transmission line 34 to the corresponding battery 28. Each diode 74 prevents power from being supplied from the corresponding battery 28 to the second power transmission line 34. Each battery 28 is charged with power supplied from the second power generation unit 26b. Furthermore, if the second power transmission line 34 is short-circuited, the power of each battery 28 is prevented from flowing to the second power transmission line 34. As a result, even if the second power transmission line 34 is short-circuited, power can be supplied from each battery 28 to the drive unit 44 and the converter 46 in each drive module 30.

[0047] A transistor 76 is provided in parallel with each diode 74. When the transistor 76 is on, power is supplied from each battery 28 to the second power transmission line 34, bypassing the diode 74. The power supplied from each battery 28 operates the generator 40, and can start the gas turbine 38.

[0048] [Wiring structure inside an aircraft] Fig. 3 is a diagram showing the wiring structure inside the aircraft 10. In Fig. 3, thick dashed lines indicate DC wiring, and thick solid lines indicate AC wiring.

[0049] The AC power generated by each generator 40 is converted into DC power by each PCU 42. The converted DC power is sent to the power supply circuit 24 through DC wiring.

[0050] An inverter 50 that controls the electric motor 48 that drives each VTOL rotor 18 is provided on the boom 17L or the boom 17R. DC power sent to the power supply circuit 24 is sent to each inverter 50 through DC wiring. This DC wiring passes through the inside of the fore wing 14, the boom 17L, and the boom 17R. AC power output from each inverter 50 is sent to each electric motor 48 through AC wiring. This AC wiring passes through the inside of the boom 17L and the boom 17R.

[0051] Inverters 50 that control the electric motors 48 that drive each cruise rotor 20 are provided inside the airframe 12. DC power sent to the power supply circuit 24 is sent to each inverter 50 through DC wiring. This DC wiring runs inside the airframe 12. AC power output from each inverter 50 is sent to each electric motor 48 through AC wiring. This AC wiring runs inside the airframe 12.

[0052] 3, each power generation unit 26 is disposed within the fuselage 12. Each power generation unit 26 is disposed rearward of the center of gravity G of the fuselage 12 in the longitudinal direction. In each power generation unit 26, the gas turbine 38, the generator 40, and the PCU 42 are disposed in this order from rear to rear in the longitudinal direction of the fuselage 12.

[0053] The rotor of each gas turbine 38 rotates about a rotation axis extending parallel to the longitudinal direction of the airframe 12. The rotor of each generator 40 rotates about a rotation axis extending parallel to the longitudinal direction of the airframe 12.

[0054] Area A indicated by a thin dotted line in FIG. 3 indicates an area that is perpendicular to the rotational axis of each gas turbine 38 and perpendicular to the rotational axis of the generator 40. Of the VTOL rotors 18, rotors 18Ld and 18Rd are disposed rearward of area A. Rotors 20L and 20R, which are cruise rotors 20, are disposed rearward of area A. Electric motors 48 that drive rotors 18Ld, 18Rd, 20L, and 20R are also disposed rearward of area A. In other words, the electric motors 48 that drive rotors 18Ld, 18Rd, 20L, and 20R are disposed on the side opposite to the side on which the PCU 42 is disposed for each gas turbine 38. It can also be said that the electric motors 48 that drive rotors 18Ld, 18Rd, 20L, and 20R are disposed on the side opposite to the side on which the PCU 42 is disposed for each generator 40. On the other hand, the inverter 50 that drives these electric motors 48 is disposed forward of the area A.

[0055] As a result, AC wiring is arranged in area A, but DC wiring is not arranged. If a rotor burst occurs in the gas turbine 38 or the generator 40, there is a high possibility that debris will be scattered within the range of area A. In this case, the scattered debris may cut the AC wiring arranged in area A, causing the AC wiring to be damaged and short-circuited.

[0056] The power supply system 22 has a short-circuit detection device (not shown) that detects a short circuit in the AC wiring connecting each inverter 50 and each electric motor 48. When a short circuit occurs in the AC wiring, the inverter 50 disconnects the short-circuited AC wiring from the power supply circuit 24.

[0057] [Action and effect] In the aircraft 10, even if thrust is lost in some of the VTOL rotors 18 and the cruise rotors 20, thrust must be ensured by the remaining rotors. Therefore, even if a rotor burst in the gas turbine 38 or the generator 40 causes a short circuit in some of the wiring that supplies power from each power generating unit 26 to each electric motor 48, it is necessary to maintain the supply of power to as many electric motors 48 as possible.

[0058] In the aircraft 10 of this embodiment, the AC wiring connecting the inverter 50 and the electric motor 48 is arranged in an area A where debris is likely to fly if the gas turbine 38 or generator 40 experiences a rotor burst.

[0059] For example, as shown in FIG. 3 , if an AC wiring connecting the inverter 50 and the electric motor 48 that drives the rotor 18Rd is short-circuited, the inverter 50 disconnects the short-circuited AC wiring from the power supply circuit 24. The disconnection between the short-circuited AC wiring and the power supply circuit 24 is performed by a semiconductor switching element in the inverter 50. A semiconductor switching element can operate at a higher speed than a contactor or the like. Therefore, if the AC wiring is interrupted, the semiconductor switching element can disconnect the AC wiring from the power supply circuit 24 in an extremely short time. This allows the power supply system 22 to maintain the supply of power to the other electric motors 48 and the converter 46.

[0060] It is conceivable to use a fuse, contactor, etc. to disconnect the shorted wiring from the power supply circuit 24. However, the inverter 50 is configured with switching elements and can operate faster than fuses, contactors, etc. Therefore, the time from when a short circuit in the wiring is detected until the shorted wiring and the power supply circuit 24 are disconnected can be shortened.

[0061] The present invention is not limited to the above-described embodiment, and various configurations can be adopted without departing from the gist of the present invention.

[0062] [Inventions Obtained from the Embodiments] The invention that can be understood from the above embodiment will be described below.

[0063] In an aircraft (10) having a generator (40) that generates electric power, an engine (38) that drives the generator, an electric motor (48) that operates on AC power, a rotor (18, 20) that is driven by the electric motor and generates thrust, a power control unit (42) that converts AC power output from the generator into DC power, an inverter (50) that converts DC power supplied from the power control unit into AC power and outputs the AC power to the electric motor, DC wiring that connects the power control unit and the inverter, and AC wiring that connects the inverter and the electric motor, the AC wiring is arranged relative to the generator in a direction perpendicular to the direction of extension of the generator's rotational axis, or relative to the engine in a direction perpendicular to the direction of extension of the engine's rotational axis, and the DC wiring is not arranged. This ensures thrust even in the event of a rotor burst of the engine or the generator.

[0064] In the aircraft described above, the electric motor may be disposed on the opposite side of the generator or the engine from the side on which the power control unit is disposed in relation to the direction in which the rotation shaft of the generator or the engine extends, thereby ensuring thrust even in the event of a rotor burst in the engine or the generator. [Explanation of symbols]

[0065] 10...Aircraft 18, 20...Rotor 38...Gas turbine (engine) 40...Generator 42...Power control unit (PCU) 48...Electric motor 50...Inverter

Claims

1. A generator that generates electricity; an engine that drives the generator; an electric motor that operates on AC power; a rotor driven by the electric motor to generate thrust; a power control unit that converts AC power output from the generator into DC power; an inverter that converts DC power supplied from the power control unit into AC power and outputs the AC power to the electric motor; a DC wiring that connects the power control unit and the inverter; AC wiring connecting the inverter and the electric motor; An aircraft having: the generator is disposed such that a rotation axis of the generator extends along a longitudinal direction of a fuselage of the aircraft, the engine is disposed so that a rotation axis of the engine extends along the front-rear direction of the airframe, the DC wiring connecting the power control unit and the inverter is not arranged in a predetermined portion, but the AC wiring connecting the inverter and the electric motor is arranged, an aircraft, wherein the predetermined portion is a portion of the generator body located in a direction perpendicular to the rotation axis of the generator, or a portion of the engine body located in a direction perpendicular to the rotation axis of the engine.

2. 2. The aircraft of claim 1, an electric motor disposed on the opposite side of the generator or the engine from the side on which the power control unit is disposed in relation to the generator or the engine in a direction in which the rotation shaft of the generator or the engine extends;

3. An aircraft as claimed in claim 1 or 2, The aircraft further includes a boom extending in a longitudinal direction of the aircraft, the inverter and the electric motor are provided on the boom, the AC wiring connecting the inverter and the electric motor passes through the inside of the boom, the predetermined portion overlaps with the AC wiring connecting the inverter and the electric motor in a longitudinal direction of the aircraft.

4. An aircraft as claimed in claim 3, The aircraft further includes wings extending laterally from the fuselage of the aircraft, the wing overlaps with the AC wiring connecting the inverter and the electric motor in the longitudinal direction of the aircraft.

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