An integrated flywheel motor system and a control method thereof

Abstract

The application discloses an integrated flywheel motor system, which comprises a flywheel motor, a tail rotor motor, a separator, a clutch, a power module, a power battery, a flywheel motor controller, an ECU and a fuel tank; wherein the flywheel motor integrates the functions of a starter, a generator and a flywheel, and is connected with a transmission through the clutch; the engine is directly connected with the flywheel motor through a crankshaft; the flywheel motor is connected with the transmission through the clutch, and then connected with a main rotor; the tail rotor motor is directly powered by the power battery and connected with a tail rotor; the separator is connected with the engine and the flywheel motor under normal conditions, but will be opened and the connection with the engine will be cut off when the engine fails and the helicopter performs autorotation landing; the flywheel motor controller is connected with the ECU and the power module through signal lines; and a corresponding control method is also disclosed, which has the advantages of strong starting ability, large power generation and large system power density, and improves the safety of the helicopter.

Description

Technical Field

[0001] This invention relates to the field of aviation, and in particular to an integrated flywheel motor system for helicopters and its control method. Background Technology

[0002] With the development of aviation technology, multi-electrified helicopters have become a research hotspot. The traditional aviation piston engine starting / generator / flywheel system adopts a separate design, which has the following disadvantages: (1) The starter motor increases torque through gear reduction. In order to reduce weight, the design success rate is generally designed to just meet the engine starting requirements. The actual working engine speed range is relatively narrow, generally not exceeding 300 r / min, which makes it difficult to provide assistance to the engine and cannot meet the electric emergency landing requirements of helicopters; (2) The generator is connected to the crankshaft through a belt. The generator power output is difficult to exceed 3kW, which cannot meet the power requirements of multi-electrified engines; (3) The starter motor and generator are decoupled during the working time. There is waste during engine operation, and the structure is scattered and complex, which is no longer suitable for the space and weight reduction requirements of the aviation field. Therefore, an integrated flywheel motor system with a compact structure, light weight, and meeting the requirements for power and emergency landing is needed. Summary of the Invention

[0003] The present invention aims to solve the problems of the dispersed and complex structure of the traditional aviation piston engine starting / generating / flywheel system, which is not suitable for the aviation field's requirements for space and weight reduction, as well as its inability to meet the needs of electric power and emergency landing.

[0004] To address the aforementioned deficiencies or improvement needs of existing technologies, this invention specifically relates to an integrated flywheel motor system, comprising a flywheel motor, a tail rotor motor, a separator, a clutch, a power module, a power battery, a flywheel motor controller (FCU), an ECU, and a fuel tank. The flywheel motor integrates the functions of a starter, generator, and flywheel, and is connected to the transmission via a clutch. The engine is directly connected to the flywheel motor via a crankshaft. The flywheel motor is connected to the transmission via a clutch (the flywheel motor functions in different operating modes such as starting, generating electricity, and electric emergency landing), and is subsequently connected to the main rotor. The tail rotor motor is directly powered by the power battery and is connected to the tail rotor (the tail rotor motor is used to provide tail...). The propeller provides power to the helicopter for yaw control; the power module is connected to the flywheel motor and is responsible for power conversion and voltage regulation; the separator connects the engine and flywheel motor under normal conditions, but opens to disconnect from the engine during autorotation landing in case of engine failure; the flywheel motor controller (FCU) is connected to the ECU and power module via signal lines to control the entire system; the engine serves as the helicopter's power source, outputting mechanical energy through the crankshaft; the engine is a compression-ignition heavy oil piston type with rated speed and power; the power battery provides electrical energy to the entire flywheel motor system; the ECU is an electronic control unit responsible for controlling engine operation.

[0005] Furthermore, the clutch is used to control the mechanical connection between the flywheel motor and the rotor; when starting the engine, the clutch connects the flywheel motor and the gearbox; during an electric forced landing, the clutch disengages to prevent the engine from being dragged backward.

[0006] Furthermore, the power module includes a reversible PWM rectifier circuit, which is responsible for inversion and rectification voltage regulation; in electric mode, the power module is used as an inverter; in power generation mode, it outputs constant voltage DC power.

[0007] Furthermore, the PWM rectifier circuit includes three parallel single-phase half-bridge rectifier circuits. Each single-phase half-bridge rectifier circuit includes a power electronic switch, a diode, a winding inductor, a winding internal resistance, and a DC terminal capacitor. The power electronic switch includes an upper bridge switch and a lower bridge switch, used to control the positive and negative half-cycles of the AC side voltage. The winding inductor and winding internal resistance constitute the phase windings of the flywheel motor, used to store energy in motoring mode and release energy in generator mode.

[0008] Furthermore, the flywheel motor controller (FCU) controls the operating modes of the flywheel motor, including starting, power generation, and electric forced landing; the FCU achieves precise control of the flywheel motor through communication between the ECU (electronic control unit) and the FCU.

[0009] Furthermore, the flywheel motor comprises a rotor core, a stator core, permanent magnets, and a winding rotor structure. The flywheel motor employs an external rotor, a small length-to-diameter ratio external rotor structure, and a permanent magnet motor with protruding magnetic poles on the surface. The permanent magnets are tightly attached to the inner surface of the rotor; during high-speed rotation, centrifugal force strengthens the bond between the permanent magnets and the rotor, eliminating the need for additional measures to secure and protect the permanent magnets on the inner rotor. Finally, the external rotor structure provides better rotor cooling. In the heat dissipation design, the internal stator can be water-cooled, while the rotor, due to its increased surface area exposed to air, can achieve large-area effective air cooling.

[0010] Furthermore, the number of slots q per pole per phase of the permanent magnet motor is calculated according to the following formula, where Z is the number of slots, p is the number of pole pairs, and m is the number of phases;

[0011]

[0012] When q is an integer, it is an integer-slot motor. To obtain a sinusoidal voltage, an integer-slot motor uses short-pitch distributed windings. When q is a fraction, the motor is a fractional-slot motor, which has the inherent advantage of improving the electromotive force waveform. Fractional-slot motors generally use concentrated windings, that is, a pitch of 1, which can reduce the length of ineffective windings at the ends, reduce winding weight and resistance, and thus improve the power density and efficiency of the motor.

[0013] Increasing the number of pole pairs is beneficial to improving the power density of the motor, but it will increase the alternation frequency of the magnetic field, thereby increasing the core loss and eddy current loss. It will also place higher demands on the controller. Taking into account the characteristics of the flywheel motor, the slot-to-pole ratio of the fractional-slot concentrated winding is selected as 18 slots / 16 poles. Considering the winding process, the stator slots of the flywheel motor adopt sloping shoulder flat bottom slots.

[0014] The length of each turn of the winding is calculated using the following formula:

[0015]

[0016] In the formula, D o1 D is the stator outer diameter. i1 h is the stator inner diameter. j L is the stator yoke height, d is the length of the winding extending out of the core, and L is the length of the stator yoke height. ef This represents the effective length of the winding.

[0017] As another aspect of the present invention, a control method for an integrated flywheel motor system is also provided, comprising the following steps:

[0018] (1) When the ignition switch is turned on, the flywheel motor enters the starting mode, drags the engine to rotate to the idle speed, the engine ignites, the starting is completed, and the engine enters the idle speed.

[0019] (2) After entering idle speed, the flywheel motor enters the power generation mode. Subsequently, the helicopter goes through idle-warm-up and slow-speed operation. The flywheel motor not only supplies power to the electrical equipment, but also operates at SOC. <SOC high At the same time, the battery also needs to be charged;

[0020] (3) Once the helicopter reaches its rated speed, the battery is fully charged and ready for takeoff.

[0021] As the helicopter rotor pitch increases, the power required by the main rotor increases until the helicopter leaves the ground and enters ground effect hovering, at which point the tail rotor motor starts to work.

[0022] (4) When the helicopter takes off vertically, the power required by the main rotor exceeds the maximum power of the engine. The flywheel motor enters the electric assist mode to supplement the insufficient engine power. At this time, the battery also needs to supply power to the tail rotor motor.

[0023] (5) When the helicopter takes off normally, it begins to fly horizontally and climb at an angle, with the main rotor...

[0024] As the required power continues to increase, when the power required by the main rotor exceeds P... limt1 At this time, the flywheel motor enters sleep mode, the engine power is provided to the main rotor, and the battery supplies power to the tail rotor motor and other electrical equipment.

[0025] (6) Once the helicopter has taken off, if it needs to continue its rapid ascent, the main rotor needs to use...

[0026] As the power continues to increase and exceeds the engine's maximum power, the flywheel motor enters electric power assist mode to supplement the insufficient engine power. At this time, the battery also needs to supply power to the flywheel motor.

[0027] (7) After the helicopter enters forward flight mode, the power required by the main rotor increases with the increase of forward flight speed.

[0028] First decrease, then increase. When it falls below the engine's maximum power, the flywheel motor switches from electric assist mode to sleep mode, and the main rotor's power requirement continues to decrease. When the main rotor's power requirement is less than P... limt1 At this time, the flywheel motor enters the power generation mode and begins to charge the battery;

[0029] (8) The forward speed of the helicopter continues to increase. Then, the power required by the main rotor begins to increase again, and the previous actions are repeated.

[0030] (9) When the engine fails, disconnect the power connection between the engine and the flywheel motor, and the helicopter will enter...

[0031] Entering autorotation landing mode, at this time, if the battery SOC... <SOC high The flywheel motor enters the power generation mode, using the gravitational potential energy during descent to continue charging the battery. When the autorotation landing enters the instantaneous pitch-adding phase, the flywheel motor enters the electric forced landing mode, providing instantaneous auxiliary power to the main rotor and providing more lift to the helicopter to reduce its forward speed and descent rate.

[0032] Furthermore, in vertical takeoff mode, the output power of the flywheel motor is adjusted to provide sufficient lift; in normal takeoff mode, the flywheel motor is controlled to maintain a constant forward ratio and rotor efficiency.

[0033] In summary, compared with the prior art, the above-described technical solutions conceived by this invention can achieve the following beneficial effects:

[0034] (1) The integrated flywheel motor system and its control method of the present invention have stronger starting capabilities because the flywheel motor is directly mounted on the crankshaft and can directly drive the engine to idle speed.

[0035] It has a larger power generation capacity, reaching over 10kW, making pulse-type power assistance possible.

[0036] (2) The integrated flywheel motor system and its control method of the present invention greatly improve the power density of the system due to the integration of the starter, generator and flywheel;

[0037] (3) The integrated flywheel motor system and its control method of the present invention can assist the helicopter to rotate and land when the engine fails, thereby further improving the safety of the helicopter. Attached Figure Description

[0038] Figure 1 This is a schematic diagram of the overall structure of a preferred embodiment of the present invention;

[0039] Figure 2 This is a preferred embodiment of the PWM rectifier circuit diagram of the present invention;

[0040] In the diagram: 1-Engine, 2-Tail propeller motor, 3-Flywheel motor, 4-Power module, 5-Power battery, 6-Splitter, 7-Clutch, 8-Face gear, 9-ECU, 10-Flywheel motor controller FCU. Detailed Implementation

[0041] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0042] Please refer to Figure 1This invention relates to an integrated flywheel motor system, comprising an engine 1, a tail rotor motor 2, a flywheel motor 3, a power module 4, a power battery 5, a separator 6, a clutch 7, a flywheel motor controller 10, an ECU 9, and a fuel tank. The flywheel motor integrates the functions of a starter, generator, and flywheel, and is connected to the transmission via a clutch. The engine 1 is directly connected to the flywheel motor via a crankshaft. The flywheel motor, connected to the transmission via a clutch, functions in different operating modes such as starting, power generation, and electric emergency landing, and is thus connected to the main rotor. The tail rotor motor is directly powered by the power battery 5 and connected to the tail rotor. The tail rotor motor 2 provides power to the tail rotor. The system assists in yaw control of the helicopter; the power module is connected to the flywheel motor and is responsible for power conversion and voltage regulation; the separator connects the engine and flywheel motor under normal conditions, but will open to disconnect from the engine during autorotation landing in case of engine failure; the flywheel motor controller (FCU) is connected to the ECU and power module 4 via signal lines to control the entire system; engine 1 serves as the helicopter's power source, outputting mechanical energy through the crankshaft; the engine is a compression-ignition heavy oil piston type with rated speed and power; the power battery 5 provides electrical energy to the entire flywheel motor system; the ECU 9 is an electronic control unit responsible for controlling the engine's operation. The flywheel motor controller (FCU) 10 controls the flywheel motor's operating modes, including starting, power generation, and electric forced landing; the FCU achieves precise control of the flywheel motor through communication between the ECU and the FCU.

[0043] The clutch 7 is used to control the mechanical connection between the flywheel motor and the rotor; when starting the engine, the clutch connects the flywheel motor and the gearbox; during electric emergency landing, the clutch disconnects to prevent the engine from being dragged backward.

[0044] Please refer to Figure 2 As a preferred embodiment, the power module 4 includes a reversible PWM rectifier circuit, which is responsible for inversion and rectification voltage regulation; in electric mode, the power module is used as an inverter; in power generation mode, it outputs constant voltage DC power.

[0045] As a preferred embodiment, the PWM rectifier circuit includes three parallel single-phase half-bridge rectifier circuits. Each single-phase half-bridge rectifier circuit includes a power electronic switch, a diode, a winding inductor, a winding internal resistance, and a DC terminal capacitor. The power electronic switch includes an upper bridge switch and a lower bridge switch, used to control the positive and negative half-cycles of the AC side voltage. The winding inductor and winding internal resistance constitute the phase windings of the flywheel motor, used to store energy in motoring mode and release energy in generator mode.

[0046] Specifically, Figure 2In the diagram, La, Lb, and Lc represent the inductances of each phase winding of the flywheel motor, Ra, Rb, and Rc represent the internal resistances of each phase winding, and ua, ub, and uc represent the induced voltages of each phase winding. The inverter and rectifier share a single three-phase half-bridge, and since only capacitors are used on the DC side without additional inductors, the weight of the entire power module can be significantly reduced. In electric mode, the reversible PWM rectifier acts as the inverter, and the FCU controls the inverter to drive the flywheel motor and output power. When the flywheel motor operates as a starter, the clutch disconnects the mechanical connection with the rotor to ensure rapid engine start-up. When the flywheel motor performs an electric forced landing, a separator disconnects the mechanical connection with the engine to prevent the engine from being dragged backward and consuming energy. In generator mode, the FCU controls the reversible PWM rectifier to output constant voltage DC power to supply the tail rotor motor, other engine electrical units (oil pump, main fuel pump, coolant pump, fan, etc.), and to charge the power battery.

[0047] Unlike traditional motors that prioritize maximizing dynamic response speed while minimizing rotor inertia, flywheel motors require a certain amount of rotor inertia. A flywheel motor comprises a rotor core, stator core, permanent magnets, and winding rotor structure. It employs an external rotor with a small length-to-diameter ratio and a permanent magnet arrangement with protruding magnetic poles. The permanent magnets are tightly attached to the inner surface of the rotor; during high-speed rotation, centrifugal force strengthens the bond between the permanent magnets and the rotor, eliminating the need for additional measures to secure the permanent magnets in the inner rotor. Finally, the external rotor structure provides better rotor cooling. In the heat dissipation design, the internal stator can be water-cooled, while the rotor, with its increased surface area exposed to air, can achieve effective air cooling over a large area.

[0048] As a preferred option, the number of slots q per pole and per phase of the permanent magnet motor is calculated according to the following formula, where Z is the number of slots, p is the number of pole pairs, and m is the number of phases;

[0049]

[0050] When q is an integer, it is an integer-slot motor. To obtain a sinusoidal voltage, an integer-slot motor uses short-pitch distributed windings. When q is a fraction, the motor is a fractional-slot motor, which has the inherent advantage of improving the electromotive force waveform. Fractional-slot motors generally use concentrated windings, that is, a pitch of 1, which can reduce the length of ineffective windings at the ends, reduce winding weight and resistance, and thus improve the power density and efficiency of the motor.

[0051] Increasing the number of pole pairs is beneficial to improving the power density of the motor, but it will increase the alternation frequency of the magnetic field, thereby increasing the core loss and eddy current loss. It will also place higher demands on the controller. Taking into account the characteristics of the flywheel motor, the slot-to-pole ratio of the fractional-slot concentrated winding is selected as 18 slots / 16 poles. Considering the winding process, the stator slots of the flywheel motor adopt sloping shoulder flat bottom slots.

[0052] The length of each turn of the winding is calculated using the following formula:

[0053]

[0054] In the formula, D o1 D is the stator outer diameter. i1 h is the stator inner diameter. j L is the stator yoke height, d is the length of the winding extending out of the core, and L is the length of the stator yoke height. ef This represents the effective length of the winding.

[0055] Based on the aforementioned modular flywheel motor system, a control method for an integrated flywheel motor system is also involved, comprising the following steps:

[0056] (1) When the ignition switch is turned on, the flywheel motor enters the starting mode, drags the engine to rotate to the idle speed, the engine ignites, the starting is completed, and the engine enters the idle speed.

[0057] (2) After entering idle speed, the flywheel motor enters the power generation mode. Subsequently, the helicopter goes through idle-warm-up and slow-speed operation. The flywheel motor not only supplies power to the electrical equipment, but also operates at SOC. <SOC high At the same time, the battery also needs to be charged;

[0058] (3) Once the helicopter reaches its rated speed, the battery is fully charged and ready for takeoff.

[0059] As the helicopter rotor pitch increases, the power required by the main rotor increases until the helicopter leaves the ground and enters ground effect hovering, at which point the tail rotor motor starts to work.

[0060] (4) When the helicopter takes off vertically, the power required by the main rotor exceeds the maximum power of the engine. The flywheel motor enters the electric assist mode to supplement the insufficient engine power. At this time, the battery also needs to supply power to the tail rotor motor.

[0061] (5) When the helicopter takes off normally, it begins to fly horizontally and climb at an angle, with the main rotor...

[0062] As the required power continues to increase, when the power required by the main rotor exceeds P... limt1 At this time, the flywheel motor enters sleep mode, all engine power is provided to the main rotor, and the battery supplies power to the tail rotor motor and other electrical equipment; (P limt1 It is the difference between the engine's maximum power and the power required by the tail rotor.

[0063] (6) Once the helicopter has taken off, if it needs to continue its rapid ascent, the main rotor needs to use...

[0064] As the power continues to increase and exceeds the engine's maximum power, the flywheel motor enters electric power assist mode to supplement the insufficient engine power. At this time, the battery also needs to supply power to the flywheel motor.

[0065] (7) After the helicopter enters forward flight mode, the power required by the main rotor increases with the increase of forward flight speed.

[0066] First decrease, then increase. When it falls below the engine's maximum power, the flywheel motor switches from electric assist mode to sleep mode, and the main rotor's power requirement continues to decrease. When the main rotor's power requirement is less than P... limt1 At this time, the flywheel motor enters the power generation mode and begins to charge the battery;

[0067] (8) As the forward speed of the helicopter continues to increase, when μ > 0.154, the power required by the main rotor begins to rise again, and the previous actions are repeated.

[0068] (9) When the engine fails, disconnect the power connection between the engine and the flywheel motor, and the helicopter will enter...

[0069] Entering autorotation landing mode, at this time, if the battery SOC... <SOC high The flywheel motor enters power generation mode, utilizing gravitational potential energy during descent to continue charging the battery. When the autorotation landing enters the instantaneous thrust-addition phase, the flywheel motor enters electric emergency landing mode, providing instantaneous auxiliary power to the main rotor to generate more lift for the helicopter, reducing its forward speed and descent rate (SOC). low This indicates the lower limit of the battery's State of Charge (SOC). high (This indicates the maximum SOC value of the battery).

[0070] In vertical takeoff mode, the output power of the flywheel motor is adjusted to provide sufficient lift; in normal takeoff mode, the flywheel motor is controlled to maintain a constant forward ratio and rotor efficiency.

[0071] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A control method for an integrated flywheel motor system, characterized in that, comprising the following steps: (1) When the ignition switch is turned on, the flywheel motor enters the starting mode, drives the engine to rotate to the idle speed, the engine ignites to complete the start, and enters the idle state; (2) After entering the idle state, the flywheel motor enters the power generation mode. After that, the helicopter goes through the idle-warm-up and low-speed operating conditions. The flywheel motor not only supplies power to the electrical equipment, but also needs to charge the storage battery when the remaining state of charge SOC < SOChigh; (3) When the helicopter enters the rated speed, the storage battery is sufficiently charged and the helicopter is ready for takeoff. As the pitch of the helicopter blades increases, the required power of the main rotor increases until the helicopter lifts off and enters ground effect hover, and the tail rotor motor starts to work; (4) When the helicopter takes off vertically, the required power of the main rotor exceeds the maximum power of the engine, the flywheel motor enters the electric assist mode to supplement the insufficient power of the engine, and at this time the storage battery also needs to supply power to the tail rotor motor; (5) When the helicopter takes off normally, the helicopter starts to fly horizontally and climb obliquely, and the required power of the main rotor continues to increase. When the required power of the main rotor is greater than Plimt1, the flywheel motor enters the sleep mode, all engine power is supplied to the main rotor, and the storage battery supplies power to the tail rotor motor and other electrical equipment; (6) The helicopter completes takeoff. If the helicopter needs to continue to rise rapidly, the required power of the main rotor will continue to increase. After exceeding the maximum power of the engine, the flywheel motor enters the electric assist mode to supplement the insufficient power of the engine, and at this time the storage battery also needs to supply power to the flywheel motor; (7) After the helicopter enters the forward flight state, the required power of the main rotor increases with the increase of the forward flight speed, decreases first and then increases. After being less than the maximum power of the engine, the flywheel motor switches from the electric assist mode to the sleep mode. The required power of the main rotor continues to decrease, and when the required power of the main rotor is less than Plimt1, the flywheel motor enters the power generation mode and starts to charge the storage battery; (8) The forward flight speed of the helicopter continues to increase. When μ>0.154, the required power of the main rotor starts to rise again, and the previous actions are repeated; (9) When the engine fails, the power connection between the engine and the flywheel motor is cut off, and the helicopter enters the autorotation landing condition. At this time, if the SOC of the storage battery < SOChigh, the flywheel motor enters the power generation mode, and continues to charge the storage battery by using the gravitational potential energy during the descending process. When the autorotation landing enters the instantaneous pitch increase phase, the flywheel motor enters the electric forced landing mode, provides instantaneous auxiliary power to the main rotor, and provides more lift for the helicopter to reduce the forward flight speed and descending rate of the helicopter; The integrated flywheel motor system involved in the control method of the above-mentioned integrated flywheel motor system includes an engine (1), a tail rotor motor (2), a flywheel motor (3), a power module (4), a power battery (5), a separator (6), a clutch (7), a flywheel motor controller (10), an ECU (9), and a fuel tank; wherein, the flywheel motor integrates the functions of a starter, a generator, and a flywheel, and is connected to the transmission via a clutch; the engine (1) is directly connected to the flywheel motor via a crankshaft; the flywheel motor is connected to the transmission via a clutch, and then connected to the main rotor; the tail rotor motor is directly powered by the power battery (5) and is connected to the tail rotor; the power module is connected to the flywheel motor and is responsible for the conversion and voltage regulation of electrical energy; the separator connects the engine and the flywheel motor under normal conditions, but will open when the engine malfunctions and performs autorotation landing, cutting off the connection with the engine; the flywheel motor controller is connected to the ECU and the power module (4) via a signal line to realize the control of the entire system; the engine (1) serves as the power source of the helicopter, and the engine outputs mechanical energy through the crankshaft; The engine is a compression-ignition heavy oil piston type with rated speed and power; the power battery (5) provides electrical energy for the entire flywheel motor system; the ECU (9) is an electronic control unit responsible for controlling the operation of the engine.

2. The control method for the integrated flywheel motor system according to claim 1, characterized in that: The clutch (7) is used to control the mechanical connection between the flywheel motor and the rotor; when starting the engine, the clutch connects the flywheel motor and the gearbox; during electric emergency landing, the clutch disconnects to prevent the engine from being dragged backward.

3. The control method for the integrated flywheel motor system according to claim 1, characterized in that: The power module (4) includes a reversible PWM rectifier circuit, which is responsible for inversion and rectification and voltage regulation. In electric mode, the power module is used as an inverter. In power generation mode, it outputs constant voltage DC power.

4. The control method for the integrated flywheel motor system according to claim 3, characterized in that: The PWM rectifier circuit includes three parallel single-phase half-bridge rectifier circuits. Each single-phase half-bridge rectifier circuit includes a power electronic switch, a diode, a winding inductor, a winding internal resistance, and a DC terminal capacitor. The power electronic switch includes an upper bridge switch and a lower bridge switch, which are used to control the positive and negative half-cycles of the AC side voltage. The winding inductor and winding internal resistance constitute the phase windings of the flywheel motor, which are used to store energy in motor mode and release energy in generator mode.

5. The control method for the integrated flywheel motor system according to claim 1, characterized in that: The flywheel motor controller (10) controls the working mode of the flywheel motor, including starting, power generation and electric forced landing; the FCU achieves precise control of the flywheel motor through communication between the ECU and the FCU.

6. The control method for the integrated flywheel motor system according to claim 1, characterized in that: The flywheel motor comprises a rotor core, a stator core, permanent magnets, and a winding rotor structure. It employs an external rotor with a small length-to-diameter ratio and a permanent magnet motor with protruding magnetic poles. The permanent magnets are tightly attached to the inner surface of the rotor. During high-speed rotation, centrifugal force strengthens the bond between the permanent magnets and the rotor, eliminating the need for additional measures to secure the permanent magnets to the inner rotor. Finally, the external rotor structure provides better cooling. In the heat dissipation design, the internal stator uses water cooling, while the rotor, with its increased surface area exposed to air, achieves large-area effective air cooling.

7. The control method for the integrated flywheel motor system according to claim 6, characterized in that: The number of slots q per pole and per phase of a permanent magnet motor is calculated according to the following formula, where Z is the number of slots, p is the number of pole pairs, and m is the number of phases; ； When q is an integer, the motor is an integer-slot motor. In order to obtain a sinusoidal voltage, the integer-slot motor uses short-pitch distributed windings. When q is a fraction, the motor is a fractional-slot motor, which has the inherent advantage of improving the electromotive force waveform. Fractional slot motors use concentrated windings, which means the pitch is 1, reducing the length of ineffective windings at the ends, reducing winding weight and resistance, and thus improving the power density and efficiency of the motor. Increasing the number of pole pairs is beneficial for improving the power density of the motor, but it also increases the alternation frequency of the magnetic field, thereby increasing core losses and eddy current losses. Furthermore, it places higher demands on the controller. Considering the characteristics of flywheel motors, a fractional-slot concentrated winding with pole pairs is recommended. The ratio is selected as 18 slots / 16 poles; considering the winding process, the flywheel motor stator slots adopt sloping shoulder flat bottom slots; The length Lav per turn of the winding is calculated using the following formula: ； In the formula, Do1 is the stator outer diameter, Di1 is the stator inner diameter, hj is the stator yoke height, d is the length of the winding extending out of the iron core end, Lef is the effective length of the winding, and Z is the number of slots.

8. The control method for the integrated flywheel motor system according to claim 1, characterized in that, In vertical takeoff mode, the output power of the flywheel motor is adjusted to provide sufficient lift; in normal takeoff mode, the flywheel motor is controlled to maintain a constant forward ratio and rotor efficiency.

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