An anti-reverse electrical system for rotary-wing unmanned aerial vehicles and its design method

Abstract

This invention discloses an anti-reverse rotation electrical system for rotary-wing unmanned aerial vehicles (UAVs), comprising a power module, a UAV flight control system, a rotor motor, an electronic speed controller (ESC) module, and a shorting electrical device. The shorting electrical device includes a buffer circuit, a power supply, a drive circuit, and a power transistor. The buffer circuit receives switching signals from the UAV flight control system and also drives the power transistor. The power supply powers the drive circuit, which in turn drives the power transistor, which specifically withstands the current from the reverse rotation of the rotor motor. A chip within the buffer circuit drives the power transistor, providing driving capability. This invention solves the problem of rotor blade reversal in rotary-wing UAVs under high drop speeds, enabling rapid and reliable starting of the UAV under such conditions.

Description

Technical Field

[0001] This invention belongs to the field of aircraft propulsion system technology, specifically relating to an anti-reverse electrical system for rotary-wing unmanned aerial vehicles and its design method. Background Technology

[0002] With the trend towards systematization, intelligence, and clustering in weaponry, unmanned aerial vehicles (UAVs) are widely used in military and civilian fields due to their advantages such as miniaturization, low cost, and convenience. Compared to fixed-wing UAVs, rotary-wing UAVs possess the ability to hover in place and remain airborne for extended periods, enabling them to perform specific tasks such as long-duration precision reconnaissance, pinpoint jamming, and precision strikes. As the core component of a UAV, the power system directly affects its flight time, stability, and reliability. Electric propulsion systems, with their advantages of simple structure, large payload, fast control response, and environmental friendliness, are widely used in small UAVs. The rotor, as the core output component of the electric propulsion system, needs to be lightweight, high-strength, and highly efficient. Furthermore, for certain specific missions, rotary-wing UAVs need to start rapidly under high descent speeds. Due to the high descent wind speed, the rotor is easily blown around by the high-speed wind, and the blades will quickly reverse to an extremely high speed. The large back electromotive force generated by this extremely high reverse speed can damage the power transistors of the electronic speed controller (ESC), preventing the rotor motor from starting normally in the air. Therefore, anti-rotor reversal in the power system of rotary-wing UAVs is a key problem that urgently needs to be solved in this field. Summary of the Invention

[0003] To address the issue of rotor blades being blown backwards by wind during high descent speeds in rotorcraft drones, and to prevent back electromotive force from damaging the power transistors of the electronic speed controller (ESC) and causing the motor to fail to start normally in the air, this invention provides an anti-reverse rotation electrical system and its design method for rotorcraft drones. Primarily, it adds a three-phase short-circuit electrical device to the existing rotor power system. This device is independently controlled by the flight control system. Applying this system before the rotorcraft drone's rapid descent and start-up generates a considerable no-load current in the rotor motor. The large electromagnetic torque generated by this current balances the load caused by the high-speed wind, thus preventing the rotor blades from rotating backwards and burning out the ESC. Furthermore, it provides a good starting environment for the rotorcraft drone's positionless (without position sensors) start-up.

[0004] To achieve the above objectives, the present invention provides the following method:

[0005] An anti-reverse electrical system for a rotary-wing unmanned aerial vehicle (UAV) includes a power module, a UAV flight control system, a rotor motor, and an electronic speed controller (ESC) module. Its distinguishing feature is that it also includes...

[0006] The short-circuit electrical device includes a buffer circuit, a power supply, a drive circuit, and a power transistor. The buffer circuit receives a switching signal sent by the UAV flight control system and also drives the power transistor. The power supply supplies power to the drive circuit, which drives the power transistor. The power transistor specifically bears the current of the rotor motor reversing. The buffer circuit contains a chip whose function is to drive the power transistor and has driving capability.

[0007] The short-circuit electrical device is connected to the rotor motor through a switching circuit. When it receives an open signal from the UAV flight control system through the buffer circuit, the short-circuit electrical device short-circuits the three phases of the rotor motor and enters the working state. When it receives an off signal from the UAV flight control system through the buffer circuit, the short-circuit electrical device disconnects the three phases of the rotor motor, allowing the rotor motor to be normally controlled by the ESC.

[0008] The power module supplies power to the ESC module;

[0009] The UAV flight control system is equipped with two independent communication interfaces, which are respectively connected to the ESC module and the short-circuit electrical device.

[0010] The ESC module controls the rotor motor via control signals sent from the UAV flight control system.

[0011] Furthermore, the rotor motor, the shorting electrical device, and the ESC module are also n in number, where n is a natural number that is not zero; each shorting electrical device and each ESC module are connected to a rotor motor.

[0012] Furthermore, the rotor motor interface is split into two paths using a changeover switch, one of which is connected to the electronic speed control module, and the other is connected to the short-circuit electrical device.

[0013] Furthermore, the short-circuiting electrical device adopts an integrated design, integrating n short-circuiting modules into the same PCB, which can simultaneously short-circuit n motors.

[0014] This invention also provides a design method for an anti-reverse electrical system for a rotary-wing unmanned aerial vehicle, comprising the following steps:

[0015] Based on the maximum wind speed during the descent of the rotorcraft drone in the actual application scenario, and combined with the aerodynamic performance parameters of the rotor blades, the rotor reversal load torque T is determined. e Alternatively, the reverse load torque T at the maximum wind speed during rotor descent can be directly tested in a rotor wind tunnel. e ;

[0016] The required rated current I is calculated based on the torque formula. q Size, the formula is as follows:

[0017]

[0018] Calculate the required rated voltage U based on the motor's phase resistance R and the tube voltage drop. e The formula is as follows:

[0019] U e =I q R

[0020] According to the required back potential U e and magnetic flux linkage parameter Ψ f The rotational speed w is calculated using the following formula:

[0021]

[0022] According to the back electromotive force U e and current I q Select the power transistor's withstand voltage and current parameters to design the circuit for short-circuiting electrical devices;

[0023] Based on the above design results, the short-circuit electrical device was manufactured, and the anti-reverse electrical system of the rotary-wing UAV was installed. Further testing and commissioning of the flight control system and rotor motor were completed.

[0024] Compared with the prior art, the above-described technical solutions conceived in this invention can achieve the following beneficial effects:

[0025] This solution addresses the problem of rotor blade reversal in rotary-wing UAVs under high fall speeds, enabling rapid and reliable start-up of rotary-wing UAVs under such conditions. By utilizing independent short-circuit electrical devices and an independent control mode, it not only solves the control coupling problem and achieves a simplified design, but also does not modify the original power system's overall structure or control mode. Furthermore, this design method has strong engineering application value, enabling rotor anti-reversal design even when the original power system's ESC algorithm is unknown. Generally, ESC algorithms are not disclosed as core technologies, thus bypassing this technical barrier. Attached Figure Description

[0026] Figure 1 This is a schematic block diagram showing the connection between the short-circuit electrical device of the present invention and the UAV power system (including 1-power module, 2-UAV flight control system, 21-control signal, 3-rotor motor, 4-Electronic speed controller module, 5-short-circuit electrical device). The diagram shows four rotor motors - motors 1, 2, 3, and 4, and four electronic speed controller modules - electronic speed controllers 1, 2, 3, and 4.

[0027] Figure 2 This is a circuit connection diagram of the short-circuit electrical device of the system of the present invention;

[0028] Figure 3 This is a frontal view of the rotor motor, the object controlled by the system of the present invention.

[0029] in: Figure 1 In the diagram, q and d represent coordinate axes, and w is the angular velocity (rotation speed); the q-axis current is the effective torque current, while the d-axis current is not the effective torque current, and 31 represents the coil of the rotor motor;

[0030] Figure 2 There are four short-circuit electrical devices that are connected to the four rotor motors through a switching circuit, 51-buffer circuit, 52-power supply, 53-drive circuit, and 54-power transistor;

[0031] Figure 3 The UAV power system includes 1-power module, 2-UAV flight control system, 21-control signal, 3-rotor motor, 4-electronic speed controller module, and 5-short-circuit electrical device. The figure shows four rotor motors - motors 1, 2, 3, and 4, and four electronic speed controller modules - electronic speed controllers 1, 2, 3, and 4. Detailed Implementation

[0032] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0033] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. The following embodiments are merely illustrative and do not constitute a limitation of the present invention.

[0034] This embodiment provides an anti-reverse electrical system for a rotary-wing unmanned aerial vehicle, such as... Figure 1 As shown, it includes a power module, a drone flight control system, rotor motors, an ESC module, and also includes...

[0035] Short-circuit electrical devices, such as Figure 2 As shown, the short-circuit electrical device includes a buffer circuit, a power supply, a drive circuit, and a power transistor. The buffer circuit receives the switching signal sent by the UAV flight control system. The buffer circuit is also used to drive the power transistor. The power supply supplies power to the drive circuit, and the drive circuit drives the power transistor. The power transistor specifically bears the current of the rotor motor reversing. The buffer circuit contains a chip whose function is to drive the power transistor and has driving capability.

[0036] The short-circuit electrical device is connected to the rotor motor through a switching circuit. When it receives an open signal from the UAV flight control system through the buffer circuit, the short-circuit electrical device short-circuits the three phases of the rotor motor and enters the working state. When it receives an off signal from the UAV flight control system through the buffer circuit, the short-circuit electrical device disconnects the three phases of the rotor motor, allowing the rotor motor to be normally controlled by the ESC.

[0037] The power module supplies power to the ESC module;

[0038] The UAV flight control system is equipped with two independent communication interfaces, which are respectively connected to the ESC module and the short-circuit electrical device.

[0039] The ESC module controls the rotor motor via control signals sent from the UAV flight control system.

[0040] The short-circuit electrical device control method connects to the reserved interface of the UAV flight control system via a signal line. It does not share the original control interface of the ESC module. The flight control system directly and independently controls the short-circuit electrical device, thereby controlling the short-circuit of the rotor motor. The short-circuit characteristic is used to achieve the purpose of preventing the rotor blades from reversing.

[0041] During the rapid descent of the rotorcraft drone at high landing speed and before it starts, the drone flight control system sends a command (high level) to the short-circuit electrical device to make it conduct (circuit closed), thus short-circuiting the motor. When it needs to start, the drone flight control system sends a command (low level) to make the short-circuit electrical device close (circuit open) and quickly switches the control mode back to the normal control ESC mode.

[0042] The rotor motor, shorting electrical device, and ESC module are also provided in n quantities, where n is a non-zero natural number. Each shorting electrical device and each ESC module are connected to a rotor motor. The shorting electrical device can be used in independent shorting control schemes designed under conditions where it is difficult to improve the original power system. This embodiment is applied to quadcopter UAVs and can be extended to tricopter, hexacopter, octocopter, and other rotor UAVs.

[0043] The rotor motor controlled by the short-circuited electrical device is a permanent magnet synchronous motor; its schematic diagram is attached. Figure 3 .

[0044] The rotor motor interface uses a changeover switch to split the current into two paths, one of which is connected to the ESC module and the other is connected to the short-circuit electrical device.

[0045] The short-circuiting electrical device adopts an integrated design, integrating n short-circuiting modules into the same PCB, which can simultaneously short-circuit n motors. In this embodiment, n = 4.

[0046] The working principle of the system of this invention is as follows: When the rotor motor is in the generating state, the generator produces a large current through three-phase short-circuiting, which in turn generates a large electromagnetic torque, achieving load electromagnetic balance. The working modes of the short-circuiting device are mainly on and off. On means fully opening to short-circuit the three phases, and off means disconnecting the circuit to cancel the three-phase short-circuit function, allowing the power system to be normally controlled by the ESC.

[0047] This embodiment also provides a design method for an anti-reverse electrical system for a rotary-wing unmanned aerial vehicle, including the following steps:

[0048] Based on the maximum wind speed during the descent of the rotorcraft drone in the actual application scenario, and combined with the aerodynamic performance parameters of the rotor blades, the rotor reversal load torque T is determined. e Alternatively, the reverse load torque T at the maximum wind speed during rotor descent can be directly tested in a rotor wind tunnel. e ;

[0049] The required rated current I is calculated based on the torque formula. q Size, the formula is as follows:

[0050]

[0051] Calculate the required rated voltage U based on the motor's phase resistance R and the tube voltage drop. e The formula is as follows:

[0052] U e =I q R

[0053] According to the required back potential U e and magnetic flux linkage parameter Ψ f The rotational speed w is calculated using the following formula:

[0054]

[0055] According to the back electromotive force U e and current I q Select the power transistor's withstand voltage and current parameters to design the circuit for short-circuiting electrical devices;

[0056] Based on the above design results, the short-circuit electrical device was manufactured, and the anti-reverse electrical system of the rotary-wing UAV was installed. Further testing and commissioning of the flight control system and rotor motor were completed.

Claims

1. An anti-reverse electrical system for a rotary-wing unmanned aerial vehicle (UAV), comprising a power module, a UAV flight control system, a rotor motor, and an electronic speed controller (ESC) module, characterized in that... Also includes A short-circuit electrical device is provided, comprising a buffer circuit, a power supply, a drive circuit, and a power transistor. The buffer circuit receives a switching signal from the UAV flight control system and is also used to drive the power transistor. The power supply provides power to the drive circuit, and the drive circuit drives the power transistor. The power transistor specifically bears the current of the rotor motor reversing. The short-circuit electrical device is connected to the rotor motor through a switching circuit. When it receives an open signal from the UAV flight control system through the buffer circuit, the short-circuit electrical device short-circuits the three phases of the rotor motor and enters the working state. When it receives an off signal from the UAV flight control system through the buffer circuit, the short-circuit electrical device disconnects the three phases of the rotor motor, allowing the rotor motor to be normally controlled by the ESC. The power module supplies power to the ESC module; The UAV flight control system is equipped with two independent communication interfaces, which are respectively connected to the ESC module and the short-circuit electrical device. The ESC module controls the rotor motor via control signals sent from the UAV flight control system.

2. The anti-reverse electrical system for rotary-wing unmanned aerial vehicles according to claim 1, characterized in that... The rotor motor, the shorting electrical device, and the ESC module are also n in number, where n is a non-zero natural number; one of the shorting electrical devices and one of the ESC modules are respectively connected to one rotor motor.

3. The anti-reverse electrical system for rotary-wing unmanned aerial vehicles according to claim 2, characterized in that... The rotor motor interface is split into two paths by a changeover switch, one of which is connected to the ESC module and the other is connected to the short-circuit electrical device.

4. The anti-reverse electrical system for a rotary-wing unmanned aerial vehicle according to any one of claims 1-3, characterized in that... The short-circuit electrical device adopts an integrated design, integrating n short-circuit modules into the same PCB, which can short-circuit n motors simultaneously.

5. A design method for an anti-reverse electrical system of a rotary-wing unmanned aerial vehicle, characterized in that... Includes the following steps: Based on the maximum wind speed during the descent of the rotorcraft drone in the actual application scenario, and combined with the aerodynamic performance parameters of the rotor blades, the rotor reversal load torque T is determined. e Alternatively, the reverse load torque T at the maximum wind speed during rotor descent can be directly tested in a rotor wind tunnel. e ; The required rated current I is calculated based on the torque formula. q Size, the formula is as follows: Calculate the required rated voltage U based on the motor's phase resistance R and the tube voltage drop. e The formula is as follows: U e =I q R According to the required back potential U e and magnetic flux linkage parameter Ψ f The rotational speed w is calculated using the following formula: According to the back electromotive force U e and current I q Select the power transistor's withstand voltage and current parameters to design the circuit for short-circuiting electrical devices; Based on the above design results, the short-circuit electrical device was manufactured, and the anti-reverse electrical system of the rotary-wing UAV was installed. Further testing and commissioning of the flight control system and rotor motor were completed.

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