阅读说明：本技术 一种双电机推进系统及控制方法 (Double-motor propulsion system and control method ) 是由 张华� 王顺伟 唐勇斌 李志阔 徐晓龙 曹兴帅 孟楠 于 2020-12-16 设计创作，主要内容包括：本发明公开了一种双电机推进系统及其控制方法,所述方法包括：主电机控制器与外部通信接收转速指令并向外部反馈电动机的状态信息；从电机控制器与外部通信接收转速指令并向外部反馈电动机的状态信息；所述转速指令包括主电机的主转速指令和从电机的从转速指令；所述主电机控制器和所述从电机控制器之间内部通信相互传递数据。本发明提供的双电机推进系统控制方法,可有效控制双电机按照转速指令和螺旋桨负载均衡输出转速和转矩,基于协同控制以及冗余设计使得系统具备容错性能好的特点,出现部分故障时能保证整个电动机系统能继续工作。(The invention discloses a double-motor propulsion system and a control method thereof, wherein the method comprises the following steps: the main motor controller is communicated with the outside to receive a rotating speed command and feed back the state information of the motor to the outside; receiving a rotating speed instruction from the motor controller through communication with the outside and feeding back state information of the motor to the outside; the rotating speed instruction comprises a main rotating speed instruction of the main motor and a slave rotating speed instruction of the slave motor; the master motor controller and the slave motor controller communicate data to each other. The control method of the dual-motor propulsion system provided by the invention can effectively control the dual motors to output rotating speed and torque according to rotating speed instructions and propeller load balance, and the system has the characteristic of good fault tolerance performance based on cooperative control and redundancy design, and can ensure that the whole motor system can continue to work when partial faults occur.)

1. A dual motor propulsion system, comprising: a master motor, a slave motor, a master motor controller, and a slave motor controller; wherein the master motor and the slave motor use independent stators and rotors, and share a rotor housing and a motor shaft; the output of the master motor controller is connected with the three-phase line of the master motor, and the output of the slave motor controller is connected with the three-phase line of the slave motor; the master motor controller is in communication connection with the slave motor controller.

2. The dual-motor propulsion system of claim 1,

the main motor controller includes: the main voltage acquisition circuit and the slave current sensor are respectively connected with a main digital signal processor;

the slave motor controller includes: the slave current sensor is connected with a phase line of the slave motor, the slave voltage acquisition circuit is connected with a bus of the slave motor, and the slave voltage acquisition circuit and the slave current sensor are respectively connected with a slave digital signal processor.

3. The dual-motor propulsion system of claim 2,

the main motor controller includes: the main digital signal processor is respectively connected with the main motor vector controller, an output of the main Park conversion and the main inverse Park conversion, the main digital signal processor is also connected with the main speed ring controller, the main speed ring controller is connected with the main current ring controller, and the main current ring controller is connected with the main inverse Park conversion;

the slave motor controller includes: the motor speed control system comprises a slave speed loop controller, a slave current loop controller, a slave motor vector controller, a slave Park conversion and a slave inverse Park conversion, wherein the slave digital signal processor is respectively connected with the slave motor vector controller, an output converted by the slave Park conversion and the slave inverse Park conversion, the master digital signal processor is also connected with the slave speed loop controller, the slave speed loop controller is connected with the slave current loop controller, and the slave current loop controller is connected with the slave inverse Park conversion.

4. A method of controlling a dual motor propulsion system, the method comprising:

the main motor controller is communicated with the outside to receive a rotating speed instruction and feed back the state information of the dual-motor propulsion system to the outside;

receiving the rotating speed instruction from the motor controller in communication with the outside and feeding back state information of the dual-motor propulsion system to the outside; the rotating speed instruction comprises a main rotating speed instruction of the main motor and a slave rotating speed instruction of the slave motor;

the master motor controller and the slave motor controller communicate data to each other.

5. The method of controlling a dual motor propulsion system as in claim 4, further comprising: independently executing for each of the master motor controller and the slave motor controller:

the current sensor collects the current of the phase line to obtain the three-phase current of the phase line;

the voltage acquisition circuit acquires bus voltage;

according to the bus voltage digital signal processor DSP, three-phase voltages are calculated by a bus voltage and phase voltage reconstruction algorithm;

the digital signal processor learns motor parameters, the motor parameters including: stator resistance value, direct axis inductance value, quadrature axis inductance value and permanent magnet flux linkage amplitude value;

and calculating the electric angle of the motor rotor according to the three-phase current, the bus voltage, the three-phase voltage and the motor parameters.

6. The method for controlling a dual motor propulsion system as set forth in claim 5, wherein the current sensor collects current of the phase line to obtain three-phase current of the phase line, comprising:

using 2 paths of Hall current sensors to collect the phase current of the motor at a phase line, and calculating the phase current of the 3 rd path according to the sum of three-phase currents of kirchhoff's law to be zero;

and/or (c) and/or,

the calculating the electric angle of the motor rotor according to the three-phase current, the bus voltage, the three-phase voltage and the motor parameter comprises the following steps:

and calculating the electric angle of the motor rotor by utilizing a FAST observer embedded in a read-only memory on the DSP according to the three-phase current, the bus voltage, the three-phase voltage and the motor parameters.

7. The method of controlling a dual motor propulsion system as in any of claims 5-6, further comprising:

the main motor controller directly determines the main rotating speed instruction as a target rotating speed instruction of the main motor;

the slave motor controller adjusts the slave rotating speed command into a target execution command of the slave motor under the action of a coordination coefficient; the value range of the coordination coefficient is more than 0 and less than or equal to 1;

the main speed loop controller calculates a main target current value input to the main current loop controller according to the target rotating speed instruction and the main feedback rotating speed obtained by the main DSP;

the slave speed loop controller calculates a slave target current value input to the slave current loop controller according to the target execution instruction and the slave feedback rotating speed obtained by the slave DSP;

the master motor controller sends the master target current value to the slave motor controller;

the slave motor controller adjusts a current value input to the slave current loop controller according to the master target current value.

8. The method of controlling a dual motor propulsion system as in claim 7, further comprising, when in the torque imbalance operating mode:

setting a command with a higher rotation speed out of the master rotation speed command and the slave rotation speed command as an execution rotation speed command for the master motor and the slave motor;

the torque distribution proportion of the main motor to the slave motor is the ratio of the main rotating speed instruction to the slave rotating speed instruction;

the master motor controller sends a result of multiplying the master target current value by the ratio to the slave motor controller.

9. The method of controlling a dual motor propulsion system as in claim 7, further comprising:

if the main motor and/or the main motor controller are/is in fault, the slave motor controller does not use the current value sent by the internal communication of the main motor controller any more, and the coordination coefficient is adjusted to be 1;

and/or (c) and/or,

if the main motor and/or the main motor controller fails, the main motor controller works by depending on the main speed ring controller;

and/or (c) and/or,

if the external communication of the main motor controller fails, the main motor controller receives a rotating speed instruction forwarded by the slave motor controller through internal communication, and sends the rotating speed, current, voltage and fault state of the rotating speed instruction to the slave motor controller;

and/or (c) and/or,

if the slave motor controller is in external communication failure, the slave motor controller receives a rotating speed instruction forwarded by the main motor controller through internal communication and sends the rotating speed, current, voltage and failure state of the rotating speed instruction to the main motor controller;

and/or (c) and/or,

in a torque balancing working mode, if the rotating speed commands received by the master motor controller and the slave motor controller are inconsistent, executing:

if Spd1_ M ≠ Spd2_ M, then Spd _ M ═ Spd1_ M;

if Spd1_ S ≠ Spd2_ S, Spd _ S ═ Spd1_ S;

if Spd _ M is not equal to Spd _ S and λ × Spd _ S is not greater than Spd _ M, Spd is equal to Spd _ M; and λ × Spd _ S > Spd _ M, then Spd — λ × Spd _ S;

spd1_ M is a main rotating speed instruction in the rotating speed instructions received by the main motor controller, and Spd2_ M is a slave rotating speed instruction in the rotating speed instructions received by the main motor controller; spd1_ S is a main rotating speed command in the rotating speed commands received from the motor controller, and Spd2_ S is a slave rotating speed command in the rotating speed commands received from the motor controller; spd _ M is an intermediate rotating speed instruction of the main motor controller; spd _ S is an intermediate rotating speed instruction of the slave motor controller; spd is a rotating speed instruction executed by the main motor and the slave motor;

and/or (c) and/or,

and when the rotating speed instruction exceeds the maximum output of the current motor, taking the highest rotating speed under the limitation of the bus voltage as the rotating speed instructions executed by the main motor and the slave motor.

10. The method of controlling a dual motor propulsion system as in any of claims 4-6, wherein the internal communication between the master motor controller and the slave motor controller communicates data to each other, comprising:

the controller comprises a master motor controller, a slave motor controller, a controller bus and a controller bus, wherein CAN communication and RS485 redundant communication are provided between the master motor controller and the slave motor controller, data of CAN communication are used when the master motor controller and the slave motor controller are normal, and data of RS485 communication are used when the CAN communication fails; the data includes, but is not limited to, speed commands, current commands, fault information, phase currents, controller temperature, motor temperature.

Technical Field

The invention relates to the technical field of aircrafts, in particular to a dual-motor propulsion system and a control method.

Background

The propulsion systems of electric airplanes, solar unmanned planes and stratospheric airships adopt a motor device to drive propellers to generate propulsion power. The propulsion system comprises a motor device and a propeller, wherein the motor device consists of a motor and a motor controller and is a core component of the propulsion system. The motor device has the technical characteristics of high power-weight ratio, high efficiency, high fault tolerance and good consistency of cooperative work of double motors due to the limitation of energy density of a battery and the requirement of long-term flight.

The existing high-altitude aircraft electric propulsion scheme is mainly a distributed direct-current brushless motor scheme with position sensors, a plurality of motor devices are distributed on wings or a machine head and a machine tail, the problem of power-to-weight ratio reduction caused by the distribution, the problem of reliability and power-to-weight ratio caused by the position sensors, and the problems of efficiency reduction and torque pulsation of the whole system caused by a direct-current brushless motor square wave control mode. In addition, the consistency of the cooperative work of the double motors (also called double motors, including a main motor and a slave motor, also called main motor and slave motor) is also a difficulty in the prior art, and the asynchronous cooperation of the double motors easily causes the motors to be relatively powerful with each other or to be subjected to overcurrent protection. Therefore, a new control method is designed aiming at the double-motor propulsion system and has the characteristics.

Disclosure of Invention

To address at least one of the above technical problems, the present disclosure provides a dual motor propulsion system and a control method.

In a first aspect, an embodiment of the present invention provides a dual-motor propulsion system, including: a master motor, a slave motor, a master motor controller, and a slave motor controller; wherein the master motor and the slave motor use independent stators and rotors, and share a rotor housing and a motor shaft; the output of the master motor controller is connected with the three-phase line of the master motor, and the output of the slave motor controller is connected with the three-phase line of the slave motor; the master motor controller is in communication connection with the slave motor controller.

Optionally, the main motor controller comprises: the main voltage acquisition circuit and the slave current sensor are respectively connected with a main digital signal processor;

the slave motor controller includes: the slave current sensor is connected with a phase line of the slave motor, the slave voltage acquisition circuit is connected with a bus of the slave motor, and the slave voltage acquisition circuit and the slave current sensor are respectively connected with a slave digital signal processor.

Optionally, the main motor controller comprises: the device comprises a main speed ring controller, a main current ring controller, a main motor vector controller, main Clark conversion, main Park conversion and main inverse Park conversion, wherein the main digital signal processor is respectively connected with the main motor vector controller, the output of the main Park conversion and the main inverse Park conversion, the main digital signal processor is also connected with the main speed ring controller, the main speed ring controller is connected with the main current ring controller, and the main current ring controller is connected with the main inverse Park conversion;

the slave motor controller includes: the motor speed control system comprises a slave speed loop controller, a slave current loop controller, a slave motor vector controller, a slave Clark conversion, a slave Park conversion and a slave inverse Park conversion, wherein the slave digital signal processor is respectively connected with the slave motor vector controller, the slave Park conversion output and the slave inverse Park conversion, the master digital signal processor is also connected with the slave speed loop controller, the slave speed loop controller is connected with the slave current loop controller, and the slave current loop controller is connected with the slave inverse Park conversion.

In a second aspect, the present invention provides a method of controlling a dual motor propulsion system, the method comprising:

the main motor controller is communicated with the outside to receive a rotating speed instruction and feed back the state information of the dual-motor propulsion system to the outside;

receiving the rotating speed instruction from the motor controller in communication with the outside and feeding back state information of the dual-motor propulsion system to the outside;

the rotating speed instruction comprises a main rotating speed instruction of the main motor and a slave rotating speed instruction of the slave motor;

the master motor controller and the slave motor controller communicate data to each other.

Optionally, the method further comprises: independently executing for each of the master motor controller and the slave motor controller:

the current sensor collects the current of the phase line to obtain the three-phase current of the phase line;

the voltage acquisition circuit acquires bus voltage;

according to the bus voltage, the digital signal processor DSP utilizes the bus voltage and a phase voltage reconstruction algorithm to calculate three-phase voltage;

the digital signal processor learns motor parameters, the motor parameters including: stator resistance value, direct axis inductance value, quadrature axis inductance value and permanent magnet flux linkage amplitude value;

and calculating the electric angle of the motor rotor according to the three-phase current, the bus voltage, the three-phase voltage and the motor parameters.

Optionally, the current sensor collects a current of the phase line to obtain a three-phase current of the phase line, and includes:

using 2 paths of Hall current sensors to collect the phase current of the motor at a phase line, and calculating the phase current of the 3 rd path according to the sum of three-phase currents of kirchhoff's law to be zero;

and/or (c) and/or,

the calculating the electric angle of the motor rotor according to the three-phase current, the bus voltage, the three-phase voltage and the motor parameter comprises the following steps:

and calculating the electrical angle of the rotor by utilizing a FAST observer embedded in a read-only memory on the DSP according to the three-phase current, the bus voltage, the three-phase voltage and the motor parameters.

Optionally, the method further comprises:

the main motor controller directly determines the main rotating speed instruction as a target rotating speed instruction of the main motor;

the slave motor controller adjusts the slave rotating speed command into a target execution command of the slave motor under the action of a coordination coefficient; the value range of the coordination coefficient is more than 0 and less than or equal to 1;

the main speed loop controller calculates a main target current value input to the main current loop PI controller according to the target rotating speed instruction and the main feedback rotating speed obtained by the main DSP;

the slave speed loop controller calculates a slave target current value input to the slave current loop PI controller according to the target execution instruction and the slave feedback rotating speed;

the master motor controller sends the master target current value to the slave motor controller;

the slave motor controller adjusts a current value input to the slave current loop controller according to the master target current value.

Optionally, when in the torque imbalance operating mode, the method further comprises:

setting a command with a higher rotation speed out of the master rotation speed command and the slave rotation speed command as an execution rotation speed command for the master motor and the slave motor;

the torque distribution proportion of the main motor to the slave motor is the ratio of the main rotating speed instruction to the slave rotating speed instruction;

the master motor controller sends a result of multiplying the master target current value by the ratio to the slave motor controller.

Optionally, the method further comprises:

and if the main motor and/or the main motor controller have faults, the slave motor controller does not use the current value sent by the internal communication of the main motor controller any longer, and the coordination coefficient is adjusted to be 1.

Optionally, the main motor controller is operable on its own by means of the main speed loop control if the main motor and/or the main motor controller fails.

Optionally, if the external communication of the master motor controller fails, the master motor controller receives the rotating speed command forwarded by the slave motor controller through internal communication, and sends the rotating speed, the current, the voltage and the fault state of the rotating speed command to the slave motor controller.

Optionally, if the slave motor controller fails in external communication, the slave motor controller receives a rotating speed command forwarded by the master motor controller through internal communication, and sends the rotating speed, current, voltage and fault state of the rotating speed command to the master motor controller.

Optionally, in a torque balancing operation mode, if the rotation speed commands received by the master motor controller and the slave motor controller are inconsistent, the following steps are performed:

if Spd1_ M ≠ Spd2_ M, then Spd _ M ═ Spd1_ M;

if Spd1_ S ≠ Spd2_ S, Spd _ S ═ Spd1_ S;

if Spd _ M is not equal to Spd _ S and λ × Spd _ S is not greater than Spd _ M, Spd is equal to Spd _ M; and λ × Spd _ S > Spd _ M, then Spd — λ × Spd _ S;

spd1_ M is a main rotating speed instruction in the rotating speed instructions received by the main motor controller, and Spd2_ M is a slave rotating speed instruction in the rotating speed instructions received by the main motor controller; spd1_ S is a main rotating speed command in the rotating speed commands received from the motor controller, and Spd2_ S is a slave rotating speed command in the rotating speed commands received from the motor controller; spd _ M is an intermediate rotating speed instruction of the main motor controller; spd _ S is an intermediate rotating speed instruction of the slave motor controller; spd is a rotating speed instruction executed by the main motor and the slave motor;

alternatively, when the rotating speed instruction exceeds the maximum output of the current motor, the highest rotating speed under the limitation of the bus voltage is used as the rotating speed instruction executed by the main motor and the slave motor.

Optionally, the internal communication between the master motor controller and the slave motor controller communicates data to each other, including:

the controller comprises a master motor controller, a slave motor controller, a controller bus and a controller bus, wherein CAN communication and RS485 redundant communication are provided between the master motor controller and the slave motor controller, data of CAN communication are used when the master motor controller and the slave motor controller are normal, and data of RS485 communication are used when the CAN communication fails; the data includes, but is not limited to, speed commands, current commands, fault information, phase currents, controller temperature, motor temperature.

Compared with the prior art, the invention has at least the following beneficial effects:

the control method of the double-motor propulsion system can effectively control the double motors to output rotating speed and torque according to rotating speed instructions and propeller load balance; by adopting a scheme of double-motor system and no position sensor control, the system has high power-weight ratio; by adopting a permanent magnet synchronous motor vector control technology based on a non-position algorithm and a dual-motor cooperative control technology, the system has the technical characteristics of high efficiency and good cooperative working consistency; based on cooperative control and redundancy design, the system has the characteristic of good fault tolerance, and the whole motor system can be ensured to continue working when partial faults occur.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.

FIG. 1 is a schematic illustration of a dual motor propulsion system according to an embodiment of the present invention;

FIG. 2 is a schematic diagram of a position sensorless control module for an electric machine according to an embodiment of the present invention;

fig. 3 is a schematic structural diagram of a two-motor cooperative control module according to an embodiment of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer and more complete, the technical solutions in the embodiments of the present invention will be described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention, and based on the embodiments of the present invention, all other embodiments obtained by a person of ordinary skill in the art without creative efforts belong to the scope of the present invention.

As shown in FIG. 1, a dual motor propulsion system includes a master motor, a slave motor, a master motor controller, and a slave motor controller; the main motor and the auxiliary motor adopt independent stators and rotors, share a rotor shell and a motor shaft, and the rotor shell is connected with the propeller through a propeller hub mechanism. The power supplies of the main motor controller and the slave motor controller are both connected with a power line of the battery, the output of the main motor controller is connected with a three-phase line of the main motor, and the output of the slave motor controller is connected with a three-phase line of the slave motor. The main motor controller is in information interaction with the flight control computer through external communication, receives a rotating speed instruction and feeds back state information of the dual-motor propulsion system, wherein the state information comprises state information of the main motor, the main motor controller, the slave motor and the slave motor controller, the external communication adopts an RS485 bus communication mode, the baud rate is 460800bps, and the communication period is 20 ms. The slave motor controller is in information interaction with the flight control computer through external communication, receives a rotating speed instruction and feeds back state information of the dual-motor propulsion system, wherein the state information comprises state information of the master motor, the master motor controller, the slave motor and the slave motor controller, and the external communication adopts an RS485 bus communication mode, the baud rate is 460800bps, and the communication period is 20 ms. The flight control computer and the master-slave double-motor controller construct two RS485 bus networks, data is received and transmitted between the flight control computer and the master motor controller through an A bus, data is received and transmitted between the flight control computer and the slave motor controller through a B bus, and the two buses run synchronously. The internal communication between the master motor controller and the slave motor controller comprises RS485 communication and CAN communication, and transmits instructions and state information mutually, wherein the RS485 communication baud rate is 115200bps, the CAN communication baud rate is 500kbps, the communication period is 1ms, and the contents transmitted by the RS485 communication and the CAN communication are the same.

As shown in fig. 2, the dual-motor propulsion system does not need to be provided with a rotor position sensor, the rotor electrical angle is calculated by using a position-free control algorithm, and the position-free control algorithm needs to acquire 7 parameters including bus voltage, 3-phase voltage and 3-phase current. To avoid interference, the power section needs to be isolated from the control section. The master motor controller collects 7 parameters of the master motor, the slave motor controller collects 7 parameters of the slave motor, and the master motor controller and the slave motor controller respectively and independently run a position-free control algorithm. The specific implementation of each is as follows:

step 1: and (5) configuring motor phase current sampling parameters.

The phase current of the motor is collected at the phase line position by using 2 paths of Hall current sensors, and the phase current of the 3 rd path can be calculated according to the kirchhoff law that the sum of the three-phase currents is zero. The current sensor is a Hall current sensor with an isolation sampling function, and is preferably of a type HC5FW600-S/SP 1. The output midpoint voltage of the current sensor is 2.5V, the output voltage is 4.5V when the maximum positive current is output, and the output voltage is 0.5V when the maximum negative current is output. The output voltage of the current sensor is input to an ADC (analog to digital converter) inlet of the DSP chip after being subjected to voltage division by a resistor and a voltage following circuit, the division reduction factor is 2/3 times, the ADC input range of the DSP is 0-3.3V, and therefore the full-scale current of the ADC is 1440A.

Step 2: and configuring bus voltage sampling parameters.

A voltage acquisition circuit consisting of resistors with 100K resistance and 3.3K resistance is selected to acquire bus voltage, and the acquired voltage is connected to an ADC (analog to digital converter) inlet of the DSP after being isolated. Preferably, the isolation amplifier chip signal is ISO124, and the amplification factor is 1. The ADC input range of the DSP is 0-3.3V, so the full scale voltage of the ADC is configured to be 103.3V.

And step 3: and configuring phase voltage reconstruction parameters.

And (3) three-phase voltage obtained by utilizing a bus voltage and phase voltage reconstruction algorithm. The reconstruction formula of the a-phase voltage of the motor is as followsWherein T is_aThe ideal conduction time of the bridge MOSFET on the a phase of the motor in one period, T is the switching period, V_dcThe bus voltage value is a known parameter which can be directly read when software runs. Actual dead time T_shutCan be obtained in the stator resistance identification process, and the identification process is carried out according to the electrical angle sigma of 0 DEG, I_d＝I_Rs，I_qThe excitation is applied in 0. The Vb and Vc voltage reconstruction equations are similar to Va and are not listed.

And 4, step 4: and (5) learning and storing motor parameters.

And learning parameters of the motor, including a stator resistance value, a direct axis inductance value, a quadrature axis inductance value and a permanent magnet flux linkage amplitude value, by using InstasPIN-FOC software solidified in the DSP, and storing the parameters in an EEPROM (electrically erasable programmable read-only memory) after learning.

And 5: closed-loop control without a position sensor.

Based on 7 variables of the collected bus voltage, 3-phase voltage and 3-phase current and 4 parameters of a stator resistance value, a direct-axis inductance value, a quadrature-axis inductance value and a permanent magnet Flux linkage amplitude value in the motor, a FAST (Flux linkage Flux, an electric Angle, a rotating Speed and a Torque) observer embedded in a read-only memory on the DSP is operated to calculate the rotor electric Angle. FAST observer starts at zero speed with a forced angle, at 1H_zAnd the electrical frequency is switched to observer angle closed-loop control. The DSP model may be TMS320F28069F, TMS320F28062F, TMS320F28027F, TMS320F280049C, and so on in embodiments of the present invention.

The upper half is the master motor controller portion and the lower half is the slave motor controller portion as shown in fig. 3. For a main motor controller part and a slave motor control department, a Clark converter converts three-phase current of a motor ABC natural coordinate system into motor current under an alpha-beta static coordinate system, a Park converter converts current under the alpha-beta static coordinate system into motor current under a d-q synchronous rotating coordinate system, and an inverse Park converter converts motor voltage under the d-q synchronous rotating coordinate system into motor voltage under the alpha-beta static coordinate systemAnd (4) the machine voltage. The VR-FAST observer calculates the position theta and the rotating speed omega of the rotor of the motor by utilizing the alpha-beta axis voltage and current of a motor vector control unit (in the embodiment, a space vector pulse width modulation unit SVPWM), wherein the position theta of the rotor is an input parameter of a Park converter and an inverse Park converter, and the rotating speed omega and a given rotating speed command Spd are output as cross-axis current through a speed loop PI controllerThen converted into quadrature axis voltage after passing through a current loop PI controllerConverted into alpha-axis voltage by an inverse Park converterAnd finally, outputting six paths of control signals through SVPWM to drive the inverter to work, and outputting three-phase sinusoidal current with variable amplitude and frequency to the stator of the motor. The master motor controller and the slave motor controller are controlled by adopting a double closed loop PI of an outer loop speed loop and an inner loop current loop, the master motor controller works in a speed loop mode and a current loop mode under a normal working condition, and the slave motor controller adopts an outer loop pseudo speed loop mode and a current loop mode and controls double-motor torque balance through a coordination algorithm. If the master motor or master motor controller fails, the slave motor can switch from the pseudo speed loop to the speed loop, maintaining a closed loop output of speed and current. The coordination algorithm comprises the following specific steps:

step 1: and acquiring a rotating speed instruction.

Main motor controller omega₁The flight control sent speed command Spd1 is fully executed. Slave motor controller omega₂After receiving the flight control rotation speed command Spd2, λ × Spd2 is used as an actual execution command, 0 < λ < 1 is a pseudo speed loop mode, and λ ═ 1 is a speed loop mode. When the lambda is used as a coordination coefficient, the lambda is selected according to the actual effect, if the lambda is 0, only the current loop runs, and when the motor is switched to the double-loop work of the speed loop and the current loop, the torque jitter or the overcurrent shutdown can be caused.

Step 2: and (4) resolving the speed PI.

The main motor controller has a speed command of omega₁The FAST observer calculates the feedback rotation speed omega according to the back electromotive force of the main motor_MCalculating the current loop input target current value of the main motor controller at the resolving position of the speed loop PI controllerThe rotation speed command of the slave motor controller is omega₂Feedback speed of ω_SCalculating the input target current value from the current loop of the motor controller at the resolving position of the speed loop PI controllerSince the main motor and the slave motor share the rotor, the actual rotation speed of the two motors is ω, and ω is ω during normal operation_M＝ω_S。

And step 3: the internal communication forwards the current loop target current value.

The main motor is communicated with the main motor through internal CAN communication or RS485 communicationTo the slave motor controller. The data received from the motor controller preferably uses CAN communication.

And 4, step 4: and (4) judging from a motor controller current loop target value.

In the torque balancing mode of operation:

for the output result of the slave motor speed loop PI controller, since the master motor controls the speed loop, the slave motor controller takes 0 < λ < 1, and the slave motor controller operates in the pseudo speed loop mode, the normal operating condition is that the actual speed command λ x Spd2 < ω from the motor, ω being the actual speed of the motor in rpm. Slave motor controller speed loop operation result Spd _ out2(λ × Spd2)ω) will always be in integral saturation, with the coordination algorithm specifyingNot less thanIs the result of the decision of the target value of the current loop input from the motor controller, so that the target value of the current loop of the slave motor controller is obtained during actual workTarget value of current loop of main motor controllerAnd similarly, the dual-redundancy motor works in a balanced manner. According to the non-reversing characteristic of the propeller, the limiting current loops are all positive currents, i.e. the minimum value is 0. In this embodiment, on the premise of ensuring that the output of the single motor is not less than 60n.m torque, the maximum output phase current peak value of the motor is limited to 500A, and the decision result is:

in the torque imbalance operating mode:

in the torque imbalance mode, the phase current of the master motor may be set in proportion to the phase current of the slave motor as commanded. The current loop input of the main motor controller isThe current command sent by the master motor controller to the slave motor controller via internal communication isTaking Spd _ out2(λ Spd2, ω) andlarge values of both. It is noted that in the torque imbalance mode, the master motor controller controlling the speed loop executes the speed command at the maximum max (Spd1, Spd2), and the master and slave motor torque sharing ratio is Spd 1: Spd 2.

The double-motor controller fault tolerance comprises a main motor controller halt fault, a slave motor controller halt fault, an external communication fault, an internal communication fault and a rotating speed instruction fault. The specific implementation is as follows:

the slave motor controller judges the working state of the master motor through internal communication, and specifically, if the internal communication is normal, the slave motor controller judges whether the master motor fails according to state information sent to the slave motor controller by the master motor controller. If the master motor controller or the master motor fails, the slave motor controller switches from the pseudo speed loop mode to the speed loop mode for stand-alone operation, and the current value sent by the internal communication of the master motor controller is not used any more. If the slave motor controller does not receive the internal communication data of the master motor controller for 1 second continuously, the slave motor controller switches from the pseudo speed loop mode to the speed loop mode to work alone. If the main motor controller can be recovered to be normal, the main motor can be controlled to restart under the condition of not electrifying again, the main motor works at the 120rpm instruction firstly when restarting, overcurrent protection is avoided when the runaway is started, and the flight control rotating speed instruction is executed after the starting is successful. And after the master motor controller is started successfully, the slave motor controller is switched to work from the speed ring mode to the pseudo speed ring mode.

The master motor controller judges the working state of the slave motor through internal communication, and specifically, if the internal communication is normal, the master motor controller judges whether the slave motor fails according to state information sent to the master motor controller by the slave motor controller. If the slave motor fails, the master motor controller is operated in a single machine mode. If the motor controller can be recovered to be normal from the head, the motor controller can be controlled to restart under the condition of not electrifying again, the slave motor works at the 120rpm instruction firstly during restarting, overcurrent protection during starting of the runaway is avoided, and the rotating speed instruction of the runaway is executed after the starting is successful. And after the motor controller is started successfully, the motor controller is switched to a pseudo speed loop mode to work.

If the external communication of the main motor controller fails, the main motor controller can receive all instructions of the flight control computer forwarded by the slave motor controller through internal communication, and the instructions specifically comprise a working mode, a main motor rotating speed instruction and a slave motor rotating speed instruction. And the rotating speed, the current, the voltage and the fault state of the master motor controller are sent to the slave motor controller. The external communication from the motor controller includes all information of the dual motor system. If the slave motor controller is in external communication failure, the slave motor controller can receive a rotating speed command forwarded by the master motor controller through internal communication and send the rotating speed, current, voltage and failure state of the slave motor controller to the master motor controller. The external communication of the master computer controller includes all the information of the dual motor system. The fault-tolerant control of the external communication is embodied in that the dual-motor system works normally as long as any path of external communication is normal.

The main motor controller and the slave motor controller are in CAN communication and RS485 redundancy communication, the normal working conditions of the main motor controller and the slave motor controller preferentially use CAN communication data, and if the CAN communication fails, the RS485 communication data is used. The internal communication fault tolerance control is realized in the way that the dual-motor system works normally as long as any path of internal communication is normal. The internal communication content comprises a rotating speed instruction, a current instruction, fault information, a phase current, a controller temperature, a motor temperature and the like.

The rotating speed instruction faults comprise a fault that a main rotating speed instruction and a slave rotating speed instruction are inconsistent and a fault that a rotating speed instruction exceeds the maximum output capacity of a current voltage motor. It is assumed that the master motor controller receives rotational speed commands Spd1_ M and Spd2_ M, the slave motor controller receives rotational speed commands Spd1_ S and Spd2_ S, M indicates the master motor side, S indicates the slave motor side, Spd1 indicates the rotational speed command to the master motor controller, and Spd2 indicates the rotational speed command to the slave motor controller. In the torque balancing mode, Spd1_ M is Spd2_ M, Spd1_ S is Spd2_ S at the time of normal command. In the case of a fault command, if Spd1_ M ≠ Spd2_ M, Spd _ M is Spd1_ M. If Spd1_ S ≠ Spd2_ S, Spd _ S is Spd1_ S. Spd _ M is the rotational speed command first determined by the master motor controller, and Spd _ S is the rotational speed command first determined by the slave motor controller. If Spd _ M ≠ Spd _ S and λ × Spd _ S ≦ Spd _ M, Spd is equal to Spd _ M, and if λ × Spd _ S > Spd _ M, Spd is equal to λ × Spd _ S. And Spd is a rotating speed instruction finally executed by the double motors. In the working mode of torque balance, the value range of the coordination coefficient is more than 0 and less than 1.

And if the battery voltage is reduced due to insufficient electric quantity of the power supply battery, the motor has the capacity of outputting the peak rotating speed under the low bus voltage. Let Spd _ Fly be the rotational speed command received by the controller, Spd _ Limit be the maximum rotational speed limited by the bus voltage, and Spd be the rotational speed command finally executed by the dual motors. If Spd _ Fly < Spd _ Limit, Spd is Spd _ Fly. If the Spd _ Fly is larger than or equal to the Spd _ Limit, the Spd is equal to the Spd _ Limit. In this embodiment, the battery voltage Vdc takes a range of 40V to 60V, and Spd _ Limit is set to 50 Vdc-200 according to the back electromotive force coefficient of the motor, and if Spd _ Limit > 2200, Spd _ Limit is 2200. If Spd _ Limit < 1800, Spd _ Limit is 1800.

It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other similar elements in a process, method, article, or apparatus that comprises the element.

Those of ordinary skill in the art will understand that: all or part of the steps for realizing the method embodiments can be completed by hardware related to program instructions, the program can be stored in a computer readable storage medium, and the program executes the steps comprising the method embodiments when executed; and the aforementioned storage medium includes: various media that can store program codes, such as ROM, RAM, magnetic or optical disks.

Finally, it is to be noted that: the above description is only a preferred embodiment of the present invention, and is only used to illustrate the technical solutions of the present invention, and not to limit the protection scope of the present invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention shall fall within the protection scope of the present invention.