Research On Torque Impulse Balance Control Method Of Fault Tolerant Flux Switching Permanent Magnet Machine

The electric driving system of all-electric/more-electric aircraft is required to deliver high power density,high reliability and fault tolerance ability.Flux switching permanent magnet motor has low risk of irreversible demagnetization,good heat dissipation performance of permanent magnet,high sinusoidal back EMF,which make it suitable for the whole electric driving system of the aircraft.This paper focuses on the control method of the fault tolerant flux switching permanent magnetic motor.In this paper,the torque impulse balance control strategy is proposed to improve the dynamic response of the speed,which is always affected by the PI parameters in both vector control and direct torque control.The speed and the torque waveforms are respectively analyzed under the sudden changes of the speed and load torque,respectively.Based on the torque impulse balance control,the ideal waveforms of the speed and torque are deduced during dynamic process.The system can reach the steady state by acceleration and deceleration only once,and the combination of optimal vector can be obtained.The control method can realize quick adjustment,and improve the dynamic performance of the system.The torque impulse balance control combining with the fault tolerant control under different condition is also investigated.Based on torque impulse balance control thought,the period of dynamic process is decided by the the electromagnetic torque rising time.And the slope of the rise of electromagnetic torque is affected by the space voltage vector.In case of faulty,the shorter the length of the space voltage vector,the weaker the ability of changing electromagnetic torque and the longer the dynamic response time.In general,the longer the space voltage vector,the stronger the ability of changing the electromagnetic torque.Conversely,the shorter,the weaker.The general rule that the ability of changing the electromagnetic torque using power converter is established.The method of torque impulse balance control can be extended to AC motor speed governing system.The mathematical model of permanent magnet synchronous motor,brushless dc motor and asynchronous motor are introduced,the impulse torque balance equation and torque impulse balance control strategy block diagram are established.The research results have laid the basis for establishing AC motor speed governing system based on torque impulse balance control strategy.Finally,the control strategy is carried out on a 6/19 fault-tolerant flux switching permanent magnetic motor,and the effectiveness and feasibility of this control strategy are verified by comparison.