Research On Disturbance Rejection Strategy And Fault-tolerant Control Method For Permanent Magnet Synchronous Machine

Due to the ever-expanding application conditions,the disturbance rejection performance and reliability of permanent magnet synchronous machine(PMSM)are required to be higher.As far as the disturbance rejection performance,the PMSM control system can not only effectively suppress the influence of non-periodic disturbance caused by parameter mismatch and periodic disturbance caused by dead-time effect of inverter and non-sinusoidal distribution of rotor flux,but can also ensure the speed tracking performance in many applications.In addition,in order to meet the needs of aerospace,traction locomotive and other applications,the PMSM should have the uninterrupted operation ability under fault.Therefore,there are higher requirements for fault-tolerant control strategy.Based on this background,a zero-order-hold equivalent discrete-time model of PMSM is established in this paper,which considers the non-periodic disturbance,the zero-order-hold characteristic of PWM,and the output voltage locking phenomenon of inverter in a single sampling period.On this basis,the predictive controller and the disturbance observer are designed,and the parameter tuning method of them is proposed.Besides,the robustness of the system under different operating conditions is analyzed.Theoretical analysis and experimental results show that the proposed current predictive control strategy based on zero-order-hold model can not only effectively suppress non-periodic disturbances,but also has strong robustness while guaranteeing fast dynamic response.At the same time,in order to suppress the periodic disturbance introduced by the nonideal factors of the machine and inverter,the periodic disturbance is taken into account when the zero-order-hold model of the machine is established.The vector-resonance controller is embedded into the predictive controller,and the predictive-resonance controller of PMSM is designed.Besides,the corresponding parameter tuning method is put forward.Theoretical analysis and experimental results show that the proposed current predictive resonant controller can not only suppress periodic disturbances effectively,but also has good steady-state performance,transient performance and stability margin.In addition,in order to improve the reliability of PMSM,the operation characteristics of electromagnetic torque and current before and after the open-phase fault of open-winding PMSM are studied.Based on the operation characteristics,a predictive fault-tolerant controller is designed to suppress the torque ripple.The experimental results show that the faulttolerant control strategy proposed in this paper can not only effectively suppress the speed and torque fluctuations in the fault operation state,but also has good control performance in the normal operation state,which meets the control requirements without switching the controller before and after the fault occurs.