Research On Open Winding Vector Control And Fault Tolerant Technology Of Permanent Magnet Synchronous Motor

In order to further improve power factor,safety and reliability of the permanent magnet synchronous motor(PMSM)control system,the open winding PMSM(OWPMSM)with single power supply and double inverters is carried out under the support of the financial foundation "Research on asymmetric rotor permanent magnet auxiliary synchronous reluctance motor for electric vehicles"(No.: LFGD2019002).The specific research contents are summarized as follows:(1)A control strategy of OWPMSM with single power supply of main inverter and reactive power compensation of secondary inverter capacitor is proposed,which realizes the unit power factor operation and flux weakening control of PMSM control system.Aiming at the problems of open circuit and short circuit existing in the operation of inverter,a fault detection circuit is designed according to the bridge arm neutral point to ground potential to locate the fault,and a capacitor is used to replace the fault IGBT.A four-switch three-phase fault-tolerant topology and control strategy of OWPMSM are proposed to realize the fault-tolerant control of OWPMSM in fault state.(2)The mathematical model of OWPMSM is analyzed.Based on three-phase static,twophase static and two-phase rotating coordinate system,the voltage equation,flux linkage equation,torque equation and mechanical motion equation of the motor are analyzed,which lays a foundation for the research of OWPMSM speed control system.(3)Based on MATLAB/Simulink software,the simulation model of OWPMSM control system is established.The reactive power compensation principle and limiting conditions are analyzed from the motor vector diagram.The specific implementation processes of topology,main inverter control strategy,secondary inverter control strategy,PI parameter setting,unit power factor operation,flux weakening control and fault-tolerant control of OWPMSM control system are given.The simulation research is carried out.The influence of the supply capacitor of the secondary inverter on the control system is analyzed,and it is verified that the strategy can effectively expand the working range of the PMSM in the constant torque and constant power region.(4)The fault-tolerant control method of OWPMSM is analyzed in different situations.The motor motion state,voltage,current,and reactive power compensation efficiency under different fault-tolerant conditions are given.The results show that the system can operate normally in the constant torque region,and the voltage utilization rate is low in the constant power region.(5)The experimental platform of OWPMSM control system is designed,and the hardware and software of OWPMSM control system are described including main circuit power design,DSP control board design,sampling detection circuit design,drive circuit design,switching power supply design.Taking TI company DSP28335 as the control core,the main program,detection program,SVPWM program,PI regulator program and protection program of the control system are designed.