Research On Drive System Of Dual Three-Phase Permanent Magnet Synchronous Motor For Electric Vehicles

Compared with the traditional three-phase motor drive system,the dual three-phase permanent magnet synchronous motor(PMSM)drive system can realize low-voltage highpower or fault-tolerant control,which is especially suitable for electric vehicle field.In view of the operation conditions of normal operation and one open phase fault,the model of dual three-phase PMSM under stationary and rotating coordinate system is built up according to the vector space decomposition(VSD)theory.Using MATLAB/Simulink simulation platform,the simulation model of the motor is built,and the correctness of the model is verified.Considering the voltage utilization and the space harmonic voltage,the space vector pulse width modulation(SVPWM)based on vector space decomposition and overmodulation technology are introduced,the harmonic voltage is increased according to the reference voltage to realize the smooth transition betweem sinusoidal voltage modulation area and non-sinusoidal voltage modulation.At the same time,for the problem that SVPWM modulation cannot realize four-dimensional current vector control,carrierbase pulse width modulation(CBPWM)is introduced,and the zero sequence voltage is injected into each set of three-phase winding to improve the modulation index.Simulation results show the effectiveness of the proposed modulation algorithm.In view of the symmetric case and asymmetric case of position sensor output signal,adopting single synchronous reference frame software phase-locked loop(SSRF-SPLL)and double second-order generalized integrator software phase-locked loop(DSOGI-SPLL)to realize the rotor position angle accurately acquiring.In case of the normal operation of the motor,four-dimensional current vector control methods based on PI regulator and PR regulator are adopted to suppress the harmonic current of z1-z2 plane.The vector control method based on PR regulator was improved,furthermore,the vector control method based on frequency adaptation PR regulator is provided.The simulation results show that the harmonic suppression of the improved method is good.In case of one open phase fault,the thesis uses smallest stator copper loss and smallest stator current amplitude to conduct faulttolerant control.Based on the differences and similarities between two kinds of faulttolerant control methods,fault tolerant control scheme of electric vehicle under different conditions are given,and the validity of the presented scheme is verified by simulation.The design and transformation of the motor body are completed,and the experimental platform of the dual three-phase PMSM drive system is built.Furthermore,the vector control experiment with the normal operation and the open phase operation of motor was carried out.The correctness and validity of the theoretical method are proved by experiments.