Research And Implementation Of SVPWM Control Technology For Six Phase Permanent Magnet Synchronous Motor With Dual Y Shift 30°Based On The Optimal Switching Frequency

Compared with conventional three-phase AC motor,multiphase motor owing to large power output with low voltage,low torque ripple and good redundancy attract more and more attentions with the development of high-performance permanent magnetic materials.In this paper,dual Y shift 30° permanent magnet synchronous motor is investigated.Its mathematical model and pulse width modulation(PWM)algorithms based on the optimal switching frequency are developed,and the availability and superiority of the algorithm are validated by simulations and experiments.The main tasks are as follows:Firstly,mathematical models of multiphase motor are derived based on winding theory.Then,mathematical models of dual Y shift 30° six phase permanent magnet synchronous motor(PMSM)with non-sinusoidal winding and neutral-point isolation under natural and rotating frames are developed.Secondly,an optimal switching frequency space vector PWM(SVPWM)control algorithm is proposed to overcome the shortcomings existing in four-vector SVPWM.This method suggests that the objective voltage vector can be composed by three maximum basic vectors and one middle basic vector,and switching waveforms of each phase in a PWM period can be central symmetry by reasonable sequences of basic vectors.Besides,the power device can be switched only once in a PWM period,which is easy to be implemented by digital signal process(DSP)devices.The simulation results show that the optimal switching frequency space vector PWM algorithm is effective.It has better inhibitory effects on the fifth harmonic and less harmonic losses compared with the four-vector SVPWM.Thirdly,two vector control strategies related to dual Y shift 30° six phase permanent magnet synchronous motor with non-sinusoidal winding and neutral-point isolation are analyzed and investigated.In vector space decomposition control with optimal switching frequency SVPWM,the current is controlled in fundamental and harmonic subspaces,while in double d-q decomposition control with conventional three-phase SVPWM,only fundamental current is controlled.The experimental results show that the former control strategy has better effects on harmonic inhibition.Finally,the paper presents the hardware circuits and software flow-chart of the six-phase controller.The experiments of the proposed control algorithms for dual Y shift 30° six-phase permanent magnet synchronous motor are carried out on the test bench.Results of the experiments are accordant with simulation results,and provide a reference for the engineering.