Research On Open Phase Operation And Fault-tolerance Of Five Phase Permanent Magnet Synchronous Motor

In some demand high reliability fields, multi-phase permanent magnetsynchronous motor receiving more and more attention, due to its good fault-tolerantoperation ability. Therefore, multiphase PMSM is gradually becoming a hotspot incurrent research of motor.In this paper, five phase PMSM is the object of study. The characteristics of openphase operation are in-depth researched. The purpose of the paper is to find out effectivefault-tolerant control strategies, ensures five phase PMSM can operate stably when itappears one phase open-circuit fault and two phases open-circuit fault. The organizationof this study is as follows:First, according to Fourier decomposition, it can get the winding function of fivephase windings and the expression of five phase current function, and then, the MMFharmonic of five phase symmetrical windings is analyzed quantitatively.And then, this paper analyzes the MMF of five phase PMSM during open phase indetail. It mainly includes two research contents: One is analyzes the mathematicalmodel of MMF during one phase open-circuit and two phases open-circuit in case ofsupplied sinusoidal alternating current, to give a suitable fault-tolerant current controlstrategies, so as to remain the MMF unchanged when the motor in open phase operation;The other is analyzes the mathematical model of MMF during one phase open-circuitand two phases open-circuit in case of supplied with sinusoidal alternating current plusthird harmonic current, to give a suitable fault-tolerant current control strategies, so asto remain the MMF unchanged when the motor in open phase operation.Finally, this paper deeply analyzes the output torque of five phase PMSM duringopen phase operation. The analysis covers the open-circuit of one phase and twononadjacent phases and two adjacent phases. Through the analysis on mathematicsmodel of three kinds of fault cases, to offer an effective fault-tolerant control strategy.As a result, the torque ripple of five phase PMSM during open phase operation isgreatly reduced. The simulation results demonstrate the validity of the theoreticalanalysis.