Fault Tolerant Control Method for Half Centralized Open End Winding Permanent Magnet Linear Motor Drive Systems with Open Phase Fault

In this paper, a fault tolerant control method is proposed for half-centralized open-end winding permanent magnet linear motor (HCOW-PMLM) drive systems with open phase fault. When the open phase fault occurs in one phase, the c VSI bridge arm of the whole phase will be cut off. To reduce the system loss, the proposed method injects symmetrical second harmonic into thrust currents in two motors. The second harmonic current injection is related to the angle error of two motors. Then the voltage distribution term is applied to distributes the voltage command to remaining phase bridge arms. Compared to conventional fault tolerant method, the proposed method can effectively reduce system loss. Finally, the proposed method has been validated by simulated and experimental results.

I. Introduction

With its excellent control performance, high power density and efficiency, permanent magnet motors are increasingly widely used in many fields [1]-[2]. Due to the merits of wide speed range, multilevel modulation and better fault tolerance, open winding drive system have attracted much attentions [3]. In the open winding topology, the end of motor winding is open and two side are supplied by two voltage-source-inverters (VSIs).