Fault-Tolerant Operation with 1-Phase Open in Parallel-Connected Motor

摘要

This paper proposes a fault-tolerant operation for 3-phase surface mounted permanent magnet machines in which a parallel-connected motor drives a same mechanical shaft. A healthy 3-phase motor and a faulted 3-phase motor with 1-phase open are operated in parallel. In the stationary reference frame, the d-axis component affects only to the healthy 3-phase motor, whereas both of motors share the q-axis component. It is possible to operate the motor continuously even in a fault circumstance. In this paper, separated d- and q-axis current controllers utilize torque under both normal and the fault conditions of 1-phase open. The output torque is generated up to a sum of the rated torque of healthy and faulted motors. The proposed control method has robust characteristics, which is proved by stability analysis using system transfer function. This paper also presents a method of reducing the torque ripple caused by the correlated voltage circuit. Accordingly, a cost-effective and enhanced reliability system is implemented without any configuration adjustment. The simulation results are presented to verify the performance of proposed fault-tolerant operation.