Open-Circuit Fault-Tolerant Control of Five-Phase Permanent-Magnet Synchronous Motor using Control Variable Method

In this paper, a fault-tolerant current calculation strategy using control variable method is proposed for single-phase, two-phase and three-phase open-circuit faults of five-phase permanent-magnet synchronous motor. First, set current amplitude unchanged after fault, and the optimal angle of current is determined according to minimum torque harmonic component. Then, set current angle as the optimal value unchanged, and current amplitude is determined according to the same average torque under both the healthy and fault conditions. The calculation of current amplitude has two cases: adjusting current amplitude in the same proportion without round magnetomotive force limit, which forms an elliptical magnetomotive force, and adjusting current amplitude at different ratios with round magnetomotive force limit, which reconstructs round magnetomotive force. Finally, the simulation results show that stable fault-tolerant operation can be achieved in both cases, and torque ripple under elliptical magnetomotive force is lower than that under round magnetomotive force.