Windings Reconfigured Fault-Tolerant Control for Five-Phase PMSMs With Reduced Torque Ripple

This paper proposes a winding reconfigured fault-tolerant control strategy for five-phase permanent magnet synchronous motors with an open circuit fault. First, a new decoupling matrix is derived from the referenced fault-tolerant currents, which effectively decouples the phase currents into the fundamental subspace and dual-zero-sequence subspace. In order to mitigate the harmonic current, a novel winding connection topology is proposed in which the harmonic plane current can be eliminated without closed-loop control. Thereby, the pulsating term in the torque equation can be eliminated. Moreover, the post-fault four-phase motor can operate in the two-phase mode. As a result, only the currents of two phases are required for coordinate transformation, and the coordinate transformation process can be greatly simplified. The analysis of voltage utilization shows that the elimination of the harmonic subspace can improve the voltage utilization rate. Experimental results verify that the proposed strategy can achieve lower torque ripples, lower system loss and less computation time compared with the existing fault-tolerant strategy.