Fault-Tolerant Control for Multiple Open-Leg Faults in Open-End Winding Permanent Magnet Synchronous Motor System Based on Winding Reconnection

Abstract

The dual-inverter fed open-end winding permanent magnet synchronous motor (OEW-PMSM) driving system with a common dc bus is attracting more attention in electric vehicle applications due to its simple structure, wide speed range, and strong fault-tolerant capability. To improve the fault-tolerant capability of the OEW-PMSM driving system for multiple open-leg faults, a fault-tolerant control (FTC) method based on winding reconnection is proposed in this article. Based on the idea of leg sharing, five-leg operation, four-leg operation, and even three-leg operation can be realized by winding reconnection, hence providing fault-tolerant operation for open-circuit fault in up to three legs. Since all three windings can work and the three-phase voltages are practically unchanged in FTC mode, the output capacity in the FTC mode is not reduced. By adopting the phase shift decoupled space vector pulsewidth modulation, the pulsewidth modulation strategy used in different operation modes can be unified, resulting in a simpler FTC method. The effect of the dead time is analyzed to explain the variation of the zero-sequence current in different operation modes. Experimental results are established to validate the proposed method.