Simplified PWM for fault tolerant control of open winding PMSM fed by hybrid inverter

Abstract

This paper proposes a simplified PWM strategy for fault tolerant control of an open winding permanent magnet synchronous motor (OW-PMSM) fed by hybrid inverter (HI). The HI usually consists of two six-switch three-phase inverters (SSTPIs), the inverter powered by a DC source is named as main inverter (MI) and the inverter powered by a capacitor is named as compensation inverter (CI). When a power switch or a leg of CI fails, the CI can be reconfigured to a four-switch three-phase inverter (FSTPI). Since the phase current flows through the two capacitors in the FSTPI, it would introduce the neutral-point voltage fluctuation. By taking the unexpected neutral-point voltage fluctuation into account, a simplified PWM strategy is designed for the FSTPI, which can guarantee the high-quality voltages and currents even at the low speed states, it can also reduce the computation time of the system. Simulation studies have been carried out to verify the effectiveness and superiorities of the proposed strategy.