Low-Vibration Fault-Tolerant Control for Five-Phase PMSM Using Modified SVPWM and Random Modulation Strategy

Abstract

Vibration issues due to open-circuit faults have been overlooked by existing fault-tolerant control methods. To reduce vibrations in five-phase permanent magnet synchronous motors (PMSMs) under open-circuit fault conditions, a low-vibration fault-tolerant control method using modified space vector pulsewidth modulation (SVPWM) and random switching frequency (RSF) SVPWM is proposed. Virtual voltage vectors for the faulty PMSM are reconstructed using basic vectors with the constraint of zero harmonic spatial components. The action time of the virtual voltage vectors, considering the back electromotive force (EMF) of the faulty phase, is then calculated. To suppress high-frequency harmonics without compromising the fault-tolerant performance of the motor, a new RSF-SVPWM with restricted random numbers and improved probability density is proposed. By combining the modified SVPWM with the RSF-SVPWM, the proposed method can reduce vibration while maintaining good fault-tolerant performance. Experimental results validate the feasibility of the control strategy.