A Natural Fault-Tolerant Method for Six-Phase PMSM Using Model Predictive Current Control

The open-end winding six phase permanent magnet synchronous motor (PMSM) in safety-critical applications such as ship propulsion and electric vehicles, primarily due to robust fault-tolerant capabilities. Recently, natural fault-tolerant control methods are becoming more popular in the remedial strategy under open-phase faults. This paper investigates the performance of model predictive current control (MPCC) under single-phase open-circuit conditions, both before and after the fault occurs. Then, a duty ratio optimization (DRO) based on QPR controller is proposed for the first time. After the fault occurs, the QPR controller automatically corrects the duty ratio, mitigating control errors caused by vector shifting. This correction is achieved without the need of complex reconfiguration, fault diagnosis, or current reference adjustments. The proposed method is applicable to open-circuit faults (OCF) in any phase, simplifying the faulttolerant strategy. The transition from the healthy to the postfault operation can be improved, meanwhile, both steady-state and dynamic performance in prefault and postfault situations can be guaranteed. Extensive experimental results verify the effectiveness of the proposed method.