Compensation Strategy Based on Rotating Rhombus Method for Five-Phase PMSM With One-Phase Terminal Short-Circuit Fault

Abstract

Based on the rotating rhombus method (RRM), an equal-magnitude sinusoidal current compensation strategy is proposed to improve the post-fault performance of the five-phase permanent-magnet synchronous machine (PMSM) with short-circuit fault. RRM is a graphic method which is proposed to obtain optimal compensation currents, and the equal-magnitude phase currents are treated as rhombic current vectors. To maintain the same magnetomotive force (MMF) under fault condition, the geometric relations of a rhombus are used to derive phase angles of the compensation currents. The effectiveness of the proposed strategy is verified by a 10-slot/8-pole five-phase PMSM, and the torque ripple caused by short-circuit fault is significantly reduced. In addition, the proposed strategy is compared with an existing strategy from aspects of torque, torque ripple, losses, and efficiency, and the proposed strategy has advantages of balanced copper loss of the healthy phases and lower inverter cost.