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In this article, we investigate the short-circuit (SC) fault-tolerant control (FTC) method for a five-phase permanent-magnet synchronous machine (PMSM) with surface-mounted permanent magnets. By relieving the constraint of zero d-axis armature magnetomotive force (MMF) and restraining the backward-rotating MMF components to be zero, round-rotating armature MMF with maximum q-axis armature MMF is achieved, which enables five-phase PMSM to output maximum smooth torque with lower losses and higher efficiency under SC fault condition. To ensure smooth postfault operation in full-speed range, the influence of winding resistance on SC current is further considered, which improves low-speed operation performance. The proposed FTC method features sinusoidal currents with equal amplitude, which ensures better control simplicity and postfault thermal uniformity between phases. The finite-element analysis and experiments are carried out to verify the proposed method. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]