Abstract: Fault tolerant permanent magnet (FTPM) motor not only has the ability of fault toleration and isolation, but also has the advantages of high power density and low torque ripple inherited from traditional permanent magnet motor, which makes it develop rapidly in aeronautical electric actuation system. Optimal torque control (OTC) strategy can get a ripple-free electromagnetic torque under both healthy and faulted (one phase is short-circuit or open-circuit) conditions. In this article, two simple and reliable winding fault diagnosis methods are proposed based on a designed 750 W six-phase ten-pole FTPM motor control system. Furthermore, experimental study on OTC strategy is carried out. The experimental results show that by OTC strategy, torque and speed characteristics under faulted condition are as good as those under healthy condition, and torque ripples are both less than 20%. What’s more, the dynamic response is fast.

Key words: fault tolerant permanent magnet motor, optimal torque control, six-phase ten-pole, winding fault, actuators