Sensorless Fault-Tolerant Control of A Nine-phase Permanent Magnet Synchronous Motor under One-phase Open-Circuited Fault

In order to realize sensorless control of multiphase permanent magnet synchronous motors (PMSMs) under open-phase open-circuited fault, in this paper, a newfangled sensorless fault-tolerant control strategy based on the offset coordinate transformation is proposed in this paper. Firstly, the fault nine-phase PMSM’s fundamental mathematical model of is constructed with the proposed coordinate transformation. Secondly, the accuracy of rotor position information estimation is improved by modified sliding mode observer (SMO) and orthogonal phase-locked loop (PLL), which can eliminate the higher harmonics and DC bias in the back electromotive force (EMF) effectively. Finally, simulation phenomenons certify that the newfangled sensorless fault-tolerant control strategy can guarantee operating performance of PMSMs under one-phase open-circuited fault.