Design and analysis of a new six-phase fault-tolerant hybrid-excitation motor for electric vehicle

The interior permanent-magnet (IPM) motor has been widely used in EVs, due to its advantages of high efficiency, high density and wide constant-power speed range inherently. The traditional IPM with three-phase winding has a low reliability at the fault conditions and high torque ripples. To improve the reliability of driving system, a fractional-slot concentrated-winding fault-tolerant interior permanent-magnet motor is investigated in. However, it couldn´t work under the demagnetization fault, which will deteriorate the performance of driving system. Hybrid excitation machines can resolve the demagnetization problem of PM when motor operates at high speed. Nevertheless, traditional excitation machines have the problems of complicated structures or sliding contacts. To overcome the above-mentioned problems, a new six-phase fault-tolerant hybrid-excited (FTHE) motor is proposed and investigated in this paper. It can reduce the overall system weight instead of having redundancy at the drive system level. Moreover, it has a high fault-tolerant capacity with short-circuit fault, open circuit fault, demagnetization fault, and so on.