Fault-Tolerant Direct Torque Control of Five-Phase FTFSCW-IPM Motor Based on Analogous Three-Phase SVPWM for Electric Vehicle Applications

Abstract

High reliability is important in motor driving system for electric vehicle applications. In this paper, a fault-tolerant direct torque control for a five-phase fault-tolerant fractional-slot concentrated-winding interior-permanent-magnet (FTFSCW-IPM) motor under the open-circuit condition of a single phase is proposed, in which an analogous three-phase space vector pulse width modulation (SVPWM) control strategy is adopted. The DTC system for the five-phase PM motor based on healthy SVPWM has several advantages of improved currents and low torque and flux ripples. To achieve the fault-tolerant operation of the SVPWM-DTC system, an analogous three-phase SVPWM strategy is proposed. The proposed SVPWM fault-tolerant control scheme is achieved by the division of six sectors and the reconfiguration of six equal nonzero voltage vectors, which is quickly computed and easily realized. In addition, based on a 2-kW FTFSCW-IPM motor prototype, the good performances of the proposed fault-tolerant drive are validated by both simulations and experiments, in which the average torque and low torque ripple during fault can be maintained. Finally, the dynamic performances under healthy and fault-tolerant conditions are measured. The results show that the proposed analogous three-phase SVPWM control can offer good dynamic performance, which is comparable to the healthy SVPWM.