Open-Circuit Fault-Tolerant Control for Five-Phase Permanent Magnet Motors with Trapezoidal Back-EMF by Deadbeat Current Tracking

When an open-circuit fault occurs, the third harmonic current needs to be injected to utilize the third harmonic back-EMF for the five-phase permanent magnet motor with trapezoidal back EMF. In this case, the fault-tolerant reference current in the static coordinate system is the AC quantity. Due to the bandwidth limitation, the traditional proportional-integral (PI) controller is difficult to track the AC fault-tolerant current accurately, which limits the smooth operation of the system. For this reason, this paper proposes a new fault-tolerant control strategy based on deadbeat current tracking. Firstly, to generate smooth torque under fault condition, the fault-tolerant reference current is obtained according to the principle of zero torque ripple. Secondly, by Euler's discrete method, the discrete models of the motor under single-phase open-circuit and two-phase open-circuit faults are constructed respectively. And then, the deadbeat method is used to track the alternating fault-tolerant reference current, which provides accurate reference voltages for the carrier pulse width modulation (CPWM). Finally, an experimental platform is constructed, and the results verify the effectiveness of the proposed control strategy. © 2022, Electrical Technology Press Co. Ltd. All right reserved.