采用无差拍电流跟踪的五相梯形反电动势永磁电机开路容错控制

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

在开路故障下,为了利用五相梯形反电动势永磁电机的3次谐波反电动势,需注入3次谐波电流。此时,静止坐标系下的容错参考电流为交流量,传统比例积分控制器由于带宽的限制,难以准确跟踪交流容错电流,维持系统的平稳运行。为此,该文提出采用无差拍电流跟踪的新型容错控制策略。首先,根据故障后转矩脉动为零的原则获取故障后的容错参考电流,使电机在故障情况下仍能输出平滑的转矩;其次,以欧拉离散的方法构建单相开路、两相开路故障状态下电机的离散模型,利用无差拍方法追踪交变的容错参考电流,为载波脉宽调制提供准确的参考电压;最后,构建驱动实验平台,实验验证所提控制策略的有效性。

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.