基于DTC的异步电机三相六开关容错控制策略

Three-phase six-switch tolerant control strategy of induction machine based on DTC

基于DTC的三相四开关逆变器容错控制策略只能解决单管故障问题,且具有转矩脉动大的缺点。在深入分析三相四开关和六开关逆变器电压矢量特点的基础上,充分挖掘正常开关管的潜能,在不改变逆变器拓扑结构和开关管数量的前提下,重构了单管故障状态下的电压矢量扇区和开关表,提出了一种在故障状态下的三相六开关容错控制策略,可形成六个电压矢量和一个零电压矢量,较三相四开关容错控制策略仅可提供四个电压矢量有明显改善。在此基础上,分析了三相六开关可能出现的连锁故障现象,并提出了相应的容错控制策略。仿真结果表明,所提出的三相六开关容错控制策略可有效降低转矩脉动,并可处理大部分开关管连锁故障的情况,具有更大的优越性。

The tolerant control strategy of three-phase four-switch inverter based on direct torque control can only solve the single-switch fault problem with the disadvantage of large torque ripple. By analyzing three-phase four-switch and six-switch inverter voltage vector characteristics, to make full use of the nor-mal switches, the voltage vector sector and switch table at the inverter fault were reconstructed and a new kind of tolerant control strategy, three-phase six-switch tolerant control strategy, was proposed under the precondition of the same inverter topological structure and switch quantity. This new tolerant control strat-egy can provide six voltage vectors and one zero-voltage vector. It is better than the three-phase four-switch tolerant control strategy which has only four voltage vectors to choose. Furthermore, the possible cascading faults of three-phase six-switch were analyzed and the corresponding tolerant control strategy was proposed. The simulation results show that the new tolerant control strategy proposed has more advan-tages such as effectively reducing the torque ripple and adaptability for the cascading faults.