This article proposes a novel type of the 2nd and 4th harmonic torque suppression methods during conventional single-phase open-circuit fault-tolerant operation when considering the 3rd harmonic back-EMF of permanent magnet synchronous motor (PMSM). These suppression methods are based on injecting the 3rd harmonic currents into the two remaining healthy phases, which produces harmonic torque of opposite phase to cancel the original one. The suppression can have three different constraints: maintaining the average torque, eliminating the 2nd harmonic torque, and eliminating the 4th harmonic torque. They cannot be achieved simultaneously. Combining any two of them leads to a particular injection method. Three particular methods are developed and their performance are investigated by theoretical analysis and compared against the conventional one. The proposed fault tolerant control strategies are applicable to various fault-tolerant inverter topologies by using these novel phase current references, whereas the current tracking algorithms could be different. To ease validation, a four-leg inverter topology is selected to implement such injection methods to a three-phase star-connected 10-pole/9-slot PMSM. The experiments validate that tracking the proposed current references can effectively suppress the harmonic torque, which confirms the theoretical analysis.

中文翻译：

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考虑三次谐波BEMF的PMSM单相开路容错运行谐波扭矩抑制方法


本文在考虑永磁同步电机（PMSM）的三次谐波反电动势时，提出了一种新型的传统单相开路容错运行期间的二次和四次谐波转矩抑制方法。这些抑制方法的基础是向剩余的两个正常相位注入三次谐波电流，产生相反相位的谐波扭矩来抵消原来的谐波扭矩。抑制可以具有三个不同的约束：维持平均扭矩、消除二次谐波扭矩以及消除四次谐波扭矩。它们不能同时实现。将它们中的任何两个组合起来就会产生特定的注入方法。开发了三种特殊方法，通过理论分析研究了它们的性能，并与传统方法进行了比较。通过使用这些新颖的相电流参考，所提出的容错控制策略适用于各种容错逆变器拓扑，而电流跟踪算法可能不同。为了简化验证，选择四桥臂逆变器拓扑来对三相星形连接的 10 极/9 槽 PMSM 实施此类注入方法。实验验证了跟踪所提出的电流参考可以有效抑制谐波扭矩，这证实了理论分析。