Analysis and Real-Time Calculation of Post-Fault Current of Standard Surface-Mounted PMSM Drives with Dysfunctional Power Switches

• Published in: IEEE transactions on power electronics 2023-05, p.1-11
• Main Authors: Zhang, Zeliang, Hu, Yihua, Luo, Guangzhao, Xu, Hui, Gong, Chao
• Format: Article
• Language: English
• Subjects: Circuit faults; Fault tolerance; Fault tolerant systems; Integrated circuit modeling; Inverters; Open Circuits; PMSM; Power Switches; Rails; Switches
• ISSN: 0885-8993
• DOI: 10.1109/TPEL.2023.3277913

Fault diagnosis and fault-tolerant control significantly rely on the knowledge of fault mechanisms and post-fault states. Regarding open circuits in permanent magnet synchronous motor drives, the post-fault states, especially phase voltages, depend on whether the faulty phase is conducting. Under the open-switch fault featuring dysfunctional power switches, the faulty phase is possible to conduct through the still functional diodes. In contrast, the open-phase fault completely blocks the faulty phase. However, the mechanism and effects of the open-switch conduction have not been thoroughly studied, which obscures the boundary between the open-switch fault and the open-phase fault, and fails to realize effective diagnosis and optimal fault-tolerant control. This paper not only reveals the mechanism of the open-switch conduction, but also proposes a model that can calculate the post-fault conducting current in real time. The proposed model provides an estimation value of the post-fault current for further utilization and validates the correctness of the analysis. Firstly, equivalent circuits are analyzed to explain the conduction condition. Subsequently, switching states fulfilling the conditions are studied, and finally, the mathematical model of the post-fault current is built. The analysis and model are experimentally validated.