Influence of Inverter Open Circuit Fault on Multiple Physical Quantities in the PMSM

The fault of the drive system mainly occurs in the power transistor of the inverter. Compared with the short-circuit fault, open-circuit fault is not easy to perceive and accurately detect, and it will not cause instantaneously devastating damage to the system. In the case of the open-circuit fault, the motor will be in limp operation mode. At present, most of the research results are focused on fault detection methods, and have not analyzed the situation of multiple physical quantities in the limp mode. In this article, the system hybrid logic dynamic model in different combinations of open-circuit faults under vector control mode is established, and the transient characterization of the current is presented. Furthermore, the system-level analysis model of inverter and motor coupling for fault analysis is proposed, and the change rule of electrical parameters, magnetic field, speed, torque, and loss of PMSM under four fault modes is comprehensively studied. Based on the theory of transient temperature field and fluid dynamics, the three-dimensional global temperature analysis model with electromagnetic-temperature bidirectional coupling is established, and the thermal evolution law and limit temperature rise of permanent magnet synchronous motor (PMSM) are revealed. A lot of experiments are done to verify the analysis correctness, combining with the theoretical research results, the fault conditions, and working range of the motor that can maintain the limp operation are given.