A Diagnosis Method of Semiconductor Power Switch Open-Circuit Fault in the PMSM Drive System with the MPCC Method

The model predictive current control (MPCC) method has been widely used in permanent magnet synchronous motor (PMSM) drive systems for excellent dynamic performance. The fault diagnosis of the PMSM drive system becomes as important as dynamic performance improvement. The open-circuit fault of the semiconductor power switches is commonly seen in the PMSM drive system, which causes safety issues due to the abnormal operation of the system if the fault has not been detected. However, the previous fault diagnosis methods are mainly aimed at PMSM drive systems with conventional control methods. Focused on PMSM drive system with MPCC method, a diagnosis method of semiconductor power switch open-circuit fault has been proposed. The calculated result of the cost function in implementing the MPCC algorithm has been picked as the primary characteristic parameter for fault diagnosis, which is derived through comparative analysis of the operation in fault conditions with normal conditions. In addition, the monitored stator current and the gate-driving signals of the switches are used as subordinate fault characteristic parameters. The selected three fault indices together with a digital filtering algorithm complete the switches' open-circuit fault diagnosis. A MATLAB/Simulink model has been built to validate the effectiveness of the proposed fault diagnosis method. The simulation results verify the proposed method's robustness against the operating point and parameter mismatch of the PMSM drive system.