Open-Circuit Fault Analysis of Permanent Magnet Synchronous Motor Inverter

As a high-performance motor, the permanent magnet synchronous motor (PMSM) is widely utilized in the field of industrial automation. However, open circuit faults may occur during the operation of the PMSM, and these faults can be categorized into various types based on the working principle of the inverter. The traditional method of error current normalization is limited in its applicability to a small number of fault types and does not satisfy the requirements for subsequent fault diagnosis and fault-tolerant control. To address this issue, this paper focuses on the inverter of a three-phase PMSM drive system, identifies the types and characteristics of faults under inverter open-circuit conditions, and proposes a fault feature extraction method based on current fault information. This method requires only the three-phase output current of the motor to achieve the detection and location of five types of inverter open-circuit faults. By calculating the periodic average value of the three-phase current and the periodic average value of the absolute value of the three-phase current, the fault detection variables are constructed. Consequently, the characteristic values for fault diagnosis are obtained, enabling the detection and location of power tube open-circuit faults. Experimental results demonstrate that the proposed method can correspond to different combinations of eigenvalues for each fault, thereby facilitating the extraction of fault features for each type of open-circuit fault.