A Simultaneous Diagnosis Method for Current Sensor and Power Switch Faults in Three-Phase VSI-Based PMSM Drives

The safety of permanent magnet synchronous motor (PMSM) drives has received increasing attention. The current sensor is one of the most sensitive components in the motor drives, which determines the control performance and is of great significance for the realization of fault tolerant control and maintenance decisions. The features of current sensor and power switch faults are similar to some extent, so it is necessary to identify them simultaneously. On the basis of establishing the high-confidence faulty current model, this paper proposes a diagnosis method which can identify 15 kinds of current sensor faults and 9 kinds of power switch open-circuit faults. The zero sequence current is used to distinguish the faults of current sensor and power switch. The integrated operator, calculus operator and zero-phase current ratio are used to identify various fault types, and the anti-misdiagnosis function is added to improve the robustness of the method. The fault diagnosis method is not affected by the change of control parameters and operating parameters, so it has high flexibility. Finally, the effectiveness and robustness of the proposed method are verified by a large number of experiments under various operating conditions.