Current Sensor Fault Diagnosis in PMSM Drives Without Additional Hardware

This article investigates the influence of faults in the phase current measurement channel on torque generation in permanent magnet synchronous motor (PMSM) drives. It is demonstrated that measurement errors, depending on their type and origin, significantly distort the actual electromagnetic torque as a function of the motor shaft angle. Since the current controller operates on incorrect values, indirect diagnostic methods are required. This study shows that analyzing the output signals of the current component controllers, particularly the torque regulator output and its phase relation to the electrical or mechanical angle, enables fault detection and classification. The waveform, frequency, and amplitude of these signals provide information about the fault’s nature, with offset errors having a more pronounced impact on torque across the entire load range than gain-related errors.