Commutation Error Autocorrection Method of Position Sensorless BLDCM Based on Terminal Voltage Transformation

This article focuses on a commutation error autocorrection method of position sensorless brushless dc motor, implemented through terminal voltage transformation. First, based on the correlation between commutation error and the inactive phase terminal voltage integral (IPTVI), a conversion circuit, transforming the IPTVI into a smoothly-varying analog voltage, is developed. Then, a closed-loop controller fed by the voltage sampled in low-frequency is established to correct the commutation automatically. This approach overcomes the conventional limitation of high sampling speed required for accurate feedback, enabling precise commutation error correction. Finally, experiments on a magnetically suspended control moment gyro verify the proposed method.