Simple and Effective Position Estimation Error Compensation Method for Sensorless SPMSM Drives

In the existing high frequency signal injection sensorless control methods for Surface mounted Permanent Magnet Synchronous Machine (SPMSM), use of filters in the estimator, inverter voltage error and cross-saturation effects will all influence the position estimation accuracy. Particularly, errors caused by shifted rotor magnetic saliency related to the load current is difficult be compensated by the sensorless algorithm itself. This paper proposes a new on-line method to compensate the position estimation error for sensorless SPMSM drives. The proposed method can identify effectively the position estimation error by simply varying the direction of the current vector and utilizing the machine torque equation. Experimental results are presented to validate the proposed solution.