Sensorless Control of IPMSM Drives Based on Extended State Observer With Enhanced Position Estimation Accuracy

In sensorless control of interior permanent magnet synchronous motor (IPMSM) drives, extended state observers (ESOs) are preferred due to their advantages, e.g., flexible application, and simple implementation. However, the conventional ESOs may experience the degraded performance with the challenging issues of rapidly changing back electromotive force (BEMF) in a sinusoidal form and ramp disturbances in position estimation. To enhance the position estimation accuracy, this article proposes an estimation scheme based on a novel generalized integrator ESO (NGI-ESO) and an integrally compensated (IC)-third-order (3rd)-linear ESO (IC-3rd-LESO). In the proposed estimation scheme, with the modified mathematical model of the BEMF, the NGI-ESO is designed to achieve accurate estimations of the BEMF. Moreover, the IC-3rd-LESO with a compensation loop is used to mitigate position estimation errors caused by the ramp disturbances. Consequently, the overall performance of sensorless-controlled-IPMSM drives is enhanced. The performance of the proposed estimation scheme under different conditions is verified and compared to that of the conventional ESO schemes by using extensive experimental tests.