Sensorless Control of PMSM based on Modified Sliding Mode Observer

This paper proposes three novel methodologies to improve the performance of sensorless control of permanent magnet synchronous motor (PMSM) based on sliding mode observer (SMO). One is using improved saturation function as the control function of SMO to weaken the inherent chattering of Sliding Mode Control. The second is constructing back electromotive force (EMF) observer instead of the traditional low-pass filter to eliminate the lag of estimated position caused by the filter. The third is adapting the dead-time compensation in the vector control algorithms to reduce the current distortion. The three improvements above can effectively improve the accuracy of the estimated position during PMSM high-speed operation, which are validated by experiments.