An Improved Control Strategy Based On Sliding Mode Observer for Sensorless PMSM Drives

In the medium and high speed range applications, the sensorless speed control of PMSM based on the back EMF are reliable as well as low cost. This paper proposes a simplified sliding mode observer to obtain precise rotor position and applies a closed-loop current regulator in startup process. The method can meet different load conditions and smoothly transition to the double closed-loop sensorless vector control state. The entire control strategy has features of simple structure and high robustness. It only requires little computing power and is suitable for low-cost microchips. The validity of the proposed control method is verified on a PMSM experimental platform.