A novel sliding mode observer for PMSM sensorless vector control

This paper presents a novel second order sliding mode observer to estimate the rotor position and speed in the sensorless control for PMSM. The second order sliding mode control law is achieved by a Lyapunov function approach and the algorithm is easily to be realized. Compared to the conventional sliding mode observer, the novel method can successfully eliminate the system chattering problem omitting the low pass filter in the conventional sliding mode observer and improve the precision of the estimated motor position and speed. Its feasibility and effectiveness are validated through computer simulation.