A New Composite Sensorless Control Strategy for PMSM Used in Electric Vehicle

The conventional (sliding mode observer) SMO employed in the sensorless control for the permanent magnet synchronous machine (PMSM) has the problems of chattering phenomena and phase delay, which always results in a large error between the estimation and actual values of the rotor speed and position. Thus, this paper proposes an improved SMO based on fuzzy logic controller (FLC) and dual second-order generalized integrator-frequency-locked loop (DSOGI-FLL) structure. The FLC is used to adjust the parameters of the SMO to improve the adaptive ability of the system and reduce the chattering phenomena. At the same time, in order to reduce the adverse effects from LPF, DSOGI-FLL is used to accurately extract the back electromotive force (back-EMF) and effectively eliminate the high-order harmonic components. The methods are verified by simulation in Matlab /Simulink and compared with the conventional SMO, the results show that the improved SMO has better performance.