Research on sensorless control strategy of PMSM

Aiming at the problems of overshoot, chattering and slow response in the sensorless control system of permanent magnet synchronous motor (PMSM) for electronic water pump, PMSM sensorless control algorithm based on hybrid sliding mode speed controller and Luenberger observer was proposed. In the speed loop, a sliding mode speed controller based on the new reaching law was designed. On the basis of the traditional exponential reaching law, the motion error of the moving point was introduced into the constant velocity term, and the hyperbolic tangent function was adopted to replace the comparison switching function, so as to improve the convergence speed and chattering suppression ability of the sliding mode. The Luenberger observer of the linear control structure combined with the phase-locked loop was applied to the sensorless control system, in order to improve the chattering problem and stability of the estimated speed. The simulation results show that under the no-load starting and external disturbance conditions of the motor, the algorithm can effectively improve the speed tracking effect of PMSM sensorless control system, improve the speed overshoot and chattering problems, and enhance the anti-interference ability of the system.