Cascaded Nonsmooth Observer-Based Position Sensorless Control of Permanent Magnet Synchronous Motor

This paper proposes a sensorless algorithm based on a cascaded nonsmooth state observer structure for permanent magnet synchronous motor. Specifically, the front-stage nonsmooth observer is used to extract the back electromotive force (EMF) information of the motor in the paper, and the backstage nonsmooth observer uses the EMF extracted by the front-stage observer to synchronously solve the motor’s position and velocity information. Compared with the traditional technique of super-twisted sliding mode observer combined with a phase-locked loop to estimate the angle and angular velocity of the motor, the speed chattering can be further reduced to a certain extent, the position estimation accuracy can be improved, and the dynamic performance of the motor control system can be enhanced.