Generalized proportional integral observer based sliding mode control method for PMSM speed regulation system

In this paper, we discuss the speed regulation problem of permanent magnet synchronous motor (PMSM) system under unknown time-varying disturbances. Firstly, considering system disturbances, which generally include model uncertainties and external disturbances, as lumped time-varying disturbances, it is estimated by a generalized proportional integral (GPI) observer. Secondly, combining disturbances estimation and continuous sliding mode control (SMC) method, a composite sliding mode control method, called the SMC+GPI method, is obtained for the speed loop of PMSM system. Compared with conventional sliding mode control technique, the proposed method completely eliminates chattering phenomenon caused by switching function in control law. Also, by feed-forward compensating the estimated value of system disturbances, the disturbance rejection capability of continuous SMC method is enhanced largely. simulation results are provided to demonstrate the superior properties of the proposed control method.