Speed Control for PMSM Based on Sliding Mode Control With a Nonlinear Disturbance Observer

This paper aimed at the speed control of PMSM. To optimize the response speed, gain satisfactory tracking performance and robustness of the PMSM, a hybrid approach is proposed by including novel sliding mode control (SMC) and nonlinear disturbance observer (NDO). Firstly, the SMC method is presented and applied to the design of speed controller to ameliorate speed tracking performance of the motor and reduce the adjusting difficulty of the controller parameters. The SMC speed controller is designed by including the speed loop and the feed-back q-axis current loop. Secondly, considering the effect of unknown disturbances in motor speed performance, a NDO is designed to observe matched and mismatched disturbances. Then, the estimated disturbances are introduced for the speed controller. Finally, the simulation results revealed that, the SMC+NDO method can guarantee strong robustness and possess the desired disturbance rejection capability for the PMSM with ensured good tracking performance.