Improved PMSM speed control based on a novel sliding-mode load disturbance observer

A novel load disturbance observer based on the second-order sliding-mode theory is proposed in this paper, which can effectively improve the dynamic response of the speed control loop and the anti-disturbance performance of the whole system under the external load disturbance and mechanical parameter mismatch of PMSM. The load disturbance observer is constructed by considering the parameter variation and external load disturbance to estimate the total disturbance in the speed control loop. Moreover, based on the second-order sliding-mode theory, an appropriate sliding mode function is selected to improve the observation accuracy of the disturbance and essentially alleviates the chattering phenomenon. Experimental results verify the effectiveness of the proposed method.