Research on Fractional-Order Sliding Mode PMSM Speed Regulation Based on Load Observer

In this paper, a fractional-order sliding mode control (FOSMC) strategy based on load observer is proposed. First, a FOSMC strategy is designed to control the speed loop of the permanent magnet synchronous motor (PMSM). The fractional-order calculus is introduced and the exponential reaching law is improved to enhance the chatter suppression capability of the system, which solves the contradiction between fastness and chatter in the traditional sliding mode control (SMC). Second, a load observer with a state error differential term is designed to observe the system disturbances and compensate the observed values into the control system to improve the anti-disturbance capability of the system. In addition, to avoid trial and error of the arrival method parameters, an improved particle swarm optimization (PSO) algorithm is designed to optimize the controller parameters. By simulation, the proposed method is superior to PI and integer-order sliding mode control (IOSMC) in anti-disturbance capability, which verifies the validity of the proposed method.