Fractional order PID sliding mode control for speed regulation of permanent magnet synchronous motor

Abstract

This paper proposed a fractional order PID sliding mode control (FOSMC-PID) for speed regulation of permanent magnet synchronous motor (PMSM). Fractional calculus has been incorporated in sliding mode controller (SMC) design to enhance chattering suppression ability. However, the design of fractional sliding surface is crucial to ensure that speed tracking accuracy is not jeopardized. The proposed controller is designed with a fractional order PID sliding surface, which balances the characteristics of sliding surface with PI or PD structure in terms of robustness and dynamic performance of the controller. By simulation, speed tracking is proven to be faster and more robust with the proposed controller compared to SMC with integer order. Both integration and derivative terms in the surface design outperform FOSMC-PI and FOSMC-PD in terms of disturbance rejection and chattering. Experimental validation proves the advantage of the proposed controller in terms of robustness.