Fractional order robust control for cogging effect compensation in PMSM position servo systems: Stability analysis and experiments

Fractional calculus is a generalization of the integration and differentiation to the fractional (non-integer) order. In this paper, for the first time, a fractional order robust control (FO-RC) method is devised for cogging effect compensation on permanent magnetic synchronous motors (PMSM) position and velocity servo system. In this FO-RC scheme, a fractional order robust controller is designed to compensate the cogging effect, and guarantee the boundedness of all signals. Stability properties have been proven for the systems with the traditional integer order robust control method and the proposed fractional order robust control scheme, respectively. Simulation illustration and experimental validation are presented to show the advantage of the proposed FO-RC scheme for cogging effect compensation over the conventional integer order method.