Second order sliding output control of Permanent Magnet Synchronous Machines

In this paper, a robust MIMO output control law for Permanent Magnet Synchronous Machines (PMSM) is considered. The nonlinear model of the motor is presented, and a control strategy is proposed, based on high order sliding manifold dynamic output control concepts. A rigorous proof of the stability is presented, based on nonlinear Lyapunov theory and fuzzy mathematics tools (although the controller is not fuzzy), and a constructive numerical approach based on a step by step design of the controller, involving the solution of a set of LMI (Linear Matrix Inequalities) and the selection of parameters defining the bandwidth of the controller is proposed. The controller structure has intrinsically a set of poles at the origin, thus embedding an integral action in the design always required in the case of motor control. Different extensions and generalizations are also proposed. Numerical simulations show the effectiveness of the proposed approach in terms of disturbance rejection.