Robust nonlinear predictive control of a permanent magnet synchronous motor

A robust nonlinear predictive controller with a disturbance observer for a permanent magnet synchronous motor (PMSM) is presented. As the disturbance relative degree is less than that of the input, it is quite challenging to adopt the existing disturbance observer-based predictive control techniques. In the proposed controller, robustness of the closed loop system with respect to mismatched parameters and unknown load torque is significantly improved. Stability of the closed-loop system is proved, and the controller is easy to implement. Validity of the proposed controller was experimentally tested on a dSPACE DS1104 board driving a 0.25 kW PMSM drive. Excellent results were obtained with respect to the speed trajectory tracking performance and robustness.