Robust Nonlinear Receding-Horizon Control of Induction Motors

A nonlinear robust receding-horizon control is designed and applied to fifth-order model of induction motor in cascade structure. The control uses only measurement of the rotor speed and stator currents. The rotor flux is estimated by Kalman filter. The controller is based on a finite horizon continuous time minimization of the predicted tracking errors and no online optimization is needed. An integral action is incorporated in external loop to increase the robustness with respect to unknown time-varying load torque. The proposed nonlinear controller permits to achieve asymptotic speed and flux tracking in presence of the unknown load torque and resistances variations. In addition, it assures asymptotic decoupling of the speed and flux subsystems. The controller is applied, via simulation, to a benchmark example.