Nonlinear Torque Tracking Control of Induction Motors

Abstract In a recent paper (Ortega and Espincsa. 1991) presented a globally stable controller for torque regulation of a complete induction motor model with partial state feedback, i.e. no assumption of flux measurement. The result was established under the assumptions that both the desired and lead torques are constant, that the fermer does not excede certain bounds which depend on the systems natural camping, and that the motor parameters are known. In the present contribution we extend these results in several directions. First, by “adding mechanical damping” to the closed-loop system we relax the upper bound condition on the desired torque. Second, we use a new controller structure that allows us to treat the case of time-varying desired torque. Finally, a new estimator is proposed to handle time-varying, but linearly parametrized unknown loads.