Robust stator-flux-oriented induction motor drive with hybrid sliding mode speed controller

A robust stator-flux-oriented induction motor (IM) drive using on-line rotor time-constant estimation with a hybrid sliding mode speed controller is introduced in this paper. The estimation of the rotor time-constant is made on the basis of the model reference adaptive system (MRAS) using an energy function; and the estimated rotor time-constant is used in the current decoupled controller, which is designed to decouple the torque and flux in the stator flux field-oriented control. Moreover, a hybrid sliding-mode speed controller, comprised of an integral-proportional (IP) speed controller and a sliding-mode controller with an integral-operation sliding surface, is designed to increase the robustness of the speed control loop. When a sliding mode occurs on the sliding surface, the control system acts as a robust state feedback system.