Robust speed sensorless control of universal field oriented induction motor drive with on-line stator resistance tuning

In this paper, a speed sensorless induction motor drive is introduced which is direct vector controlled in a universal field-oriented (UFO) reference frame. Based on partial feedback linearization theory, a nominal speed control is designed first, regardless of the system parameter uncertainties and external load disturbance. Then, in the perturbed condition, a fuzzy-adaptive sliding mode controller is employed which ensures the sliding motion through the entire drive system state trajectory. Furthermore, a model reference adaptive system (MRAS) estimator is used to estimate the rotor speed and a simple method is also proposed for on-line estimation of the stator resistance. Finally, a digital simulation study is carried out to demonstrate the effectiveness of the proposed speed controller scheme.