Speed sensorless control of induction motor based on feedback linearization

In this paper, a robust sensorless speed-control of induction motor has been developed, which the rotor speed and flux are estimated by a Model Reference Adaptive System (MRAS) algorithm. First, a feedback linearization associated to a sliding mode method is applied to field- oriented induction motor model. The sliding surface is a second order equation which allows us to impose the dynamics of induction motor model by the choice of the roots of the surface equation. The choice of a particular switching surface permits to create a link between sliding mode theory and input–output linearization, ensuring an exact decoupling of the mecanical speed and rotor flux amplitude. A Model Reference Adaptive System technique is proposed to develop suitable adaptation mechanism, that generate the estimates of rotor speed and rotor flux amplitude. Some experimental results are presented to verify the control theory and demonstrate the robustness and effectiveness of the proposed sliding mode linearization technique.