Integrated design of speed sensorless control algorithms for induction motors

Bandwidth limitation hinders the economical and broad application of induction motors promised by speed sensorless drive. This paper proposes an integrated control and observer design for speed sensorless control of induction motors with stator voltage and current measurements. With a general observer structure, the backstepping-based robust control design explicitly considers the errors of both the state estimation and tracking, and thus avoids the commonly used time scale separation. The gain selection for the controller becomes easy and straightforward. As a case study, the extended Kalman filter is used as a state estimator in order to simplify the gain tuning process. Simulation results validate the effectiveness of proposed method.