Sensorless vector controlled induction motors using adaptive observation

This paper presents the synthesis of an adaptive observer which is used for the improvement of the Direct Field Oriented Control (DFOC) of induction motor drives. The observer detects the rotor flux components in the stationary reference frame and the rotor speed using the measure of the stator terminal voltages and currents. The observer is adapted using a simple algorithm which does not imply a high computational load. Stability analysis based on Lyapunov theory is performed in order to guarantee the closed loop stability. Simulation tests under disturbances are provided to evaluate the consistency of the proposed control technique.