Luenberger state observer for speed sensorless ISFOC induction motor drives

Abstract

This paper presents an original method for the implementation of a sensorless indirect stator-flux-oriented control (ISFOC) of induction motor (IM) drives. Indeed, the proposed method for speed estimation is based on Luenberger observer (LO). The adaptive rotor speed is actually derived from Lyapunov stability theory by using measured and estimated stator currents and estimated stator flux. The proposed control scheme, as a result, achieves a good performance with computational complexity reduction obtained by using the analytical relation to determine the LO gain matrix. Again, the observer is simple and robust, when compared with the previously developed observers, and suitable for online implementation. For current regulation, however, this paper suggests a conventional Proportional–Integral (PI) controller with feed-forward compensation terms in the synchronous frame. Owing to its advantages, an Integral–Proportional (IP) controller is used for rotor speed regulation. The simulation and experimental results additionally show its validity and effectiveness.