High Gain Observer with Updated Gain for Sensorless Induction Motor

The main contribution of this paper was to design a new high gain adaptive observer with updated gain for speed-sensorless induction motor (IM) drives using only the stator current measurements. The proposed algorithm transforms the IM model into a canonical observable form by a change of state coordinates, and then performs an observer design in the new coordinates. The proposed observer can be viewed as an improved version of the observers proposed in the literature. The main advantage of this observer lies in the nature of the observer gain that involves a scalar time-varying design parameter governed by Riccati equation. Simulation results have been given to demonstrate this engineering feature. Future work includes experimental validation in the feedback loop.