Discrete-time Observer for Induction Machine in Presence Magnetic Saturation

We are considering the problem of state estimation in induction motors. One key feature of this work is that the problem is dealt with based upon a model that accounts for the saturation effect of the magnetic circuit characteristic. Indeed, magnetic saturation cannot be ignored, especially when high power machines are considered. The above model is first based upon to analyse the machine observability. Then, a continuous-time high-gain observer is presented and discretized for omplementation purpose. Timediscretization is necessary because real-time implementation can only be done using digital equipments. The discretization task constitutes a crucial issue due to the nonlinear feature of the (continuous) observer. It is coped with using the Taylor-Lie method and the (discrete-time) observer thus obtained is validated experimentally using an asynchronous motor of 7.5 KW.