A methodology to determine gains of induction motor flux observers based on a theoretical parameter sensitivity analysis

A method to compute gains of induction machine flux observers, based on a theoretical sensitivity analysis taking the magnetic saturation into account, with the aim to minimize the observer sensitivity to electrical parameter uncertainties is proposed in this paper. It is shown for a reduced order observer, that the sensitivity to parameter uncertainties may be independent of the reference frame, when a modification is introduced in the classical determination of the slip frequency. It is also shown how to extend the proposed method to a full order observer. The theoretical study is completed by experiments on a 750 W induction machine (using DSP TMS320C31) which confirms the theoretical results.