On line tuning of the stator inductance in a MRAS observer for sensorless DFIM drives

This paper proposes a scheme for the self tuning of the stator inductance in a Rotor Current MRAS Observer for the sensorless control of Doubly Fed Induction Machines. The effect of mismatched parameters in this observer is briefly discussed and the strong dependence of the estimated rotor position on the stator inductance is highlighted. A self tuning scheme is formulated by using only quantities which are already exploited by the observer, so that only a marginally additional computational effort is required in the implementation. Some guidelines to design the tuning loop are given. Finally the performances of the proposed scheme are experimentally tested and discussed.