Adaptive flux observer for induction machines with on-line estimation of stator and rotor resistances

A nonlinear adaptive control algorithm is proposed for induction machines. It is based on a two time-scale observer that allows the on-line identification of three critical uncertain parameters, i.e., load torque and motor stator and rotor resistances. In addition, the set-point of the rotor flux is adjusted in order to minimize the Joule losses and to improve the power efficiency. Experimental results illustrate the feasibility of the developed approach.