Rotor Flux and Rotor Resistance Estimation Using Extended Luenberger-Sliding Mode Observer (ELSMO) for Three Phase Induction Motor Control

The accuracy for the three-phase induction motor control highly depends on obtaining/estimating the undetectable motor parameter values such as the rotor resistance and flux. An extended Luenberger-sliding mode observer (ELSMO) is proposed in this paper to estimate the rotor flux and resistance along with the adaptation method to compensate for the error caused by the motor parameter mismatch with the model in the controller. The motor parameter mismatch is caused mainly by resistance variation due to changes in the temperature during the operation and must be rectified in real time. The rotor resistance estimation is based on the Lyapunov stability theory and fed back into the ELSMO for more accurate current/flux/resistance estimation.