A nonlinear Luenberger observer for sensorless vector control of induction motors

This paper presents a nonlinear Luenberger observer for induction motors. The proposed estimation method is based on the combination of two different state observers, i.e., a full order state-observer and a reduced order state-observer of the motor variables. The state estimation of the full order observer is adjusted by comparing the estimated stator currents with the measured currents, and the estimated components of the rotor flux vector with the predicted flux components provided by the reduced order observer. The performance of the observer is assessed by experimental tests.