Design of Full-Order Flux Observer for Induction Motor Drive Robust to Rotor Time Constant Variation

This paper proposes a novel full-order flux observer for flux estimation of an induction motor robust to rotor time constant variation. The influence of rotor time constant error in the conventional full-order flux observer is analyzed in the frequency domain, and it is verified that the proposed method has better property on the rejection of the rotor time constant error on flux estimation. The proposed observer is designed on the synchronous reference frame with a simple synchronous speed estimator which doesn't require additional control loop such as phase locked loop or position estimator which was commonly used when constructing the observer on the synchronous reference frame. The reduced influence of rotor time constant error to the observer is verified with simulation and experimental results.