Parameters estimation of IM with the Extended Kalman filter and least-squares

In the AC drive system, the control performance is highly dependent on the accuracy of the electromagnetic parameters. In order to reduce the influences of the parameter variations, a new scheme for on-line rotor time-constant and magnetizing inductance estimation in induction motors is proposed. The algorithm is obtained by interlacing a Bi-Loop recursive least squares algorithm with forgetting factors (BLFRLS) estimator and an Extended Kalman filter. At every time step, the former provides the rotor time-constant estimate which is used by the latter for the state variable reconstruction. Both computer simulation and experimental results demonstrate that the proposed scheme show a high estimation accuracy of induction motor parameters.