A novel sensor-less position and speed estimation scheme for wound rotor induction machine

A novel sensor-less position and speed estimation scheme for a three phase wound rotor induction machine is described in this paper. The algorithm is based on axes transformations. The algorithm can be started on the fly without the knowledge of the initial rotor position. Estimation at or near synchronous speed, corresponding to zero rotor frequency, is accurate. Effects of step changes in load torque and changes in supply voltage and supply frequency on the position/speed estimator performance have been investigated through MATLAB simulations. Simulation results are shown for the proposed scheme. It is found that the algorithm is very robust, with a maximum error of less than 2% in all.