Sensorless control of grid-connected doubly-fed slip-ring induction motor drive

A speed estimation method is presented in this paper for a grid connected doubly-fed slip-ring induction motor drive. The proposed method is formulated with reactive power based model reference adaptive system (MRAS). The method does not require any estimation of flux and is also independent of stator and rotor resistance variation. Extensive simulation results are presented to validate the technique. The proposed method is also simulated for regenerative mode of operation and the results obtained are satisfactory.