A new instantaneous reactive power based MRAS for sensorless induction motor drive

A model reference adaptive system (MRAS) based speed estimator for sensorless induction motor (IM) drive is proposed in this paper. The MRAS is formed with instantaneous reactive power and the estimated stator current vector. Current, being a vector quantity, is configured in terms of reactive power, which is a scalar quantity. The advantage is that we need not equate either or both the in-phase and quadrature components of the current vector. The performance of the estimator under regeneration is an important aspect, which is studied in this paper through the small signal analysis. Graphical representation in the speed–torque domain gives a clear idea about the stable and unstable zones of operation in the regenerating mode. Sensorless IM drive along with the proposed MRAS is verified through computer simulation.