Performance assessment of rotor flux and reactive power based MRAS for speed sensorless induction motor drive in a common test rig

In this paper, two different model reference adaptive systems (MRASs) based on the rotor-flux and the instantaneous reactive power errors for the speed estimation of an induction motor (IM) drive are compared from the stability point of view. The rotor-flux error based MRAS (RF-MRAS) involves the computation of rotor flux for the estimation of rotor speed. This, however, suffers from the integrator related problems and stator resistance sensitivity at low speed operation. This problem is overcome by the instantaneous reactive power based MRAS (Q-MRAS) which completely eliminates the requirement of any flux-estimation in process of computation and makes the system immune to the variation of stator resistance. The stability of both the techniques is verified by an in-detailed simulation study in Matlab/Simulink in the low speed region.