A New V × I based adaptive speed sensorless four quadrant vector controlled induction motor drive

A Novel model reference adaptive system (MRAS) based speed estimation technique is presented in this paper. The speed estimator utilizes instantaneous and steady state values of V⃗* × I⃗ in the reference and adjustable models of the MRAS respectively. The major advantages of this method are: (i) flux estimation is not required and (ii) the method is stable in all the 4-quadrants of operation. The estimation technique is also suitable for low and zero speed operation. The formulation is found to depend on stator resistance (R_s) that is compensated by adding an active power based MRAS. Therefore, the proposed V⃗* × I⃗ together with an active power based MRAS (for R_s compensation) eliminates all the existing limitations of speed estimation. The implementation does not require any additional sensors and therefore is very suitable for retrofit applications. The proposed technique is simulated in MATLAB/SIMULINK and experimentally validated through a dSPACE-1104 based laboratory prototype.