DefinePK

Abstract

The main aim of this paper is to present hybrid space vector pulse width modulation (HPWM) based model reference adaptive system (MRAS) speed observer for sensorless control of induction motor drive. The proposed method is designed by using the notion of stator flux ripple and the switching times are calculated by utilizing the concept of imaginary switching times that uses the instantaneous values of the reference voltage of the three phases. By using this method ripples present in the torque can be minimized and also the speed performance can be improved in the way that the error between the adaptive model speed and the reference model speed is made as low as possible so that the estimated speed is made as nearly equal as the speed of the reference model. Also in this paper the conventionally used PI controller in the adaptation mechanism of the MRAS observer is replaced by a fuzzy logic controller (FLC). In conventionally used PI controller when the reference speed or the load changes the control parameters are to be changed manually but when a FLC is used in place of PI controller this is not necessarily required. The fuzzy logic is also helpful in keeping the speed relatively constant during the load variations which can be seen from the simulation results. The simulations of the proposed method are performed and the results are presented to validate the proposed method.