K. Abed  , K. Nabti  , H. Benalla  , 
    A Fuzzy IRFOC Application Based Speed Sensorless Control of Induction Machine Using a Speed and Load Torque Observer,
    International Journal of Electrical and Power Engineering,
    Volume 2,Issue 3,
    2008,
    Pages 179-184,
    ISSN 1990-7958,
    ijepe.2008.179.184,
    (https://makhillpublications.co/view-article.php?doi=ijepe.2008.179.184)
    Abstract: In this study, a Fuzzy controller of an Indirect Rotor Field Oriented Control (IRFOC) using a speed observer for an Induction Machine (IM) drive, feed through an ameliorate voltage inverter is proposed. A superiority of the proposed fuzzy controller over conventional PI controller in handling nonlinear such as an induction motor has been effectively demonstrated by comparing F-PI speed controller with the conventional PI under varying operating conditions like step change in speed reference and torque reference. Observers use a model to predict the speed by the phase currents and voltages as state variables, these estimates are improved by an error feedback compensator that measures the difference between the estimated and actual values. The observed value of speed is then used by the FOC to adjust the PWM waveform in exactly the same way as an actual measured value.
    Keywords: IRFOC;sensorless control;Induction Machine (IM);ameliorate three level voltage inverter;PWM;Fuzzy-PI (F-PI) controller;Luenberger observer;simulink