A new control strategy of direct torque fuzzy control of a PWM inverter fed induction motor drive

This paper presents an original direct torque fuzzy control (DTFC) of a voltage source PWM inverter fed induction motor drive. First a direct torque fuzzy control (DNFC) of a voltage source PWM inverter fed induction motor drive is presented and its performances are compared to those of a classical DTC control. Then a variable gain PI speed controller is introduced to improve these performances.. The DTFC control scheme uses the stator flux amplitude and the electromagnetic torque errors through two fuzzy controllers to generate the amplitude and the angle of the reference voltage which is used by a space vector modulator to generate the inverter switching states. Simulation of the DTFC induction motor drive using VGPI for speed control shows promising results. The motor reaches the reference speed rapidly and without overshoot, load disturbances are rapidly rejected, torque and current ripples are greatly attenuated and variation of the stator resistance is fairly well dealt with.