FUZZY CONTROLLED DTC FED BY A FOUR SWITCH INVERTER FOR INDUCTION MOTOR

Abstract

Direct Torque Control of induction motor fed drives has become popular and widely used in industries due to fast and good torque response. Induction motors (IM) are simple in construction and are less sensitive to the motor parameters compared to other vector control methods. The conventional DTC is based on flux and torque hysteresis controllers. Induction motor is fed from a Four Switch Inverter generating the voltage vectors of the Six Switch Inverter by reconfiguration. Applying the most optimized voltage vector that produce fastest dynamic torque response during transient states. Fuzzy logic concept is a most efficient artificial integilence method which has high application in electric motor drives. A method to achieve fastest dynamic performance by modifying the two leg inverter fed DTC of induction motor based on Fuzzy Logic Concept is used here. This paper presents a rule-based fuzzy logic controller scheme designed and applied for the speed control of an induction motor fed from a four switch three phase inverter emulating the six switch three phase inverter. Due to the usage of the Fuzzy logic concept, the reliability, efficiency and performance of ac drive increases. Initial torque peak and torque ripple are minimized in the four switch three phase inverter based DTC using Fuzzy Logic.