Design of Fuzzy Controllers for Direct Torque Control Systems

This study adopts fuzzy control theory to design a torque controller and a magnetic flux controller for application to the direct torque control (DTC) of induction motors. Traditional direct torque controllers produce two voltage vector commands through two proportional integral (PI) controllers. However, PI controllers cannot present good dynamic response because their parameters are constant. To resolve this defect in traditional DTC, this study designed a fuzzy torque controller (FTC) and a fuzzy flux controller (FFC) to replace traditional PI controllers. These controllers can improve the response of stator flux and reduce torque ripples to enhance the dynamic performance of a speed sensor-less DTC system.