Direct Torque Control of Induction Motor Based on Sliding Mode Variable Structure

In view of problems of big flux linkage and torque ripple, imprecise low speed control of conventional direct torque control of induction motors, the paper proposed a new direct torque control method based on sliding mode variable structure on basis of establishment of mathematical model of induction motor under α-β coordinate system. The method uses speed sliding mode variable structure controller to replace PI controller of conventional direct torque control, which can effectively reduce flux linkage and torque ripple of conventional direct torque control, enhance stability of the system. The simulation results proved validity of the method.