A Combined Stator Vector Control – SVM-Direct Torque Control for High Performance Induction Machine Drives

Abstract

In this paper, a novel direct torque control method has been proposed for high performance induction machine drives. The control system enjoys the advantages of stator vector control and direct torque control and avoids some of the implementation difficulties of either of the two control methods. The stator flux orientation is used to keep constant the amplitude of stator flux vector, and to develop the relationship between the machine torque and the slip angular speed. At this stage, the electromagnetic torque can be regulated as in the case of direct torque control. The proportional–integral controllers and space vector modulation technique are used to obtain a fixed switching frequency and low torque ripple. Simulation experiments results indicate that, with the proposed scheme, a precise control of the stator flux and machine torque can be achieved. Compared to conventional direct torque control, presented method is easily implemented, and the steady performances of ripples of both torque and flux are considerably improved. Ill. 5, bibl. 7 (in English; summaries in English, Russian and Lithuanian).