DTC-SVM control for three phase induction motors

By principle, Direct Torque Control (DTC) is used to adjust stator flux and electromagnetic torque. Simple structure and very good dynamic behavior are main features of DTC. However classical DTC has some disadvantages, the most important of them is the high ripple torque. In this paper we propose some variety of DTC combined with FOC structures. Hysteresis controllers and switching table are replaced by PI controllers and space vector modulator. Three algorithms work in fixed switching frequency are developed, can overcome the aforementioned drawback. The proposed schemes are described clearly. Simulation results prove the effectiveness, reliability and correctness of the proposed methods.