A Sliding Mode Control Approach for Improved Speed Performance in DTCHysteresis-Based Induction Motor

Recent development in power electronics and soft computing techniques made it possible to design and implement the sophisticated control strategies of AC motor drives. In this paper the Direct Torque Control (DTC) which is one of the most excellent control strategies of ac motors which give very good steady and dynamic response which is quite different from that of the field-oriented control is proposed. The proposed scheme is based on limit cycle control of both flux and torque using optimum PWM output voltage; a switching table is employed for selecting the optimum inverter output voltage vectors so as to attain as to attain as fast a torque response, as low an inverter switching frequency, and as low harmonic losses as possible. The current research directed towards the improving the performance of this technique by improving the speed performance. Sliding Mode Control technique is used to estimate the rotor speed. The main objective of this paper to improve the speed performance of the drive against uncertainties caused by load disturbances, an integral switching surface sliding mode speed controller is proposed. To verify the feasibility of the proposed method, simulation as well as comparison with the conventional DTC scheme is carried out.