Discrete Duty-Cycle-Control Method for Direct Torque Control of Induction Motor Drives With Model Predictive Solution

In this paper, a new duty cycle control method is proposed to reduce torque and flux ripples of the conventional direct torque control (DTC). In the proposed method, a new approach is initially introduced to select the appropriate active voltage vector (VV) precisely. Then by inserting the zero VV along with the selected one, a finite set of new candidate VVs with different duty cycles are synthesized. Finally, the model predictive control method is employed to select the appropriate VV among the candidate ones to reduce flux and torque errors. Simulation and experimental studies are conducted to show the good performance and the superiority of the proposed method over classical DTC and model predictive control methods. As a result, lower torque and flux ripples are achieved in the proposed method. Furthermore, the proposed method works with almost a fixed switching frequency for all speed ranges.