An Optimized Switching Strategy for Quick Dynamic Torque Control in DTC Hysteresis-Based Induction Machines

A dynamic overmodulation strategy for fast dynamic torque control in direct torque control (DTC)-hysteresis based induction machine is proposed. The fastest dynamic torque response with six-step mode can be achieved in the proposed method by switching only the most optimized voltage vector that produce the largest tangential component to the circular flux locus. The paper also discusses the performance of dynamic torque control in basic DTC in order to justify on how the proposed selected voltage vector results in excellent dynamic torque performance. The main benefit of the proposed method is its simplicity since it only requires a minor modification to the conventional DTC hysteresis-based structure and does not require the space vector modulator. To verify the feasibility of the proposed dynamic overmodulation strategy simulation and experimentation as well as comparison with the conventional DTC scheme are carried out. The results showed the significant improvement in the dynamic torque response when compared to the conventional DTC hysteresis-based method