Research on Direct Torque´s Control Strategy for Three-Level Inverters Based on PI Regulating

Since there´s a biggish output ripple in current direct torque´s control, we design a direct torque control system for three-level inverters used in asynchronous motors by analyzing the operational principle of the diode clamped three-level inverters, and simulation is done as well. Ripples of the torque and the rotational speed of the motor can be deduced effectively, and a stable output and a good control effect could be achieved. The system lowers its complexity and is easy to come true for the switching frequency could keep steady without any complex deadbeat controllers and the midpoint´s control could be separated from the direct torque´s control.