Research of Direct Torque Control System within Full-speed Regions

A simulation system of direct torque control speed adjustment is introduced, it include field-weakening control. The simulation system realized induction-motor speed control within full-speed regions, constant torque adjustment less than foundation speed and constant power adjustment greater than foundation speed. The results of simulation show that system performance is excellent. The ripple and overshoot of speed are reduced, the four-quadrant characteristic of induction-motor varying speed is achieved successfully, the field-weakening control is very smooth. The simulation model has better reference meaning for researching direct torque control system within full-speed regions.