Direct Torque Control and Vector Control of Three-phase Asynchronous Motors

When the motor is running at high speed with the vector control, the rotor resistance will change with the load in a larger range, and the magnetic field orientation is not accurate. When the torque control is controlled by the electromagnetic torque and the hysteresis loop, the torque of the motor is inevitably pulsed, which directly affects the stability of the motor at low speed and the range of speed adjustment. Design of a three-phase asynchronous motor vector control and direct torque control system, while at a low speed, to control the motor by vector control system, when the motor speed to high speed, switch to direct torque control system.