Through the matching of motor speed and torque with the requirements of the driven load, variable speed transmission (VSD) has provided unprecedented performance for the motor and saved a lot of energy.Most VSD's on the market rely on modulation stages.It can adjust the voltage and frequency inputs to the motor, but it will cause congenital delays in the process control signal.In contrast, the excellent transmission adopts innovative direct torque control (DTC), which greatly enhances the torque response of