Design Of AC Speed Regulation System Based On PWM Rectifier

AC adjustable speed system based on PWM rectifier uses the AC-DC-AC style. In comparison with the traditional converter, the diode rectifier is replaced by PWM rectifier. PWM rectifier not only can greatly improve the power factor of the whole system, but also reaches the energy conservation by realizing the bidirectional flow of energy when the motor brakes. A new AC speed-regulation system is presented in this paper. In PWM rectifier, Direct Power Control method, which is practical and can be digitized easily, is used to improve the power factor significantly by controlling the instantaneous active/reactive power. As for Motor, Direct Torque Control method, which is easy to be realized and robust to the rotor parameters, is adopted to improve the drive performance through controlling directly the stator flux and electromagnetic torque. Finally, the corresponding simulation is completed and the results show that the new adjustable speed system can improve the power factor to be±1, lower the harmonic distortion of input current, accomplish the four-quadrant operation and bidirectional flow of energy.