The Research On Motor Drives Control System Based On PWM Rectifier

With the continual improvement of the performance requirements for motor drives system, PWM rectifier has been becoming one of the hot topics in the power transmission system with its advantages of high power factor, and two-way flow of energy.The control methods of three-phase Voltage Source Rectifier are introduced, and dual closed-loop control system of three-phase Voltage Source Rectifier is analyzed. The current inner loop hysteresis PWM current control circuit is selected. For the reason that there is a greater disadvantage switching loss in the hysteresis PWM current control system, the improved three-phase Voltage Source Rectifier control method is proposed, with which a new control method of the hysteresis loop width can be controlled.The key and innovation of this paper is that method of fuzzy control is pulled into it, and then gives a new method that the loop width of the hysteresis could be controlled. In this new control method, the hysteresis PWM current is controlled by the fuzzy controller, so that hysteresis loop width can be changed according to different needs, and the system will realize the hysteresis loop width control, thereby the control method of the hysteresis PWM current is greatly improved.Finally, based on the intensive study, the simulation model of three-phase Voltage Source Rectifier system is built and the simulation is carried on, and do some analysis for this results.The simulation results show that the method based on the loop width controlled could limit the average switching frequency and reduce the switching loss,compared to conventional method.