| High voltage power supply is widely used in the fields of medicine,industry,military affairs,agriculture and so on.The existing high frequency and high voltage power supply adopts three-phase uncontrolled rectifier,which has the disadvantages of uncontrollable starting,low power factor,low voltage regulating range,and slow protective action.Therefore,in order to solve these problems,this paper studied the three-phase PWM rectifier in the high voltage power supply and its control strategy.1.An improved of three-phase PWM rectifier is proposed by analyzing the advantages and disadvantages of the traditional six switch PWM rectifier topology when it’s applied to high voltage power supply.It not only has the advantages of high power factor,wide voltage regulation range,but also can realize controllable soft start and fast protection of high voltage power supply.2.The control strategy of three-phase rectifier is studied: in order to improve the power factor and broaden the range of voltage regulation,an improved predictive current control strategy is adopted,and it has the function of phase compensation.In order to realize controllable soft start and fast protection,the related control method is presented.3.The proposed three-phase PWM rectifier is designed: The hardware circuit of soft starter,sampling and driving is designed;The software programs are designed,such as start,predictive current control,output voltage regulation and protection.Simulation and experimental study on the design of the rectifier and its control strategy have been done.4.A prototype is developed based on theoretical analysis and simulation.Prototype test results show that the developed prototype can realize controllable soft start,power factor correction,output voltage regulation and fast protection.It verifies the rationality and feasibility of the rectifier and its control strategy proposed in this paper. |
