The Study Of Digital Soft Switching Power Battery Charger With High Power Factor

This paper conducts an in-depth and detailed study on the subject of high power factor digital soft switch.The purpose is to study the charger with high power factor and low switching loss.The charger is a two level structure.The former is a rectifier to improve the utilization efficiency of the grid resources and to solve higher harmonics pollution of power g-rid caused by load.In this paper,the reasons for the selection of the boost circuit are introduced in detail,and the characteristics of different DC-DC topologies are described.In this paper,the chip UC3854 is chosen as the control chip to realize the high power factor,the advantages and working principle of which are introduced in detail.The phase shifted full bridge zero voltage switching converter has the advantages of simple structure and excellent performance.As post charger,it can greatly reduce the switching loss through phase control and soft switching.In this paper,the working process and control mode of the converter are analyzed in detail.Based on this structure,the paper analyzes the conditions of the realization of zero voltage conduction and the reasons for the loss of duty cycle.And the design process of hardware circuit is described in detail.The charging mode of the storage battery determines the efficiency of electricity,and affects the life of the battery.So it's very important to choose a right charging way,which is analyzed and explained in the end of this paper.Based on the small signal model analysis of converter,this paper designs the digital control system and gives the corresponding control algorithm.According to the experimental requirements,the software is written which is showed in the form of program flow chart.And the main circuit is simulated and analyzed by using the simulink module in the MATLAB simulation software.According to the output voltage of 350 V,the output current of 10 A,this paper designs an experimental prototype of 220 V single-phase AC power supply.The experimental results show that the charger power factor is higher than 0.99,and all of the four switches in the full bridge circuit realize zero voltage conduction.The program runs normally,and the charger realizes constant voltage charging and constant current charging on the output side.At the same time,the information interaction between control chip and computer is realized.