The Design Of Interleaving Two-transistor Forward Converter With Power Factor Correction

At present,switching power supply is widely used in various electronic equipment due to its advantages of low power consumption,small size,wide voltage regulation range,etc.It is an indispensable power supply method in the field of electronic technology.But it also has the disadvantages of low power factor and low reliability,and these are also important topics that modern power electronics technology needs to devote to research.In order to improve its shortcomings,this paper designs an interleaved parallel two-tube forward converter with power factor correction at the front end.The main research work of the paper is as follows:(i)This paper introduces the importance of reducing harmonic current components for improving power factor and realizing a "green grid",expounds the basic methods of power factor correction,conduction mode and typical control strategies,and gives the former stage power factor correction circuit of main circuit and control circuit is designed based on control chip UCC28019 parameter calculation process.(ii)This paper analyzes the working principle of the post-stage staggered parallel double-tube forward circuit,and analyzes its working mode in half a switching cycle in detail.The analysis points out that the staggered parallel double-tube forward topology is compared with push-pull and full-bridge topology.There is neither the defect of transformer bias nor the problem of bridge arm straight-through.At the same time,it can alleviate the voltage stress suffered by the power device,and has the advantage of high reliability.Then the main circuit to establish a small signal model for analysis,and the introduction of voltage control and current control two control strategies,through the comparison of the advantages and disadvantages of the two control strategies and the application of the final use of single voltage loop control strategy to control the second stage of the converter.The main circuit and control circuit of the system are designed in detail based on the actual demand index of the converter,and the control chip of the subsequent control circuit selects SG3525.(iii)Finally,using the simulation software Saber to simulate and analyze the entire circuit system,the simulation results confirmed the rationality of the design,and an experimental prototype was built,and the load experiment was carried out on it.The power supply of the prototype was stable during the experiment,the experimental results have also reached the expected requirements and have a certain practicability.