ZCS Two-switch Forward Converter With Variable Inductor

In today's fast-paced era,power supplies occupy a very important position.At present,switching power supply technology is developing rapidly,and it is moving toward digitalization,high frequency,high efficiency,and miniaturization.Although the switching power supply is more complicated and more noisy than the traditional linear regulated power supply,it is widely used because of its high efficiency,low loss,stable performance,light weight,safety and reliability.The double-switch Forward converter solves the problem of straight-through bridge arms of the full bridge or the half bridge,which greatly improves the reliability,and has the advantages of low switching voltage stress and low price.Therefore,it is widely used in many fields,especially low voltage and high current applications.In this paper,the single-switch Forward converter and the two-switch Forward converter using various magnetic reset modes will be briefly introduced,and the influence of the secondary rectifier on the efficiency is analyzed.In order to further improve the power efficiency,a variable-inductance-based ZCS dual-switch Forward converter is adopted.The resonant circuit is added to enable the secondary side rectifier of the transformer to realize zero-current switching under various working conditions.Secondly,according to the theoretical analysis,a ZCS double-switch forward power supply is designed.The main power circuit module of the power supply prototype is designed and its parameter calculation and component selection are completed.The design and calculation process of the high frequency transformer are mainly introduced.Also included are: EMI filter circuit,variable inductor winding,control circuit,totem pole amplifier circuit,flyback auxiliary power supply,etc.Finally,the simulation of the main circuit of the power supply is completed by Matlab,and the key point waveforms are analyzed to verify whether the design of the power supply parameters is reasonable and feasible.On this basis,Altium Designer 2013 software is used to design the schematic and PCB of the power prototype,complete the welding of the whole board and set up the experimental platform to debug the power prototype,and verify the correct design of the double-switch forward power supply.