Comparative And Analysis Of Single-stage DC/DC Converter With Two-stage DC/DC Converter

With the rapid development of aircraft application,270 V high voltage direct current power supply system(HVDC) has been extensively applied,which is to increase the its efficiency, reduce the volume and mass.However, there are many equipment electric equipment depends on 28 V DC.So,it's great practical significance to further study of high step-down ratio aircraft DC converter.At the present stage, There are two kinds of widely used DC/DC converter,they are single-stage DC converter and two-stage DC converter.These two modes have their own advantages and characters. this paper is based on the comparative analysis of loss and efficiency in the processing of two DC converter using 270V/28 V. The advantage and disadvantage of each one are got, which will make research work convenient and deeply.Next,This paper choose the LLC resonant converter as the two-stage DC cinverter,As former stage, its frequency is stability in system normal running,and the resonance frequency is equals to the LLC resonant converter,then,synchronous rectification BUCK converter serves as two-stage.As for single-stage DC converter,its use full bridge LLC resonant converter.In this paper, basic information of full bridge LLC resonant converter is first described, and carried out preliminary studies. According to the study, when the switching frequency less than resonance frequency,the converter can have two functions that primary-side switches realizing zero-voltage-switching and secondary rectifier diode Zero Current Switching,Besides,when the switching frequency equals resonance frequency,it output voltage is independent of its payload size,and this moment is the highest efficiency moment.After that,This introduces and analysis the principle and characters of LLC-DCX DC converter.To compare the converter's losses and synchronous rectification from different angles.and compare the control strategy and synchronous rectification of full bridge LLC resonant converter.Meanwhile,through respective 270V/28 V principle prototype,comparing the experiment results.