一种改进型高转换比两相串联电容变换器  

An Improved Two-Phase Series-Capacitor Converter with High Conversion Ratio

作　　者：刘桂花[1] 王博鑫 王卫[1] 焦文渤 Liu Guihua;Wang Boxin;Wang Wei;Jiao Wenbo(School of Electrical Engineering and Automation Harbin Institute of Technology Harbin 150001,China)

机构地区：[1]哈尔滨工业大学电气工程及自动化学院,哈尔滨150001

出　　处：《电工技术学报》2023年第S01期114-123,共10页Transactions of China Electrotechnical Society

基　　金：国家自然科学基金资助项目(51977045)。

摘　　要：传统两相串联电容降压变换器具有自动相电流平衡、稳态开关电压应力小等优点,该文在传统两相串联电容降压变换器的基础上,增加两个电容和一个开关,提出一种改进型高转换比的两相串联电容变换器。该变换器具有传统两相串联电容降压变换器优点,同时还具有更高的电压转换比和更低的输出电流纹波,可以有效降低输入滤波电容值和变换器启动过程中开关的电压应力。该文在详细分析该变换器工作原理的基础上,搭建了110 W的实验样机,实验结果证明了理论分析的正确性。For traditional buck converter,the duty cycle is narrow in high conversion ratio applications.This results in high losses and low efficiency of the converter.At the same time,the output current ripple of the converter becomes larger,and the stability will also deteriorate.In order to solve the above problems,scholars have proposed many methods to improve the voltage conversion ratio of converters.Among them,SC(Series Capacitor)Buck converter is a commonly used high voltage conversion ratio converter,and has the advantage of low voltage stress of switches in steady state.However,the voltage stress of the switches is high during converter start-up.This paper proposes an improved two-phase series-capacitor converter with high conversion ratio.While inheriting the advantages of the SC Buck converter,the converter has a higher voltage conversion ratio and lower output current ripple,and can effectively reduce the input filter capacitor value and the voltage stress of the switches during converter start-up.The proposed converter adds two capacitors and a switch to the SC Buck converter,which has the following advantages.First,compared to the SC Buck converter,the voltage distribution across the capacitor is changed,which results in a higher voltage conversion ratio and lower switching voltage stress in steady state.Second,the voltage across the inductor of the proposed converter is lower than that of the SC Buck converter,so the inductor current ripple and output current ripple of the proposed converter are smaller.Third,in the steady state,the voltage on the series capacitor satisfies the ampere-second balance,which provides a balanced loop between the two phases.This current sharing mechanism is inherent to the topology and acts like a damped harmonic oscillator.Fourth,the capacitor on the input side of the proposed converter is pre-charged before the converter starts,which reduces the voltage stress of the switches during start-up.Therefore,the proposed converter can use switches with lower voltage rating,which help

关 键 词：DC-DC变换器 高转换比 串联电容 电压应力 

分 类 号：TM61[电气工程—电力系统及自动化]