基于变压器双电容模型的光伏全桥LLC变换器共模干扰建模分析  

Modeling and Analysis of Common Mode Interference for Photovoltaic Full Bridge LLC Converter Based on Double-capacitor Model of Transformer

作　　者：金陵 苏建徽[1] 赖纪东[1] 于翔 尹浩[1] 马昆 JIN Ling;SU Jianhui;LAI Jidong;YU Xiang;YIN Hao;MA Kun(Research Center for Photovoltaic Systems Engineering of Ministry of Education(Hefei University of Technology),Hefei 230009,China)

机构地区：[1]教育部光伏系统工程研究中心(合肥工业大学),合肥230009

出　　处：《电源学报》2020年第6期50-58,共9页Journal of Power Supply

基　　金：国家重点研发计划资助项目(2018YFB0904100);国家电网公司科技资助项目(SGHB0000KXJS1800685)。

摘　　要：LLC变换器因其在全负载范围内可实现软开关,在变换器效率及功率密度等方面优势明显,因而在以光伏发电形式为主的直流微网中得到了广泛的应用。随着碳化硅等第三代半导体器件的渐渐普及,LLC变换器的工作频率越来越高,其高频变压器寄生电容对变换器共模干扰的影响愈发明显。现有针对变压器寄生电容的简化建模主要基于变压器内部绕组结构,使得集总电容模型的解析式较为复杂,不利于工程应用。为此,基于独立电压变量个数推导出一种适用于全桥LLC变换器共模干扰建模的变压器双电容模型,得到了简洁易用的解析计算表达式,且该模型可适配不同结构变压器,具有普适性。在推导的双电容模型的基础上建立了全桥LLC变换器共模传导干扰模型,通过Matlab/Simulink仿真验证了所提双电容模型和共模干扰模型的准确性。LLC converter has been widely used in DC micro grid based on photovoltaic power generation because it can realize soft switch in the full load range and has obvious superiority in the aspects of converter efficiency and power density.With the extensive application of the third-generation semiconductor devices(e.g.,silicon carbide),the operating frequency of the LLC converters is increasingly higher,and the influences of parasitic capacitance in its high-frequency transformer on its common mode(CM)interference are more serious.The existing simplified modeling of transformer pa-rasitic capacitance is mainly based on the winding structure inside the trans-former,which makes the analytical formula for the lumped capacitance model more complex and unsuitable for practical applications.Therefore,based on the number of independent voltage variables,a double-capacitor model of transformer suitable for the modeling of CM interference of a full-bridge LLC converter is derived and thus a simple analytical expression is obtained.Moreover,this model can be adapted to transformers of different structures and has universal applicability.A CM interference model of the full-bridge LLC converter is built based on the derived double-capacitor model,and the accuracy of the proposed model is verified by simulations using Matlab/Simulink.

关 键 词：共模干扰 双电容模型 光伏全桥LLC 

分 类 号：TM46[电气工程—电器]