直流配网用级联DC-DC变换系统稳定性分析  

Stability Analysis of Cascaded DC-DC Converter System for DC Distribution Network

作　　者：杨国朝 杨朝雯 刘仲英 张宏艳 杨智 YANG Guochao;YANG Zhaowen;LIU Zhongying;ZHANG Hongyan;YANG Zhi(State Grid Tianjin Chengdong Electric Power Supply Company,Tianjin 300250,China)

机构地区：[1]国网天津市电力公司城东供电分公司,天津300250

出　　处：《电气传动》2021年第20期24-28,35,共6页Electric Drive

基　　金：天津电力科技项目(KJ20-1-09)。

摘　　要：相较于传统交流配网系统,直流配用电系统凭借着高效、低耗、可靠等特性近些年受到了广泛的关注。其中,作为直流系统中的核心设备,隔离型DC-DC变换器面对着小型化、高效化、稳定性等新的需求,而稳定性对于一个系统而言则至关重要。因此,针对直流微网系统中含谐振拓扑的级联型DC-DC变换器进行研究分析,以LLC+Buck为例采用Middlebrook判据,通过比较LLC与Buck的输出和输入阻抗,对该级联系统的稳定性加以判定。在此基础之上,提出改进型的系统参数设计方法。通过Pisim和Matlab等仿真软件的仿真结果证明了基于Middlebrook判据以及所提出参数设计方法具有很好的效果。最终,基于所提出的参数设计方法所获得的参数组建立对应1 000 W试验样机,验证变换器的高效、可靠、稳定运行以及理论的准确性。Compared with the traditional AC distribution network system,DC power distribution system with high efficiency,low consumption,reliability and other characteristics has been widely concerned in recent years.As the core equipment of DC system,isolated DC-DC converter has to face the new requirements of miniaturization,high efficiency and stability.Among them,stable and reliable application is more important.Therefore,the cascaded DC-DC converter with isolated resonant topology in DC microgrid system was studied and analyzed.Taking LLC+Buck as an example,the stability of the cascaded DC-DC system was determined by comparing the output and input impedances of LLC resonant structure and Buck converter by using the Middlebrook criterion.On this basis,an improved system parameter design method was proposed.The method based on Pisim and Matlab was proved to be effective.Finally,based on the parameters obtained by the proposed parameter design method,the corresponding 1000 W prototype was established to verify the efficient,reliable and stable operation of the converter and the theoretical accuracy.

关 键 词：直流微电网 Middlebrook判据 LLC谐振变换器 稳定性 小信号模型 

分 类 号：TM46[电气工程—电器] TM28[一般工业技术—材料科学与工程]