非隔离型模块化多电平DC/DC变换器的最小化桥臂环流控制  

A minimized AC circulating control strategy for a non-isolated modular multilevel DC/DC converter

作　　者：马文忠[1] 田洪英 刘慧玉 胡范青 李沐书 张奎同 MA Wenzhong;TIAN Hongying;LIU Huiyu;HU Fanqing;LI Mushu;ZHANG Kuitong(Institute of New Energy,China University of Petroleum(East China),Qingdao 266580,China;Shandong Energy Group Co.,Ltd.,Jining 273500,China)

机构地区：[1]中国石油大学(华东)新能源学院,山东青岛266580 [2]山东能源集团,山东济宁273500

出　　处：《电力系统保护与控制》2021年第22期51-58,共8页Power System Protection and Control

基　　金：国家自然科学基金项目资助(51777216);山东省自然科学基金项目资助(ZR2018MEE040,ZR2019MEE094)。

摘　　要：用于中高压直流电压转换和直流电网互联的高压大功率直流变压器一般采用中间交流变压器,存在损耗高和体积大等不足。对一种非隔离型的模块化多电平DC/DC变换器进行了研究,与普通双有源桥式DC/DC变换器相比,避免了交流变压器的存在。首先分析了此变换器的工作原理,建立了变换器的等效数学模型。考虑子模块电容电压存在特殊的不平衡,变换器需要引入交流循环电流,提出了一种保证桥臂功率均衡的最小化桥臂环流的控制策略,减小了桥臂电流的交流分量,降低了变换器的损耗。在Matlab/Simulink中仿真验证了变换器的性能和最小环流控制策略的有效性。最后搭建实验平台进行了实验验证。Intermediate AC transformers are commonly used in high voltage high power DC transformers which are used for medium and high voltage DC conversion and interconnection of DC power grids.These bring greater loss and volume.In this paper,a non-isolated multilevel modular DC/DC converter is studied.The converter avoids the need for an AC transformer compared with the common dual active bridge DC/DC converter.This paper first analyzes the working principle of this converter and establishes an equivalent mathematical model.Because of the special imbalance of the sub-module capacitor voltage,the converter needs to introduce an AC circulating current.A minimized AC circulating control strategy is proposed,which ensures the power balance of the bridge arm,reduces the AC component of the bridge arm current and the loss of the converter.The performance of the converter and the effectiveness of the proposed control strategy are verified in a Matlab/Simulink simulation.Finally,an experimental platform is built to verify the effectiveness of the converter topology and the control strategy.

关 键 词：模块化多电平DC/DC变换器 直流电网 能源互联网 直流变压器 

分 类 号：TM46[电气工程—电器]