电流源双向直流变换器的并联环流抑制方法  

Circulating Current Suppression Method for Paralleled Current-Fed Bidirectional DC-DC Converters

作　　者：张曌[1] 谢少军[1] 尚晓凤 杨楷文 Zhang Zhao;Xie Shaojun;Shang Xiaofeng;Yang Kaiwen(College of Automation Engineering Nanjing University of Aeronautics and Astronautics,Nanjing 211106 China)

机构地区：[1]南京航空航天大学自动化学院,南京211106

出　　处：《电工技术学报》2022年第S01期181-189,共9页Transactions of China Electrotechnical Society

基　　金：国家自然科学基金资助项目(51877104)。

摘　　要：电池储能系统中可采用电流源型隔离双向直流变换器作为蓄电池与直流母线之间的接口。为解决多个电流源型隔离双向直流变换器挂接在母线上产生的并联环流问题,提出一种基于直流母线端口电容的并联环流抑制方法。首先基于变换器的直流母线端口导纳,分析得到并联系统稳定和并联模块间电流均衡的通用条件;进而针对电流源半桥变换器的结构特点与控制策略,以及基于通用平均模型得到的变换器的开环传递函数,结合下垂控制的控制框图,分析推导电池储能模块的直流母线侧端口导纳表达式;通过将变换器的端口导纳代入并联系统稳定和并联模块间的电流均衡条件,发现变换器内在的LC谐振结构是并联环流存在的重要原因;最后分析直流母线端口电容对端口导纳的影响。仿真结果验证了所提环流抑制方法的正确性。Current-fed isolated bidirectional DC-DC converters(CF-IBDC)are suitable as the interfaces between the batteries and dc bus in the battery energy storage systems.To solve the problem of circulating currents between the CF-IBDCs connected at the DC bus together,a method for suppressing the circulating currents based on the capacitors at the DC bus ports was proposed.Firstly,general conditions for paralleled system’s stability and the balance of dc bus currents were derived based on the dc bus ports’admittances of the CF-IBDCs.Secondly,the closed-loop admittance at the dc bus port of the CF-IBDCs was analyzed and derived according to the control block diagram of the droop control and the open-loop transfer functions based on the generalized average model.Thirdly,the LC resonance structure at the battery side of the CF-IBDC is found to be the cause of the circulating currents and the imbalance of the dc bus currents after substituting the admittance of the CF-IBDC into the derived general stability conditions.At last,the effects of the DC bus port capacitors on the admittances of the CF-IBDCs were analyzed.Simulations of the paralleled system were conducted,and the correctness of the circulating current suppression method is verified by the simulation results.

关 键 词：双向直流变换器 并联环流 下垂控制 通用平均模型 

分 类 号：TM46[电气工程—电器]