摘要
该文基于半有源桥(SAB)结构,提出一种带有LC串联谐振功率自均衡单元的输入独立输出串联(IIOS)型光伏直流升压变换器。该变换器采用半有源桥隔离变换器作为子模块单元,实现输入输出电气隔离以及最大功率点跟踪(MPPT)控制,并通过多个子模块单元输出串联实现端口电压匹配以满足直流并网要求。在LC功率均衡支路作用下,该变换器能实现各子模块输出端口的均压控制,控制方法简单,二次侧通过器件复用进一步减少了开关管使用数量,且原二次侧所有开关管均能实现零电压开通(ZVS),效率较高。针对起动时可能产生的系统过电流及谐振电容过电压问题,提出软起动控制策略,保证了系统的可靠性。基于Matlab/Simulink仿真证明了所提变换器工作原理和子模块输出均压方法的可行性,最后通过搭建输出功率600 W三模块小型样机进行了实验验证。
Input-independent and output-series(IIOS)DC-DC converters can achieve multi-input port-independent MPPT control and series high gain output while maintaining the overall single-stage power conversion of the converter,suitable for large-scale photovoltaic collection.The topology of the IIOS converter is an ideal solution to achieve a high boost ratio,high efficiency,and multi-input port conversion.Since the output side of each sub-module of the IIOS converter is connected in series,if the input power is different,the output voltage of each sub-module will be unbalanced,which may cause some sub-modules to exceed the gain range and exit the MPPT operation.If the input power difference is too large,overvoltage damage to some devices will occur.Therefore,the technical difficulty to be solved is to ensure the safe and stable operation of the converter while maintaining low loss and high economy.This paper proposes an IIOS photovoltaic converter with LC series resonant power balance unit based on the semi-active bridge(SAB).The proposed topology employs the SAB converter as a sub-module,which has the advantages of a dual active bridge converter(DAB),such as soft switching,high power density,high efficiency,simple control,and electrical isolation.Compared with the dual-active bridge converter,the SAB converter has fewer switching devices,a larger soft-switching range,and is more suitable for unidirectional power flow,such as photovoltaic power generation.In order to solve the problem of unbalanced output port voltage of each sub-module of the proposed converter,only a low-value LC power self-balancing unit branch is needed to be added to the secondary arm of each sub-module.The self-balancing function does not require additional control variables,and the complementary conduction of all upper and lower switches can be achieved by relying on the sub-module side.In addition,the proposed converter can synchronously realize MPPT control and output port voltage-sharing control of the photovoltaic array.The control method is si
作者
朱小全
侯鹏辉
侯锦涛
金科
张波
Zhu Xiaoquan;Hou Penghui;Hou Jintao;Jin Ke;Zhang Bo(College of Automation Engineering Nanjing University of Aeronautics and Astronautics,Nanjing 211106 China;School of Electric Power Engineering South China University of Technology,Guangzhou 510641 China)
出处
《电工技术学报》
EI
CSCD
北大核心
2024年第4期1087-1102,共16页
Transactions of China Electrotechnical Society
基金
国家自然科学基金(62201256)
江苏省自然科学基金(BK20210306)
南京航空航天大学研究生创新实验竞赛培育基金资助项目。
