摘要
针对光伏中压直流变换器串联系统中光伏发电单元功率失配导致的变换器输出过电压及功率损失问题,分析了光伏直流变换器串联系统运行特性,推导了限电压控制下串联系统光伏功率损失与光伏发电单元功率不均衡度及变换器输出电压限幅值之间的关系;提出了改进型Boost全桥隔离功率模块拓扑及其调制策略,基于功率模块输入并联输出串联形成模块级联型直流变换器,通过占空比灵活调节,实现直流变换器宽输出电压范围运行,解决直流变换器调压能力不足导致的功率损失问题;针对光伏直流变换器串联系统复杂运行工况,提出了串联系统直流变换器自适应电压分段式控制策略,实现了串联系统直流变换器多模式自适应稳定运行。研制了3kV/80kW功率模块及20kV/500kW光伏中压直流变换器,基于3台直流变换器输出串联实现了光伏中压直流变换器串联升压并网系统实证应用,现场实验结果验证了所提直流变换器拓扑方案的可行性与控制策略的有效性。
Aiming at the problem of the DC/DC converter output overvoltage and power loss caused by power mismatch of the photovoltaic(PV) power generation units in the PV medium voltage(MV) DC converter series system,the operation characteristics of PV DC/DC converter series system are analyzed,and the relationship between the PV power loss of series system under voltage limiting control,the power imbalance of PV power generation units and the output voltage limit amplitude of converter is deduced.An improved boost full bridge isolated power module topology and its modulation strategy are proposed.Based on the scheme of power module input parallel and output series,a modular cascade DC/DC converter is formed.Through the flexible adjustment of duty cycle,the operation of DC/DC converter with wide output voltage range is realized,solving the problem of power loss caused by the insufficient voltage regulation ability of the DC/DC converter;Aiming at the complex operation conditions of the PV DC/DC converter series system,an adaptive voltage segmented control strategy is proposed to realize the multi-mode adaptive and stable operation of the DC/DC converter in series system.The 3kV/80kW power module and the 20kV/500kW PV MVDC converter are developed.Based on the output series of three DC/DC converters,the demonstration application of PV MVDC converter series boost collection and grid-connection system is realized.The field experimental results verifies the feasibility of the proposed DC/DC converter topology scheme and the effectiveness of the proposed control strategy.
作者
黄欣科
王环
卢俊龙
张新雷
王一波
许洪华
HUANG Xinke;WANG Huan;LU Junlong;ZHANG Xinlei;WANG Yibo;XU Honghua(Institute of Electrical Engineering,Chinese Academy of Sciences,Haidian District,Beijing 100190,China;School of Electronic,Electrical and Communication Engineering(EECE),University of Chinese Academy of Sciences,Shijingshan District,Beijing 100049,China)
出处
《电网技术》
EI
CSCD
北大核心
2022年第6期2327-2338,共12页
Power System Technology
基金
青海省科学技术厅项目(2021-GX-A2)
中国科学院战略性先导科技专项(A类)子课题(XDA21050301)。
关键词
光伏发电
中压直流汇集
直流串联并网
直流变换器
限电压控制
photovoltaic generation
MVDC collection
DC-series grid-connection
DC/DC converter
voltage limiting control
