光照不均时独立输入串联输出型光伏升压DC-DC变流器组合电平法均压稳流控制  

Voltage Balance and Current Smoothing Modulation for Independent Input Serial Output Photovoltaic Boost DC-DC Converter Control Under Uneven Illumination

作　　者：田艳军 高皓楠 王毅[1] 陈映妃 冀茂 TIAN Yanjun;GAO Haonan;WANG Yi;CHEN Yingfei;JI Mao(State Key Laboratory of New Energy Power Systems,North China Electric Power University,Baoding 071003,China)

机构地区：[1]华北电力大学新能源电力系统国家重点实验室,保定071003

出　　处：《高电压技术》2020年第7期2425-2433,共9页High Voltage Engineering

基　　金：国家重点研发计划(2018YFB0904104);中央高校基本科研业务费项目(2017MS097)。

摘　　要：在光伏直流汇集系统中,光伏侧独立输入的DC-DC变流器通过输出侧级联可提升电压等级,但光照不均时,级联DC-DC变流器输出侧存在电压不均衡的问题。在DC-DC变流器级联输出侧设置均压单元可实现输出侧电压均衡,但均压单元的引入会显著增加直流汇集系统的输出电流纹波。为此,提出对均压单元采用移相组合电平法的调制策略,通过控制级联DC-DC变流器均压单元间的电压相移,使级联输出侧电压更接近直流电网电压,进而减小输出电流纹波;之后,引入LC滤波器来滤除级联输出侧的电压尖峰,以保证级联输出侧电压稳定;最后,将所提控制策略应用于光伏直流汇集系统进行仿真。结果表明:该策略能够在实现输出侧电压均衡的同时,有效减小并网电流的纹波。论文研究可为光伏直流汇集系统的稳定运行和功率优化提供一定的理论依据。In a photovoltaic(PV)DC collection system,DC-DC converters with independent input on the PV side can improve the voltage level by cascading on the output side.But when the illumination is uneven,there is a problem of voltage imbalance on the output side of the cascade DC-DC converter.The voltage equalization unit can be set on the output side of the DC-DC converter to achieve output side voltage equalization,but the introduction of the voltage equalization unit will significantly increase the output current ripple of the DC collection system.To this end,we propose a shift-phase combined level modulation strategy for the equalizing unit.By controlling the voltage phase shift between the voltage equalization units of cascaded DC-DC converters,the cascaded output side voltage is controlled to be closer to the DC grid voltage,thus reducing the output current ripple.Then an LC filter is introduced to filter the voltage spike at the cascaded output side to ensure the voltage stability at the cascaded output side.Finally,the proposed control strategy is applied in the simulation of the PV DC collection system.The results show that the proposed strategy can effectively reduce the ripple of grid-connected current while achieving voltage balance at the output side.The research can provide theoretical basis for the stable operation and power optimization of the PV DC collection system.

关 键 词：光伏发电 直流汇集 光照不均 DC-DC变换器 均压控制 移相调制 

分 类 号：TM46[电气工程—电器]