不对称故障下向无源网络供电的MMC-HVDC微分平坦控制策略  

Differential Flatness Controller Strategy of MMC-HVDC to Supply Power to Passive Network Under Asymmetric Faults

作　　者：林波 王斌 程启明 万炳才 蒋谦 黄志豪 LIN Bo;WANG Bin;CHENG Qiming;WAN Bingcai;JIANG Qian;HUANG Zhihao(State Grid Shanghai Electric Power Company,Shanghai 200122,China;School of Automation Engineering,Shanghai University of Electric Power,Shanghai 200090,China)

机构地区：[1]国网上海市电力公司,上海200122 [2]上海电力大学自动化工程学院,上海200090

出　　处：《高电压技术》2021年第11期4023-4032,共10页High Voltage Engineering

基　　金：国家自然科学基金(61905139);上海市电站自动化技术重点实验室资助项目(13DZ2273800)。

摘　　要：模块化多电平技术(modular multilevel converter,MMC)因其电磁兼容性好、谐波含量低、开关损耗较小等优势已经在高压直流输电(high voltage direct current,HVDC)中得到了广泛的运用。在MMC-HVDC向无源网络供电的情况下,为了抑制不对称故障对向无源网络供电的电能质量的影响,采用了将微分平坦理论应用于向无源网络供电的MMC-HVDC系统的方法,以提高发生不对称故障时MMC换流器的动态性能。首先分析了向无源网络供电的MMC-HVDC的系统结构和工作原理,针对MMC-HVDC整流级的MMC换流器建立了在不平衡电网电压时基于正负序系统的数学模型;其次针对不同输出变量,分别进行了平坦性分析;接着,对MMC系统进行稳定性分析,并根据微分平坦理论设计了MMC-HVDC换流站的内外环正负序控制器;最后,在Matlab/Simulink中建立一个对无源网络供电的MMC-HVDC系统,结果表明:在发生不对称故障的运行条件下,MMC-HVDC系统的控制策略具有较好的动态性能。Modular multilevel converter(MMC)has been widely used in high voltage direct current(HVDC)due to its advantages of good electromagnetic compatibility,low harmonic components,and low switching losses.In the case of MMC-HVDC supplying power to the passive network,in order to suppress the impact of asymmetric faults on the power quality of the passive network,the application of the differential flatness theory to the MMC-HVDC system that supplies power to the passive network was adopted to improve the dynamic performance of MMC converter when an asymmetric fault occurred.First,the system structure and working principle of MMC-HVDC that supplies power to the passive network were analyzed.For the MMC converter of the MMC-HVDC rectifier stage,a mathematical model based on the positive and negative sequence system was established when the grid voltage was unbalanced.Different output variables were analyzed for flatness,respectively.Then,stability analysis of the MMC system was performed,and the positive and negative sequence controllers of the inner and outer loops of the MMC-HVDC converter station were designed according to the differential flatness theory.Finally,a MMC-HVDC system was established on the MATLAB/Simulink to supply power to the passive network.The results show that the control strategy of the MMC-HVDC system has better dynamic performance under the operating conditions of an asymmetric fault.

关 键 词：模块化多电平变换器 高压直流输电 不对称故障 正负序系统 微分平坦控制 稳定性分析 

分 类 号：TM721.1[电气工程—电力系统及自动化]