模块化多电平换流器的环流分析及抑制方法  

Circulation Analysis and Suppression Methods of Modular Multilevel Converter

作　　者：强国栋 罗伟 QIANG Guodong;LUO Wei(Liuzhou Railway Vocational Technical College Liuzhou 545616, China)

机构地区：[1]柳州铁道职业技术学院,广西柳州545616

出　　处：《红水河》2024年第2期107-111,共5页Hongshui River

基　　金：广西高校中青年教师科研基础能力提升项目(2021KY1395)。

摘　　要：模块化多电平换流器(modular multilevel converter,MMC)由于子模块电容充放电导致电容电压的不一致,进而导致MMC三相之间存在环流,不仅增加了系统损耗,还影响系统稳定运行。通过建立MMC数学模型,分析不平衡电网下MMC环流形成机理及环流成分,设计了结合二阶广义积分器(SOGI)与准比例谐振(QPR)控制器的环流抑制器,首先通过SOGI提取环流中的二倍频分量,然后与参考值作差后送入QPR控制器,实现对MMC相间环流的抑制,并在MATLAB/Simulink中搭建MMC仿真模型验证了所提方法的可行性和有效性。结果表明:该控制策略能够对桥臂环流实现有效抑制,环流电流峰值下降约41%,子模块电容电压下降约20%,桥臂电流总谐波失真下降93.91%。Due to the inconsistency of capacitor voltage caused by the charging and discharging of submodule capacitor in modular multilevel converter MMC there is a circulation between the three phases of MMC which not only increases the system loss but also affects the stable operation of the system.By establishing the mathematical model of MMC the formation mechanism and components of MMC circulation under unbalanced grid are analyzed and a circulation suppressor combining second-order generalized integrator SOGI and quasi-proportional resonant QPR controller is designed.Firstly the double frequency component in the circulation is extracted by SOGI and then sent to QPR controller after the difference with the reference value so as to suppress the inter-phase circulation of MMC.The MMC simulation model is built in MATLAB/Simulink to verify the feasibility and effectiveness of the proposed method.The results show that the control strategy can effectively suppress the arm circulating current the peak value of the circulating current decreases by about 41%the capacitor voltage of the submodule decreases by about 20%and the total harmonic distortion of the bridge arm current decreases by 93.91%.

关 键 词：模块化多电平换流器 环流 环流抑制 

分 类 号：TM46[电气工程—电器]