基于改进MMC的静止无功发生器  

Static VAR Generator Based on Improved MMC

作　　者：朱亮亮 陈洁[1] 王小军 段生强 郑凯凯 杨国 ZHU Liangliang;CHEN Jie;WANG Xiaojun;DUAN Shengqiang;ZHENG Kaikai;YANG Guo(Research Center of Renewable Energy Power Generation and Grid Control Engineering,Ministry of Education,School of Electrical Engineering,Xinjiang University,Urumqi 830046,China;State Grid Xinjiang Kezhou Power Supply Company,Kizilsu Kirghiz Autonomous Prefecture,Xinjiang 845350,China)

机构地区：[1]新疆大学电气工程学院教育部可再生能源发电与并网控制工程技术研究中心,乌鲁木齐830046 [2]国网新疆克州供电公司,新疆克孜勒苏柯尔克孜自治州845350

出　　处：《南方电网技术》2021年第7期47-53,共7页Southern Power System Technology

基　　金：新疆维吾尔自治区高校科研重点项目(XJEDU20181005);国家自然科学基金项目(51467020);新疆维吾尔自治区自然科学基金(2019D01C78)。

摘　　要：通过分析级联半桥子模块双星型结构的模块化多电平换流器(modular multilevel converter,MMC)拓扑,提出了一种含门级可关断晶闸管(gate turn-off thyristor,GTO)的改进MMC的静止无功发生器拓扑结构。与级联H桥静止无功发生器(static synchronous compensator,STATCOM)等拓扑相比,改进MMC拓扑的级联部分只需用双星型MMC结构的下半桥臂,并在MMC结构的下半桥臂上层加入一个H桥模块,但H桥模块在高压场景需要较高的耐压等级,且对频率要求相对较低,所以选择GTO组建H桥电路。针对电路拓扑结构设计了与之对应的调制与控制策略。然后,将改进的MMC-STATCOM与传统级联H桥结构的STATCOM进行比较,在使用相同级联模块情况下,该方案与级联H桥的补偿电流THD均小于2%,且改进MMC-STATCOM使用的开关器件数量更少。最后,通过对比无功电流指令值与补偿电流无功分量,验证了改进MMC-STATCOM在无功补偿动态性能及控制方案的有效性。By analyzing the modular multilevel converter(MMC)double star structure topology of cascaded half-bridge sub-modules,a static var generator topology of improved MMC containing gate turn-off thyristor(GTO)is proposed.Compared with topologies such as cascaded H-bridge static synchronous compensator(STATCOM),it only uses the lower half bridge-arm of the double-star MMC structure,and an H-bridge module is added to the upper layer of the lower half bridge-arm of the MMC structure.However,the H-bridge module requires to withstand higher voltage level in high-voltage scenarios.and has relatively low frequency requirements,so GTO is choosed to form the H-bridge circuit.The corresponding modulation and control strategy are designed for the circuit topology.Then,the improved MMC-STATCOM and the traditional cascaded H-bridge structure STATCOM are compared,the compensation current THD of this solution and the cascaded H-bridge are both less than 2%when the same cascaded modules are used,and the number of switching devices used in improved MMC-STATCOM is less.Finally,by comparing the reactive current command value with the reactive component of compensating current,the dynamic performance of the improved MMC-STATCOM in reactive power compensation and the effectiveness of the control scheme are verified.

关 键 词：模块化多电平换流器 静止无功发生器 半桥MMC 直流侧电压控制 

分 类 号：TM721.1[电气工程—电力系统及自动化]