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.
作者
朱亮亮
陈洁
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)
出处
《南方电网技术》
CSCD
北大核心
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)。
