MMC线性调制区扩大方法及其对桥臂功率波动影响的统一分析模型  

Unified Analysis Model for Expanding Linear Modulation Region of MMC and Its Influence on Arm Power Fluctuation

作　　者：周月宾 宋强[2] 张楠[3] 高盛 孟经伟 ZHOU Yuebin;SONG Qiang;ZHANG Nan;GAO Sheng;MENG Jingwei(State Key Laboratory of HVDC,China Southern Power Grid Electric Power Research Institute,Guangzhou 510663,China;State Key Laboratory of Power System and Generation Equipment,Tsinghua University,Beijing 100084,China;Maintenance and Test Center of Extra High Voltage Power Transmission Co.,China Southern Power Grid,Guangzhou 510663,China)

机构地区：[1]南方电网科学研究院直流输电技术国家重点实验室,广州510663 [2]清华大学电力系统及大型发电设备安全控制和仿真国家重点实验室,北京100084 [3]中国南方电网有限责任公司超高压输电公司检修试验中心,广州510663

出　　处：《高电压技术》2021年第12期4451-4460,共10页High Voltage Engineering

基　　金：南方电网公司科技项目(ZBKJXM20180663);国家重点研发计划(2016YFB0901005)。

摘　　要：为了通过扩大线性调制区实现模块化多电平换流器(modular multilevel converter,MMC)运行特性和体积成本的优化,分析了3次谐波注入和全桥子模块负电平输出对MMC线性调制区的影响,建立了综合计及3次谐波注入和负电平利用因素的MMC线性调制区统一分析模型,得到了综合计及两方面因素影响的最大调制比解析表达式。建立了桥臂功率波动随调制比变化的解析分析模型,揭示了在有功功率工况下桥臂基频功率波动随调制比的提高存在一个极低点。基于一个400 kV/1250 MW的MMC实例,对几种线性调制区扩大方式对MMC参数设计和桥臂功率波动的影响进行了对比分析,通过3次谐波注入和负电平利用的协调配合,可以使MMC调制比运行在最优点附近,大幅降低子模块电容电压波动。数字仿真结果验证了所提分析模型的正确性,并表明了3次谐波注入和负电平利用的协调优化运行方式的有效性。In order to optimize characteristics,cost and volume of modular multilevel converter(MMC)through expanding linear modulation region,the influence of third-order harmonic voltage injection and negative voltage level utilization of full-bridge submodules on the linear modulation region of MMC is analyzed comprehensively.A unified analysis model of the linear modulation region of MMC is established,and an analytical expression of the maximum attainable modulation index of MMC considering both the factors of third-order harmonic voltage injection and negative voltage level utilization is obtained.Moreover,an analytical analysis model of the power fluctuation of the arm with the variation of modulation index is established,which reveals that there is a minimal point of the fundamental frequency power fluctuation with the increase of the modulation index under the active power condition.Based on a 400 kV/1250 MW MMC example,the influences of several schemes for expanding linear modulation region on the MMC parameter design and arm power fluctuation and capacitor voltage ripples are compared and analyzed.Through the coordination of the third-harmonic injection and negative voltage level utilization,the modulation index can be operated near the optimal value,and the submodule capacitor voltage fluctuation can be greatly reduced.Digital simulation results verify the correctness of the proposed analysis model,and show the effectiveness of the feasibility of the third-harmonic injection and negative voltage level utilization.

关 键 词：模块化多电平换流器 柔性直流输电 3次谐波电压注入 全桥子模块负电平利用 线性调制区 

分 类 号：TM46[电气工程—电器]