具有直流电压极性反转能力的双交流端口模块化多电平换流器  

Dual-AC-port Modular Multilevel Converter with DC Polarity Reversal Ability

作　　者：陈阳 王晗[1] 朱淼[1] 马建军 蔡旭[1] CHEN Yang;WANG Han;ZHU Miao;MA Jianjun;CAI Xu(School of Electronic Information and Electrical Engineering,Shanghai Jiao Tong University,Shanghai 200240,China)

机构地区：[1]上海交通大学电子信息与电气工程学院,上海200240

出　　处：《高电压技术》2022年第3期980-991,共12页High Voltage Engineering

基　　金：国家重点研发计划(2018YFB0904100);国家电网公司科技项目(SGHB0000KXJS1800685)。

摘　　要：基于半桥子模块的传统模块化多电平换流器(modular multilevel converter,MMC)仅含有一个交流端口,且难以实现直流电压极性反转,不能与电网换相换流器高压直流输电(line commutated converter-high-voltage DC,LCC-HVDC)直接互联和交换功率。为此,提出一种改进型MMC拓扑,在全桥MMC的基础上,相单元上下桥臂之间增加1组由全桥子模块和桥臂电感组成的中间桥臂。所提出的双交流端口新型MMC能够在保持直流电压极性反转能力以接入LCC-HVDC的同时,提供双独立交流端口。控制一组交流端口实现直流侧电压极性反转的同时,能够维持另一交流端口输出功率不变。介绍了所提出的新型MMC的详细拓扑,分析了装置的基本工作原理,建立了完整的数学模型并提出相应的输出控制策略;在分析装置环流组成及其有效成分的基础上,给出了相应的环流控制策略;提出了直流电压极性反转控制方法,能够维持另一组交流端口输出不变的同时实现直流端口电压极性反转。仿真结果验证了所提出的新型换流器拓扑、理论分析以及控制策略的正确性。Traditional half-bridge-submodule-based modular multilevel converter(MMC)has a single AC port and lacks of DC polarity reversal ability with the structure.It cannot be connected to the LCC-HVDC(line commutated converterhigh-voltage DC)directly.A novel MMC with dual AC ports is proposed in this paper by adding a middle arm cell with full-bridge submodules in each phase leg.Full-bridge submodules are adopted in the upper and lower arm cells to achieve the DC polarity reversal ability and free power transfer with LCC-HVDC.The proposed MMC can provide DC voltage polarity reversal by one AC port while maintaining the output of the other AC port.Detailed topology and working principles are introduced firstly.An output control strategy is designed based on the mathematical modeling.The circulating current suppression strategy is proposed based on the essential component analysis of the circulating current.A DC polarity reversal strategy is proposed,thus the DC voltage polarity reversal is realized by controlling one AC port and the output of the other AC port maintains unchanged.Simulation results validate the correctness of the proposed approach.

关 键 词：模块化多电平换流器 双交流端口 环流抑制 直流电压极性反转 最近电平逼近调制 

分 类 号：TM721.1[电气工程—电力系统及自动化]