MMC子模块故障后线电压恢复容错控制策略  

Fault-tolerant control strategy of line voltage recovery after MMC sub-modules fault

作　　者：夏长江 韩民晓[1] 耿治 寇龙泽 XIA Changjiang;HAN Minxiao;GENG Zhi;KOU Longze(School of Electrical and Electronic Engineering,North China Electric Power University,Beijing 102206,China;State Key Laboratory of Advanced Power Transmission Technology(Global Energy Interconnection Research Institute Co.,Ltd.),Beijing 102209,China)

机构地区：[1]华北电力大学电气与电子工程学院,北京102206 [2]先进输电技术国家重点实验室(全球能源互联网研究院有限公司),北京102209

出　　处：《电力工程技术》2021年第4期2-9,共8页Electric Power Engineering Technology

基　　金：国家重点研发计划资助项目(2018YFB0904700)。

摘　　要：模块化多电平换流器(MMC)桥臂无冗余子模块(SM)时,SM故障将导致故障相电压输出能力降低,进而导致MMC输出线电压不平衡。为恢复故障后无冗余MMC输出线电压特性,提高非故障桥臂SM利用率,文中基于中性点转移(NT)与直流分量注入(DCCI)控制,提出应用于无冗余MMC的SM故障容错控制策略。该容错策略通过NT控制,调整三相电压相角,确保输出线电压平衡。此外,文中提出三段式最优DCCI幅值计算方法。与现有方法相比,最优幅值DCCI能进一步提升非故障桥臂SM利用率,提高输出线电压幅值。基于PSCAD/EMTDC平台搭建三相MMC仿真模型,仿真结果验证了所提容错控制策略的有效性。When the modular multilevel converter(MMC)arms do not have redundant sub-modules,the fault of the sub-modules decreases the output voltage capability of the faulty phase,which leads to the unbalanced output line voltage of the MMC.In order to restore the post-fault output line voltage characteristics of the no-redundant MMC and improve the utilization rate of the non-faulty arm′s sub-modules,a sub-module fault-tolerant control strategy which is suitable for non-redundant MMC is proposed based on neutral point transfer(NT)and direct current component injection(DCCI)control.The fault-tolerant strategy adjusts the phase angle of the three-phase voltage through NT control for ensuring the balance of the output line voltage.In addition,a three-stage optimal DCCI amplitude calculation method is proposed.Compared with the existing methods,the optimal amplitude DCCI further improves the utilization rate of the non-faulty arm′s sub-modules and increases the output line voltage amplitude.A three-phase MMC simulation model based on the PSCAD/EMTDC platform is built,and the effectiveness of the proposed no-redundant fault-tolerant control strategy is verified through the simulation results.

关 键 词：模块化多电平换流器(MMC) 无冗余容错控制 子模块(SM)故障 中性点转移(NT) 直流分量注入(DCCI) 

分 类 号：TM76[电气工程—电力系统及自动化]