模块化多电平直流变压器容错控制策略  

Fault-Tolerant Control Strategy of Modular Multilevel DC Transformer

作　　者：孙冠群 尹项根[1] 赖锦木 王祯 杜云飞 Sun Guanqun;Yin Xianggen;Lai Jinmu;Wang Zhen;Du Yunfei(State Key Laboratory of Advanced Electromagnetic Engineering and TechnologyHuazhong University of Science and Technology,Wuhan 430074 China)

机构地区：[1]强电磁工程与新技术国家重点实验室(华中科技大学),武汉430074

出　　处：《电工技术学报》2022年第S01期246-256,287,共12页Transactions of China Electrotechnical Society

基　　金：国家自然科学基金资助项目(51877089)。

摘　　要：为了提高模块化多电平直流变压器子模块故障后的容错能力,该文提出一种基于单侧双重移相控制的模块化多电平换流器(MMC)型直流变压器容错控制策略。首先,针对MMC-H桥型直流变压器,分析了双重移相控制下的工作原理与功率模型,研究了发生子模块不对称故障后的系统运行特性,揭示了旁路故障子模块导致系统桥臂电压不对称、子模块电压不稳定与环流波动的机理;然后,以单侧双重移相控制为基础,将一次侧桥臂内和桥臂间的移相角作为控制量,提出一种MMC型直流变压器容错控制策略,通过平衡故障桥臂平均子模块电压,解决桥臂不对称引起的系统不稳定问题,抑制了桥臂环流波动;最后,在Matlab/Simulink平台搭建了每个桥臂10个子模块的变压器模型,对单侧双重移相下的稳态控制与子模块故障后的容错控制进行仿真,验证了所提容错控制策略的有效性。In order to improve the fault tolerance under the sub-module fault of the modular multilevel DC transformer(MMDCT),this paper proposes a fault-tolerant control strategy for the MMDCT based on single-side-dual-phase-shift control.First,this paper analyzed the working principle and power model under dual-phase-shift control of MMDCT,and the system operating characteristic under the sub-module faults was investigated.The mechanisms of the arm voltage asymmetry,submodule voltage instability and circulating current fluctuation causing by the bypass fault sub-module were revealed.Then based on the single-side-dual-phase-shift control,a fault-tolerant control strategy of MMDCT was proposed,which used the single-side-phase-shift angle in and between the primary side arm as the control variable.By balancing the average sub-module voltage of the fault arm,the system instability caused by the asymmetric arm was solved,and the arm circulation fluctuation was also suppressed.Finally,a MMC DC transformer with 10 sub-modules per arm was built in the Matlab/Simulink platform.The effectiveness of the proposed fault tolerant control strategy was verified by both the steady-state and submodule fault operation conditions.

关 键 词：模块化多电平直流变压器 单侧双重移相控制 子模块故障 环流 容错 

分 类 号：TM46[电气工程—电器]