中文摘要：

冗余子模块（SM）是保证模块化多电平换流器（MMC）正常稳定运行的前提.介绍了MMC含冗余SM的工作原理和数学模型,分析了3种SM冗余保护方案,提出MMC动态冗余运行方案.为抑制SM电容电压波动,提出能量均衡控制及基于电容电压排序算法的调制策略.基于Matlab/Simulink所构建模型的仿真结果表明,动态冗余控制策略可保证冗余SM正常参与工作并保持电容电压稳定,系统整流侧可输出良好的直流电压.

英文摘要：

The redundant sub-module（SM） is the guarantee of normal operation of modular multilevel converter（MMC）. The principle and mathematic model of MMC which has redundant SM are introduced, three redundancy strategies of SM are analyzed,and the MMC dynamic redundant operation method is presented.In order to suppress capacitance voltage fluctuation,energy balancing control strategy and an optimized modulation strategy by sorting the capacitance voltages of SM are proposed.Results of simulation model built in Maflab/Simulink show that the redundant SM can work as normal SM and keep capacitance voltage stability.Output voltage of rectifier side is verified by the experiment.