具有交流源完全阻断能力的混合式MMC拓扑

摘要

In several kinds of MMC(Modular Multilevel Converter) sub-modules with DC fault eliminating capability,the clamp double sub-module has the lowest investment cost and additional power loss but relatively weaker AC-side source blocking capability,nevertheless,the series double sub-module and self-blocking submodule have strong enough AC-side source blocking capability but high investment cost and additional power loss.According to the different advantages of different sub-modules,a hybrid MMC topology is designed.Taking the requirement of the complete AC-side source blocking as the constraints and the lowest investment cost and additional power loss as the objectives,the sub-module number calculation principle is proposed.The simulation models of flexible DC system based on different sub-modules are built with MATLAB/Simulink,and the simulative results verify the correctness of theoretical analysis and the feasibility of the proposed hybrid MMC topology.%在具有直流故障清除能力的多种模块化多电平换流器(MMC)子模块中,箝位双子模块投资成本和附加损耗最低,但是交流源阻断能力相对较弱;串联双子模块和增强自阻型子模块交流源阻断能力足够强,但是投资成本和附加损耗较大.结合不同类型子模块所具备的不同优势,设计了一种混合式MMC拓扑结构.以闭锁后交流源完全阻断为约束,以投资成本、附加损耗最低为目标,提出了子模块数量的混合配置原则.基于MATLAB/Simulink仿真平台搭建相应的基于不同子模块的柔性直流系统模型,通过大量的仿真测试验证了理论分析的正确性以及所设计的混合式MMC拓扑的可行性.