【作者】 周云； 周臻；

【Author】 Zhou Yun;Zhou Zhen;Changsha University of Science and Technology;

【机构】 长沙理工大学电气与信息工程学院；

【摘要】 海上风电的迅速发展使得技术先进的柔性直流输电系统得到越来越多的关注。针对海上风电柔性直流输电系统中普通模块化多电平(modular multilevel converter,MMC)换流器因子模块数量较多,系统需采集和处理的信息量大,导致控制系统硬件构成复杂,本文提出一种基于循环嵌套机理的MMC拓扑(nested-loop MMC,NLMMC),分析了该拓扑的构成方式及基本参数选取原则;并针对循环嵌套结构,设计了相应的模块协调控制策略。与普通MMC拓扑相比,新型拓扑具备更强的电平输出能力,能够利用较少的子模块数量实现较好的交流电压输出波形品质,无需滤波器,减少占地面积等。仿真结果表明,NLMMC输出电压波形更平滑,成本更低,非常适用于海上风电场输电场合。更多还原

【Abstract】 As the rapid development of offshore wind power, technologically advanced flexible HVDC systems get more and more attention. For offshore wind power HVDC flexible modular system,there are a large number of power sub-modules(SMs) in ordinary multi-level(modular multilevel converter, MMC) inverter, causing that quantities of data are needed to collect and process. It results in the complicated hardware construction of control system. A novel MMC topology based on nested-loop mechanism( NLMMC) is proposed in this paper,its composition and basic parameters design are analysised, the control strategies are also designed for the nested-loop structure. Compared with ordinary MMC topology, the new topology have stronger level output capability,It can use fewer sub-modules to achieve a better quality of output waveform of the AC voltage without filter, and reduce floor space and so on. Simulation results show that NLMMC output voltage waveform smoother, lower cost, which is very applicative for the power transmission of offshore wind farm.更多还原