摘要
模块化多电平换流器(MMC)因其具有输出波形质量高、可靠性高等优势,在高压直流输电、新能源并网等领域得到广泛研究与应用。针对MMC型多端柔性直流输电系统(MTDC),研究换流器的基本拓扑结构及工作原理,在建立MMC详细模型的基础上推导其平均值模型;并针对多端直流输电系统大功率变化时,直流电压下垂控制导致直流电压偏差较大的问题,提出一种改进的下垂反馈控制策略,在稳定直流电压的同时实现系统功率的平衡;最后,在PSCAD/EMTDC仿真环境下搭建四端高压直流输电系统,对系统稳态时和出现功率扰动情况下,进行仿真分析,仿真结果验证了所提方法的有效性。
With the advantages of output power high quality and reliability, modular multilevel converter （MMC） has been applied in high-voltage DC and new energy grid-connected fields. Firstly, according to the multi-terminal HVDC transmission system with MMC, the basic topology and operating principle of the converter was introduced in this paper, and then the MMC averaged mode was derived. Secondly, in order to solve the problem of direct voltage large offset caused by voltage droop control under the larger power changing in the multi-terminal HVDC system, an improved droop control strategy was proposed. The DC voltage was stabled, and the system power was balanced. Finally, a model of three-terminal MMC-MTDC system in PSCAD/EMTDC was established. The simulation results verified the validity and effectiveness of the improved droop control method .
出处
《电力科学与技术学报》
CAS
北大核心
2017年第2期47-53,共7页
Journal of Electric Power Science And Technology
基金
湖南省自然科学基金(2016JJ4001)
湖南省教育厅科学研究重点项目(16A006)
关键词
多端直流输电
多电平换流器
模块化
平均值模型
下垂控制
multi-terminal high voltage direct current （MTDC）
modular multilevel converter （MMC）
averaged model
droop control
