中国电机工程学报2017，Vol.37Issue(9)：2516-2524,9.DOI:10.13334/j.0258-8013.pcsee.160362
应用于直流电网的直接耦合式直流变压器
Direct-coupled DC Transformers Applied to DC Grids
摘要
Abstract
The multi-terminal high voltage direct current (HVDC) and DC grid technologies are the efficient methods to resolve the problems of renewable energy integration, and the DC transformer is the key equipment to interconnect DC sources with different voltage levels and to build DC grids. This paper presented a new direct-coupled DC transformer topology based on cascaded submodules. A step-wave quasi 2-level modulation was introduced to achieve the voltage balance of the submodule capacitors. Additionally, the dv/dt of the DC transformer was also reduced by the modulation. Compared with the prior arts where sine-wave modulation was applied, the proposed DC transformer offers several merits: 1)the switching frequency is reduced because the IGBTs in the DC transformer are switched on and off once in a period; 2)the amplitude of the AC circulating current is lower, so that the conducting and switching losses are both reduced; 3)the requirement of the submodule capacitance is reduced dramatically, thus the cost and the volume of the submodules are reduced. Finally, the simulation of the proposed DC transformer based on Matlab/Simulink platform was given to verify the theoretical analysis.关键词
直流电网/直流变压器/直流–直流变换器/模块化多电平变换器Key words
DC grid/DC transformer/DC-DC converter/modular multilevel converter (MMC)分类
信息技术与安全科学引用本文复制引用
游洪程,蔡旭..应用于直流电网的直接耦合式直流变压器[J].中国电机工程学报,2017,37(9):2516-2524,9.基金项目
国家自然科学基金项目(51677117) （51677117）
上海市科学技术委员会科研计划课题(16DZ1203402). Project Supported by National Natural Science Foundation of China (51677117) （16DZ1203402）
Shanghai Science and Technology Committee Scientific Research Program (16DZ1203402). （16DZ1203402）
