Isolated Bipolar Modular Multilevel DC-DC Converter with Self-balancing Capability for Interconnection of MVDC and LVDC Grids
作者机构:School of Electricaland Information EngineeringZhengzhou UniversityZhengzhou 450001China Department of Electrical Engineeringand ElectronicsUniversity of LiverpoolLiverpoolUK State Key Laboratory of Advanced Electromagnetic Engineeringand TechnologyHuazhong University of Scienceand TechnologyWuhan 430074China
出 版 物:《CSEE Journal of Power and Energy Systems》 (中国电机工程学会电力与能源系统学报(英文))
年 卷 期:2023年第9卷第1期
页 面:365-379页
核心收录:
学科分类:0820[工学-石油与天然气工程] 080801[工学-电机与电器] 0808[工学-电气工程] 08[工学]
基 金:This work was supported in part by the National Natural Science Foundation of China(No.51877089)。
主 题:Bipolar DC-DC converter equivalent circuit modular monopolar operation multilevel self-balancing
摘 要:Bipolar medium-voltage DC(MVDC)and lowvoltage DC(LVDC)grids have the advantages of flexible integration of distributed renewable-energy generation and reliable power supply.In order to achieve voltage conversion,power transfer,and electrical isolation for bipolar MVDC and LVDC grids,a high-power DC-DC converter is essential.Therefore,this paper proposes an isolated bipolar modular multilevel DCDC converter(BiMMDC)with power self-balancing capability for interconnection of MVDC and LVDC grids.The proposed BiMMDC consists of two series connected MMCs in the MV stage to configure a bipolar MVDC interface,and interleaved converters combined with a dual-transformer are designed in the LV stage to configure the bipolar LVDC interface and to provide a self-balancing capability.Equivalent circuits of two series-connected MMCs and a dual-transformer with interleaved converters are derived.After that,operation principles of the proposed BiMMDC are introduced,considering balanced/unbalanced power transfer of bipolar LVDC grid and monopolar shortcircuit or open-circuit faults at MVDC grid.The control scheme is also presented for the proposed BiMMDC under different operating conditions.Finally,a Matlab simulation and controller hardware-in-the-loop(CHIL)evaluation results are provided to validate the feasibility and effectiveness of the proposed typology and its operating performance.