Cascaded LC-AC Transformer Unidirectional DC-DC Converter with High Stepping Ratio
Li Mengbo1, Xie Zhujun1, Lin Weixing1,2, Wen Jinyu1, Wang Shaorong1
1. State Key Laboratory of Advanced Electromagnetic Engineering and Technology School of Electrical and Electronic Engineering Huazhong University of Science and Technology Wuhan 430074 China 2. TBEA Sunoasis Co., Ltd Urumchi 830011 China
Abstract：This paper proposes a cascaded LC-AC transformer unidirectional DC-DC converter (LCT DC-DC), which has high stepping ratio and is suitable for integrating renewable energy sources to DC grid. The presented LCT DC-DC converter can achieve about 40 times stepping ratio through the two-stage step-up of voltage. To begin with, the voltage source converters (VSC) are used to invert DC to AC, an adequately designed inductor-capacitor circuit is then employed to achieve voltage step up in the first stage. In the second stage, an AC transformer will further boost the output voltage. Diode rectifiers are finally used to rectify AC to DC. This paper firstly introduces the design procedures of the LCT DC-DC. The corresponding active power control strategy and the power loss estimations are studied as well. The simulations on PSCAD/EMTDC confirm the technical feasibility of the proposed topology.
[1] 刘世林, 文劲宇, 孙海顺, 等. 风电并网中的储能技术研究进展[J]. 电力系统保护与控制, 2013, 41(23): 145-153. Liu Shilin, Wen Jinyu, Sun Haishun, et al. Progress on applications of energy storage technology in wind power integrated to the grid[J]. Power System Protection and Control, 2013, 41(23): 145-153. [2] 艾小猛, 韩杏宁, 文劲宇, 等. 考虑风电爬坡事件的鲁棒机组组合[J]. 电工技术学报, 2015, 30(24): 188-195. Ai Xiaomeng, Han Xingning, Wen Jinyu, et al. Robust unit commitment considering wind power ramp events[J]. Transactions of China Electro- technical Society, 2015, 30(24): 188-195. [3] 陈沛华, 赵会茹, 李娜娜. 分布式光伏电源并网影响与应对措施[J]. 电气技术, 2015, 16(1): 125-127. Chen Peihua, Zhao Huiru, Li Nana. The influence and the response of the distributed photovoltaic power integrated to the grid[J]. Electrical Engineering, 2015, 16(1): 125-127. [4] 刘巨, 姚伟, 侯云鹤, 等. 一种储能改善低电压穿越期间风电场注入电流特性的致稳策略[J]. 电工技术学报, 2016, 31(14): 93-103. Liu Ju, Yao Wei, Hou Yunhe, et al. Stability control for improving the characteristic of wind farm injection current during low voltage ride-through using energy storage system[J]. Transactions of China Electrotechnical Society, 2016, 31(14): 93-103. [5] 罗剑波, 陈永华, 刘强. 大规模间歇性新能源并网控制技术综述[J]. 电力系统保护与控制, 2014, 42(22): 140-146. Luo Jianbo, Chen Yonghua, Liu Qiang. Overview of large-scale intermittent new energy grid-connected control technology[J]. Power System Protection and Control, 2014, 42(22): 140-146. [6] 肖湘宁, 罗超, 廖坤玉. 新能源电力系统次同步振荡问题研究综述[J]. 电工技术学报, 2017, 32(6): 85-97. Xiao Xiangning, Luo Chao, Liao Kunyu. Review of the research on subsynchronous oscillation issues in electric power system with renewable energy sources[J]. Transactions of China Electrotechnical Society, 2017, 32(6): 85-97. [7] Lin W, Wen J, Liang J, et al. A three-terminal HVDC system to bundle wind farms with conventional power plants[J]. IEEE Transactions on Power Systems, 2013, 28(3): 2292-2300. [8] 黄晟, 王辉, 廖武, 等. 基于VSC-HVDC海上串联拓扑风电场低电压穿越控制策略研究[J]. 电工技术学报, 2015, 30(14): 362-369. Huang Sheng, Wang Hui, Liao Wu, et al. Control strategy based on VSC-HVDC series topology offshore wind farm for low voltage ride through[J]. Transactions of China Electrotechnical Society, 2015, 30(14): 362-369. [9] Dorn J, Gambach H, Retzmann D. HVDC trans- mission technology for sustainable power supply[C]// 2012 9th International Multi-Conference on Systems, Signals and Devices (SSD), Chemnitz, Germany, 2012: 1-6. [10] 陈霞, 林卫星, 孙海顺, 等. 基于多端直流输电的风电并网技术[J]. 电工技术学报, 2011, 26(7): 60-67. Chen Xia, Lin Weixing, Sun Haishun, et al. LCC- MTDC technology for wind farms integration[J]. Transactions of China Electrotechnical Society, 2011, 26(7): 60-67. [11] 徐殿国, 刘瑜超, 武健. 多端直流输电系统控制研究综述[J]. 电工技术学报, 2015, 30(17): 1-12. Xu Dianguo, Liu Yuchao, Wu Jian. Review on control strategies on multi-terminal direct current transmission system[J]. Transactions of China Electrotechnical Society, 2015, 30(17): 1-12. [12] Echeverría J, Kouro S, Perez M, et al. Multi-modular cascaded DC-DC converter for HVDC grid connection of large-scale photovoltaic power systems[C]//Industrial Electronics Society, IECON 2013-39th Annual Conference of the IEEE, Vienna, Austria, 2013: 6999-7005. [13] Robinson J, Jovcic D, Joós G. Analysis and design of an offshore wind farm using a MV DC grid[J]. IEEE Transactions on Power Delivery, 2010, 25(4): 2164- 2173. [14] Chen W, Huang A Q, Li C, et al. Analysis and comparison of medium voltage high power DC/DC converters for offshore wind energy systems[J]. IEEE Transactions on Power Electronics, 2013, 28(4): 2014-2023. [15] Alsharif R, Odavic M. Photovoltaic generators interfacing a dc micro-grid: design considerations for a double-stage boost power converter system[C]// The 18th European Conference on Power Elec- tronics and Applications (EPE'16 ECCE Europe), Karlsruhe, Germany, 2016: 1-10. [16] Stieneker M, De Doncker R W. Medium-voltage DC distribution grids in urban areas[C]//2016 IEEE 7th International Symposium on Power Electronics for Distributed Generation Systems (PEDG), Vancouver, BC, Canada, 2016: 1-7. [17] 陈武, 吴小刚, 蒋玮, 等. 一种适用于新能源并网的谐振升压变换器[J]. 电工技术学报, 2016, 31(8): 27-33. Chen Wu, Wu Xiaogang, Jiang Wei, et al. A Step-up resonant converter for grid-connected renewable energy sources[J]. Transactions of China Electro- technical Society, 2016, 31(8): 27-33. [18] 武琳, 刘志刚, 洪祥. 隔离式双向全桥DC-DC变换器的功率控制特性比较与分析[J]. 电工技术学报, 2013, 28(10): 179-187. Wu Lin, Liu Zhigang, Hong Xiang. Comparison and analysis of power control characteristic for isolated bidirectional full-bridge DC-DC converter[J]. Transa- ctions of China Electrotechnical Society, 2013, 28(10): 179-187. [19] 胡义华, 陈昊, 徐瑞东, 等. 一种高升压比直流变换器[J]. 电工技术学报, 2012, 27(9): 224-230. Hu Yihua, Chen Hao, Xu Ruidong, et al. A type of high step-up DC-DC converter[J]. Transactions of China Electrotechnical Society, 2012, 27(9): 224-230. [20] Adam G P, Gowaid I A, Finney S J, et al. Review of DC-DC converters for multi-terminal HVDC trans- mission networks[J]. IET Power Electronics, 2016, 9(2): 281-296. [21] Engel S P, Stieneker M, Soltau N, et al. Comparison of the modular multilevel DC converter and the dual-active bridge converter for power conversion in HVDC and MVDC grids[J]. IEEE Transactions on Power Electronics, 2015, 30(1): 124-137. [22] Jovcic D, Zhang L. LCL DC/DC converter for DC grids[J]. IEEE Transactions on Power Delivery, 2013, 28(4): 2071-2079. [23] Jovcic D, Lin W. Multiport high-power LCL DC hub for use in DC transmission grids[J]. IEEE Transa- ctions on Power Delivery, 2014, 29(2): 760-768. [24] 李梦柏,林卫星,文劲宇. 单向LC型直流—直流变换器的设计与控制[J]. 电力系统自动化, 2016, 40(21): 112-116, 194. Li Mengbo, Lin Weixing, Wen Jinyu. Control and design of unidirectional LC DC/DC converter[J]. Automation of Electric Power Systems, 2016, 40(21): 112-116, 194. [25] Chang G W, Chen S K, Su H J, et al. Accurate assessment of harmonic and interharmonic currents generated by VSI-fed drives under unbalanced supply voltages[J]. IEEE Transactions on Power Delivery, 2011, 26(2): 1083-1091. [26] Lian K L, Perkins B K, Lehn P W. Harmonic analysis of a three-phase diode bridge rectifier based on sampled-data model[J]. IEEE Transactions on Power Delivery, 2008, 23(2): 1088-1096. [27] 王兆安. 电力电子技术[M]. 北京: 机械工业出版社, 2009. [28] Hajian M, Robinson J, Jovcic D, Wu B. 30kV, 200V/ 900V, thyristors LCL DC/DC converter laboratory prototype design and testing[J]. IEEE Transactions on Power Electronics, 2014, 29(3): 1094-1102. [29] 汤广福. 基于电压源换流器的高压直流输电技术[M]. 北京: 中国电力出版社, 2010. [30] 李程昊, 谢竹君, 林卫星, 等. 中高频模块化多电平换流器阀损耗的精确计算方法与分析平台[J]. 中国电机工程学报, 2015, 35(17): 4361-4370. Li Chenghao, Xie Zhujun, Lin Weixing, et al. Accurate valve loss calculation method and analyzing platform for medium and high-frequency MMC[J]. Proceedings of the CSEE, 2015, 35(17): 4361-4370. [31] McLyman C W T. Transformer and inductor design handbook[M]. Boca Raton: CRC Press, 2011.
2018, Vol. 33 
