Mode Transition for Low Voltage AC Port of Power Electronic Transformers Based on Duty Cycle Synchronization
Yuan Liqiang1, Gao Shen1, Ji Shiqi1, Xiao Fengliang2, Wu Mingkuan2
1. StateKey Laboratory of Control and Simulation of Power System and Generation Equipment Tsinghua University Beijing 100084 China; 2. Shangdong Taikai High-Voltage Switchgear Co. Ltd Tai'an 271000 China
Abstract：Multi-port power electronic transformer(PET) is the critical equipment in the future smart grid and is applied to new energy generation, hybrid AC-DC grid and DC(data center) power supply system. When multiple PETs are running in cluster, function of interconnection, information sharing, complementation and optimization is provided. Thus, mode transition which is the base of the cluster running is significant for the PETs. A duty cycle synchronization based mode transition method was proposed for a PET cluster demonstration system. The proposed method can effectively reduce the mode transition impact while the similar control scheme is not required for master and slave inverter. The impedance characteristics of the parallel inverter system were analyzed by the harmonic linearization method, which explained the reason of system oscillation during mode transition.Thus, the multi-step switchover method was applied to improve the stability of the mode transition. Finally, the proposed method was verified by mode transition experiments on two parallel MV·A PETs system.
袁立强, 高深, 姬世奇, 肖风良, 吴明宽. 基于占空比同步的电力电子变压器低压交流端口模式切换控制[J]. 电工技术学报, 2022, 37(3): 729-738.
Yuan Liqiang, Gao Shen, Ji Shiqi, Xiao Fengliang, Wu Mingkuan. Mode Transition for Low Voltage AC Port of Power Electronic Transformers Based on Duty Cycle Synchronization. Transactions of China Electrotechnical Society, 2022, 37(3): 729-738.
[1] 赵争鸣, 冯高辉, 袁立强,等. 电能路由器的发展及其关键技术[J]. 中国电机工程学报, 2017, 37(13): 3823-3834. Zhao Zhengming, Feng Gaohui, Yuan Liqiang, et al.The development and key technologies of electric energy router[J]. Proceedings of the CSEE, 2017, 37(13): 3823-3834. [2] 李凯, 赵争鸣, 袁立强, 等. 面向交直流混合配电系统的多端口电力电子变压器研究综述[J]. 高电压技术, 2021, 47(4): 1233-1250. LI Kai, Zhao Zhengming, Yuan Liqiang, et al.Overview on research of multi-port power electronic transformer oriented for AC/DC hybrid distribution grid[J]. High Voltage Engineering, 2021, 47(4): 1233-1250. [3] 文武松, 赵争鸣, 莫昕, 等. 基于高频汇集母线的电能路由器能量自循环系统及功率协同控制策略[J]. 电工技术学报, 2020, 35(11): 2328-2338. Wen Wusong, Zhao Zhengming, Mo Xin, et al.Energy self-circulation scheme and power coordinated control of high-frequency-bus based electric energy router[J]. Transactions of China Electrotechnical Society, 2020, 35(11): 2328-2338. [4] 文武松, 赵争鸣, 袁立强, 等. 电能路由器公共高频母线超瞬态过程机理及抑制措施[J]. 中国电机工程学报, 2021, 41(15): 5283-5294. Wen Wusong, Zhao Zhengming, Yuan Liqiang, et al.Mechanism and suppression strategy of the ultra-transient behavior of high-frequency-bus in electric energy router[J]. Proceedings of the CSEE, 2021, 41(15): 5283-5294. [5] 蔡伟谦, 沈瑜, 李凯, 等. 共高频交流母线的电能路由器直流端口控制策略[J]. 电网技术, 2020, 44(12): 4600-4607. CaiWeiqian, Shen Yu, Li Kai, et al. DC port control strategy for electric energy router with high frequency AC link[J]. Power System Technology, 2020, 44(12): 4600-4607. [6] Zhao Zhengming, Tan Dong, Shi Bochen, et al.A breakthrough in design verification of megawatt power electronic systems[J]. IEEE Power Electronics Magazine, 2020, 7(3): 36-43. [7] 陈新, 姬秋华, 刘飞. 基于微网主从结构的平滑切换控制策略[J]. 电工技术学报, 2014, 29(2): 163-170. Chen Xin, Ji Qiuhua, Liu Fei.Smooth transferring control method of microgrids based on master-slave configuration[J]. Transactions of China Electrotechnical Society, 2014, 29(2): 163-170. [8] 郑竞宏, 王燕廷, 李兴旺, 等. 微电网平滑切换控制方法及策略[J].电力系统自动化, 2011, 35(18): 17-24. Zheng Jinghong, Wang Yanting, Li Xingwang, et al.Control methods and strategies of microgrid smooth switchover[J]. Automation of Electric Power Systems, 2011, 35(18): 17-24. [9] 李鑫卓. 基于主从控制的微电网平滑切换控制[J].电气自动化, 2019, 41(4): 27-29. Li Xinzhuo.Smooth switching control of microgrids based on master-slave control[J]. Electrical Automation, 2019, 41(4): 27-29. [10] 王明玥, 罗安, 陈燕东, 等. 三相逆变器的双模式及其平滑切换控制方法[J]. 电工技术学报, 2016, 31(16): 124-134. Wang Mingyue, Luo An, Chen Yandong, et al.The dual-mode control and seamless transfer control method of three-phase inverter[J]. Transactions of China Electrotechnical Society, 2016, 31(16): 124-134. [11] 梁建钢, 金新民, 吴学智, 等. 微电网逆变器VCS模式与CCS模式的切换技术[J]. 电网技术, 2014, 38(4): 830-837. Liang Jiangang, Jin Xinmin, Wu Xuezhi, et al.Switching technology between VCS mode and CCS mode of inverters in microgrids[J]. Power System Technology, 2014, 38(4): 830-837. [12] Wang Jing, Chang N C P, Feng Xiaowei. Design of a generalized control algorithm for parallel inverters for smooth microgrid transition operation[J]. IEEE Transactions on Industrial Electronics, 2015, 62(8): 4900-4914. [13] Micallef A, Apap M, Spiteri-Staines C, et al.Single-phase microgrid with seamless transition capabilities between modes of operation[J]. IEEE Transactions on Smart Grid, 2015, 6(6): 2736-2745. [14] 杨彦杰, 杨康, 邵永明, 等. 微电网的并离网平滑切换控制策略研究[J]. 可再生能源, 2018, 36(1): 36-42. Yang Yanjie, Yang Kang, Shao Yongming, et al.Control strategy for smooth switching between island operation mode and grid-connection operation mode of microgrid[J]. Renewable Energy Resources, 2018, 36(1): 36-42. [15] 杨向真. 微网逆变器及其协调控制策略研究[D]. 合肥: 合肥工业大学,2011. [16] Ramezani M, Li S, Musavi F, et al.Seamless transition of synchronous inverters using synchronizing virtual torque and flux linkage[J]. IEEE Transactions on Industrial Electronics, 2020, 67(1): 319-328. [17] 梁建钢. 微电网变流器并网运行及并网和孤岛切换技术研究[D]. 北京: 北京交通大学, 2015. [18] 王大获. 数据中心电源系统节能方案设计[D]. 广州: 华南理工大学, 2017. [19] 杨荣峰, 于雁南, 俞万能, 等. 新能源船舶并网逆变器电网支撑协调控制[J]. 电工技术学报, 2019, 34(10): 2141-2154. Yang Rongfeng, Yu Yannan, Yu Wanneng, et al.New energy ship grid-connected inverter grid support and cooperative control[J]. Transactions of China Electrotechnical Society, 2019, 34(10): 2141-2154. [20] 姜齐荣, 王玉芝. 电力电子设备高占比电力系统电磁振荡分析与抑制综述[J]. 中国电机工程学报, 2020, 40(22): 7185-7201. Jiang Qirong, Wang Yuzhi.Overview of the analysis and mitigation methods of electromagnetic oscillations in power systems with high proportion of power electronic equipment[J]. Proceedings of the CSEE, 2020, 40(22): 7185-7201. [21] 谢志为, 陈燕东, 伍文华, 等. 弱电网下多逆变器并网系统的全局高频振荡抑制方法[J]. 电工技术学报, 2020, 35(4): 885-895. XieZhiwei, Chen Yandong, Wu Wenhua, et al.A global high-frequency oscillation suppression method for multi-inverter grid-connected system in weak grid[J]. Transactions of China Electrotechnical Society, 2020, 35(4): 885-895. [22] Shah S, Parsa L.Impedance modeling of three-phase voltage source converters in dq, sequence, and phasor domains[J]. IEEE Transactions on Energy Conversion, 2017, 32(3): 1139-1150. [23] Cespedes M, Sun J.Impedance modeling and analysis of grid-connected voltage-source converters[J]. IEEE Transactions on Power Electronics, 2013, 29(3): 1254-1261. [24] 姚骏, 谭义, 杜红彪, 等. 孤岛模式下逆变器并联系统的谐振特性分析及其抑制策略研究[J]. 电工技术学报, 2016, 31(23): 199-210. YaoJun, Tan Yi, Du Hongbiao, et al. Analysis of resonant characteristics and resonance suppression strategy of inverter parallel system in islanding mode[J]. Transactions of China Electrotechnical Society, 2016, 31(23): 199-210. [25] Zong Haoxiang, Lu Jing, Cai Xu, et al.Analysis of bifurcation behaviors in MMC connected to a weak grid[C]// IECON 2018-44th Annual Conference of the IEEE Industrial Electronics Society, Washington, DC, USA, 2018, DOI: 10.1109/IECON. 2018. 8592728. [26] 张旸, 陈新, 王昀, 等. 弱电网下并网逆变器的阻抗相角动态控制方法[J]. 电工技术学报, 2017, 32(1): 97-106. Zhang Yang, Chen Xin, Wang Yun, et al.Impedance-phased dynamic control method of grid-connected inverters under weak grid condition[J]. Transactions of China Electrotechnical Society, 2017, 32(1): 97-106.
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