Abstract：With the increasing scale of new energy grid connection, the interaction between grid connected inverter and grid impedance becomes more and more significant. The interaction between inverter and grid impedance reduces the damping effect of power varing of grid connected system, resulting in significant energy exchange between inverter and grid according to specific frequency, leading to instability problems such as oscillation. In this paper, a small signal model of grid connected inverter system is established, and the mechanism of interaction instability between grid impedance and grid connected inverter is analyzed from the perspective of damping. On this basis, a control strategy is proposed to improve the damping effect of power oscillation of grid connected inverter system in weak gird. The control strategy introduces the DC voltage differential into the voltage loop and current loop input link, which is essentially a series virtual resistance on the DC side, so as to improve the damping of the system. The theoretical analysis shows that the strategy can not only improve the stability of the grid connected inverter, but also expand the stability control parameter field of the inverter. Finally, the effectiveness of the proposed method is verified by Hardware in the loop simulation.
汪春江, 孙建军, 宫金武, 查晓明. 并网逆变器与电网阻抗交互失稳机理及阻尼策略[J]. 电工技术学报, 2020, 35(zk2): 503-511.
Wang Chunjiang, Sun Jianjun, Gong Jinwu, Zha Xiaoming. Mechanism and Damping Strategy of Interactive Instability Between Grid-Connected Inverter and Grid Impedance. Transactions of China Electrotechnical Society, 2020, 35(zk2): 503-511.
[1] 阮新波. LCL型逆变器的控制技术[M]. 北京: 科学出版社, 2015. [2] 姚骏, 曾欣, 李嘉伟. 并网双馈感应风电系统轴系振荡特性[J]. 电工技术学报, 2017, 32(6): 123-135. Yao Jun, Zeng Xin, Li Jiawei.Shaft oscillation characteristics of grid-connected doubly-fed induction generator-based wind power generation system[J]. Transactions of China Electrotechnical Society, 2017, 32(6): 123-135. [3] 陈宝平, 林涛, 陈汝斯, 等. 直驱风电场经VSC-HVDC并网系统的多频段振荡特性分析[J]. 电工技术学报, 2018, 33(增刊1): 176-184. Chen Baoping, Lin Tao, Chen Rusi, et al.Characteristics of multi-band oscillation for direct drive wind farm interfaced with VSC-HVDC system[J]. Transactions of China Electrotechnical Society, 2018, 33(S1): 176-184. [4] Kocewiak L H, Hjerrild J, Bak C L.Wind turbine control impact on stability of wind farms based on real-life systems analysis[C]//Proceedings of the EWEA, Copenhagen, Denmark, 2012. [5] 杜平, 万玉良, 项颂, 等. VSC变流器与弱电网交互作用的次同步振荡关键参数研究[J]. 电力系统保护与控制, 2019, 47(14): 44-49. Du Ping, Wan Yuliang, Xiang Song, et al.Study on key parameters of subsynchronous oscillation between VSC converter and weak power grid[J]. Power System Protection and Control, 2019, 47(14): 44-49. [6] 毕天姝, 孔永乐, 肖仕武, 等. 大规模风电外送中的次同步振荡问题[J]. 电力科学与技术学报, 2012, 27(1): 10-15. Bi Tianshu, Kong Yongle, Xiao Shiwu, et al.Review of sub-synchronous oscillation with large-scale wind power transmission[J]. Journal of Electric Power Science and Technology, 2012, 27(1): 10-15. [7] 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. [8] Huang Yunhui, Yuan Xiaoming, Hu Jiabing, et al.DC-Bus voltage control stability affected by AC-bus voltage control in VSCs connected to weak AC grids[J]. IEEE Journal of Emerging and Selected Topics in Power Electronics, 2016, 4(2): 445-457. [9] Huang Yunhui, Yuan Xiaoming, Hu Jiabing, et al.Modeling of VSC connected to weak grid for stability analysis of DC-link voltage control[J]. IEEE Journal of Emerging and Selected Topics in Power Electronics, 2015, 3(4): 1193-1204. [10] Zhou Pian, Yuan Xiaoming, Hu Jiabing, et al.Stability of DC-link voltage as affected by phase locked loop in VSC when attached to weak grid[C]//PES General Meeting Conference & Exposition, 2014. [11] Xiong Liansong, Zhuo Fang, Wang Feng, et al.Static synchronous generator model: a new perspective to investigate dynamic characteristics and stability issues of grid-tied PWM inverter[J]. IEEE Transactions on Power Electronic, 2016, 31(9): 6264-6280. [12] 袁小明, 程时杰, 胡家兵. 电力电子化电力系统多尺度电压功角动态稳定问题[J]. 中国电机工程学报, 2016, 36(19): 5145-5154. Yuan Xiaoming, Cheng Shijie, Hu Jiabing.Multi-time scale voltage and power angle dynamics in power electronics dominated large power systems[J]. Proceedings of the CSEE, 2016, 36(19): 5145-5154. [13] 张琛, 蔡旭, 李征. 电压源型并网变流器的机-网电气振荡机理及稳定判据研究[J]. 中国电机工程学报, 2017, 37(11): 3174-3183, 3372. Zhang Chen, Cai Xu, Li Zheng.Stability criterion and mechanisms analysis of electrical oscillations in the grid-tied VSC system[J]. Proceedings of the CSEE, 2017, 37(11): 3174-3183, 3372. [14] Sainz L, Cheah-Mane M, Monjo L, et al.Positive-net-damping stability criterion in grid-connected VSC systems[J]. IEEE Journal of Emerging and Selected Topics in Power Electronics, 2017, 5(4): 1499-1512. [15] Cheah-Mane, Sainz L, Liang J, et al.Criterion for the electrical resonance stability of off shore wind power plants connected through HVDC links[J]. IEEE Transactions on Power System, 2017, 32(6): 4579-4589. [16] 宋瑞华, 郭剑波, 李柏青, 等. 基于输入导纳的直驱风电次同步振荡机理与特性分析[J]. 中国电机工程学报, 2017, 37(16): 4662-4670, 4891. Song Ruihua, Guo Jianbo, Li Baiqing, et al.Mechanism and characteristics of subsynchronous oscillation in direct-drive wind power generation system based on input-admittance analysis[J]. Proceedings of the CSEE, 2017, 37(16): 4662-4670, 4891. [17] 解宝, 周林, 郝高锋, 等. 考虑电网阻抗影响的光伏并网逆变器稳定性与谐振分析及设计[J]. 中国电机工程学报, 2018, 38(22): 6662-6671. Xie Bao, Zhou Lin, Hao Gaofeng, et al.Stability and resonance analysis and design of photovoltaic grid-connected inverters with effect of grid impedance[J]. Proceedings of the CSEE, 2018, 38(22): 6662-6671. [18] 杨东升, 阮新波, 吴恒. 提高LCL型并网逆变器对弱电网适应性的虚拟阻抗方法[J]. 中国电机工程学报, 2014, 34(15): 2327-2335. Yang Dongsheng, Ruan Xinbo, Wu Heng.A virtual impedance method to improve the performance of LCL-type grid-connected inverters under weak grid conditions[J]. Proceedings of the CSEE, 2014, 34(15): 2327-2335. [19] Mauricio Céspedes, Jian Sun.Impedance shaping of three-phase grid-paralled voltage-source converters[C]// Twenty-Seventh Annual IEEE Applied Power Electronics Conference and Exposition, Orlando, FL, 2012: 754-760. [20] 钱强, 谢少军, 季林, 等. 一种提升逆变器对电网适应能力的电流控制策略[J]. 中国电机工程学报, 2016, 36(22): 6193-6201. Qian Qiang, Xie Shaojun, Ji Lin, et al.A current control strategy to improve the adaptability to utility for inverters[J]. Proceedings of the CSEE, 2016, 36(22): 6193-6201. [21] 许津铭, 谢少军, 唐婷. 弱电网下LCL滤波并网逆变器自适应电流控制[J]. 中国电机工程学报, 2014, 34(24): 4031-4039. Xu Jinming, Xie Shaojun, Tang Ting.An adaptive current control for grid-connected LCL-filtered inverters in weak grid case[J]. Proceedings of the CSEE, 2014, 34(24): 4031-4039. [22] 季宇, 王东旭, 吴红斌, 等. 提高直流微电网稳定性的有源阻尼方法[J]. 电工技术学报, 2018, 33(2): 370-379. Ji Yu, Wang Dongxu, Wu Hongbin, et al.The active damping method for improving the stability of DC microgrid[J]. Transactions of China Electrotechnical Society, 2018, 33(2): 370-379. [23] Sun Jian.Impedance-based stability criterion for grid-connected inverters[J]. IEEE Transactions on Power Electronics, 2011, 26(11): 3075-3078. [24] 许津铭, 谢少军, 肖华锋. LCL滤波器有源阻尼策略机制研究[J]. 中国电机工程学报, 2012, 32(9): 27-33. Xu Jinming, Xie Shaojun, Xiao Huafeng.Research on control mechanism of active damping for LCL filters[J]. Proceedings of the CSEE, 2012, 32(9): 27-33.
2020, Vol. 35 
