Quasi-Proportional Resonance Control of Grid-Connected Inverter Based on Grid Impedance

doi:10.11930/j.issn.1004-9649.201805135

Abstract

Abstract: With the large-scale integration of renewable energy to the grid, the problem of sub/super-synchronous oscillations caused by the interaction of renewable energy grid-connected inverters with the grid has drawn great public attention. Such oscillation problems are closely related to the output impedance of the grid-connected inverter and the characteristics of grid impedance. Therefore, a small-signal output impedance model of the three-phase LCL–type grid-connected inverter is developed in this paper with harmonic linearization method, and the impacts of different current control strategies on its output impedance are evaluated, and the influence of grid impedance on system stability is analyzed with the impedance ratio Nyquist criterion. The inherent resonance peak of LCL filter is suppressed by combining passive damping with active damping, and the parameters of quasi-proportional resonance (QPR) controller and the feedback coefficient of capacitance current are adjusted according to the change of grid impedance at the point of common coupling, which enhances the robustness of the system without changing the system damping, and ensures the stable operation of the system. Finally, the effectiveness of the proposed control strategy is verified by combination of time-domain simulation and numerical analysis.

Key words: quasi-proportional resonance control, three-phase grid-connected inverter, grid impedance, damping control

CLC Number:

TM615

SONG Shaojian, YANG Xi, LIU Bin, LIAO Bilian, SONG Chunning. Quasi-Proportional Resonance Control of Grid-Connected Inverter Based on Grid Impedance[J]. Electric Power, 2019, 52(12): 90-96.

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URL: https://www.electricpower.com.cn/EN/10.11930/j.issn.1004-9649.201805135

https://www.electricpower.com.cn/EN/Y2019/V52/I12/90

References

[1] 余希瑞, 周林, 郭珂, 等. 含新能源发电接入的电力系统低频振荡阻尼控制研究综述[J]. 中国电机工程学报, 2017, 37(21):6278-6290 YU Xirui, ZHOU Lin, GUO Ke, et al. A survey on low frequency oscillation damping control in power system integrated with new energy power generation[J]. Proceedings of the CSEE, 2017, 37(21):6278-6290
[2] 谢文浩, 刘一琦, 王建赜, 等.提高LCL型并网逆变器阻抗重塑控制鲁棒性的延时补偿方法[J]. 电工技术学报, 2017, 32(增刊1):178−185. XIE Wenhao, LIU Yiqi, WANG Jianze. et al. A delay compensation method of the grid-connected inverter with LCL filter to improve robustness of the impedance shaping control[J]. Transactions of China Electrotechnical Society, 2017, 32(S1):178−185.
[3] ZHOU X, ZHOU L, CHEN Y, et al. Robust grid-current-feedback resonance suppression method for LCL-type grid-connected inverter connected to weak grid[J]. IEEE Journal of Emerging and Selected Topics in Power Electronics, 2018, 6(4):2126-2137.
[4] 季林, 张晓蕊, 许津铭, 等. 非理想电网下三相LCL滤波并网逆变器对称电流控制[J]. 电源学报, 2016, 14(5):47-53 JI Lin, ZHANG Xiaorui, XU Jinming, et al. Symmetrical current control for three-phase grid-connected inverters under non-ideal grid conditions[J]. Journal of Power Supply, 2016, 14(5):47-53
[5] DANNEHL J, FUCHS F W, THOGERSEN P B. PI state space current control of grid-connected PWM converters with LCL filters[J]. IEEE Transactions on Power Electronics, 2010, 25(9):2320-2330.
[6] WAGNER M, BARTH T, ALVAREZ R, et al. Discrete-time active damping of LCL-resonance by proportional capacitor current feedback[J]. IEEE Transactions on Industry Applications, 2014, 50(6):3911-3920.
[7] WU E, LEHN P W. Digital current control of a voltage source converter with active damping of LCL resonance[J]. IEEE Transactions on Power Electronics, 2006, 21(5):1364-1373.
[8] 杨东升, 阮新波, 吴恒. 提高LCL型并网逆变器对弱电网适应能力的虚拟阻抗方法[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
[9] 陈新, 王赟程, 华淼杰, 等. 采用混合阻尼自适应调整的并网逆变器控制方法[J]. 中国电机工程学报, 2016, 36(3):765-774 CHEN Xin, WANG Yuncheng, HUA Miaojie, et al. Grid-connected inverters control schemes based on hybrid damping adaptive control[J]. Proceedings of the CSEE, 2016, 36(3):765-774
[10] 欧阳逸风, 邹宇. 弱电网条件下并网逆变器的锁相环静态稳定分析[J]. 电力系统保护与控制, 2018, 46(18):74-79 OUYANG Yifeng, ZOU Yu. Static stability analysis of phase-locked loop in grid-connected inverters under weak grid condition[J]. Power System Protection and Control, 2018, 46(18):74-79
[11] SUN J. Impedance-based stability criterion for grid-connected inverters[J]. IEEE Transactions on Power Electronics, 2011, 26(11):3075-3078.
[12] YU Y, LI H, LI Z. Impedance modeling and stability analysis of LCL-type grid-connected inverters with different current sampling schemes[C]//2016 IEEE 8th International Power Electronics and Motion Control Conference (IPEMC-ECCE Asia), May 22-26, 2016. Hefei:IEEE, 2016:974-981.
[13] HE Y B, CHUNG H S H, LAI J C T, et al. Active cancelation of equivalent grid impedance for improving stability and injected power quality of grid-connected inverter under variable grid condition[J]. IEEE Transactions on Power Electronics, 2018, 33(11):9387-9398.
[14] PAN D H, RUAN X B, BAO C C, et al. Optimized controller design for LCL-type grid-connected inverter to achieve high robustness against grid-impedance variation[J]. IEEE Transactions on Industrial Electronics, 2015, 62(3):1537-1547.
[15] 陈新, 张旸, 王赟程. 基于阻抗分析法研究光伏并网逆变器与电网的动态交互影响[J]. 中国电机工程学报, 2014, 34(27):4559-4567 CHEN Xin, ZHANG Yang, WANG Yuncheng. A study of dynamic interaction between PV grid-connected inverters and grid based on the impedance analysis method[J]. Proceedings of the CSEE, 2014, 34(27):4559-4567
[16] LIU Y, WU W, HE Y, et al. An efficient and robust hybrid damper for LCL-or LLCL-based grid-tied inverter with strong grid-side harmonic voltage effect rejection[J]. IEEE Transactions on Industrial Electronics, 2016, 63(2):926-936.
[17] 阳喜. 基于电网阻抗的微网并网逆变器自适应控制研究[D]. 南宁:广西大学, 2018. YANG Xi. Adaptive control of grid connected inverter for micro-grid based on grid impedance[D]. Nanning:Guangxi University, 2018.
[18] MIDTSUND T, SUUL J A, UNDELAND T. Evaluation of current controller performance and stability for voltage source converters connected to a weak grid[C]//The 2nd International Symposium on Power Electronics for Distributed Generation Systems. June 16-18, 2010. Hefei, China:IEEE, 2010:382−388.
[19] 佟强, 张东来, 徐殿国. 分布式电源系统中变换器的输出阻抗与稳定性分析[J]. 中国电机工程学报, 2011, 31(12):57-64 TONG Qiang, ZHANG Donglai, XU Dianguo. Output impedance and stability analysis of converters in distributed power systems[J]. Proceedings of the CSEE, 2011, 31(12):57-64
[20] 吴广禄, 周孝信, 李亚楼, 等. 弱交流电网条件下VSC-HVDC改进矢量控制方法[J]. 中国电机工程学报, 2017, 37(16):4577-4590 WU Guanglu, ZHOU Xiaoxin, LI Yalou, et al. Improved vector control for VSC-HVDC connected to weak AC grids[J]. Proceedings of the CSEE, 2017, 37(16):4577-4590