Resonance Suppression Strategy for LCL-Type Grid-Con‍nected Converter Based on Three-Frequency-Ban‍d Impedance Re‍model‍ing

doi:10.3969/j.issn.1008-0198.2024.06.010

Abstract

Abstract: The use of voltage feed-forward control under a weak grid will increase the negative phase shift of the output impedance of the grid-connected converter at the cross-cutting frequency,which may lead to the harmonic resonance of the grid-connected current. Aiming at the problem a resonance suppression strategy for the LCL-type grid-connected converter based on the three-frequency-band impedance remodeling is proposed. The strategy establishes a three-frequency-band equivalent model of output impedance on the basis of grid voltage feed-forward control, and uses the three-frequency band reshaping gain factor to reshape the output impedance of the grid-connected converter in different frequency bands, which reduces the negative phase shift of the output impedance in the mid-frequency band,and improves the stable operation capability of the grid-connected converter under a weak power grid.Simulation results show that the strategy retains the ability of traditional voltage feed-forward control to suppress grid background harmonics, improves the phase margin of the grid-connected system, and effectively suppresses the resonance phenomenon of the grid-connected current.

Key words: weak grid, LCL grid-connected converter, background harmonic voltage, three-frequency-band impedance remodeling, grid voltage feed-forward

CLC Number:

TM46

FENG Haozhe, XIA Xiangyang, LIU Junxiang, CHEN Guiquan, ZHAO Xiaoyue. Resonance Suppression Strategy for LCL-Type Grid-Con‍nected Converter Based on Three-Frequency-Ban‍d Impedance Re‍model‍ing[J]. Hunan Electric Power, 2024, 44(6): 67-75.

References

[1] 李国庆,刘先超,辛业春,等. 含高比例新能源的电力系统频率稳定研究综述[J]. 高电压技术,2024,50(3):1165-1181.
[2] 梁军,李传玥. 并网换流器控制模式发展及弱电网稳定研究[J]. 电网技术,2022,46(10):3703-3712.
[3] 高子鹏,肖国春,田圆媛,等. 考虑频率耦合的并网逆变器不同域控制的稳定性比较[J]. 电力系统保护与控制,2023,51(15):22-32.
[4] 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.
[5] 杨兴武,何昕益,王涛,等. 基于阻抗分析的LCL型并网逆变器多谐振控制[J]. 电力电子技术,2021,55(9):55-58.
[6] WANG X H,RUAN X B,LIU S W,et al.Full feedforward of grid voltage for grid-connected inverter with LCL filter to suppress current distortion due to grid voltage harmonics[J]. IEEE Transactions on Power Electronics,2010,25(12):3110-3127.
[7] 徐飞,汤雨,谷伟. 弱电网条件下LCL型并网逆变器谐振前馈控制策略研究[J]. 中国电机工程学报,2016,36(18):4970-4979,5122.
[8] WANG X H,QIN K,RUAN X B,et al.A robust grid-voltage feedforward scheme to improve adaptability of grid-connected inverter to weak grid condition[J]. IEEE Transactions on Power Electronics,2020,36(2):2384-2395.
[9] 刘桂花,石桐,马田源,等. 弱电网下光伏并网逆变器自适应准PRD控制方法[J]. 电网技术,2017,41(1):112-117.
[10] 曹子恒,肖先勇,李媛,等. 弱电网下LCL型并网逆变器的自适应改进前馈控制策略[J]. 高电压技术,2020,46(5):1560-1570.
[11] XU J M,XIE S J,QIAN Q,et al.Adaptive feedforward algorithm without grid impedance estimation for inverters to suppress grid current instabilities and harmonics due to grid impedance and grid voltage distortion[J]. IEEE Transactions on Industrial Electronics,2017,64(9):7574-7586.
[12] 郑勇,唐莎莎,张丽,等. 弱电网条件下提升LCL型逆变器稳定性的控制策略[J]. 电力系统及其自动化学报,2022,34(2):71-81.
[13] Sun J.Impedance-based stability criterion for grid-connected inverters[J]. IEEE Transactions on Power Electronics,2011,26(11):3075-3078.
[14] 陈林,徐永海,王天泽,等. 弱电网下计及背景谐波的多并网逆变器阻抗重塑谐振抑制方法[J]. 电力系统保护与控制,2024,52(1):59-72.
[15] 朱坤龙,孙鹏菊,王林,等. 弱电网下LCL型并网逆变器的高鲁棒性加权平均电流控制策略[J]. 中国电机工程学报,2020,40(11):3592-3602.
[16] 魏石磊,田艳军,王毅,等. 弱电网中增强LCL逆变器稳定性的虚拟阻抗控制[J]. 高电压技术,2019,45(6):1827-1834.
[17] 金国彬,谢飞,李国庆,等. 弱电网且谐波畸变背景下分布式电源并网系统谐振抑制[J]. 电力系统保护与控制,2023,51(5):1-10.
[18] 郑嘉龙,杨鸽,陈开宇,等. LCL型多逆变器并网系统谐振研究综述[J]. 电力系统保护与控制,2022,50(21):177-186.
[19] 刘宝泉,郭华,朱一昕,等. 三相变流器无源阻尼型LCL滤波器的分析与设计[J]. 电工技术学报,2017,32(2):195-205.
[20] 金国彬,苑忠奇,李国庆,等. 基于无源性的并网逆变器扩展阻尼区域方法研究[J]. 电力系统保护与控制,2022,50(19):25-35.
[21] 徐佳,杨树德,张新闻. 基于并网电流谐波反馈的有源阻尼策略[J]. 中国电力,2023,56(8):126-135.
[22] 林盛超,熊健,贺诗明,等. 基于并网电流反馈的新型有源阻尼方法[J]. 电网技术,2021,45(3):926-936.
[23] WANG F,DUARTE J L,HENDRIX M A M,et al. Modeling and analysis of grid harmonic distortion impact of aggregated DG inverters[J]. IEEE Transactions On Power Electronics,2010,26(3):786-797.
[24] 涂春鸣,高家元,赵晋斌,等. 弱电网下具有定稳定裕度的并网逆变器阻抗重塑分析与设计[J]. 电工技术学报,2020,35(6):1327-1335.