Frequency Adaptive Feedforward Dual-Mode Repetitive Control and Proportional Control for Grid-Connected Inverters in Microgrid
Zhao Qiangsong1, Chen Hao1, Wang Qifan1, Wang Yan1, Xie Wenwen2
1. School of Electronic and Information Zhongyuan University of Technology Zhengzhou 451191 China; 2. Zhenzhou Power Supply Company State Grid Electric Power Company Zhengzhou 450001 China
Abstract：Repetitive control (RC) based on the internal model principle can achieve zero tracking error for periodic reference and disturbance in a steady state. It has been widely used in grid-connected inverters to improve the current control performance. Owing to a recursive form and an inherent delay of one fundamental period in the internal model, the RC has a relatively slow transient response. At the same time, grid frequency fluctuations in the microgrid lead to the higher harmonic content of the inverter grid current. Therefore, this paper proposes the frequency adaptive feedforward dual-mode repetitive control and proportional control (FA-FDMRC-PC) scheme for grid-connected inverters in the microgrid to track the fundamental reference signal and suppress the harmonic signals simultaneously. First, the principle of feedforward dual-mode repetitive control (FDMRC) is analyzed. The feedforward links are added to the internal models of the dual-mode repetitive control (DMRC) to improve the dynamic performance of the system. From the open-loop bode plots of FDMRC, DMRC, and RC, it can be seen that the FDMRC has much larger open-loop gains at the frequencies of interest with better harmonic suppression capability. Then, the FA-FDMRC-PC scheme is proposed, which connects the FDMRC and the proportional control in parallel to form the feedforward dual-mode repetitive control and proportional control (FDMRC-PC), further improving the dynamic performance of the system and realizing the fractional delay through the infinite impulse response (IIR) filter. The stability analysis provides the relevant stability conditions, which are then utilized in designing the proportional gain, internal mode filter, compensator, phase lead compensator, and repetitive control gain. Subsequently, a single-phase LCL-type grid-connected inverter experimental platform is set up. The controller based on repetitive control and proportional control (RC-PC) and FA-FDMRC-PC are compared at the grid frequency of 50 Hz to verify the harmonics suppression capability and dynamic performance of the proposed control scheme under the ideal grid. The total harmonic distortion (THD) of the grid current of the proposed FA-FDMRC-PC is 1.0%. However, for the RC-PC, the THD value is 1.5%, higher than the THD of the FA-FDMRC-PC. To verify the dynamic performance of the FA-FDMRC-PC, output current waveforms are recorded and analyzed when the peak value of the reference current is changed from 5 A to 10 A. The waveform of the grid current tends to be stable after about two cycles for the FA-FDMRC-PC when the reference current changes abruptly, which shows that the proposed FA-FDMRC-PC has a faster transient response than the RC-PC. When the grid frequency is 49.6 Hz, the THD of the FA-FDMRC-PC is only 0.8%, but the THD of the FDMRC-PC rises to 1.6%. When the grid frequency is 50.4 Hz, the THD of the FA-FDMRC-PC is only 0.8%, but the THD of the FDMRC-PC rises to 1.9%. When the grid frequencies are 49.6 Hz and 50.4 Hz, the waveforms of the grid current tend to be stable after about two cycles for the FA-FDMRC-PC when the peak value of the reference current is changed from 5 A to 10 A. Experimental results verify that the proposed FA-FDMRC-PC scheme has a better immunity to grid frequency fluctuation and a faster dynamic response when the grid frequency fluctuates.
赵强松, 陈昊, 王启帆, 王燕, 谢文文. 微电网并网逆变器频率自适应前馈双模重复-比例控制[J]. 电工技术学报, 2024, 39(15): 4843-4855.
Zhao Qiangsong, Chen Hao, Wang Qifan, Wang Yan, Xie Wenwen. Frequency Adaptive Feedforward Dual-Mode Repetitive Control and Proportional Control for Grid-Connected Inverters in Microgrid. Transactions of China Electrotechnical Society, 2024, 39(15): 4843-4855.
[1] 洪芦诚, 徐佳裕, 唐润悦, 等. 三相LCL型逆变器序阻抗简化建模方法及并网稳定性分析[J]. 电力系统自动化, 2023, 47(7): 150-157. Hong Lucheng, Xu Jiayu, Tang Runyue, et al.Simplified modeling method of sequence impedance and grid-connected stability analysis for three-phase LCL inverter[J]. Automation of Electric Power Systems, 2023, 47(7): 150-157. [2] 王晴, 刘增, 韩鹏程, 等. 基于变流器输出阻抗的直流微电网下垂并联系统振荡机理与稳定边界分析[J]. 电工技术学报, 2023, 38(8): 2148-2161. Wang Qing, Liu Zeng, Han Pengcheng, et al.Analysis of oscillation mechanism and stability boundary of droop-controlled parallel converters based on output impedances of individual converters in DC microgrids[J]. Transactions of China Electrotechnical Society, 2023, 38(8): 2148-2161. [3] 罗朋, 潘锦超, 洪濬哲, 等. 用于直流微电网的高升压变换器设计及效率优化[J]. 电工技术学报, 2023, 38(20): 5530-5546. Luo Peng, Pan Jinchao, Hong Junzhe, et al.Design and efficiency optimization of a high step-up converter for DC microgird[J]. Transactions of China Electrotechnical Society, 2023, 38(20): 5530-5546. [4] 吴天昊, 谢小荣, 姜齐荣. 风电系统次同步等幅振荡的机理与特性分析[J]. 中国电机工程学报, 2023, 43(7): 2689-2699. Wu Tianhao, Xie Xiaorong, Jiang Qirong.On subsynchronous sustained oscillation issues of wind power systems[J]. Proceedings of the CSEE, 2023, 43(7): 2689-2699. [5] 张洪亮, 张子成, 陈杰, 等. 自适应三次谐波注入的回接型LCL光伏逆变器共模谐振电流抑制方法[J]. 电工技术学报, 2023, 38(1): 220-233. Zhang Hongliang, Zhang Zicheng, Chen Jie, et al.Common-mode resonant current suppression for back-connected LCL photovoltaic inverter using adaptive third harmonic injection[J]. Transactions of China Electrotechnical Society, 2023, 38(1): 220-233. [6] 杨权, 梁永昌, 魏建荣, 等. 多谐波源下分布式电源并网逆变器的谐波抑制策略[J]. 电工技术学报, 2023, 38(11): 2908-2920. Yang Quan, Liang Yongchang, Wei Jianrong, et al.Research on harmonic suppression strategy of grid connected inverter under multi-harmonic sources[J]. Transactions of China Electrotechnical Society, 2023, 38(11): 2908-2920. [7] 芮涛, 尹政, 汪凤翔, 等. 基于双矢量的并网逆变器无模型预测电流控制策略[J]. 电工技术学报, 2023, 38(14): 3759-3768. Rui Tao, Yin Zheng, Wang Fengxiang, et al.Model-free predictive current control strategy of grid-connected inverter based on double-vector[J]. Transactions of China Electrotechnical Society, 2023, 38(14): 3759-3768. [8] 李文番, 张国钢, 钟浩杰, 等. 一种高频率分辨率的谐波、间谐波分析模型[J]. 电工技术学报, 2022, 37(13): 3372-3379, 3403. Li Wenfan, Zhang Guogang, Zhong Haojie, et al.A high frequency resolution harmonic and inter- harmonic analysis model[J]. Transactions of China Electrotechnical Society, 2022, 37(13): 3372-3379, 3403. [9] 李勇, 刘珮瑶, 胡斯佳, 等. 基于感应滤波的光伏电站谐波谐振抑制方法[J]. 电工技术学报, 2022, 37(15): 3781-3793. Li Yong, Liu Peiyao, Hu Sijia, et al.Harmonic resonance damping method of photovoltaic power station based on inductive filtering[J]. Transactions of China Electrotechnical Society, 2022, 37(15): 3781-3793. [10] IEEE standard for harmonic control in electric power systems: IEEEStd 519-2022[S]. Institute of Electrical and Electronics Engineers, 2022. [11] 国家市场监督管理总局, 国家标准化管理委员会. 光伏发电并网逆变器技术要求: GB/T 37408-2019[S]. 北京: 中国标准出版社, 2019. [12] 兰梓冉, 郝瑞祥, 角宏林, 等. 基于重复控制和状态反馈的三相逆变器最优预见控制[J]. 电工技术学报, 2022, 37(6): 1473-1481. Lan Ziran, Hao Ruixiang, Jiao Honglin, et al.Optimal preview control of three-phase inverter based on repetitive control and state-feedback[J]. Transactions of China Electrotechnical Society, 2022, 37(6): 1473-1481. [13] He Liqun, Zhang Kai, Xiong Jian, et al.A repetitive control scheme for harmonic suppression of circulating current in modular multilevel converters[J]. IEEE Transactions on Power Electronics, 2015, 30(1): 471-481. [14] Wu Xinhui, Panda S K, Xu Jianxin.Design of a plug-in repetitive control scheme for eliminating supply-side current harmonics of three-phase PWM boost rectifiers under generalized supply voltage conditions[J]. IEEE Transactions on Power Elec- tronics, 2010, 25(7): 1800-1810. [15] 张旗, 蔡逢煌, 黄丽梅, 等. 单相程控电流源PI+ 重复控制[J]. 电工技术学报, 2019, 34(增刊1): 163-170. Zhang Qi, Cai Fenghuang, Huang Limei, et al.PI+ repetitive control of single-phase programmable current source[J]. Transactions of China Electrotechnical Society, 2019, 34(S1): 163-170. [16] 李鑫, 孟亨, 杨桢, 等. 基于BP神经网络递推积分PI-重复控制在微电网APF中的研究[J]. 电力系统保护与控制, 2019, 47(6): 132-140. Li Xin, Meng Heng, Yang Zhen, et al.Research on recursive integral PI-repetitive control based on BP neural network in micro-grid APF[J]. Power System Protection and Control, 2019, 47(6): 132-140. [17] 宫金武, 查晓明, 陈佰锋. 一种快速重复控制策略在APF中的实现和分析[J]. 电工技术学报, 2011, 26(10): 110-117. Gong Jinwu, Zha Xiaoming, Chen Baifeng.Analysis and realization of a fast repetitive controller in active power filter system[J]. Transactions of China Electrotechnical Society, 2011, 26(10): 110-117. [18] 王吉彪, 陈启宏, 张立炎, 等. 基于内模原理的并网逆变器双模PI控制[J]. 电工技术学报, 2018, 33(23): 5484-5495. Wang Jibiao, Chen Qihong, Zhang Liyan, et al.Internal model principle based dual-mode PI control for grid-tied inverters[J]. Transactions of China Electrotechnical Society, 2018, 33(23): 5484-5495. [19] Zhao Qiangsong, Ye Yongqiang.A PIMR-type repetitive control for a grid-tied inverter: structure, analysis, and design[J]. IEEE Transactions on Power Electronics, 2018, 33(3): 2730-2739. [20] 赵强松, 陈莎莎, 周晓宇, 等. 用于并网逆变器谐波抑制的重复-比例复合控制器分析与设计[J]. 电工技术学报, 2019, 34(24): 5189-5198. Zhao Qiangsong, Chen Shasha, Zhou Xiaoyu, et al.Analysis and design of combination controller based on repetitive control and proportional control for harmonics suppression of grid-tied inverters[J]. Transactions of China Electrotechnical Society, 2019, 34(24): 5189-5198. [21] Chen Sainan, Zhao Qiangsong, Ye Yongqiang, et al.Using IIR filter in fractional order phase lead compensation PIMR-RC for grid-tied inverters[J]. IEEE Transactions on Industrial Electronics, 2023, 70(9): 9399-9409. [22] Zhou Keliang, Wang Danwei, Zhang Bin.Dual mode structure repetitive control of CVCF PWM inverters[C]// 2009 IEEE 6th International Power Electronics and Motion Control Conference, Wuhan, China, 2009: 1524-1526. [23] 邹志翔, 王政, 程明, 等. 双模结构重复控制器在单相并联有源滤波器中的应用[J]. 中国电机工程学报, 2013, 33(36): 88-95, 13. Zou Zhixiang, Wang Zheng, Cheng Ming, et al.A hybrid current regulation scheme for single-phase active power filters based on dual-mode structure repetitive control[J]. Proceedings of the CSEE, 2013, 33(36): 88-95, 13. [24] Cui Peiling, Wang Qirui, Zhang Guoxi, et al.Hybrid fractional repetitive control for magnetically suspended rotor systems[J]. IEEE Transactions on Industrial Electronics, 2018, 65(4): 3491-3498. [25] Zhu Mingzhe, Ye Yongqiang, Xiong Yongkang, et al.Multibandwidth repetitive control resisting frequency variation in grid-tied inverters[J]. IEEE Journal of Emerging and Selected Topics in Power Electronics, 2022, 10(1): 446-454. [26] Kurniawan E, Cao Zhenwei, Man Zhihong.Design of robust repetitive control with time-varying sampling periods[J]. IEEE Transactions on Industrial Elec- tronics, 2014, 61(6): 2834-2841. [27] Zhao Qiangsong, Chen Sainan, Wen Shengjun, et al.A frequency adaptive PIMR-type repetitive control for a grid-tied inverter[J]. IEEE Access, 2018, 6: 65418-65428. [28] Chen Yuxuan, Zhou Keliang, Tang Chao, et al.Fractional-order multiperiodic odd-harmonic repetitive control of programmable AC power sources[J]. IEEE Transactions on Power Electronics, 2022, 37(7): 7751-7758. [29] 赵强松. 新型比例积分多谐振控制及其并网逆变器应用研究[D]. 南京: 南京航空航天大学, 2016. Zhao Qiangsong.Research on novel proportional integral multi-resonant control scheme and its application in grid-connected inverters[D]. Nanjing: Nanjing University of Aeronautics and Astronautics, 2016. [30] Ye Jie, Liu Linguo, Xu Jinbang, et al.Frequency adaptive proportional-repetitive control for grid- connected inverters[J]. IEEE Transactions on Industrial Electronics, 2021, 68(9): 7965-7974. [31] Zhao Qiangsong, Zhang Hongwei, Gao Yang, et al.Novel fractional-order repetitive controller based on thiran IIR filter for grid-connected inverters[J]. IEEE Access, 2015, 10: 82015-82024.
2024, Vol. 39 
