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ISSN 0254-0096 CN 11-2082/K

太阳能学报 ›› 2023, Vol. 44 ›› Issue (2): 399-408.DOI: 10.19912/j.0254-0096.tynxb.2021-1052

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LCL型并网逆变器新型电容电压有源阻尼策略

杨明1, 宋明洋1, 张国澎1, 解宝2   

  1. 1.河南理工大学电气工程与自动化学院(河南省煤矿装备智能检测与控制重点实验室),焦作 454003;
    2.光伏系统教育部工程研究中心(合肥工业大学),合肥 230009
  • 收稿日期:2021-09-03 出版日期:2023-02-28 发布日期:2023-08-28
  • 通讯作者: 杨 明(1982—),男,博士、副教授、硕士生导师,主要从事新能源并网发电技术、电能质量控制等方面的研究。yangming0391@163.com
  • 基金资助:
    国家自然科学基金(U1804143); 河南省科技攻关项目(202102210294); 河南理工大学骨干教师资助计划(2020XQG-18)

NEW TYPE CAPACITTIVE VOLTAGE ACTIVE DAMPING STRATEGY FOR LCL GRID-CONNECTED INVERTER

Yang Ming1, Song Mingyang1, Zhang Guopeng1, Xie Bao2   

  1. 1. School of Electrical Engineering and Automation, He'nan Key Laboratory of Intelligent Detection and Control of Coal Mine Equipment, He'nan Polytechnic University, Jiaozuo 454003, China;
    2. Research Center for Photovoltaic Systems Engineering of Ministry of Education, Hefei University of Technology, Hefei 230009, China
  • Received:2021-09-03 Online:2023-02-28 Published:2023-08-28

摘要: 在弱电网条件下,数字控制延时会导致虚拟阻抗呈现负阻性,无法起到阻尼效果,因此并网逆变器在电网阻抗变化情况下不能稳定运行,鲁棒性受到严重威胁。针对上述问题,提出一种双线性正反馈有源阻尼策略,以扩大系统的有效阻尼区。为了节省传感器成本,将其优化为电容电压正反馈有源阻尼策略,在电容电压两端添加合适的正反馈阻尼环节,使得系统的有效阻尼区扩大为(0,0.477f3)。分析结果表明该策略使得并网逆变器在弱电网条件下始终具有良好的鲁棒性,即使谐振频率等于1/6采样频率时,系统也具有较好的稳定性。最后,以三相LCL型并网逆变器为例进行实验验证,实验结果验证了该策略的正确性。

关键词: 数字控制, 弱电网, 并网逆变器, 有源阻尼, 有效阻尼区

Abstract: Under weak grid conditions, the digital control delay will cause the virtual impedance to show negative resistance and cannot achieve the damping effect. Therefore, the grid-connected inverter cannot operate stably under the change of grid impedance, and its robustness is seriously threatened. In response to the above problems, this paper proposes a bilinear positive feedback active damping strategy to expand the effective damping zone of the system. To save the cost the sensors, it is optimized as a capacitive voltage positive feedback active damping strategy, adding appropriate positive feedback damping links at both ends of the capacitor voltage, so that the effective damping area of the system is expanded to (0, 0.477fs). The analysis results show that this strategy makes the grid-connected inverter always have good robustness under weak grid conditions, and the system has good stability even when the resonance frequency is equal to 1/6 of the sampling frequency. Finally, a three-phase LCL grid-connected inverter is taken as an example to carry out experimental verification, and the experimental results verify the correctness of the strategy.

Key words: digital control, weak grid, grid-connected inverter, active damping, effective damping zone

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