弱电网下PLL结构引入的不对称正反馈环路对并网逆变器稳定性的影响分析  

Analysis of the Influence of the Asymmetric Positive-feedback Loop Introduced by the PLL Structure on the Stability of Grid-connected Inverter in Weak Grids

作　　者：高家元 涂春鸣[1] 肖凡[1] 郭祺[1] 姜飞[2] 岳菁鹏 GAO Jiayuan;TU Chunming;XIAO Fan;GUO Qi;JIANG Fei;YUE Jingpeng(National Electric Power Conversion and Control Engineering Technology Research Center(Hunan University),Changsha 410082,Hunan Province,China;School of Electrical and Information Engineering,Changsha University of Science and Technology,Changsha 410004,Hunan Province,China;Electric Power Research Institute Guangdong Power Grid Co.,Ltd.,Guangzhou 510030,Guangdong Province,China)

机构地区：[1]国家电能变换与控制工程技术研究中心(湖南大学),湖南省长沙市410082 [2]长沙理工大学电气与信息工程学院,湖南省长沙市410004 [3]广东电网有限责任公司电力科学研究院,广东省广州市510030

出　　处：《中国电机工程学报》2022年第3期1113-1124,共12页Proceedings of the CSEE

基　　金：国家自然科学基金(青年科学基金项目)(51907057);湖南省科技创新领军人才项目(2019RS3014)。

摘　　要：弱电网下锁相环(phase-locked loop,PLL)结构引入的不对称正反馈机制会恶化并网逆变器(grid-connected inverter,GCI)系统的稳定性。在相同的主电路参数与控制环参数下,通过分别构建dq域与αβ域下GCI控制环路的小信号模型,αβ域下GCI相较于dq域少引入1条PLL正反馈环路。分析比较αβ域下GCI系统的稳定性强于dq域的原因,并对PLL结构引入的不对称正反馈环路在小信号模型中的位置差异性进行解析,揭示不同位置的不对称正反馈环路对GCI稳定性的影响程度与影响机理。最后,通过仿真与实验验证本文所提分析方法的正确性与有效性。The stability of the grid-connected inverter(GCI)system under weak grids is deteriorated due to the asymmetric positive-feedback mechanism introduced by the phase-locked loop(PLL) structure. Under the same main circuit parameters and control loop parameters, the small-signal models of the control loop of GCI in dq domain and αβ domain were constructed respectively. It showed that the positive-feedback loop introduced by PLL in the αβ domain was less than that in the dq domain. By comparison, the reason why the stability of the GCI system in the αβ domain was stronger than that in the dq domain was analyzed. Meanwhile, by analyzing the position difference of the asymmetric positive-feedback loop introduced by the PLL structure in the small-signal model, the influence degree and mechanism of the asymmetric positive-feedback loop in different positions on the stability of GCI were revealed for the first time. Finally, simulations and experiments verified the correctness and effectiveness of the theoretical analysis.

关 键 词：弱电网 并网逆变器 锁相环 小信号模型 不对称正反馈机制 稳定裕度 

分 类 号：TM46[电气工程—电器]