弱电网下逆变器的虚拟节点电压反馈控制策略  

Virtual Node Voltage Feedback Control Scheme for Inverter in Weak Grid

作　　者：葛路明 汤涌 朱凌志 陈宁 曲立楠 GE Luming;TANG Yong;ZHU Lingzhi;CHEN Ning;QU Linan(China Electric Power Research Institute,Haidian District,Beijing 100192,China)

机构地区：[1]中国电力科学研究院有限公司,北京市海淀区100192

出　　处：《中国电机工程学报》2024年第21期8392-8405,I0006,共15页PROCEEDINGS OF THE CHINESE SOCIETY FOR ELECTRICAL ENGINEERING

基　　金：国家重点研发计划项目(2021YFB2400500)。

摘　　要：新能源电站一般需通过多级变压器接入大电网,与电网的电气联系较弱,导致系统稳定性较低,迫切需要提高新能源电站对弱电网的适应性。该文分析电压馈入方式对逆变器稳定性的影响,在此基础上提出虚拟节点电压反馈控制策略。该控制策略通过控制器计算虚拟节点电压,不需要增加额外的电压传感器。在电流环内部级联一个虚拟节点电压内环,提高电压控制性能。从内环到外环,分步骤给出相关控制参数的详细设计方法。建立考虑频率耦合效应的输出阻抗模型,分析所提策略在弱电网下的稳定性。实验结果表明,虚拟节点电压反馈策略不仅在弱电网下可以提升稳定性,而且在强电网下也有较好的稳定性,从而增强了逆变器的电网适应性。Renewable energy power plants generally connect to power grid via several step-up transformers,and the electrical connection between renewable energy power plants and power grid is weak,which deteriorates the system stability.There is an urgent need to improve the grid adaptability of renewable energy power plants.In this paper,the impact of voltage feeding mode on inverter stability is analyzed.Based on this,a virtual node voltage feedback(VNVF)control scheme is proposed.In this VNVF control scheme,virtual nodes voltage is calculated by controller,no additional voltage sensor is required.An inner virtual node voltage loop is cascaded inside the current loop to improve voltage control performances.The design method of relevant control parameters from inner loop to outer loop is explained comprehensively step by step.The output impedance model considering frequency coupling effect is also established,and then the stability of the proposed scheme is researched.It can be shown from the experimental results that,the VNVF scheme can not only improve the stability in weak grid,but also has high stability performances in strong grid.It can be concluded that the grid adaptability of inverter is enhanced.

关 键 词：弱电网 稳定 虚拟节点 逆变器 电压反馈 

分 类 号：TM73[电气工程—电力系统及自动化]