低阻抗下构网型变流器多机系统小信号建模与稳定性分析  

Small signal modeling and stability analysis of multi-VSCs for grid-forming converters under low impedance grid

作　　者：陈永康 黄云辉[1] 方正 王栋 唐金锐[1] 周克亮 CHEN Yongkang;HUANG Yunhui;FANG Zheng;WANG Dong;TANG Jinrui;ZHOU Keliang(School of Automation,Wuhan University of Technology,Wuhan 430071,China)

机构地区：[1]武汉理工大学自动化学院,湖北武汉430071

出　　处：《电力工程技术》2025年第2期13-22,共10页Electric Power Engineering Technology

基　　金：国家自然科学基金资助项目(52307217);广东省基础与应用基础研究基金(2023A1515240052)。

摘　　要：构网型变流器具有电压源特性,可为高阻抗弱电网提供阻尼和频率支撑,具有良好的稳定性,但在低阻抗电网下可能会出现失稳现象。文中围绕低阻抗下构网型变流器多机系统小信号建模和稳定性展开分析。首先,建立低阻抗下构网型变流器多机系统接入电网的小信号模型,揭示系统的动态特性与耦合机理。其次,通过特征根轨迹和参与因子分析,研究不同电网强度和控制参数下系统的主导振荡模态及其对系统稳定性的影响。最后,通过MATLAB时域仿真验证了建模和稳定性分析结果的准确性。研究结果表明,电网强度增大、有功降低、下垂系数减小以及联络阻抗减小,均会削弱构网型变流器多机系统稳定性,其中功率环和电压环为影响系统稳定性的主导控制环路。The grid-forming converter has voltage source characteristics,providing damping and frequency support to highimpedance weak grids,and demonstrates good stability.However,instability may occur under low impedance grids.This paper focuses on the small-signal modeling and stability analysis of multi-voltage source converters(VSCs)for grid-forming converters under low-impedance condition.Firstly,a small-signal model of multi-VSCs for grid-forming converters connected to the grid under low impedance is established,clarifying the system’s dynamic characteristics and coupling mechanism.Secondly,through eigenvalue trajectory and participation factor analysis,the dominant oscillation modes and their impact on system stability under different grid strengths and different control parameters are discussed.Finally,MATLAB time-domain simulations are conducted to verify the accuracy of the modeling and stability analysis results.The research results show that the increase in grid strength,reduction in active power,decrease in the droop coefficient,and reduction in interconnection impedance all weaken the stability of multi-VSCs for grid-forming converters,with the power loop and voltage loop being the dominant control loops affecting system stability.

关 键 词：构网型变流器 低阻抗电网 小信号建模 特征根轨迹 主导振荡模态 稳定性分析 

分 类 号：TM712[电气工程—电力系统及自动化]