低阻抗下构网型变流器稳定性机理分析  

Stability Mechanism Analysis of Grid-forming Converter Connected to Low Impedance Grid

作　　者：严文博 黄云辉[1,2] 方正[1,2] 王栋[1,2] 唐金锐 周克亮[1,2] YAN Wenbo;HUANG Yunhui;FANG Zheng;WANG Dong;TANG Jinrui;ZHOU Keliang(State Key Laboratory of Waterway Traffic Control,Wuhan University of Technology,Wuhan 430070,China;School of Automation,Wuhan University of Technology,Wuhan 430070,China)

机构地区：[1]武汉理工大学水路交通控制全国重点实验室,武汉430070 [2]武汉理工大学自动化学院,武汉430070

出　　处：《高电压技术》2025年第3期1444-1453,I0017,共11页High Voltage Engineering

基　　金：国家重点研发计划(2021YFB2601602);国家自然科学基金智能电网联合基金(U24B20103)。

摘　　要：构网型变流器具有电压源特性,在高阻抗弱电网下具有良好的稳定性,然而在低阻抗强电网下却可能失稳。针对构网型变流器接入低阻抗电网的稳定性问题,首先建立低阻抗下构网型变流器的状态空间模型,并结合特征根轨迹和参与因子,分析不同电网强度和不同控制参数下系统的主导模态及稳定趋势。在状态空间模型的基础上,建立构网型变流器接入交流电网的动力学模型,以表征内电势动力学特性——惯量、阻尼分量、同步分量。通过分析构网型变流器阻尼分量和同步分量随电网强度和控制参数变化的演化规律,揭示低阻抗下构网型变流器的稳定性机理。分析结果表明,构网型变流器端电压控制环在低阻抗下会引入显著的附加负阻尼分量,降低系统的稳定性,通过增大端电压控制环带宽能够减少负的附加阻尼,提升系统的稳定性。同时,减小惯量系数和增大阻尼系数也能够增大阻尼分量,从而改善稳定性。The grid-forming converter has voltage source characteristics and has good stability under high-impedance weak grid,but it may be unstable in low-impedance strong grid.Aiming at the stability problem of grid-forming converter connected to low-impedance grid,that paper first establishes the state space model of grid-forming converter under low impedance,and combines the characteristic root trajectory and participation factor to analyze the dominant mode and sta-bility trend of the system under different grid strength and different control parameters.On the basis of the state space model,the dynamic model of the grid converter connected to the AC power grid is established to characterize the dynamic characteristics of the internal potential-inertia,damping component,and synchronous component.The stability mecha-nism of grid-forming converter under low impedance is revealed by analyzing the evolution law of damping component and synchronous component of grid-forming converter with the change of grid strength and control parameters.The anal-ysis results show that the terminal voltage control loop of the grid-forming converter will introduce significant additional negative damping components under low impedance,which reduces the stability of the system.By increasing the band-width of the terminal voltage control loop,the negative additional damping can be reduced and the stability can be improved.At the same time,reducing the inertia coefficient and increasing the damping coefficient can also increase the damping component and improve the stability.

关 键 词：构网型变流器 小信号稳定性 动力学特性 阻尼分量 同步分量 低阻抗电网 

分 类 号：TM46[电气工程—电器]