考虑功率耦合的构网型多VSG系统频率振荡特性分析  

Analysis of frequency oscillation characteristics in grid-forming multi-VSG systems considering power coupling

作　　者：李威 马美玲 孙伟卿 LI Wei;MA Meiling;SUN Weiqing(School of Mechanical Engineering,University of Shanghai for Science and Technology,Shanghai 200093,China;Key Laboratory of Control of Power Transmission and Conversion(SJTU),Ministry of Education,Shanghai 200240,China)

机构地区：[1]上海理工大学机械工程学院,上海200093 [2]上海交通大学输变电控制教育部重点实验室,上海200240

出　　处：《电力工程技术》2025年第2期44-54,共11页Electric Power Engineering Technology

基　　金：上海市科技创新行动计划资助项目“新能源并网系统的同步机理与暂态稳定域边界研究”(22YF1429500)。

摘　　要：虚拟同步发电机(virtual synchronous generator,VSG)控制的构网型变流器能为新能源并网提供一定的惯量和阻尼支撑。然而,VSG控制环节产生的功率耦合问题会引起系统频率振荡,严重时会威胁系统安全。针对多台VSG并网时的功率耦合交互对频率振荡的影响机理不清晰的问题,文中提出一种考虑功率耦合的多VSG并网系统阻抗建模方法,并结合参数变化分析频率的振荡特性。首先,分析单VSG并网的功率耦合机理,并基于此建立多VSG并网系统的阻抗模型,揭示多VSG下输出角频率主要受自身功率、交互功率和电网角频率影响。其次,提出一种基于动态相对增益矩阵的方法,定量分析系统参数变化对VSG间交互影响的大小,得到高、低频段下多VSG系统参数变化对系统耦合交互的影响趋势。最后,在PSCAD中构建3台VSG并网系统模型,并通过时域仿真验证理论分析的准确性。Grid-forming converters controlled by virtual synchronous generator(VSG)provide a certain amount of inertia and damping support for new energy sources to be connected to the grid.However,the power coupling generated by the VSG control link causes system frequency oscillation,which can seriously threaten the system safety.To solve the unclear mechanism of power coupling interaction on frequency oscillation when multi-VSGs are connected to the grid,a method of impedance modeling of multi-VSG grid-connected system considering power coupling is proposed.The frequency oscillation characteristics are analyzed by combining with parameters changes.Firstly,the power coupling mechanism of single VSG is analyzed.Then the impedance model of multi-VSG grid-connected system is established which reveals that output angular frequency under multi-VSGs is mainly affected by three parts:its own power,interacting power and grid angular frequency.In addition,a method based on the dynamic relative gain array is proposed to quantitatively analyze the laws of system parameter variations on the interaction effects among VSGs.The study reveals the impact trends of parameter variations in multi-VSG systems on system coupling interactions across high-frequency and low-frequency bands.Finally,the accuracy of the theoretical analysis is verified by time-domain simulation of a three-VSG grid-connected system model constructed in PSCAD.

关 键 词：虚拟同步发电机(VSG) 构网型变流器 功率耦合 阻抗模型 频率振荡 动态相对增益矩阵 

分 类 号：TM464[电气工程—电器]