构网型与跟网型逆变器并联系统精确频域建模及简化稳定判据  

Accurate Frequency-domain Modeling and Simplified Stability Criterion for Parallel Grid-forming and Grid-following Inverter System

作　　者：尚佳宇 虞家骏 刘增[1] 王施珂 李嘉瑞 刘进军[1] SHANG Jiayu;YU Jiajun;LIU Zeng;WANG Shike;LI Jiarui;LIU Jinjun(School of Electrical Engineering,Xi’an Jiaotong University,Xi’an 710049,China;China Resources Power Technology Research Institute Co.,Ltd.,Shenzhen 518001,China)

机构地区：[1]西安交通大学电气工程学院,陕西省西安市710049 [2]华润电力技术研究院有限公司,广东省深圳市518001

出　　处：《电力系统自动化》2025年第2期53-63,共11页Automation of Electric Power Systems

基　　金：国家自然科学基金资助项目(51777160)。

摘　　要：构网型逆变器与跟网型逆变器并联系统被广泛应用于可再生能源分布式接入的孤岛交流微网中。构网型逆变器功率-频率下垂控制的功率环和跟网型逆变器的锁相环均会产生基波频率小信号动态,进而并联的功率环以及锁相环之间将存在较强的基波频率相互作用,严重影响系统稳定性。针对上述问题,首先,基于端口阻抗和频率-电流端口频域特性,文中构建了构网型与跟网型逆变器单机及其并联系统的精确小信号频域模型,其中包含了主电路动态、电压电流内环动态、功率环和锁相环频率动态及其互相作用动态。进而,基于该频域模型分析了频率动态的特性及其影响,并在典型工况条件下利用盖尔圆定理推导出了基于该并联系统回率矩阵主对角元的简化稳定判据。最后,仿真和实验验证了所提频域模型和简化稳定判据的准确性和有效性。The parallel grid-forming and grid-following inverter system is widely used in the islanded AC microgrid with distributed integration of renewable energy.The power-frequency droop control loop of grid-forming inverter and the phase locked loop(PLL)of grid-following inverter both generate fundamental frequency small-signal dynamics.Consequently,there exists the strong fundamental frequency interaction between the parallel power loops and PLLs,which has a considerable effect on the stability of the system.Regarding the above mentioned issue,first,based on terminal impedances and frequency-domain frequency-current terminal characteristics,the accurate small-signal frequency-domain models are constructed for the grid forming inverter,the gridfollowing inverter and the parallel inverter system,which include the main circuit dynamics,the voltage and current inner-loop dynamics,the power loop and PLL frequency dynamics,and the interaction dynamics.Furthermore,based on the frequencydomain model,the characteristics and effects of frequency dynamics are analyzed,and a simplified stability criterion based on the principal diagonal entries of the return-ratio matrix for the parallel system is derived using the Gerschgorin circle theorem under the typical operation conditions.Finally,simulation and experimental results validate the accuracy and effectiveness of the proposed frequency-domain model and simplified stability criterion.

关 键 词：构网型逆变器 跟网型逆变器 孤岛微网 并联系统 小信号稳定性 阻抗模型 频率动态 稳定判据 

分 类 号：TM464[电气工程—电器]