摘要
变流器作为可再生能源发电并网的关键设备,在与交流电网互联时产生的系统振荡问题日益增多。阻抗模型是分析“变流器-电网”耦合系统稳定性的基础。首先基于αβ坐标系建立了特定工况下的并网系统阻抗数学模型;在此基础上,进一步建立全工况下的统一阻抗数学模型。由该阻抗模型可知,运行工况与控制器参数是影响系统阻抗特性的主要因素。通过Nyquist稳定判据量化分析两种影响因素对系统稳定性的影响。然后提出增大控制环参数Kpi以抑制系统在小干扰下的谐振,增强系统稳定性。最后,不同运行工况下的仿真与实验结果验证了所提出的全工况阻抗数学模型分析系统稳定性的准确性,同时也验证了稳定性提升方法的有效性。
As key equipment for the integration of renewable energy generation into the grid, converters are increasingly experiencing system oscillations when interconnected with the AC grid. The impedance model is the basis for analyzing the stability of the "converter-grid" coupled system. Based on the αβ coordinate system, this paper establishes the grid system impedance mathematical model of specific conditions. Then a unified impedance mathematical model under all working conditions is established. From the impedance model, the operational condition and controller parameters are the main factors influencing the system impedance characteristics. The Nyquist stability criterion is used to quantitatively analyze the influence of two kinds of influence factors on system stability. Then it proposes to increase control loop Kpi parameters to suppress system resonance under a small signal and enhance system stability. Finally, the simulation and experimental results under different operating conditions verifies the accuracy of the proposed mathematical model of impedance in all operating conditions in analyzing the stability, and also verifies the effectiveness of the stability improvement method.
作者
刘普
崔艺博
刘兆峰
梁燕
LIU Pu;CUI Yibo;LIU Zhaofeng;LIANG Yan(Department of Electrical Engineering,Zhengzhou University of Light Industry,Zhengzhou 450002,China;Department of Electrical Engineering,University of Shanghai for Science and Technology,Shanghai 200093,China)
出处
《电力系统保护与控制》
EI
CSCD
北大核心
2023年第4期114-125,共12页
Power System Protection and Control
基金
国家重点研发计划项目资助(2018YFB0106300)
河南省科技攻关项目资助(222102220089)。
关键词
并网变流器
阻抗扫频
奈奎斯特稳定判据
谐振抑制
grid-connected converter
impedance sweep
Nyquist stability criterion
resonance suppression
