基于随机子空间方法的光伏变流器模态识别和分析

光伏大量并网给电网带来大量谐波谐振问题。针对光伏变流器产生的谐振问题,建立了包含光伏变流器和电网等值阻抗的联合模型。推导了含有光伏变流器阻抗和电网阻抗的s域模型,应用反拉普拉斯变换得到的光伏输出电流不仅含有电压频率分量,还含有光伏阻抗的谐振分量。应用随机子空间方法分析光伏并网点和电流含有的模态分量,对照两者模态的区别,提取出光伏变流器阻抗模态。最后,通过仿真和实测数据分析验证了该方法的有效性。

Modal Identification and Analysis of Photovoltaic Converter Based on Random Subspace

A large number of photovoltaic grid-connection brings many harmonic resonance problems to the power grid.A joint model including photovoltaic converter and grid equivalent impedance was established for the photovoltaic converter resonance problem.The s-domain model of photovoltaic converter impedance and grid impedance was derived.The photovoltaic output current contains not only the voltage frequency component but also the resonant component of the photovoltaic impedance by using the inverse Laplace transform.The stochastic subspace method was used to analyze the modal components of photovoltaic grid-connection points and currents.The impedance modes of photovoltaic converters were extracted according to the difference between the two modes.Finally,the effectiveness of the proposed method was verified by simulation and experimental data analysis.