基于动态相量扰动量的光伏并网系统间谐波分析模型

Interharmonic Analysis Model for Grid-connected PV System Based on Dynamic Phasor Disturbances

为解决传统序分量动态相量法用于间谐波分析时模型阶数过高、求解困难的问题,建立了基于动态相量扰动量的光伏并网系统间谐波分析模型。首先,利用含有间谐波分量的周期信号动态相量计算结果,定义了动态相量扰动量和序分量动态相量扰动量;之后,在已知待分析间谐波频率的前提下,推导了含间谐波的光伏并网系统序分量动态相量模型,并利用线性叠加原理形成了动态相量扰动量模型,用于描述间谐波分量在换流器交直流侧的相互作用关系;然后,通过求取稳态运行点,求解动态相量扰动量模型,获得了间谐波分量的计算结果;最后,通过理论计算与仿真结果对比,验证了该模型的有效性。研究结果表明:所提模型能实现光伏并网系统的间谐波分析,降低了分析模型的阶数。所提模型简化了间谐波分析计算,为进行间谐波发射特性分析和抑制策略研究奠定了基础。

To solve the problem that the model order is too high and difficult to solve when the traditional dynamic phasor sequence components(DPSCs)method is used for interharmonic analysis,we establish a grid-connected PV system model for interharmonic analysis based on dynamic phasor disturbances(DPDs).First,we deduce the dynamic phasor of a signal including interharmonic components,and define DPDs and dynamic phasor sequence components disturbances(DPSCDs).According to the known frequencies of interharmonics,DPSCs model is derived containing interharmonics from which the DPDs model is established based on superposition principle.DPDs model is used to represent the interharmonic interaction between AC and DC sides of the converter.Then,by calculating the steady-state operating point and solving the DPDs model,the calculation results of interharmonic components are obtained.Finally,the theoretical calculation results and simulation ones are compared to verify the validity of the model.The results show that the proposed model can be used to realize the interharmonic analysis of PV grid-connected system and order reduction.This model simplifies the calculation of interharmonic analysis and lays the foundation for the analysis of interharmonic emission characteristics and interharmonic suppression of grid-connected PV system.