基于分段线性的光伏阵列等效模型

A Piecewise Linearization Based Equivalent Model of Photovoltaic Array

根据光伏阵列在系统分析以及仿真实验等具体应用中的要求,为了对其非线性I-U特性进行简化等效,提出了一种基于分段线性的等效方法。该方法利用相对简单的线性模型以及相应的等效电路来描述光伏阵列的I-U特性。通过分段线性化,使光伏非线性关系由多段线性方程来代替。而对于每一段线性方程,用一个等效电路表示。最终提出了一个含多个并联支路的光伏电源I-U特性等效电路。利用PSCAD软件搭建了分段线性等效电路的仿真模型,并将仿真结果与数学解析计算结果进行了比较。分析结果表明,分段线性模型能很好地表示光伏阵列的非线性I-U特性。

According to the requirements of applying photovoltaic （PV） array in system analysis and simulation experiments, to perform simplified equivalence of PV array’s non-linear characteristics of current to voltage, a piecewise linearization based equivalence method is put forward. The proposed method describes the I-U characteristics of PV array by relatively simple linear models and corresponding equivalent circuits. Through piecewise linearization, the non-linear relation of PV array is represented by multi-sectional linear equations, and each linear equation describing corresponding section of the characteristic curve is represented by an equivalent circuit. Finally, an equivalent circuit representing the I-U characteristics of PV array, which contains multi parallel branches, is proposed. Using PSCAD software, a simulation model containing piecewisely linearized equivalent circuits is constructed. Simulation results are compared with the results from mathematical analytical calculation and comparison result shows that the multi-sectional piecewisely linearized model can represent the non-linear I-U characteristics of PV array pretty well.