光伏分布式MPPT机理分析与仿真研究

采用目前常用的光伏电池模型对光伏阵列进行建模时,或者需要多个模块进行串并联,仿真电路规模较大,增加了仿真复杂性,或者由于参数简化影响精度。将建立光伏阵列模型的方法分为计算法和查表法,计算法容易收敛,但需要明确的光伏阵列输出电压电流方程,查表法比较灵活,只需知道输出电压电流的数据源,可以仿真任意规模的光伏阵列。之后基于查表法和实际产品数据实现与功率变换器进行组合连接的电路仿真,并解决建模过程的若干技术问题。?结合模型和阻抗分析,对单模块、组串和阵列等典型配置分布式MPPT机理进行分析,并得出相应控制表达式。最后针对相应配置分别设计算例进行仿真研究,并与集中式MPPT结果进行对比分析,为显著提高光伏阵列输出效率建立理论基础。

Photovoltaic distributed MPPT mechanism analysis and simulation study

The simulation circuit of PV arrays can be complex or even features low accuracy, due to the series or parallel connection of photovoltaic cells that are usually modeled by conventional models. In this paper, the PV arrays modeling methods are divided into two categories, namely, calculation method and look-up table method. The calculation method easily falls into convergence, yet needs definite PV output voltage and current equation. The look-up table method is more flexible as the modeling of PV array only requires current and voltage data. A look-up table method is proposed to verify the correctness of modeling PV arrays in a solar power converter. In this process, a few key problems are solved. According to the proposed model and the impedance analysis results, the mechanisms of distributed maximum power point tracking (MPPT) of single, series, and multiple PV arrays are investigated and the corresponding equations are obtained. Calculation cases of corresponding configurations are simulated and the results are compared with that of centralized MPPT, which provides solid theoretical foundations for improving the efficiency of PV arrays.