基于Bezier曲线的CIGS薄膜光伏电池I-V曲线简单拟合方法

精准的光伏电池输出数学模型是研究光伏系统的必要条件,然而由于厂家提供的数据有限,铜铟镓硒(CIGS)薄膜光伏电池的输出数学模型是包含若干未知参数的非线性特性曲线.因此提出仅利用厂家提供的有限数据,对CIGS薄膜光伏电池的电流-电压输出特性曲线,即I-V曲线进行拟合.首先利用Bezier曲线选取函数控制点,对CIGS薄膜光伏电池的I-V曲线进行拟合;然后找出Bezier曲线控制点位置与CIGS薄膜光伏电池的填充因子之间的函数关系;最后,利用4种新型CIGS薄膜光伏电池对该函数关系进行验证,并对结果进行了对比分析.分析结果表明,所提方法对4种CIGS薄膜光伏电池的I-V曲线的拟合方法的平均相对误差均小于0.8％,验证了所提方法的有效性.

Simple fitting method for I-V curve of CIGS thin-film PV cell based on Bezier curve

The accurate output mathematical model of PV(PhotoVoltaic) cell is a necessary condition for the study of PV system. However, due to the limited data provided by PV cell manufacturers, the output mathematical model of CIGS(Copper Indium Gallium Selenium) thin-film PV cell is a nonlinear characteristic curve with several unknown parameters. Aiming at this problem, it is proposed to fit the current-voltage output characteristic curve, i. e. I-V curve of the CIGS thin-film PV cell only by applying the limited data provided by manufacturers. Firstly, the function control points are selected by Bezier curve and the I-V curve of CIGS thin-film PV cell are fitted. Secondly, the function relationship between the position of control points of Bezier curve and the filling factor of CIGS thin-film PV cell is found out. The function relationship is verified by four new CIGS thin-film PV cells, and the verification results are compared and analyzed. The analytical results show that the average relative fitting errors of the proposed method for CIGS thin-film PV cells are less than 0.8 %,which verifies the effectiveness of the proposed method.