基于电容阵列I-V测试仪的光伏STC曲线拟合研究

现有的光伏组件在标准条件(STC)下I-V曲线的拟合算法存在计算过于复杂或准确度不足的问题。为提高曲线在偏离STC环境下的拟合准度,提出了一种依据太阳电池四参数结构,通过选取曲线最大功率点(MPP)附近6个点作为拟合点,计算组件I-V数学模型从而实现曲线拟合的拟合算法。不同光伏组件的最优拟合点间隔不同,为提高拟合精度,进一步提出了自适应拟合点选取方法,同时设计了以电容阵列为负载的I-V测试仪结构并研制了一套完整仪器。该测试仪可通过增加MPP附近数据点的密度,提升拟合点的选取精度。经过MATLAB仿真与实际验证表明,模型拟合算法的拟合结果在各种测试环境下的准确度均高于多项式拟合算法;所设计的I-V测试仪性能优越,适用于工程测量之中。

Research on photovoltaic STC curves fitting based on capacitors array I V tracer

Existing fitting algorithms for photovoltaic (PV) module correction I-V curve under standard condition suffer from several problems, such as over-complicated calculation and lack of accuracy.To improve fitting accuracy under condition deviated from STC, a fitting algorithm based on solar cell four-parameter model was proposed.The module's I-V mathematical model for curves fitting is calculated by the algorithm through selecting six points as fitting points near the maximum power point.A self-adaption fitting point selection method also was presented for accuracy improvement because different PV modules have different optimal interval among fitting points.Moreover, a type of I-V tracer employing capacitors array as load to increase number of data points near the MPP was developed to improve fitting point's accuracy.Several MATLAB simulations and actual measurement were carried out, which show that the proposed algorithm fitting results were superior to that of polynomial fitting algorithm.And the designed I-V tracer not only has excellent performance but is suitable for engineering surveying.