分析了光伏电池的数学模型,提出了一种简化的工程应用模型,该模型仅需要光伏电池的5个出厂参数就可以在工程精度下完整地复现光伏电池的外部特性,采用多项式拟合方法,成功地使用4段折线对光伏电池的I-U特性曲线进行了拟合。基于多项式拟合的光伏电池阵列特性曲线设计了一种数字式光伏阵列模拟器,该模拟器以Boost变换器作为主电路,采用电流闭环PI控制。仿真与实验证明,采用多项式对光伏电池特性曲线进行分段拟合具有较高的精确度,模型误差在6%以下,可以满足光伏系统设计及仿真的精度要求,可以取代实际光伏阵列进行相关实验研究。
The mathematical model of photovoltaic cells is analyzed and a simplified mathematic model for engineering application is offered,which only needs five rated parameters to completely represent its external features with engineering precision.Four-segment broken-line is applied to precisely fit the I-U characteristic curve of photovoltaic cells and a digital photovoltaic cells simulator is then designed based on the characteristic curve by polynomial fitting.Its main circuit is a Boost converter controlled by a current-loop PI regulator.Simulative and experimental results show that its model error is below 6 %,meeting the design and simulation accuracy of photovoltaic cells system.