被部分遮挡的串联光伏组件输出特性

Characteristics of partially shadowed serial PV module output

以太阳能电池的电流方程和电路的基本理论为基础,对带有旁路二极管的串联组件在被部分遮挡的情况下的输出过程进行了细致的物理分析,并将其划分为旁路二极管导通和阻断两个阶段,从理论上推导出可以运用分段函数准确描述被部分遮挡的串联光伏组件电流和功率输出特性.对两个串联的光伏组件在非均匀光照下的电流和功率情况进行了实验验证,结果证明了文中所提方法的正确性和可行性:①分段函数法可以对被部分遮挡的带有旁路二极管串联光伏组件的电流和功率输出特性进行准确描述;②传统的MPPT法的基础,即功率输出曲线的单峰性,已经失效,因而有必要对跟踪方法进行改进.

Based on solar cell current equation and basic circuit theory, the branch output process of the partially shadowed serial solar module with bypass diode was carefully analyzed. The physical output process was divided into two phases： connection and disconnection of the bypass diode. Based on theoretical deduction, the subsection function was applied to accurately describe partially shadowed serial PV module current and power output characteristics. Finally the experiments were carried out for two serial PV module current and power output under non-uniform illumination. The experimental results demonstrate that the proposed method is correct and feasible： the subsection function can accurately describe the current and power output of partial shadowing of serial PV module with bypass diode the single peak to power output curve, which is the basis of the traditional MPPT （maximum power point tracking）, is also inexistent, so it is necessary to carry on improvement to the tracking method.