Influence of shading on electrical parameters of solar cells

Shading of solar cells not only reduces the cell power P_MPP , but also changes the open-circuit voltage V_OC, the short circuit-current I_SC, the fill factor FF, and the efficiency η. The authors introduce a shading factor S describing the amount of shading. From the well-known solar cell equations, the authors have calculated approximate equations for the solar cell parameters as a function of the shading factor S. They then compare these equations with simulated values. The approximate equations can also be used for the description of equally shaded solar modules. Furthermore, they propose a simple algorithm for the calculation of the performance of a partially shaded standard PV-generator