Influence of shading on electrical parameters of solar cells

Shading of solar cells not only reduces the cell power P/sub MPP/, but also changes the open-circuit voltage V/sub OC/, the short circuit-current I/sub SC/, the fill factor FF, and the efficiency /spl eta/. 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.