Shading effects in characteristic parameters of PV modules

Main characteristic parameters of a PV module present substantial variations in case of partial shading, resulting in important reductions of the output power. A commercial PV module formed by 36 solar cells in series has been tested varying the shadow rate of one of its cells and changes in most important characteristic parameters have been analyzed. Using parameter extraction techniques we have obtained the evolution of series and shunt resistance of the PV module in function of shadow rate.