Calculation of shading effect in PV module by graphical method with experimental validation

This paper proposed a method to calculate the operating point of photovoltaic (PV) generation system under shading effect. To simplify the algorithm, the graphical method is used in this research. The PV modules in each string are divided in to two group, i.e. shaded and unshaded groups. In addition, the double diode model with Bypass diode is proposed in this paper. This model is used to investigate the output characteristic, i.e. current, voltage, and power. The characteristic given from the PV model is used to plot the I-V and P-V graph for each PV group. The characteristic of each group is combined together to obtain the characteristic of the whole string. The graphical method is used to specify any peak power that occurs under shading effect. The result shows that the proposed method can determine the operating point of PV system when shading effect occurs without optimization.