Outdoor I-V characterization of tilted and vertical bifacial PV modules

This work proposes an experimental method to characterize bifacial photovoltaic modules through outdoor current-voltage (I-V) measurements. This characterization is an extension of methods developed for monofacial modules by considering the IEC TS 60904-1-2 standard for bifacial modules, particularly the introduction of the equivalent irradiance that accounts for albedo and bifaciality. We extract the short-circuit current, open-circuit voltage, and maximum power from the module I-V characteristic curve under outdoor conditions. We extrapolate these parameters to standard test conditions using the measured equivalent irradiance and module temperature. This method is applied on bifacial modules in two mounting orientations: 15° tilt north-oriented and vertical east-west orientation. Characterizing the bifacial modules' electrical parameters using the proposed approach yields results with similar accuracy as applying the equivalent characterization of a tilted monofacial module.