A NOVEL INDOOR APPROACH FOR THE MEASUREMENT OF THE INCIDENT ANGLE MODIFIER AT THE MODULE LEVEL

Abstract

The irradiance received by a photovoltaic (PV) module varies with sun elevation. It is therefore important to determine the impact of Angle of Incidence (AOI) on the PV module output and implement a correction, commonly referred to as the Incident Angle Modifier (IAM). To investigate this effect for commercial PV modules, a novel approach complementary to the IEC 61853-2 standard was designed. The experimental setup includes 1) a chopped and spot-like collimated light source (AC signal), 2) a customised angle probe holder, 3) bias light (DC signal) onto the cells not measured, and 4) a data acquisition system to filter the AC signal from the DC background. Measurements were conducted for three orientations at five different cells across the module to accurately represent the IAM. Factors such as the spot area size, irradiance level and module temperature were kept constant. Preliminary IAM results of our “non-destructive” approach were compared with that of a standard “destructive” approach, in which the back sheet was cut to access the busbars for direct measurement of the short circuit current (ISC). These results suggest the possibility of an alternative approach, complementary to the existing IEC 61853-2 standard to quantifying the IAM of a module. This could provide relevant and necessary insight to solar panel manufacturers too on the performance of their manufactured modules.