The Design of a Low-Cost Radiometric System for Photovoltaic Solar Cells

Abstract

Photovoltaic (PV) cell manufacturers use a standard spectrum when designing and characterizing their systems. However, various authors have shown that variations in the spectrum of light during different seasons and/or in different locations have a significant impact on the efficiency of PV cells. Consequently, metrics such as the average photon energy, the useful fraction, and the weighted useful fraction have been proposed and successfully used to demonstrate the relationship between the spectrum of the incident radiation and PV cells efficiency. In this work, we propose the use of an inexpensive radiometric system to accurately determine the spectrum of incident light and, hence, some of these efficiency metrics in real time. This system could easily be integrated within a PV cell system so that these parameters are available for both system assessment and possibly for the maximum power point tracking systems that can deal with challenging partial shading conditions.