Characterization method and analysis of misalignments in micro-concentrator photovoltaic modules

Abstract

Micro-scale concentrator photovoltaics (micro-CPV) is an emerging trend for the development of high-efficiency, low-cost photovoltaic systems. The miniaturization of optics and cells offers advantages in terms of performance and enables differentiation in the PV market. However, the sub-millimeter size of the solar cells used, the intrinsic narrow angular tolerance of CPV optical systems (typically around 0.5° and 2°), and the massive number of cells per module lead to very tight mechanical tolerances. Therefore, determining the misalignments between cells and optics is important for quality control inspection of modules. In this paper, we describe a method for characterizing these misalignments based on image acquisition and its subsequent processing and apply it to a micro-CPV module composed of 572 lens-cell units. This method is validated, using a unique experimental technique that takes advantage of the tracking system embedded in the module. The statistical distributions of misalignments are compared for two tracking positions, residuals are determined and shows the consistency of the method. Finally, the impact of misalignment distributions on the IV curve of the module is discussed.