Experimental research on characteristics of space concentrating photovoltaic system based on linear focusing Fresnel lens

The experimental research is carried out to testify the performance of space concentrating photovoltaic system based on linear focusing Fresnel lens. The experimental system is composed of Fresnel lens-silicon cell module, solar simulator, test devices, and so on. Based on this platform, the interactional relationships among defocusing distance, concentrated ratio, short circuit current, open-circuit voltage, maximum power output, the fill factor(Cff), efficiency, temperature of cell and substrate structure, and effect of transverse tracking errors on target width are tested and analyzed. The results show that the performance improvement of concentrating photovoltaic system mainly results from the increase of short-circuit current and maximum power output, and both increase linearly with the increase of concentrated ratio, while the open-circuit voltage is almost unchanged. Defocusing distance makes changes of target width, which further influences the cell surface's radiation strength and effective concentrated ratio. The series resistance is a disadvantageous factor for the performance of concentrating solar cell, so we need to select solar cell with lower series resistance and higher Cff, and solar cell with good radiator. Transverse tracking errors lead to wider target, lower concentrated ratio, and the central line of target width offsetting the central line of image plane with δ=0°. Research results above provide a significant guidance for the design of space concentrating photovoltaic system based on linear focusing Fresnel lens.