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Concentrated photovoltaic (CPV) systems can achieve high energy conversion efficiencies due to their use of concentrating optics and highly efficient solar cells; however, power losses arising from the front surface reflection and metallization shading typically contribute a significant fraction to the total power loss for these devices. In flat silicon photovoltaic (PV) modules, the front‐metal finger shape is often shaped to minimize shading losses. Finger shape is even more relevant for CPV cells where the current density and front metal shading are much higher. This study compares the optical performance of five light management finger designs in CPV systems with two different refractive homogenizers. The optical efficiency and loss analysis were determined using ray‐tracing simulations. It is shown that shaped, light diverting metal fingers can improve the optical efficiency in CPV systems by up to 9.9% absolute compared to rectangular fingers, corresponding to an absolute cell efficiency increase of 3.0%. Although sharp edged triangular finger structures may be challenging to fabricate, significant optical gains can still be achieved with trapezoid or rounded cap finger shapes. [ABSTRACT FROM AUTHOR]

The goal of this presented study was to determine the optimum parameters of secondary optical elements (SOEs) for concentrated photovoltaic (CPV) units with flat Fresnel lenses. Three types of SOEs are under consideration in the design process, including kaleidoscope with equal optical path design (KOD), kaleidoscope with flat top surface (KFTS), and open-truncated tetrahedral pyramid with specular walls (SP). The function of using a SOE with a Fresnel lens in a CPV unit is to achieve high optical efficiency, low sensitivity to the sun tracking error, and improved uniformity of irradiance distribution on the solar cell. Ray tracing technique was developed to simulate the optical characteristics of the CPV unit with various design parameters of each type of SOE. Finally, an optimum KOD-type SOE was determined by parametric design process. The resulting optical performance of the CPV unit with the optimum SOE was evaluated in both single-wavelength and broadband simulation of solar spectrum.

The Concentrated Photovoltaic (CPV) technology based on the use of high-efficiency multi-junction solar cells has higher power generation efficiency than other photovoltaic power generating technology. However, the cost and reliability of CPV technology are the primary reasons that restrict its progress. A truncated ball lens as a secondary optical element for CPV optical system is proposed in this paper to reduce the cost and improve the reliability. Theoretical analysis and experimental investigations were conducted on a concentrator with geometrical concentration ratio of 625×, a flat Fresnel lens as primary optical element and a truncated ball lens as secondary optical element. Test results show that the concentrator with power generation efficiency of 30.1% and acceptance angle of 0.73° can be obtained. Additionally, temperature effects of SOG lens on power generation are also studied. [ABSTRACT FROM AUTHOR]

Various measures should be taken to optimize the performance, minimize the cost and improve the reliability of CPV concentrator. This paper presents theoretical analysis and experimental verification on a concentrator optical system with geometrical concentration ratio of 625× consisting of a Fresnel lens as primary optical element, a ball lens as secondary optical element and a solar receiver. The solar cell and the ball lens are separated by a small air gap in this proposed CPV system and the ball lens is mounted mechanically on the receiver to enhance the reliability of the CPV system. Test results show that a power generation efficiency of 30.3% and acceptance angle of 0.72° can be obtained for a CPV device with Fresnel lens, ball lens with AR coatings and solar cell with efficiency of 40%. [ABSTRACT FROM AUTHOR]