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In order to increase the conversion efficiency of photovoltaic concentrators, as well as to reduce the solar tracking cost, a new prismatic concentrator is proposed. The concentrator optics operates both in transmission and in reflection, it has a total vertical dimension of 55 mm and a square output aperture, equivalent to the PV cell size, of 0.75 x 0.75 mm. It is essentially composed by a convex surface attached to a prismatic truncated pyramid. The design procedures followed to increase the acceptance angle of the concentrator are described. The output of simulations carried out by Zemax software allows getting a concentrating factor of 750x, a maximum optical efficiency of 95% and an angular acceptance of ±2.1°. [ABSTRACT FROM AUTHOR]

It is presented the optical design of a mirror based solar concentrator operating at concentrating factors higher than 850suns with an optical efficiency greater than 83% and an angular acceptance of at least ±0.5°. The optical system consists of an off-axis primary mirror optimized to work in conjunction with a secondary optical element which homogenizes the light on the photovoltaic (PV) cell and also increases the acceptance angle of the solar concentrator. Since in a high concentrating system the collected optical radiation can impinge on the PV cell also at high incidence angles, during the optical design and optimization particular attention was paid to reduce the number of rays impinging on the PVcell at high incidence angle. Furthermore the angular response of the PV cell was included to calculate the efficiency value of the whole system and to calculate the spatial distribution of the photocurrent in the different subcells constituting the multi-junction solar cell. [ABSTRACT FROM AUTHOR]