A sunlight-concentrator device for a photovolatic-generating system

In a photovoltaic-generating system having a plurality of photovoltaic cells, a sunlight-concentrator device is equipped with a plurality of optical units, which are provided with respective primary concentrators with a compound curved surface, each of which has an inlet aperture for the direct entry of sunlight, an outlet aperture for exit of the concentrated sunlight towards a respective photovoltaic cell and an optical axis traversing the inlet aperture and outlet aperture, and which are set alongside one another with the optical axes parallel to one another to define an overall inlet aperture for the sunlight, and each of the inlet apertures defines, in a plane orthogonal to the optical axesw, an inlet boundary shaped in such a way that the overall inlet aperture is completely covered by the set of the inlet apertures