An indoor method is presented for the quantification of the current‐matching ratio of a multijunction cell within a concentrator under arbitrary spectral irradiance conditions. The cell current is measured across a very large spectral sweep to force the relevant subcells into a limiting condition. The light spectrum is monitored using component cells to avoid the need for a spectroradiometer and spectral response measurements. The method also provides an estimation of the current losses beyond the overall current mismatch, for example, losses produced in concentrators with chromatic aberration by the non‐uniformity of the incident spectrum across the cell. The method has been applied to a pair of refractive point‐focus concentrator systems; first, a 300X single‐stage Fresnel lens over a lattice‐matched GaInP/Ga(In)As/Ge triple‐junction cell and second, a 1000X two‐stage system with the same Fresnel lens over a homogenizing secondary lens that encapsulates a triple‐junction cell of the same kind but smaller. The experiment demonstrates that the single‐stage concentrator exhibits a higher sensitivity of the current mismatch to variations in the focal distance. Copyright © 2012 John Wiley & Sons, Ltd.

The performance of different reflexive and refractive secondaries optimized for the same primary lens is studied by using ray-tracing simulation. Different solutions are approached according to materials and manufacturing processes currently available in the market, which can be potentially cost-effective for concentrator photovoltaic (CPV) modules. They are compared in terms of system optical efficiency and acceptance angle. In addition, irradiance distribution over the cell is also studied.

A solar simulator for measuring performance of large area concentrator photovoltaic (CPV) modules is presented. Its illumination system is based on a Xenon flash light and a large area collimator mirror, which simulates natural sun light. Quality requirements imposed by the CPV systems have been characterized: irradiance level and uniformity at the receiver, light collimation and spectral distribution. The simulator allows indoor fast and cost-effective performance characterization and classification of CPV systems at the production line as well as module rating carried out by laboratories.

Concentrator photovoltaics (CPV) is a special high efficiency system technology in the world of PV-technologies. The idea of CPV is to use optical light concentrators to increase the incident power on solar cells. The solar cell area is comparatively tiny, thus saving expensive semiconductor materials and allowing the use of more sophisticated and more costly multi-junction solar cells. The highest CPV module efficiency achieved is 38.9%. This CPV module uses four-junction III-Vbased solar cells. Moreover, mini-modules have already achieved an efficiency of 43.4%. The interaction between optics, cells, and layout of the module and tracker determines the overall field performance. Today, some utility scale CPV plants are installed. The CPV technology allows for many technical solutions for system designs and for optimizing performance while maintaining the economics. This paper will review the achievements and discuss the challenges for the CPV module technology and its components. We discuss the different components and the most important effects regarding the module design. Furthermore, we present the module designs that have shown the highest efficiencies.

This paper proposes an indoor procedure based on charge-coupled device camera measurements to characterize the non-uniform light patterns produced by optical systems used in concentration photovoltaic (CPV) systems. These irradiance patterns are reproduced on CPV solar cells for their characterization at concentrated irradiances by using a concentrator cell tester and placing high-resolution masks over the cells. Measured losses based on the masks method are compared with losses in concentrator optical systems measured by using the Helios 3198 solar simulator for CPV modules.