Development, characterisation and 1000 suns outdoor tests of GaAs monolithic interconnected module (MIM) receivers

Abstract

Monolithic interconnected modules (MIMs) are large area, high voltage PV devices which perform well at very high light intensities. They are therefore well suited for the assembly of dense array receivers. The latter can be employed in solar concentrator systems such as parabolic dishes at a concentration ratio of 1000 Suns or more. This paper reports on progress in the development and testing of GaAs MIMs and of water-cooled dense array receivers assembled from MIMs. The MIMs are electrically protected by integrated bypass diodes and, under indoor laboratory tests, reach an efficiency of 20.0 % at 1000 Suns and 22.9 % at 200 Suns. Several dense array receivers have been assembled, one of which was tested outdoors at 1-Sun and at concentration ratios of several hundred Suns and up to slightly above 1000 Suns using the PETAL solar dish facility in Sede Boqer, Israel. In addition to I-V curve measurements, the high-concentration tests included measurements that quantified the light intensity distribution over the dense array. Deformations in some of the I-V plots were observed for intensity distributions that departed substantially from perfect uniformity. The shapes of these plots were successfully reproduced by an electronic network simulation of the inhomogeneously illuminated receiver. 1-Sun I-V curve measurements and visual inspections performed before and after exposure of the module to concentrated sunlight revealed no indications of degradation