A high-concentration programmable solar simulator for testing multi-junction concentrator photovoltaics

We describe the design and operation of a spectrally programmable solar simulator capable of being concentrated to very high irradiance for the testing of multijunction concentrator solar cells. The simulator utilizes a spatially coherent, super-continuum laser as the light source and a hybrid pair of prism-based spectrometers with spatial light modulators to precisely control the spectrum. Spectra are presented which simulate scaled versions of the AM 1.5 solar reference spectrum, correct for spectral mismatch, and model attenuation from increasing air-mass. The simulation of attenuated spectra may be used to study conditions representative of changes in location, weather, time of day, and time of year. We used the programmable simulator to test a multi-junction solar cell at up to 138 suns. We used a static, non-programmable version of the simulator to test the same cell at well over 500 suns. Technical improvements which would achieve substantial increases in irradiance and/or cell illumination area are described.