LED-based solar simulator for terrestrial solar spectra and orientations

Light-emitting diodes (LEDs) have shown advantages in simulating complex terrestrial solar spectrum. However, it has difficulty to simulate the geometric characteristics of direct sunlight with one solar constant (100 mW/cm(2)). In this paper, A method to collect full aperture light with hyper-hemispherical aplanatic lens has been proposed, and a multi-source integrated collimating system was built. The terrestrial solar spectra and orientations under various conditions have been simulated simultaneously. Also, we conducted a control experiment with polycrystalline silicon solar cells under outdoor sunlight conditions. It has good spectral accuracy and orientational consistency. The system meets the Class AAA specifications and achieves one solar constant irradiance of AM1.5G spectrum. The divergence angle of the collimating beam is around +/- 3 degrees, and the temporal instability of irradiance is less than 0.3%. Within the range of volume space, the simulator achieves uniform illumination and the output beam follows the cosine law. The simulator has widely application in the photovoltaic industry, photochemistry, photobiology and many other fields.