Simulation of spectral match and spatial non-uniformity for LED solar simulator

The LED Solar Simulator is an equipment used to determine the characteristics of solar cells indoors by replicating the spectrum of sunlight with an LED light source. This paper presents an algorithm for simulating two important performance parameters of solar simulators, namely spectral match and spatial non-uniformity. It can be used to determine the uniformity of light falling on a plane kept below a light source at a particular distance. If the light source has a known spectrum, it can be used to find the distribution of the irradiance of the light source throughout the wavelength range of interest. Light source may be a single source or an array of sources. The required data for this algorithm is the light source intensity, number of sources, distance from the light source to the plane whose uniformity is to be calculated, viewing angle of the light source and the spectrum of the individual sources. The algorithm can also consider the effect of reflecting surfaces, if their position and average reflectance is given. From the resulting irradiance map of the test plane, the parameter spatial non-uniformity can be calculated, while from the spectral irradiance, the Spectral Match with the reference solar spectrum can be calculated.