Modeling and simulation of a solar simulator with multi-wavelength high-power LEDs

This paper presents the modeling and simulation of a solar simulator that is comprised of many high-power LEDs of various wavelengths. A solar simulator is a light source which can provide optical power to measure the characteristics of solar panels indoors. For this application, the light source requires an optical spectrum and irradiance that is similar to solar rays. A high-power LED-based light source is considered to provide a light-weight design, higher luminous efficacy, and longer operating life. To match the solar spectrum, the light source in the form of an LED array needs various types of LEDs whose wavelengths and intensities are different from one another. The proposed solar simulator includes a highdensity LED fixture containing a 5 by 5 array of high-intensity LEDs. The square fixture measures 2.5 inches (63.5 mm) per side. The goal of this work is to find the radiometric power and optimum layout for an array of high-power LEDs in order to generate an optical spectrum similar to solar rays with uniform irradiance. The fixture has 18 high-power LEDs of 18 different types in the 5 by 5 array. Each LED in the fixture has a specific wavelength and intensity set by a 3D optical modeling tool. This work presents the parameters that affect spectral match and uniformity of irradiance. The parameters are the number of different LEDs used, their intensities, and arrangement. The number of LEDs and their intensities for a spectral match were computed by a developed algorithm. Modeling an LED array for spectral match, color quality, and irradiance were carried out by a 3D optical modeling tool. The results include the spectral and irradiance distributions of the proposed solar simulator.