Research On Optical Design And Optimization Methods Of Solar Simulation System

The solar simulator is one of the important equipment for the ground test of solar sensors.With the increasingly diverse tasks of space optical remote sensors,the system structure of solar sensors is gradually becoming larger and more complex,and the demand for simulation of the large irradiance surface of solar simulators is increasingly strong,currently,due to the limitations of solar simulation technology and process level,solar simulators face the problem of radiation uniformity and irradiance decreasing with the increase of distance and irradiance surface,which hinders their performance improvement.Therefore,the optical design and optimization method of the solar simulation system are studied in this paper,combining the nonimaging optical theory and the spatial diffuse reflection theory,the overall design scheme of the solar simulator optical system consisting of xenon lamp,variable coefficient ellipsoidal condenser,integrating sphere and composite parabolic reflector is proposed.A composite light source system,a uniform light system,and a modulation system have been designed,and the optical system has been modeled and simulated.The research in this paper provides a new design idea for the optical structure of the solar simulator with large irradiation surface and high irradiation uniformity,and has certain theoretical significance and practical value for the improvement of solar simulation technology.To simulate the real solar spectrum,a xenon lamp was selected as the light source of the system,and the power of the xenon lamp was calculated based on the irradiance and energy transmission;after comparing and analyzing the surface types of the condenser lens,an ellipsoidal condenser lens was selected as the condenser system,with the aim of reducing the area of the second focal surface,concentrating light energy and improve the utilization rate of light energy,a design method for the variable coefficient ellipsoidal condenser lens was proposed,based on Newton binomial expansion,an ellipsoidal calculation model for the ellipsoidal condenser lens of the high order variable system was established,and the analysis found that the optimal coefficients for the first three items were 0.99、1.4 and 11,the spatial layout of the composite light source system was studied,and a composite light source system with a spatial off-axis angle of 8°was determined and achieved a convergence rate of 66.86%;in order to achieve high uniformity irradiation simulation,the advantages and disadvantages of light homogenizing devices were compared and analyzed,an integrating sphere was selected as the light homogenizer of the optical system,the design method of the integrating sphere was explored and the calculation formula for energy utilization was derived,an integrating sphere with a radius of 20mm for the light inlet hole and 75mm for the light outlet hole was designed,achieving an efficient homogenization effect with a radiation uniformity of 98.10%at the light outlet hole;in order to simulate a large irradiance surface,the working principle of a composite parabolic reflector was analyzed,and a method for modulating the angle of light emitted from the integrating sphere by the composite parabolic reflector was proposed,a composite parabolic reflector with a length intercept ratio of 20%was designed,and the half angle of light emitted from the integrating sphere was modulated from 82°to 25°,this solved the problem of irradiance and irradiation uniformity decreasing with the increase of distance and irradiation surface,and realized solar irradiation simulation with large irradiance surface and high irradiation uniformity.To verify the correctness of the optical system in this article,simulation models of xenon lamps,variable coefficient ellipsoidal condensers,integrating spheres,and composite parabolic reflectors were established using Light Tools,based on the Monte Carlo method,the simulation analysis of the optical system of the solar simulator with large irradiation surface and high irradiation uniformity was performed,the results show that when the working distance is 3000mm within the effective irradiation surface ofΦ1000mm,the irradiance is 540W/m~2,and the irradiation uniformity is 98.04%,which verifies the rationality of the optical system design.The influence of defocusing of each system on the irradiation surface within the allowable range of technical indicators is analyzed,providing a theoretical basis for error allocation of the system in actual engineering installation and adjustment.