Solar Simulation Technology Based On Variable Curvature Ellipsoid

Solar simulator is a device to simulate the solar radiation in outer space of the earth.It has application value in the ground simulation test,precision calibration and performance verification of satellite solar sensor.The existing optical system of solar simulator is difficult to improve the optical performance of solar simulator due to the influence of its imaging relationship and the mutual restriction between the parameters of concentrating system and uniform system.Therefore,aiming at the problems of low energy utilization and poor radiation uniformity of traditional ellipsoidal concentrating solar simulator,this paper carries out the research of solar simulation technology based on variable curvature ellipsoidal concentrating It has certain theoretical significance and practical value to improve the level of space ground test.The solar radiation such as irradiation intensity,irradiation instability,irradiation uniformity,beam collimation angle and spectrum distribution are described.The composition,overall structure and layout of the solar simulator are determined based on the theory of non imaging optics.The optical system,especially the variable curvature ellipsoid focusing system,is deeply studied and designed.Based on the technologies of concentrating,unifying and collimating,an overall design scheme of the optical system of the variable curvature ellipsoidal concentrator solar simulator is proposed,which is composed of light source,variable curvature ellipsoidal concentrator,optical integrator and collimating optical system.The problems of low energy utilization and poor irradiance uniformity are solved.Through the comparative analysis of the existing light sources,xenon lamp is selected as the system light source,and the power of xenon lamp is calculated according to the irradiance and the energy utilization rate of the optical system.Combined with the luminous characteristics of xenon lamp,in order to improve the energy utilization rate,a design method of variable curvature ellipsoidal condenser is proposed.The curve equation of variable curvature ellipsoidal condenser is obtained by Taylor series expansion.Taking the uniformity of the second focal plane of variable curvature ellipsoidal condenser as the criterion,the optimal coefficient of curve equation of variable curvature ellipsoidal condenser is determined by Matlab simulation trial and error method.The principle of the existing uniform optical devices is studied and analyzed,and an optical integrator is optimized to improve the uniformity of the irradiation surface.According to the requirements,a collimating optical system is designed to ensure the optimal size of the irradiation surface and the beam collimation.The xenon lamp modeling method based on nested model is studied.The optical system of the solar simulator is modeled and simulated by combining the variable curvature ellipsoid condenser,optical integrator and collimating optical system.The results show that the energy utilization of the second focal plane of the solar simulator is 77.41%,the maximum irradiance of the irradiation surface is 2565W/m~2,and the irradiation uniformity is 98.48%Compared with the traditional ellipsoidal mirror solar simulator,the energy utilization ratio of the second focal plane is increased by 0.95 times,and the irradiance of the irradiation surface is increased by 791W/m~2,the irradiation uniformity increased by 3.79%;At the same time,the influence of xenon lamp and optical integrator defocusing on the irradiation uniformity of the system is analyzed,the results show that proper forward defocusing of xenon lamp can significantly improve the irradiation uniformity,while defocusing of optical integrator does not improve the irradiation uniformity.