Research And Design Of Led-based Standard Solar Spectrum Lamp

Solar simulation technology is simulating sunlight irradiationcharacteristics with the artificial light. The light-emitting diode (LED) hassuch advantages over conventional light sources as long lifetime, highluminous efficiency, fast response, environmental friendly and the variety ofproducts. This article achieves a standard solar spectrum light used inmeasurement field with high spectral match by selecting different types ofLEDs and applying the spectral superposition principle.The main content of this paper can be divided into4sections:1) The test and discussion of High Power LED characteristics andparameters, Chapter2;2) The research of spectrum fitting algorithm for LED-based standardsolar research, Chapter3;3) The design and test results of adjustable constant current drive circuitbased on LED electrical properties, part of Chapter2and Chapter4; 4) Optical design and simulation of light integral system used to mixvariety types of LEDs, Chapter5.In the first section, we firstly discuss the basic principles, the opticalproperties and the spectral irradiance of LED. Then we summarize the mainfactors that affect the LED spectral characteristics by way of experimentalverification and these lay a sound theoretical basis for the following part ofspectral fitting algorithm and drive circuit design.In the second section, based on the LED spectrum model, we propose adesign of the Gaussian fitting algorithm based on the method of least squares.Combined with the actual types of LED products, we realize the non-uniformspectral peak intervals of LED spectral fitting, thereby guiding the choice ofthe LED drive current reference value. The results show that within the rangeof300-1100nm, the spectral mismatch error is less than±2.76%with feweruse of LED types. This algorithm can also be used to accurately distinguishthe absorption valley of standard solar spectrum AM1.5. When applied toAM0, this algorithm results in a spectral mismatch error of less than±1.67%.In the third section, we systematically discuss the topologies andclassification of circuits that had been applied as the LED driver. Combinedwith the characteristics of LED, we firstly propose scheme of LED constantcurrent driver. Secondly, based on the dimming circuit theory and the basis of the previous analysis, we design an adjustable constant current drive circuitwith HV9910B and PWM dimming circuit program. Finally, we represent theexperimental test waveform results which reach the specification as expected.In the fourth section, combined with the LED light distribution curve,we put forward3kinds of LED optical hybrid optical system model whichgive a good light mixing simulation results on the detecting surface.The achievement of this paper is to propose a method to realize theLED-based standard solar spectrum light which has a positive meaning forthe improvement of the performance of artificial simulated solar light source.Similarly, by choosing different LED combinations, this method can also beused to obtain spectra adjustable special-used light source in such fields asoptical remote sensor radiometric calibration, dental treatment, body beauty,insect capture and cultivation of plants and so on.