Design And Application Of Solar Radiation Tracker Based On Photoelectric Sensor

Solar radiation tracker is also called dual-axis sun tracker.As a kind of automatic sun trackers,it is a necessary device for pyranometers and pyrheliometers.Dual-axis sun tracker can ensure that the light tube of pyrheliometer is always aligned to the sun and that the pyranometer automatically shades the light.Therefore,it can accurately measure Direct Normal Irradiance(DNI)and Diffuse Horizontal Irradiance(DHI).In comparison with the manual sun tracker and semi-automatic tracker with a low degree of automation,it has obvious advantages.Because of the four quadrants photoelectric sensor,photoelectric rotary encoders,and laser displacement sensor,the dissertation is devoted to the design and application of solar radiation tracker based on photoelectric sensor.The whole design mainly includes the solar radiation tracker hardware circuit and the sun position tracking software algorithm.The hardware circuit is mainly composed of four quadrants photoelectric sensor,EnDate22 angle encoder,laser displacement sensor,DSP central control processing circuit,power supply circuit and so on.Software algorithm mainly includes several major parts:date entry subroutine,solar azimuth angle and solar elevation angle subroutine,sunrise and sunset time subroutine,and so on.Equipped with GPS(BeiDou)to receive important data such as latitude and longitude,altitude,and time,the dual-axis sun tracker can effectively improve the accuracy of the solar position tracking algorithm and avoid manual entering the calibration value when moving the sun tracker.Based on this design,this dissertation completes the research on the hardware and softeware algorithm debugging of solar radiation tracker and its function realization.Through the test,the position error of software algorithm output is within 0.06°,which is much smaller than the sun flare angle of 0.6°.The gear rotation error of the drive motor is within 0.75°,which satisfies the requirement of meteorological radiation observation equipment(pyrheliometers and pyranometers).The design of our dual-axis sun tracker has the advantages of automatic switching equipment on sunny day/cloudy day,automatic calibration of trajectory error,maintenance-free and debugging-free.Thus,it has unique advantages in the photovoltaic/photo-thermal industry and the meteorological date measurement that can play an important role in solar power plant efficiency prediction and power station operation guidance,solar power plant location,and other projects.