The Design Of Automatic Sun Tracking System

With the rapid development of world economy and rapid growth of population,the demand for various natural resources is soaring day by day, especiallynon-renewable resource. However, the oil, coal and natural gas as the main fossilfuels provide the world with about90%of the energy. Just as energy demandcontinues to increase, supplies of the main fossil fuels used in power generation arebecoming more expensive and more difficult to extract. The shortage of energysources will be a serious problem that our country faces. In recent years, the aerosolpollution over many cities in the northern and southern parts of our country isgetting worse, resulting in haze weather with visibility decreasing and air qualitydeterioration. The exploitation of the renewable energy sources is drawing attentionworldwide under the consideration of the self-sufficiency of energy supply and thereduction of greenhouse gas emissions. As a predominant energy, solar energy hasbeen paid attention to and will be a potential future energy. How to improve the heatconversion efficiency of helioplant?This has become an important topic of theutilization of solar energy in the world now. The development of auto-solar tracker isa kind of important approach which can improve solar energy utilization ratio.Based on analysis of some sun tracking scheme, this paper proposed anautomatic tracing system of sun ray. Due to the sun tracking device as an importantcomponent in the dish-style solar thermal power system,this paper designs a track ofthe combination of photoelectric tracking and the day movement trajectory tracking.With this open-loop and closed-loop joint control approach, it had been realized totrack the elevation angle and azimuth of this system continuously and accurately. Byapplying GUI function of Matlab, a new man-machine interaction interface wasdesigned.It can directly calculate any point at a given moment in the sun elevationangle, solar azimuth and solar declination angle. Meanwhile, the data is sent to AVRsingle-chip microcomputer through the serial port provided by PC computer.Afterdealing with the data, the2-axis sun tracker follow the sun’s trajectory.For an openloop controlled sun-tracking system, the computation accuracy of solar position isespecially important. Then it is accurately tracked by the photoelectric detectiontracking. According to the characteristics of sun tracker, a new type of photoelectricdetection device is designed. As the main part of the photoelectric tracking equipment, the tracking precision of the photoelectric tracking control system is aprimary index measuring photoelectric tracking equipments. The design procedure isfully illustrated.This paper mainly expounds the design and details of each part of the device,such as principle of solar auto-tracking system, the structure, the hardware circuitdesign and the software design. With ATmega8as the controller, mathematicalformulas are used to predict the sun’s location for tracking and optical sensors areused to correct errors which might occur in the process. And the design philosophyand flow charts of the software are fully discussed, such as the basic requirement ofsoftware, the design and realization of the function. The result of analysis and designindicates that the method meets the requirements of sun-tracking system.