The Research And Implementation Of Closed-Loop Sun-Tracking Controller Based On Image Sensor

In order to solve the energy crisis, achieve sustainable development and building a green community, countries in the world are actively developing the use of solar energy resources. The use of solar energy has penetrated into all aspects of society, but the solar energy utilization efficiency is low impact and this issue has been hindering the popularization of solar energy technology. To improve the efficiency of solar energy utilization, the research of automatic sun-tracking controller has important and far-reaching significance.In the analysis and comparison of several commonly used at home and abroad tracking mode, this issue designed a new type of closed-loop sun-tracking controller to track the solar trajectory depending on the use of the image sensor which was considered as sensing element. Sun-tracking controller working process: PC calculate the sun altitude and azimuth angles by access to the local latitude and longitude and the current time, convert into operation steps of two stepper motors, the drive circuit drives stepper motors, stepper motors drive tracking mechanism, to achieve sun tracking. At the end of solar trajectory tracking, image sensor capture current position of the sun and obtain the deviation by image processing. When the deviation value is greater than the set threshold value, convert into correction steps and send feedback correction to tracking device, which constitutes a closed-loop tracking system.The subject completed a tracking controller hardware and software design. Hardware design including: tracking control circuit, stepping motor drive circuit, image acquisition circuit, limit the signal acquisition circuit and the serial communication circuit. Software design including: the design of Visual C++ control platform for the preparation of human-computer interaction, design MATLAB algorithms for image processing and acquisition track bias, VC and MATLAB based MCC joint programming.Measured by the experimental analysis of the data shows that: in the cloudy case, the camera can not get the sun image, the average error of height degree tracking is less than 1.5°, the average error of azimuth degree tracking is less than 1.2°; in the normal case, the camera can get the sun image, the average error of height degree tracking is less than 0.5°, the average error of azimuth degree tracking is less than 0.4°.A new type of sun-tracking controller has been designed finally. The results and analysis of the experiment show that, sun-tracking controller achieved the desired results in reliability, tracking accuracy and interference immunity.Finally, this thesis summing up the work and gives the direction of further study.