The Research Of Sun-tracking Control System

It is the exploitation and utilization of new energy that has become an important way to improve energy consumption structure and people’s living environment, especially solar thermal power generation technology attract more attention, with the coming of industrial era, and resource depletion and environmental pollution have been two big problems of Chinese economic development. The conventional solar thermal power generation system, which has a fixed structure, can accept solar energy insufficiently. It is necessary to research on sun-tracking control system in order to improve energy absorption rate of the systems.First of all, the reach analyses the current sun-tracking control method, and proposes to use a composite tracking method that combining the sun of trajectory tracking and photoelectric tracking to realize the purpose of all-weather, multi-angle, high precision tracking the position of the sun. In terms of sun trajectory tracking methods, firstly, The author analyses the law of the sun motion; Secondly, the equator-horizontal coordinate transformation model is established, and a mathematical formula of sun-altitude Angle and azimuth is introduced; Finally, in order to make the solar concentrator gain more energy in unit time, Through the calculation and analysis, the author proposes to use a strategy that lead lag intervals sun-trajectory tracking. In terms of photoelectric tracking mode, the responsibility characteristics of several commonly used light sensors’to sun light are analyzed, and the four quadrant silicon photocell is choose as the basis of the sun position detection device; Secondly, the sun position detection principle that based the silicon photocell is analyzed, and based on the silicon photocell, the geometry structure parameters of the detection field of device are deduced. Finally, to reduce the noise of the detector, the author establishes and analyses detector noise characteristics mathematical model and noise factors, put forward the method to improve the SNR of detection device. In the sun-tracking control system, the STM32 is selected as the main controller of tracking system, SM060R20B30MN AC servo motor is choice to drive the solar concentrator. The sun tracking control program is written, according to control flow and control mode of tracking system, combining the KEIL MDK development tools and the STM32 firmware library. At last, joint-debugging on the tracking system software and hardware is conducted.The experimental results show that the sun-tracking control system can choose appropriate tracking mode to track the location of the sun according to the change of illumination, and then make the solar energy concentrator obtain more solar energy. Tracking system accumulated error is less than 2°in an hour, it is expected to meet the basic requirements, It has a certain reference value to the solar energy product development.