Research And Design Of Photovoltaic Dual-axis Tracking System

With the worldwide energy crisis becomes more serious,solar energy as an environmentally friendly,clean and inexhaustible source of new energy,has become an important way to solve the energy crisis and environmental pollution.Photovoltaic power generation is the primary means of solar energy utilization.The conventional fixed-installed photovoltaic power generation system cannot track the change of the solar position.Low solar energy utilization results in low photovoltaic power generation efficiency.In order to increase the solar energy receiving capacity of photovoltaic modules and improve the efficiency of photovoltaic power generation,a dual-axis tracking system for photovoltaic power generation is researched and designed.By analyzing and comparing the advantages and disadvantages of the existing tracking methods and tracking mechanisms,the hybrid tracking method and the dual-axis tracking mechanism are adopted with the requirements of this design.The law of the sun’s operation is studied,and the geostationary coordinate system is used to describe the change of the sun’s position.Through the error analysis and simulation verification of various solar position algorithms,the most accuracy of Wang Bingzhong’s declination angle algorithm and the Lamn time difference algorithm are used to calculate the real-time sun height angle and azimuth angle,and then to achieve the accurate tracking of the sun’s position.According to the functional requirements of the tracking system,the hardware,software and host computer of the system are designed.The control core of the tracking system adopts STM32 microcontroller.The hardware design mainly includes the power supply circuit,clock circuit,two-stage tracking photoelectric sensor,stepper motor and its driver,DGUS touch screen display,analog-to-digital conversion,automatic wind protection,mechanical limit.The software design includes the overall flow of the system,tracking the sun based trajectory,one tracking and two tracking of the photoelectric tracking,and the automatic wind protection design of the system.The LabVIEW software is used to design the host computer.The software programming has completed the tracking system security login interface,serial communication between the host computer and the STM32 host controller,and also completed the design of the display and storage functions of the main interface of the tracking system.A practical dual-axis solar tracking system device is set up.In order to be closer to the actual working environment of the photovoltaic power generation system,the photovoltaic power generation efficiency improvement and the accuracy of the tracking system are verified outdoors.The experimental results show that the efficiency of photovoltaic power generation can be increased by 30.8%in sunny days,and can be increased by 18.3%in cloudy and rainy weather.The error of the actual operation of the tracking device is within ±1.2°,reaching the preset target.