Research Of Anti-Shading Ramp-Axis Tracking Control System

As a renewable and clean energy,solar energy is of great significance in improving Chinese energy structure and environmental quality.At present,the main form of photovoltaic power generation is a large-capacity photovoltaic power station,and as the price of photovoltaic power grids is reduced,solar tracking technology,which greatly improves the power generation efficiency of photovoltaic modules,has been widely used.Aiming at the oblique monoaxial solar tracking technology is studied.First of all,the necessity of tracking is verified by theoretical calculation.Tracking technology is very helpful to increase the power generation.Under the horizontal coordinate system,the law of solar movement is studied,and the mathematical model of the trajectory of sun is obtained.Aiming at the photovoltaic tracking array of photovoltaic power plant a flat and single-axis tracking model was established.By using the Bursa-Wolfs law of transformation,the oblique and uniaxial tracking model is obtained and the rotating tracking angle of the photovoltaic array is obtained.The accurate tracking of the solar array is achieved.Photo-voltaic arrays in large-capacity PV power plants may block each other when the solar elevation angle is low,which not ony greatly reduces the power generation capacity of the system but also reduces the service life of the PV modules.Therefore,this article presents a anti-shadow tracking technology.When the altitude is low,the maximum tracking angle of the front and rear array without shade is calculated by calculating the shadow distance between the front and rear rows of PV arrays,so as to achieve shadowless shielding of the back tracking and improve the system power generation.The hardware of the whole tracking system is designed using DSP as the control core of the tracking system,including the curmt detection circuit,the driving circuit,the system running monitoring circuit and the GPRS communication circuit.The hardware circuit of the tracking system is designed,laying a solid foundation for the subsequent experiments.Three sets of 2.6KW oblique single-axis tracking system is built,and the accuracy of the system calculation model is very verified by diferent ways.The experimental results show that the efficiency of forward tracking is 28%higher than that of stationary mode and the tracking error is within 0.5 degree,which has higher tracking accuracy.The photovoltaic tracking system with back tracking has 31.2%higher power generation efficiency than the fixed tracking,3.2%higher,and the shadowing process without shadowing,shadow distance within 0.2m.