Structure Analysis And Experimental Research Of The Large Scale Dual-axis Solar Tracker

The dual-axis solar tracker is the most important device in the high concentrated photovoltaic(HCPV)system,and its tracking error has a significant effect on the system's power generation efficiency.Gravity and wind load will cause the structural deformation,and the impact load caused by the pushrod will cause large vibration,which will cause the tracking error of the solar tracker to affect the power generation efficiency of the system.Therefore,it is important to study the tracking error of the large scale dual-axis solar tracker to analyze and improve the efficiency of the system.This paper is to combine numerical simulation and experimental research to assess the structural deformation and vibration performance of the 20-kW dual-axis solar tracker under the real operating conditions.The main research contents are as follows:Firstly,the finite element analysis model of the solar tracker is established in ANSYS.The effects of gravity on the structural strength and structural deformation are simulated at different elevation angles,and the relationship between the deflection angle and the elevation angle of the solar tracker was obtained.According to the least squares surface fitting,the variation law of the tracking error on the two diagonal of the PV module with the largest deformation is obtained.The flow field of the solar tracker under the wind load is simulated by CFX.The distribution of the flow field and the surface wind pressure around the solar tracker under different operating conditions is analyzed,and the influence of the wind load in different angle on the structural strength and structural deformation of the solar tracker is discussed.The static resistance strain instrument is used to measure the structural strain of the solar tracker under different working conditions.According to the theory of bending deformation of the beam and the data fitting,the relationship between the strain and deflection angle of the solar tracker is established,and the deflection angle of the solar tracker is further predicted.The experimental results show that the maximum deflection angle of the predicted solar tracker is 0.31 °,which is less than 0.50° of the control requirement.The structural deformation has little effect on the power generation efficiency of the system.Finally,the structural dynamics of the solar tracker is analyzed by using ANSYS software.The variation of the modal parameters of the first 25 orders with the elevation angle is discussed,and the vibration performances of the solar tracker under the impact load are calculated.The results show that the stress will change with time under the impact load,the maximum Mises equivalent stress is 100.0MPa,which is less than the yield strength of the steel.From the displacement response curve,the vibration is generated in the vertical direction,and the maximum amplitude is 24 mm.The resulting deflection angle is less than 0.50° of the control requirement,thus the structural vibration has little effect on the power generation efficiency of the solar tracker.