Application Of Image Technology In Out Put Characteristics Of Photovoltaic Array

With the rapid development of science and technology,the problem of environmental pollution is becoming more and more serious,which makes it urgent for people to study new energy.In recent years,the application of solar energy is more extensive,but the photovoltaic power generation has some shortcomings.Photovoltaic modules are vulnerable to external factors such as shades and surrounding buildings.They receive uneven illumination and cause partial shadows.The output power of PV modules is significantly reduced,and the difficulty of maximum power point tracking is increased.In this paper,we put forward the application of digital image processing technology to the output characteristics of PV array,and get the output characteristic curve of PV array under partial shadow with image,and reduce the difficulty of maximum power point tracking of PV array.First,this paper describes the basic theory of photovoltaic cell,analyzes the equivalent circuit model of PV module and the output characteristics of PV array under partial occlusion.At the same time,it introduces the basic theory of digital image processing.Secondly,taking shadow screened PV modules as object of study,occlusion experiments of different parts of shadowed PV modules were conducted.The shadow area under different shading conditions is obtained by image enhancement technology and edge detection technology.Then,in the case of certain temperature and light intensity,the pixel gray value of the photovoltaic panel is extracted by image processing technology.The illumination intensity and the corresponding pixel gray value of the solar photo-voltaic module collected by the experiment are polynomial fitting.Polynomial fitting of the intensity and corresponding pixel gray value of the solar PV module collected from the experiment is done,so that the intensity of each PV module can be accurately and real-time reflected by the camera.Finally,the output voltage and current of the photovoltaic array under the partial shadow occlusion are obtained by using the shadow area and the pixel gray value according to the mathematical model of the photovoltaic array.Based on the above mathematical models,a simulation model is built in the Matlab software,and the output characteristics of partially obscured PV arrays are obtained.The validity and accuracy of the above models are verified by the actual PV system.