Research On Image Processing Technology For Partial Shadow Shading Of Photovoltaic Cells

The rapid economic development of our country is limited by a mass of factors,energy is one of the important restrictive factors.Therefore,in recent years,the use of diversified clean energy has been used,and the application of solar energy is particularly prominent.But it is worth noting that it also has some shortcomings.Solar panels,especially large-scale solar panels in photovoltaic power plants,are usually composed of multiple solar cells in a parallel and series topology.Photovoltaic modules are easily blocked by external factors such as buildings,vegetation and clouds and produce shadows only in the certain region after receiving uneven light.As a result,the solar panel becomes mismatching,the internal resistance increases significantly,and a large amount of energy is generated.When the situation gets serious,the hot-spot phenomenon may occur in the photovoltaic panel,and even the accumulated energy may damage the solar cell,which will greatly reduce the power generation efficiency of photovoltaic modules.On the other hand,it will also increase the complexity and difficulty of tracking on maximum power point.Therefore,this article tries to combine digital image processing technology based on the research of photovoltaic array output characteristics,that is,use image processing technology to extract the output characteristics of partially shaded photovoltaic array,and then control the power switch and charge pump circuit to reduce the difficulty of maximum power point tracking.At the beginning of this article,explaining the basic principles of solar cells will be the key point.On the one hand,we will focus on analyzing the equivalent circuit model of photovoltaic modules.On the other hand,we will simulate and analyze the output characteristics of photovoltaic arrays under partial shadows,and outline the related digital image processing theory.Next,we will study the photovoltaic modules covered by shadows,conduct conclusive experiments on the photovoltaic modules,and use image enhancement,edge detection and other image processing methods under various shadow conditions to extract the shaded area of the photovoltaic panel.Subsequently,not changing the temperature,image processing technology is used to extract the gray values of the solar panel images under different lighting conditions.And on this basis,this paper uses the acquired light intensity data and the obtained pixel gray value after the image processing of performing curve fitting operations.Based on the fitted curve,the light intensity of different photovoltaic modules can be obtained in real time.Finally,the shadow area and pixel gray value obtained by image processing technology are used to carry out mathematical modeling,so as to obtain the specific values of the external output voltage and current that the photovoltaic array generates under partial shadow conditions.This voltage and current are taken as the main basis for dynamic interconnection and optimization of the control system.Using step switch technology,when the solar cell group is in a state of mismatch,it can recover more than 50% of the power loss due to mismatch by using hierarchical switch technology,greatly improving the efficiency of power generation.