Research On Multi-peak MPPT Control Algorithm In Photovoltaic Power Generation System

At present,as the demand for electricity in society continues to rise,under the background of the global energy crisis and the increasingly serious environmental pollution,solar energy,as a clean,pollution-free,and inexhaustible renewable energy source,has won the whole society.Wide attention.Photovoltaic power generation technology has been widely used in various fields of military,civilian,and business.Partial shading or uneven illumination of photovoltaic cell arrays is common in the practice of photovoltaic power generation projects.These phenomena can easily lead to unstable output power of photovoltaic power generation systems,photovoltaic cells produce "hot spot effect",or single peak maximum power point Problems such as the failure of Maximum Power Point Tracking(MPPT)technology seriously affect the stability and safety of the photovoltaic power generation system and limit the application of MPPT technology.Therefore,how to ensure a stable maximum power output when the photovoltaic cell array is partially shaded or subjected to uneven light has become an urgent problem to be solved.In response to this problem,this article first analyzes the working principle and characteristics of photovoltaic cells.The equivalent circuit of photovoltaic cells is established,and the mathematical modeling of photovoltaic cells is established.On this basis,a photovoltaic cell array simulation model was built,and the output characteristic curve of the photovoltaic cell array under different environmental conditions was analyzed,and its effectiveness was verified by simulation.Then it analyzes the reason for the multi-peak phenomenon in the output characteristic curve of the photovoltaic cell array and the harm caused.For photovoltaic cell arrays under different environmental conditions,the multi-peak characteristics of the photovoltaic cell arrays are analyzed and demonstrated in detail through modeling and simulation.Subsequently,a variety of commonly used MPPT control algorithms are analyzed,the advantages and disadvantages of each algorithm are explained,and comparisons are made.On this basis,a variable step perturbation observation method and an improved POC algorithm are proposed.The variable step perturbation observation method is used as the first part of the improved POC algorithm to quickly and accurately track the photovoltaic array The first maximum power point.The improved POC algorithm adopts the idea of global scanning and equal power curve.In the process of tracking the maximum power point,the search range is continuously reduced to achieve the purpose of fast and accurate tracking and reducing power loss.Finally,the proposed MPPT control algorithm is simulated and verified under the equivalent model of different environmental conditions,as well as comparison demonstration.From the simulation and comparison results,the algorithm is feasible and has superior performance.The improved POC algorithm can not only meet the maximum power point tracking of photovoltaic cell arrays under stable environmental conditions,but also meet the maximum power point tracking of photovoltaic cell arrays under complex environmental conditions.