Research On Maximum Power Point Tracking Of Photovoltaic Power Generation System

In recent years,due to the depletion of fossil energy,the problem of global environmental pollution is becoming more and more serious,it has become an inevitable trend that new-clean energy will replace fossil energy.Solar energy has many advantages,so it has been vigorously promoted and advocated in industrial application.Photovoltaic power generation is an effective form of solar energy’s utilization.At present,photovoltaic cell is easy to be affected by external environment,which results in low conversion efficiency.Therefore,the introduction of maximum power point tracking technology is particularly critical.The process of maximum power point tracking is realized by DC-DC circuit in photovoltaic system.The paper adopts Boost circuit as the type of DC-DC circuit,then introduces the working principle of Boost circuit.Moreover,the paper introduces several usual MPPT algorithms,including disturbance observation method,increment conductance method,fuzzy control method and RBF neural network algorithm.On this basis,the advantages and disadvantages of each algorithm are analyzed and summarized.This paper analyzes the maximum power point tracking problem of photovoltaic array under uniform illumination and complex illumination.In the case of uniform illumination,the paper takes variable-step conductance increment method as research object,the arctangent function is proposed as the step coefficient in the left region of peak voltage,and the exponential function is proposed as the step coefficient in the right region of peak voltage,so as to make up for the shortcomings of original algorithm.The improved algorithm also combines the constant voltage coefficient method to provide theoretical reference for the selection of initial step’s value on both sides of the peak voltage.Through the MPPT modeling and simulation,it can be proved that the overall performance of improved algorithm is obviously better than the traditional algorithm.In the case of complex illumination,particle swarm algorithm is taken as research object.Aiming at the shortcomings of traditional particle swarm algorithm,such as long convergence time,high steady-state oscillation rate and low search accuracy,the paper proposes the improving strategy of inertia weight as well as learning factor,then introduces a last-elimination mechanism into the algorithm.The comparision of MPPT simulation results shows that the improved particle swarm algorithm can realize maximum power point tracking more effectively compared with traditional particle swarm algorithm.Finally,the pratical engineering project of alone photovoltaic system and grid-connected photovoltaic system are established based on PVsyst,and the MPPT technology is introduced to improve the engineering parameters of two types of system.From the simulation results,it can be seen that the generation efficiency of photovoltaic system is effectively improved after combining with MPPT technology.At the same time,the paper establishes the actual monitoring platform of photovoltaic system by using Lab VIEW,in order to monitor the output of photovoltaic system in better ways.