Research On Maximum Power Point Tracking Control Algorithm In Photovoltaic Power Generation System

With the gradual aggravation of global warming and the consumption of fossil energy,the evolution of renewable energy to decline carbon emissions has become the best option for the energy development of all countries in the world.With the advantages of no pollution,easy installation and easy popularization,solar energy has become the focus of many renewable energy research.However,there are still some technical problems to be solved in the process of using photovoltaic arrays to convert solar energy into photoelectric energy,and the most crucial one is to enhance the power generation efficiency of photovoltaic arrays.In order to achieve maximum power tracking effectively under uniform illumination and partial shading condition,this paper studies the Maximum Power Point Tracking(MPPT)control algorithm appropriate for the single-peak output characteristics and multi-peak output characteristics of photovoltaic array,respectively.It is of great research importance to gain the power generation efficiency of photovoltaic array.The main contents are as follows:Firstly,the background and crucial of the topic are introduced,and the recent research results of photovoltaic maximum power tracking technology and their merits and drawbacks are analyzed.On the strength of the operational theory of photovoltaic cell and the mathematical model of photovoltaic cell,the simulation model of photovoltaic array is structured by Matlab/Simulink19 b.According to the simulation results,the single-peak output features and multi-peak output features of photovoltaic array are analyzed.Secondly,the fundamental theory of photovoltaic maximum power point tracking technology and some of its conventional control approaches are analyzed and introduced.Aiming at the problems existing in the perturbation and observation method,an improved power prediction variable step size photovoltaic MPPT algorithm based on sigmoid function is proposed.Firstly,the algorithm utilizes the constant voltage method to rapidly track to the periphery of the maximum power point,and then utilizes the power prediction method ground on Hermite interpolation function and the variable step size disturbance observation method to complete the subsequent tracking,where the variable step size value S is calculated by the transformation formula based on sigmoid function.The simulation consequences reveal that the proposed algorithm can be able to track the maximum power point quickly,output power is stable,and can effectively overcome the occurrence of misjudgment.Finally,in order to solve the problem that the conventional MPPT control algorithm could not availably trail the maximum power point under partial shading,the Grey Wolf Optimization(GWO)algorithm is introduced.Based on the analysis of its principle and characteristics,GWO is improved.Improved Grey Wolf Optimization(IGWO)algorithm mainly included three core contents: non-linear convergence factor that adjusts the proportion of global search and local search to the maximum number of iterations,improved levy flight and enhanced drunken-walk strategies,and proportional weight based on step Euclidean distance.The algorithm test results show that IGWO has excellent optimization speed and accuracy.In order to improve the property of MPPT algorithm,IGWO is combined with the proposed variable step disturbance observation method,and an MPPT control algorithm based on IGWO-IP&O is proposed.The simulation pattern of MPPT energy storage supervision system found on IGWOIP&O is built by simulink.Compared with GWO,flower pollination algorithm,improved particle swarm optimization and velocity of PSO based levy flight.The simulation consequences reveal that the MPPT control algorithm based on IGWO-IP&O can rapidly track the maximum power point and achieve steady power output when partial shading occurs,and the energy storage lithium battery connected to the photovoltaic array power generation system works normally,which verifies the effectiveness of the MPPT control algorithm based on IGWO-IP&O.The above results have certain value for the research and application of the maximum power point tracking control algorithm of photovoltaic.