Research And Analysis On The Maximum Power Point Tracking Of Photovoltaic Power Generation Under The Shadow Conditon

Shadow mask is one of the most harmful factors that affect the normal operation of photovoltaic power generation system.The shadow mask not only reduces the output of photovoltaic power generation system,but also causes serious power mismatch.The P-U characteristic curve of PV array is prone to be multi-peak under shadow condition,which affects the accuracy of the maximum power point tracking algorithm.The bad effect of shadow conditions can be overcomed from two aspects,one is by optimizing the topology structure of photovoltaic array to enhance shadow resistance of photovoltaic array,thereby reduce the power loss of influence of power mismatch,another is by improving the maximum power point tracking algorithm,optimizing algorithm to let it be robust in multi peak situation,and improve searching speed and precision.Scholars at home and abroad have had a certain basis of research in the array topology and tracking algorithms,however,there are still some limitations of the study.Researches on the structure of photovoltaic power generation system has been summarized.Through the analysis and summarize of several arrangement modes of photovoltaic array,combined with the Simulink simulation experiment,studied the reason of the power mismatch of PV array.A parallel branch of photovoltaic power generation system is proposed according to the simulation experiments and literatures,the photovoltaic array structure is selected by the whole parallel topology, which can improve the system's anti shadow shielding ability by using the anti shadow effect of parallel branch,which has good anti shadow effect by using parallel branch.Design a inverter circuit for photovoltaic array of low-voltage high current output characteristics,allowing system to have good electrical characteristics,in order to achieve good simulation results.By study the maximum power point tracking algorithm based on the existing research,analysis the tracking principle of the tracking characteristics of the disturbance observation method and particle swarm algorithm.The classic photovoltaic maximum power point tracking algorithm such as disturbance tracking speed and precision measurement of the concept of mutual restraint and when the tracking precision is high,the start time is too long,resulting in loss of part of power system.Two improved algorithms are analyzed, and the performance of the method is compared with that of the starting speed, the performance under the light mutation and the shadow mask,the advantages and disadvantages of particle swarm optimization algorithm are analyzed theoretically,Through the analysis of the output characteristic curve of PV cell,According to the characteristic of output curve, the disturbance observation method and particle swarm optimization algorithm are combined to improve the tracking algorithm,the loss of power,improve the tracking speed, and through Matlabsimulation to verify the validity of the algorithm.The research shows that this algorithm can promote the tracking speed more obviously relative to perturbation and observation method in the photovoltaic power generation system at higher voltage levels.According to the characteristics of photovoltaic power generation system output characteristic curve of multi peak case,analysis of the performance of the algorithm,the simulation results show that the algorithm has the ability to find the optimal performance under the multi peak condition.