| With the rapid development of economy and society,China's demand for energy is becoming stronger and stronger,but traditional fossil energy is drying up,and the large-scale application of fossil energy also seriously threatens the ecological balance of the earth.Since solar energy is a clean,safe,and easily accessible new type of renewable energy,countries around the world are accelerating the development of the photovoltaic industry.However,under complex lighting conditions,the photovoltaic power generation system is prone to power mismatch problems,which greatly increases the output power loss of the photovoltaic system.In severe cases,it will also lead to overheating and damage to the photovoltaic power generation system.one.The main research content of this paper is the analysis of mismatch characteristics of photovoltaic power generation system and power optimization control based on bypass diode reconstruction.The main contents are as follows:(1)Based on the physical principles of photovoltaic cells,establish a mathematical model and build a photovoltaic cell model on the Matlab / Simulink simulation platform to analyze the effects of radiation intensity and temperature on the output characteristics of photovoltaic cells.(2)Analysis of mismatch characteristics of photovoltaic power generation system is a prerequisite for optimizing the control system.This paper introduces the parameter of bypass diode conduction loss,proposes and establishes a PI segmentation model of mismatch output characteristics of photovoltaic arrays under complex light conditions.Set up a test model in Matlab / Simulink environment.According to the P-I segmented model,the effect of the bypass diode on the output power of the photovoltaic array is analyzed,and the conduction loss and bypass loss of the photovoltaic array under different bypass diode configuration modes are analyzed.Based on the above research,this paper starts from reducing the power loss of photovoltaic arrays under complex lighting conditions,researches the optimal configuration mode of bypass diodes,and proposes a bypass diode reconstruction scheme based on irradiance distribution.The validity of the method is verified by simulation.Themain innovation of this solution is to reduce the bypass loss and the conduction loss of the photovoltaic array,and improve the output power of the photovoltaic array under various complex lighting.(3)According to the relationship between the working current,the short-circuit current of each module and the maximum power point based on the P-I segmental model,a bypass diode reconstruction scheme and power optimization control strategy based on the irradiance distribution are proposed.The power optimization control system is designed,and the reconstruction and optimization steps are given.By using the bypass diode reconstruction control system to predict the position of the maximum power point,the large-scale multi-peak optimization problem is transformed into a small-range single-peak optimization problem,and the perturbation observation method is used for optimization,which improves the tracking efficiency of the maximum power point algorithm.Simulation results show that this method can effectively increase the output power of photovoltaic arrays in complex shadow mode,and has a certain improvement over the tracking speed of the classic particle swarm algorithm.(4)The optimized control system for small photovoltaic modules was built,and the physical test was completed.Considering the special requirements of the design scheme of this paper,while considering cost control,each hardware functional module is designed,including the main controller module,BOOST circuit module,multi-channel signal processing module,photovoltaic array module with reconstruction structure,etc.After physical experiment verification and data analysis,the system designed in this paper can effectively increase the output power of the photovoltaic array under complex lighting conditions and achieve faster maximum power point tracking. |
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