局部阴影下光伏阵列输出特性及最大功率追踪的研究

发布时间：2018-05-07 09:33

本文选题：局部阴影 + 光伏发电　；参考：《华北电力大学》2017年硕士论文

【摘要】：传统化石能源的大量使用,造成了环境污染以及资源枯竭等问题,使得光伏发电等新技术在能源结构中占有了日益重要的地位。作为光伏发电系统的重要技术环节,光伏阵列的最大功率追踪技术一直都是研究的热点。但是,当光伏阵列处于局部阴影条件下时,其输出特性曲线会出现多个功率极值点的情况,传统的最大功率追踪技术易陷于局部最优值点,造成发电能量的浪费。因此,局部阴影下光伏阵列输出特性及最大功率追踪的研究,具有重要意义。本文首先阐述了光伏发电的研究背景和意义,详细介绍了传统最大功率追踪技术的原理和优缺点,并分析了国内外关于MPPT技术的研究现状。其次,分析了光伏电池的物理特性、工作原理和数学模型,以及最大功率追踪所涉及到的功率变流器的工作原理。在MATLAB/Simulink中建立了单位光伏电池组件的仿真模型,基于因不同光照强度所造成的电池工作温度差异,提出了仿真模型的局部改进策略,并验证其合理性。然后,针对实际工作环境中,由积状云层所造成的阴影遮蔽现象,进行了各种规模的光伏阵列在复杂阴影条件下的仿真。根据局部阴影条件下光伏阵列的输出特性,对功率极值点的最大数目以及分布规律进行了详细研究,并针对光伏阵列功率极值点出现和消失的原因进行了分析。最后,研究了常规粒子群算法的基本特性、原理以及设计流程,针对其收敛速度慢以及部分粒子易陷于局部最优解的问题,将混沌算法与粒子群算法相结合,提出了一种改进混沌粒子群算法,并将其应用于局部阴影条件下最大功率追踪的研究中,设计了基于改进混沌粒子群算法的最大功率追踪策略。通过MATLAB编程的方式,针对光伏阵列在各种阴影条件下的输出特性曲线进行仿真研究。结果表明,与常规粒子群算法相比,该方法能够使粒子跳出局部极值点,准确、迅速地找到全局最大值点,并且能够控制光伏阵列的输出电压稳定在最大功率点电压,证明了算法的优越性和有效性,提高了光伏系统的发电效率。
[Abstract]:The extensive use of traditional fossil energy has caused environmental pollution and resource depletion, which makes photovoltaic power generation and other new technologies play an increasingly important role in the energy structure. As an important part of photovoltaic power generation system, the maximum power tracing technology of photovoltaic array is always a hot topic. However, when the photovoltaic array is in the condition of local shadow, the output characteristic curve of the photovoltaic array will have multiple power extremum points. The traditional maximum power tracing technology is prone to get into the local optimal point, resulting in the waste of power generation energy. Therefore, it is of great significance to study the output characteristics and maximum power tracking of photovoltaic arrays under local shadows. In this paper, the research background and significance of photovoltaic power generation are introduced, the principle, advantages and disadvantages of traditional maximum power tracking technology are introduced in detail, and the research status of MPPT technology at home and abroad is analyzed. Secondly, the physical characteristics, working principle and mathematical model of photovoltaic cell are analyzed, as well as the working principle of power converter involved in maximum power tracing. The simulation model of unit photovoltaic cell module is established in MATLAB/Simulink. Based on the difference of operating temperature caused by different light intensity, the local improvement strategy of the simulation model is proposed, and the rationality of the simulation model is verified. Then, aiming at the shadow shadowing phenomenon caused by the accumulated clouds in the actual working environment, the simulation of photovoltaic arrays of various sizes under complex shadow conditions is carried out. According to the output characteristics of photovoltaic array under the condition of local shadow, the maximum number and distribution of power extremum are studied in detail, and the reasons for the emergence and disappearance of power extremum of photovoltaic array are analyzed. Finally, the basic characteristics, principle and design flow of the conventional particle swarm optimization (PSO) algorithm are studied. The chaotic algorithm is combined with the PSO algorithm in view of the slow convergence rate and the local optimal solution of some particles. An improved chaotic particle swarm optimization (PSO) algorithm is proposed and applied to the study of maximum power tracking under local shadow conditions. The maximum power tracking strategy based on improved chaotic PSO algorithm is designed. The output characteristic curve of photovoltaic array under various shadow conditions is simulated by MATLAB programming. The results show that compared with the conventional particle swarm optimization algorithm, the proposed method can make the particle jump out of the local extremum, find the global maximum point accurately and quickly, and control the output voltage of the photovoltaic array to stabilize at the maximum power point voltage. The superiority and effectiveness of the algorithm are proved, and the efficiency of photovoltaic system is improved.
【学位授予单位】：华北电力大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM615

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