光伏发电系统及其最大功率跟踪控制的研究

发布时间：2018-03-05 23:37

本文选题：铅酸蓄电池　切入点：DC/DC转换电路　出处：《华侨大学》2014年硕士论文　论文类型：学位论文

【摘要】：太阳能是一种绿色可再生能源，具有无污染、无噪音、无需生产原料等优点，太阳能的应用已经成为新能源领域的研究热点。光伏发电是人类利用太阳能的一种最主要的方式，进入二十一世纪后，光伏产业在世界各国都得到了迅猛发展。然而，目前太阳能电池的生产成本仍然比较高、转换效率较低，为了更有效的利用太阳能，提高光伏发电系统的转换效率，采用最大功率跟踪技术就尤为必要。光伏发电系统中太阳能电池直接将太阳能转变成电能。太阳能电池输出特性受光照强度、环境温度和负载情况影响，具有明显的非线性特征。当外界环境发生变化时，其工作电压和输出功率会发生变化，因此，利用最大功率跟踪控制技术，实时调整太阳能电池工作点，使其始终工作在最大功率点附近，提高光伏发电系统效率。本文基于KNT-SPV01光伏发电系统，对光伏发电系统原理、系统组成进行了理论分析，同时对最大功率跟踪控制技术进行了深入的研究，完成了带有最大功率跟踪控制器的小型太阳能光伏发电系统的设计。具体内容如下： 1.研究分析太阳能电池的主要特性参数，并在不同光照强度、温度等外界条件下，实际测试得到太阳能电池的输出特性曲线，验证了太阳能电池的输出特性曲线受外界条件影响且具有非线性的特性，证明了进行最大功率跟踪控制的可行性和必要性。分析了太阳能电池的原理，且针对SFM250W蓄电池，设计了其充放电保护电路，提高电池的使用寿命。 2.介绍了三种DC/DC转换电路的工作原理和等效电路，比较了它们的优缺点。选择升降压式DC/DC转换电路作为本课题的直流转换电路。 3.对几种常用的最大功率跟踪控制算法进行比较，如恒压跟踪法、导纳增量法、实际测量法、扰动观察法等，分析其工作原理及优缺点。并在扰动观察算法的基础上，提出了“变步长”扰动观察法改进算法，避免最大功率点的“误判”，，提高跟踪控制的速度和精度。 4.设计了一套小型太阳能光伏发电系统，设计制作了最大功率点跟踪控制器的硬件电路，实现跟踪控制太阳能电池的最大功率点。通过最大功率跟踪控制实验，结果说明该系统可以有效地提高响应速度和跟踪精度，提高太阳能光伏发电系统的工作效率。
[Abstract]:Solar energy is a kind of green renewable energy, which has the advantages of no pollution, no noise, no raw materials and so on. The application of solar energy has become a research hotspot in the field of new energy. Photovoltaic power generation is the most important way for human to use solar energy. Since 21th century, the photovoltaic industry has developed rapidly all over the world. However, at present, the production cost of solar cells is still relatively high, the conversion efficiency is low, in order to make more effective use of solar energy, In order to improve the conversion efficiency of photovoltaic power generation system, it is necessary to adopt maximum power tracking technology. Solar cells directly convert solar energy into electric energy in photovoltaic power generation system. The output characteristics of solar cells are influenced by light intensity, ambient temperature and load, and have obvious nonlinear characteristics. Therefore, the maximum power tracking control technology is used to adjust the working point of the solar cell in real time, so that it can always work near the maximum power point to improve the efficiency of photovoltaic power generation system. Based on KNT-SPV01 photovoltaic power generation system, the principle and system composition of photovoltaic power generation system are analyzed theoretically, and the maximum power tracking control technology is studied deeply. The design of a small solar photovoltaic power generation system with a maximum power tracking controller is completed. The details are as follows:. 1. The main characteristic parameters of solar cell are studied and analyzed, and the output characteristic curve of solar cell is obtained under different light intensity and temperature. It is verified that the output characteristic curve of solar cell is influenced by external conditions and has nonlinear characteristics. The feasibility and necessity of maximum power tracking control are proved. The principle of solar cell is analyzed, and the principle of SFM250W battery is analyzed. The charge-discharge protection circuit is designed to improve the battery life. 2. The working principle and equivalent circuit of three DC/DC converters are introduced, and their advantages and disadvantages are compared. 3. Compare several commonly used maximum power tracking control algorithms, such as constant pressure tracking method, admittance increment method, actual measurement method, disturbance observation method, etc. An improved algorithm of "variable step size" perturbation observation method is proposed to avoid "misjudgment" of maximum power points and to improve the speed and accuracy of tracking control. 4. A set of small solar photovoltaic power generation system is designed, and the hardware circuit of the maximum power point tracking controller is designed, which can track and control the maximum power point of solar cell. The results show that the system can effectively improve the response speed and tracking accuracy, and improve the efficiency of solar photovoltaic power generation system.
【学位授予单位】：华侨大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM615

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