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光伏发电跟踪系统的设计
摘要
太阳能作为一种可以永续使用的绿色可再生能源，有着巨大的开发应用潜力。但由于光伏电池的输出特性与外界环境因素的变化有很大关系，目前大规模量产的光伏电池光电转换效率仍然不高且价格昂贵。光伏发电自动跟踪装置是提高太阳能利用率，降低光伏发电成本的有效途径。研究精确的太阳跟踪装置，可使光伏电池板接收到更多的太阳辐射能量，增加发电量。本文实现了用廉价的光敏元件和单片机电路进行太阳跟踪的功能。
本文首先分析了太阳运行规律，在对比目前常用跟踪方法的基础上，采用光电检测方式为主，并与视日运动轨迹追踪方式相结合的跟踪策略，改进了以往的跟踪方式。使系统不仅能在晴天下追踪太阳，阴天情况下也能正常追踪。此外，为了确保跟踪的结果准确，在方位角和高度角调整之后，增加了一组传感器电路进行跟踪结果的验证。
通过对控制系统所实现的功能分析，论文完成了跟踪系统的硬件和软件设计。主要内容包括：单片机接口电路设计、显示电路、光强检测电路设计、控制执行部件设计以及光电跟踪和视日运动轨迹跟踪模块的软件设计。最后还根据实际情况提出了改进方案和处理快云遮问题的新方法。
本文所设计的光伏发电自动跟踪系统结构简单，成本低廉，运行稳定，可广泛应用于并网和离网光伏发电系统。
关键词 光伏发电；跟踪系统；光电检测；单片机
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Design of Photovoltaic Automatic Tracking System
Abstract
The solar energy has an enormous developing application capacity as one kind of green renewable energy source which can be continuously used forever. But there is tremendous relationship between photovoltaic cells output characteristicsand the change of external environmental factors, currently the efficiency of PV cells is not only low but also expensive on a large scale of production. The photovoltaic automatically tracking device can raise the solar energy utilization rate and bring down the cost of the solar electrical energy generation. Precise solar tracking mechanism can make solar panel receive more radiant energy and increase generating capacity. This paper makes use of cheap photo sensors and MCU circuit to realize the function of sun tracking.
Analyzed the law of the sun, compared the current tracking methods, Proposed electro-optical tracking as the major tracking mode while the sun trajectory tracking mode as additional tracking mode on unusual weather conditions，improved the previous tracking mode in the paper. Through two complementary tracking modes, on the one hand, electro-optical tracking can give full play to the advantages of high accuracy; on the other hand, the system can still achieve tracking on cloudy weather conditions. In addition, In order to guarantee that the track result is accurate, after azimuth and elevation angle adjustment, increased a group of sensor electric circuit to carry on the track result confirmation.
Through the implementation of functional analysis of control system, the thesis completed hardware and software design of the tracking device. Include: MCU interface circuit design, display circuit design, optical detector circuit design, control and implementation component design and the software design of electro-optical tracking and sun trajectory tracking module. Finally, proposed improvement program and new method to treat fast cloud according to the tracking effect of the trial.
In this paper, the designs of photovoltaic automatic tracking device have simple structure, low cost and stable operation. The device can be widely applied to grid and off-grid PV power system.
Keywords Photovoltaic；Track system；Photoelectricity examination；MCU
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目录
摘要…… ......................................................................................................................... I Abstract .......................................................................................................................... II
第1章 绪论 ................................................................................................................... 1 1.1 课题背景 .............................................................................................................. 1 1.2 光伏发电的特点 .................................................................................................. 2 1.2.1 光伏发电的优点 ........................................................................................... 2 1.2.2 光伏发电存在的问题 ................................................................................... 2 1.3 光伏发电自动跟踪技术的发展 .......................................................................... 3 1.3.1 光伏发电的发展现状 ................................................................................... 3 1.3.2 光伏发电自动跟踪技术现状 ....................................................................... 4 1.4 论文的研究内容 .................................................................................................. 6 第2章 太阳跟踪系统的总体设计 ............................................................................... 7 2.1 日照时间和太阳位置的计算 .............................................................................. 7 2.2 太阳运行轨迹的跟踪方式 .................................................................................. 8 2.2.1 视日运动轨迹跟踪 ....................................................................................... 8 2.2.2 光电跟踪 ..................................................................................................... 10 2.2.3 视日运动轨迹跟踪与光电跟踪相结合 ..................................................... 10 2.3 控制系统总体设计 ............................................................................................ 12 2.3.1 控制系统开发流程 ..................................................................................... 12 2.3.2 系统的总体设计 ......................................................................................... 12 2.4 本章小结 ............................................................................................................ 13 第3章 单片机系统的硬件设计 ................................................................................. 14 3.1 控制系统硬件总体设计 .................................................................................... 14 3.2 控制系统核心部件的选择 ................................................................................ 15 3.3 单片机接口电路设计 ........................................................................................ 15 3.3.1 电源电路 ..................................................................................................... 15 3.3.2 串口通讯电路 ............................................................................................. 16 3.3.3 系统抗干扰设计 ......................................................................................... 17 3.3.4 实时时钟电路 ............................................................................................. 19 3.4 显示电路设计 .................................................................................................... 20 3.5 光强检测电路设计 ............................................................................................ 21 3.5.1 光敏传感器的选择 ..................................................................................... 21 3.5.2 光强检测电路设计 ..................................................................................... 21 3.6 控制执行部件设计 ............................................................................................ 25 3.6.1 步进电机驱动控制系统 ............................................................................. 25 3.6.2 本系统所采用的步进电机及驱动模块 ..................................................... 26
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