独立光伏系统充电控制器的设计

发布时间：2018-01-05 04:16

本文关键词：独立光伏系统充电控制器的设计　出处：《厦门理工学院》2017年硕士论文　论文类型：学位论文

【摘要】：在能源快速消耗和环境问题日益严重的今天,太阳能因清洁、可再生等优点,深受人们关注,光伏发电作为太阳能的一种有效利用方式,得到了迅速的发展。最大功率点追踪(Maximum Power Point Tracking,MPPT)技术能够最大化的将太阳能转换为电能,提高光伏发电效率,因而在光伏发电系统中获得普遍应用,具体表现在三个方面:一是采用MPPT技术直接为负载供电;二是利用MPPT技术对蓄电池进行充电;三是在光伏并网系统中利用MPPT技术对电网输送电能。本文以独立光伏系统对铅酸蓄电池充电作为研究对象,针对光伏电池最大功率追踪和蓄电池充电方法等一些关键技术进行了研究,提出了一种以飞思卡尔MK02单片机为控制芯片的独立光伏发电系统的实现方案。文中首先介绍了太阳能电池的工作原理和输出特性,对传统的MPPT的原理和实现方法的优缺点进行了对比分析,本文的MPPT方法采用了一种通过获取DC/DC电路最大输出电流实现,该方法控制实现更为简单且能有效降低硬件成本。同时,也对铅酸蓄电池的充电方法进行了深入的探索,在传统三阶段充电方法上,结合光伏系统最大功率的特殊背景,提出了一种三段式的光伏充电方法,在最大功率追踪过程中加入了限流功能,防止过流充电对蓄电池构成损坏。其次,选用BUCK拓扑结构作为主功率电路,介绍了调节占空比以实现光伏电池最大功率输出的原理,还对控制电路部分进行了设计,其中详细介绍了基于UC3843的反激式电源的设计。此外,结合飞思卡尔官方提供的软件开发工具,完成了最大功率追踪算法和充电算法软件代码的编写,论文给出了有关程序的流程图。最后,搭建系统测试平台,利用太阳能光伏模拟器和光伏阵列对最大功率追踪和三段式充电进行了验证。测试结果表明本文的算法能够实现对最大功率的准确追踪,充电电流也能控制在限定的范围之内,且能够根据蓄电池的电压状态切换到对应的充电阶段,证实了论文所提出的设计方案是切实可行的。
[Abstract]:With the rapid consumption of energy and the increasingly serious environmental problems, solar energy, due to the advantages of clean, renewable and so on, is deeply concerned by people. Photovoltaic power generation as an effective use of solar energy. The maximum Power Point tracking (MPPTT) technology maximizes the conversion of solar energy to electricity. Improve the efficiency of photovoltaic generation, so it has been widely used in photovoltaic power generation system, the specific performance in three aspects: first, the use of MPPT technology directly for load supply; Second, using MPPT technology to charge the battery; The third is the use of MPPT technology to transmit electricity to the power grid in the photovoltaic grid-connected system. This paper takes the independent photovoltaic system to charge the lead-acid battery as the research object. Some key technologies such as maximum power tracking and battery charging are studied. An independent photovoltaic system with Freescale MK02 microcontroller as the control chip is proposed. The working principle and output characteristics of the solar cell are first introduced in this paper. The advantages and disadvantages of the traditional MPPT principle and realization method are compared and analyzed. The MPPT method in this paper is realized by obtaining the maximum output current of the DC/DC circuit. This method is more simple to realize and can effectively reduce the cost of hardware. At the same time, the charging method of lead-acid battery is deeply explored, in the traditional three-stage charging method. Combined with the special background of the maximum power of photovoltaic system, a three-stage photovoltaic charging method is proposed. In the process of maximum power tracking, the current limiting function is added to prevent overcurrent charging from damage to the battery. Secondly. BUCK topology is selected as the main power circuit. The principle of adjusting duty cycle to realize the maximum power output of photovoltaic cell is introduced. The control circuit is also designed. The design of flyback power supply based on UC3843 is introduced in detail. In addition, the maximum power tracking algorithm and the software code of charging algorithm are completed in combination with the software development tools provided by Freescale. The flow chart of the program is given in this paper. Finally, the system testing platform is built. The maximum power tracking and three-stage charging are verified by solar photovoltaic simulator and photovoltaic array. The test results show that the proposed algorithm can accurately track the maximum power. The charging current can also be controlled within a limited range and can be switched to the corresponding charging stage according to the voltage state of the battery, which proves the feasibility of the design scheme proposed in this paper.
【学位授予单位】：厦门理工学院
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM615;TM910.6

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