光伏并网逆变器的设计----最终论文.docVIP

摘 要 针对全球范围内能源紧张的局面，开发利用太阳能越来越受到重视。太阳能 并网发电是太阳能利用的主要形式，具有广阔的发展前景。本文就是在此背景下，对太阳能并网发电系统的核心器件并网逆变器进行研究。 本文对逆变器的电路拓扑结构、最大功率点跟踪、并网控制方案以及在并网过程的反孤岛技术进行了分析研究。 首先，简述了国内外光伏发电的现状和发展趋势，根据单相光伏并网发电系 的特点，本文选择了合适的主电路拓扑结构，该结构没有变压器，具有体积小、本低、控制方案易实现等优点。 其次，通过比较分析目前太阳能电池进行最大功率跟踪的各种传统方法，理论上证明了通过调节DC／DC升压电路的占空比可以改变太阳能电池的输出功率，以使太阳能电工作于最大输出功率点上。 最后，本文对光伏并网逆变器的控制方案进行了分析，以TL494为核心控制芯片对输出电流和最大功率点电压进行控制，采用了基于SPWM的电流输出控制算法，该方法具有开关频率固定、物理意义清晰、实现方便等优点。 关键词：光伏逆变器；最大功率点跟踪(MPPT)；并网运行；孤岛效应； Abstract For the strenuous energy sources currently in the global scope,exploiting and utilizing the solar energy is paid more arrention by many people than before.Photovoltaic generation, one important method of using solar energy, is very promising. Under this background, the dissertation deeply researches the pv grid-connected inverter, maximum power point tracing, the control method of the inverter and the technology of grid-connected such as anti-island. In this paper, the inverter circuit topology, the maximum power point tracking, and network control programs and in the process of anti-islanding grid technology is analyzed. Firstly,it briefly introduces the present situation and the development prospects of Photovoltaic generating at home and abroad．Based on the character of single．phase PV grid—connected system，the paper expatiated a suitable topological construction，which doesn’t use the transformer with features which the small size，low cost and easy control strategy and so on． Secondly,by comparing many different traditional methods，In this thesis，it is demonstrated theoretically that the maximum power-output can be matched by adjusting the duty ratio of the DC／DC circuit．This paper presents the needed of anti-islandingeffect，analyses the active and passive detecting methods separately,then verifies the validity of the active frequency drift with periodical disturbance and positive feedback method． Finally，In this paper, photovoltaic inverter control scheme is analyzed，To the core contro