光伏并网逆变器的分析与研究毕业论文.doc

光伏并网逆变器的分析与研究 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。太阳能光伏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，以光伏并网发电系统为研究对象，对并网逆变器的主电路拓扑、控制策略、最大功率点跟踪和孤岛效应做了详细的分析研究。同时对逆变器主电路的拓扑结构做了MATLAB/Simulink的电路仿真分析，讨论了个别参数对电路的影响。 首先，本文介绍了国内外光伏并网发电产业的现状，并对光伏并网发电系统的组成结构、优缺点、发展趋势及光伏并网发电系统对逆变器的要求做了简单介绍，对光伏并网发电系统建立了总体认识。其次，讨论研究了逆变器主电路的拓扑形式，选择了无变压器的两级结构，即前级DC/DC变换器和后级DC/AC逆变器。前级DC/DC模块采用Boost升压斩波结构，后级的DC/AC逆变器采用全桥式逆变，并向电网输送功率。再次，讨论确定了逆变器电流电压双闭环的控制方式，并最终确定了光伏并网发电系统的总体方案。应用MATLAB/Simulink中的工具箱搭建了整个系统模型，进行了仿真实验研究，验证了实现并网逆变的可行性。最后，我们知道孤岛效应问题关系到光伏并网发电系统的安全问题，本文阐述了孤岛效应产生的原因、对电网的危害和目前各种常用的被动和主动及外部孤岛效应的检测方法，提出了添加反孤岛效应保护的必要性。 关键词：光伏逆变器，最大功率点跟踪，孤岛效应，Simulink仿真 ABSTRACT For the strenuous energy sources currently in the global scope,exploiting and utilizing the solar energy is paid more attention by many people than before. Photovoltaic(PV) generation, one important method of using solar energy, is very promising. Under this back ground, this paper bases on grid-connected PV system as research object and then does detail analysis from the main circuit topology of grid-connected system,control strategies, system parameters, anti-island effect as well as analysis. Firstly, the status of PV system home and abroad is introduced. The basic structure and types of the PV source, advantages and disadvantages, development trend, requirements on inverter are also presented. An over all under standing of the system is set up naturally. Secondly, this paper discusses the topology of the main circuit of the inverter and choose two stages transform structure, DC/DC converter with Boost topology structure and DC/AC inverter with full-bridge inverter. Then this paper discusses control mode of current-voltage double-loop and then determines the overall program of grid-connected PV system. Matlab/Simulink toolboxes are used to build the whole circuit model and the simulation study. Lastly, The paper analyzes the canses and effects as well as detection methods used now, such as passive and active and external islanding detection metho