光伏微网柔性变流器并网运行混成控制研究

发布时间：2018-11-16 16:05

【摘要】：太阳能光伏发电由于资源丰富、分布广泛、建设简单、环境友好等优点,大力发展光伏发电技术已渐渐为世界所共识。分布式光伏发电以微网形式接入主电网是提高其效能的最有效措施。由于光伏发电的随机性与间歇性特征,光伏微网并网会出现各种电能质量问题,因此,对光伏微网并网功率接口及其控制方法的研究成为了一个热点课题。论文以并网柔性变流器为研究对象,开展光伏微网柔性变流器并网运行混成控制的理论和方法研究,不仅具有极其重要的学术意义,还且具有非常广泛的应用前景。首先,论文深入调研了光伏微网产生和发展的背景、概念以及国内外发展现状；综述了微网常规并网功率接口及其一般控制方法；着重探索了柔性变流器理论的基本思想、分类、原理以及研究现状,深入研究了并网柔性变流器基本拓扑与工作原理。其次,介绍了混成系统理论的概念、模型、分类、控制方法,详细分析了光伏微网柔性变流器并网运行系统的混成特性,结合并网柔性变流器中三相全桥逆变器的工作模态和混成控制决策机制,建立了三相全桥逆变器的混成自动机模型,深入研究了并网柔性变流器的离散控制器和连续控制器的设计方法；最后,运用Matlab/Simulink软件搭建了100kVA光伏微网并网运行系统的仿真模型,并针对系统不同的运行模式和工作情况进行了仿真分析。论文探索的光伏微网柔性变流器并网功率接口,是一种高性能的电力电子功率接口,具有根据光伏电源输出容量或其他外部信息自主调节其输出功能的能力；本文深入研究了光伏微网柔性变流器并网运行混成控制方法,能够客观、精细地描述光伏微网柔性变流器并网运行系统的连续特性、离散特征及其相互作用,设计的混成控制器集柔性并网变流器的功率控制、电能质量控制、运行模式切换控制等多功能控制于一体,具有控制精度高、鲁棒性强、实现容易等优势。仿真结果验证了其正确性、有效性和可行性。
[Abstract]:Due to the advantages of abundant resources, wide distribution, simple construction and friendly environment, the development of solar photovoltaic power generation technology has gradually become a common understanding in the world. The most effective way to improve the efficiency of distributed photovoltaic power generation is to connect it to the main grid in the form of microgrid. Because of the randomness and intermittency of photovoltaic power generation, there will be a variety of power quality problems in grid-connected photovoltaic microgrid. Therefore, the research on the grid-connected power interface and its control methods of photovoltaic microgrid has become a hot topic. This paper takes the grid-connected flexible converter as the research object, carries out the research on the theory and method of grid-connected hybrid control of photovoltaic microgrid flexible converter, which not only has extremely important academic significance, but also has a very wide application prospect. Firstly, the background, concept and status quo of photovoltaic microgrid generation and development are investigated, and the conventional grid-connected power interface and its control methods are summarized. The basic idea, classification, principle and research status of flexible converter theory are emphatically explored, and the basic topology and working principle of grid-connected flexible converter are deeply studied. Secondly, the concept, model, classification, control method of hybrid system theory are introduced, and the hybrid characteristics of photovoltaic microgrid flexible converter grid-connected operation system are analyzed in detail. Combined with the mode of three-phase full-bridge inverter and the decision-making mechanism of hybrid control in grid-connected flexible converter, a hybrid automaton model of three-phase full-bridge inverter is established. The design methods of discrete controller and continuous controller of grid-connected flexible converter are studied. Finally, the simulation model of 100kVA photovoltaic microgrid operation system is built by using Matlab/Simulink software, and the different operation modes and working conditions of the system are simulated and analyzed. The grid-connected power interface of photovoltaic microgrid flexible converter is a high performance power interface of power electronics. It has the ability to adjust its output function according to the output capacity of photovoltaic power supply or other external information. In this paper, the hybrid control method for grid-connected flexible photovoltaic converters is studied, which can describe the continuous characteristics, discrete characteristics and interaction of grid-connected flexible photovoltaic converters objectively and accurately. The designed hybrid controller integrates the power control, power quality control and operation mode switching control of the flexible grid-connected converter. It has the advantages of high control precision, strong robustness and easy implementation. The simulation results show that it is correct, effective and feasible.
【学位授予单位】：长沙理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM615;TM46

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