【作者】 李坤；

【导师】 李春茂；

【作者基本信息】 西南交通大学 ， 电力系统及其自动化， 2013， 硕士

【摘要】 改革开放以来我国经济的快速增长,促使电力需求迅猛增长与电网规模的不断扩大。但是大规模电力系统的缺点也越来越明显,建设成本高,运行难度大,以及难以满足用户日益增加的用电安全性和可靠性要求以及多样化需求。特别是近年来世界上发生的大面积停电事故造成的灾难性后果也充分地暴露了现有电网结构的脆弱性。分布式发电系统与传统集中单一的供电系统相比,其发电单元相互独立,可自行控制,不会发生大规模停电事故,安全可靠性较高：分布式发电可以弥补大电网安全稳定性的不足,可在意外灾难发生时继续供电；分布式电源位置灵活、分散,适合偏远地区,中小城市的居民供电,可大大减小环境污染；分布式发电输配电损耗低,大大降低了输配电成本和安装成本。虽然与大电网相比,分布式发电具有这么多优势,但大量分布式电源的并网也给电力系统的保护、实时调度和电网可靠性等各方面带来了许多问题,因此为了充分发挥分布式发电的优势的同时又能降低分布式电源对大电网的冲击和影响,目前将分布式电源和负载结合起来建立微电网(Microgrid)是解决这些问题较好的途径。本文以在充分了解微电网结构和电网结构以及相关电力电子设备性能、可靠性的基础上,以仿真手段为主,完成微电网多种微电源建模仿真、并网和孤岛运行控制等研究。主要工作包括：(1)介绍了微电网提出的背景和意义,国外内研究现状与微电网结构和关键技术。(2)建立了光伏电池的通用模型,分析光伏电池输出特性,并基于Boost变换器采用增量导纳法实现了光伏电池的最大功率点跟踪,比较了爬山法和增量导纳法的优缺点,选取增量导纳法来实现光伏电池最大功率点跟踪；介绍了双馈风力发电机基本原理与矢量控制坐标变换关系,建立双馈风力发电机S函数的空载和带负载模型。(3)介绍了DC/DC变换器原理,然后分析了LC滤波器的设计方法、dq变换技术和并网控制理论,并建立等效直流源的单相并网模型加以验证。(4)根据所用的光伏电池和风力发电机并网控制策略在MATLAB/Simulink建立仿真模型,实现了光伏电池三相并网与双馈风力机空载和带负载并网,并且完成了带负载并网后最大风能追踪控制。(5)研究微电网孤岛运行时微电源控制方法—V/f控制和Droop控制,建立微电网孤岛运行不同工况仿真模型,验证所用控制策略的有效性。更多还原

【Abstract】 Since the reform and opening up the rapid growth of economy in our country, promoted electricity demand rapid growth and the continuous expansion of grid. But the disadvantages of large power system is becoming more and more apparent, the construction cost is high, operation is difficult, and difficult to satisfy the increasingly safe and reliable and diversified demands of users for electricity. Especially in recent years, large area blackout accidents happened in the world of catastrophic consequences also fully exposed the vulnerability of the existing grid structures.Distributed power generation system is compared with the single and centralized traditional power supply system, the power generation units are independent, can control by itsself, don’t occur a massive power outage, have higher safety and reliability; Distributed generation can make up for a lack of security on the stability of interconnected power grid, may continue power supply when the unexpected disaster; Distributed power positions are flexible and dispersion, suitable for remote areas and power supply of the small and medium-sized cities, can greatly reduce the pollution of the environment; Transmission and distribution losses of distributed generations are low, greatly reduces the transmission and distribution cost and installation cost. Although compared with the large power grid, distributed generation has so many advantages, but also a large number of distributed power’s access bring many problems for grid protection and real time scheduling and power grid reliability and so on, so in order to give full play to the advantages of distributed generation and can reduce the impact and influence of distributed power for grid, currenttly combined distributed power supply and loads to construct microgrid (Microgrid) is a better way to solve these problems.Based on fully understanding the microgrid structures and the power grid structure and the related power electronics equipments of performances and reliabilities, with simulation methods mainly,this paper completed various micro energy resources’s modeling and simulation, grid-connection and island operation control.Main works include:(1) Introduced the background of microgrid, domestic and foreign research present situation and key technology.(2) Constructed the general model of photovoltaic cells, analyzed photovoltaic battery output characteristic, and realized the maximum power point tracking of photovoltaic cells based on the Boost converter using the incremental conductance method, compared the advantages and disadvantages of mountain climbing method and incremental conductance method, selected the increment conductance method to achieve photovoltaic cell’s maximum power point tracking; Introduced the basic principle of doubly-fed wind generator and vector control coordinate transformation relations, constructed no-load model of doubly-fed wind turbine with S function.(3)Introduced the principle of the DC/DC converter, then analyzed the design method of LC filter, dq transformation technology and the grid control theory, finally constructed a single-phase grid-connection for the DC source equivalent model to verify grid control theory.(4)Designed the grid-connection control strategies of photovoltaic cell and doubly-fed wind generator and constructed simulation model in MATLAB/Simulink, verified the correctness of the designed control schemes,and completed maximum wind power tracking control after the grid-connection with load.(5) Studied DER’ control method of microgrid island operation—V/f control and Droop control, constructed microgrid island operation simulation model in different operating mode,verified the validity of the designed control strategy.更多还原