微电网建模及其运行和控制的仿真

发布时间：2019-02-23 23:41

【摘要】：能源是现代社会和经济发展的动力,是人类生命存在和繁衍的生命线。传统化石能源的逐步耗竭,使能源危机已逐步逼近。中国21世纪的能源工业将是能源资源利用与环境保护可持续发展的改造型新工业,因此,合理调整能源结构,大力开发可再生能源和其它新能源,走多元化洁净能源发展道路,是我国社会可持续发展的必由之路。在此背景下分布式电源得到大力开发,但是分布式电源存在接入成本高、不易控制等缺点,并且,大系统不正常运行时,分布式电源必须马上退出运行,极大地限制了分布式电源的利用效率。微电网应运而生,微电网是一种新型的网络结构,是一组由微电源、负荷、储能系统和控制装置构成的系统单元。微电网中的电源多为分布式电源,即含有电力电子接口的小型机组,包括微型燃气轮机、燃料电池、光伏电池、风力发电机组以及超级电容、飞轮及蓄电池等储能装置,它们接在用户侧,具有成本低、电压低及污染低等特点。开发和延伸微电网能够促进分布式电源与可再生能源的大规模接入,实现对负荷多种能源形式的高可靠供给,是实现主动式配电网的一种有效的方式,使传统电网向智能电网过渡。本文在微电网的大背景下,分析了微电网系统的数学模型及不同的运行与控制策略,然后建立了相应的仿真模型进行验证。首先,对微电网进行了建模。分析了如今最为普遍应用的双馈风力发电机,从其基本原理和结构入手进行分析,建立了其风力机数学模型、风速模型,变桨距控制模型和双馈发电机模型,基于上述数学模型,在电力系统仿真软件PACAD中搭建了双馈风力发电系统的仿真模型；随后分析了光伏电池、微型燃气轮机和燃料电池的工作原理、发电特性和数学模型,并在PSCAD中搭建了仿真模型；又对常见的储能设备—超级电容器,建立了数学模型,并进行了验证分析。然后,基于微电网各个子系统的数学模型,对微电源进行了控制策略的分析,主要分为以下三种控制方式：恒功率(P/Q)控制、电压频率(U/f)控制和下垂(Droop)控制控制；随后给出了几种微电网的整体控制策略,根据本文微电源的特点,选择了主从控制作为本文的微电网整体控制策略；基于主从控制策略,建立了微电源的核心控制方式,并改进了主控制单元的超级电容控制器,用于提供稳定的电压和频率的支撑。最后,根据已建立的数学模型和控制模型,在PSCAD中建立了微电网的整体仿真模型,并对微电网的运行与控制进行仿真分析,包括：孤岛和并网模式切换的仿真、频率稳定性仿真和电压稳定性仿真,验证了数学模型和控制策略的有效性。
[Abstract]:Energy is the power of modern society and economic development, and the lifeline of human life. With the gradual depletion of traditional fossil energy, the energy crisis has gradually approached. China's energy industry in the 21st century will be a reformed new industry for the sustainable development of energy and resources utilization and environmental protection. Therefore, we should rationally adjust the energy structure, vigorously develop renewable energy and other new sources of energy, and take a diversified path of clean energy development. It is the only way to the sustainable development of our society. In this context, the distributed power supply has been developed vigorously, but the distributed power supply has the disadvantages of high access cost, difficult to control and so on. Moreover, when the large system is not working normally, the distributed power supply must be withdrawn from operation immediately. The efficiency of distributed power generation is greatly limited. Microgrid emerges as the times require. Microgrid is a new type of network structure. It is a group of system units composed of micro-power supply, load, energy storage system and control device. Most of the power sources in the microgrid are distributed generation, that is, small units with power electronic interfaces, including micro gas turbines, fuel cells, photovoltaic cells, wind turbines and energy storage devices such as super capacitors, flywheels and batteries, etc. They are connected to the user side, with low cost, low voltage and low pollution. The development and extension of microgrid can promote the large-scale access of distributed generation and renewable energy, and realize the high reliable supply of various forms of load energy. It is an effective way to realize active distribution network. The transition of traditional power grid to smart grid. In this paper, under the background of microgrid, the mathematical model and different operation and control strategies of microgrid system are analyzed, and then the corresponding simulation model is established to verify it. Firstly, the micro-grid is modeled. Based on the analysis of the basic principle and structure of doubly-fed wind turbine, the mathematical model of wind turbine, wind speed model, variable pitch control model and doubly-fed generator model are established. Based on the above mathematical model, the simulation model of doubly-fed wind power generation system is built in the power system simulation software PACAD. Then, the working principle, generation characteristics and mathematical model of photovoltaic cell, micro gas turbine and fuel cell are analyzed, and the simulation model is built in PSCAD. The mathematical model of supercapacitor, which is a common energy storage equipment, is established and verified. Then, based on the mathematical model of each subsystem of microgrid, the control strategy of micro-power supply is analyzed, which is divided into the following three control modes: constant power (P / Q) control. Voltage frequency (U / F) control and droop (Droop) control; Then, several control strategies of microgrid are given. According to the characteristics of micro-power supply in this paper, master-slave control is chosen as the overall control strategy of micro-grid. Based on the master-slave control strategy, the core control mode of micro-power supply is established, and the supercapacitor controller of the main control unit is improved to provide stable voltage and frequency support. Finally, according to the established mathematical model and control model, the whole simulation model of microgrid is established in PSCAD, and the operation and control of microgrid are simulated and analyzed, including the simulation of islanding and grid-connected mode switching. Frequency stability simulation and voltage stability simulation verify the effectiveness of the mathematical model and control strategy.
【学位授予单位】：山东大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM743

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