【作者】 郑燕；

【导师】 祝龙记；

【作者基本信息】 安徽理工大学 ， 电气工程， 2015， 硕士

【摘要】 由于太阳能地域分布不均匀,以至于光伏发电需作为分布式电源接入电网。随着分布式电源的渗透率不断提高,传统的同步发电机装机容量在比例上逐渐降低,电力系统的旋转备用容量以及转动惯量相对减少。由于一次能源具有不可控性及间歇性,而一般的分布式电源大多采用并网逆变器和负荷组成微网,这种并网方式使并网单元不具有常规电力系统固有的惯性,这使得电网的稳定性问题愈发严峻。本文将光伏并网逆变器作为研究对象,对并网逆变器在微网环境中的控制策略和应用进行研究。本文首先简要的介绍了光伏并网发电的结构与微电网技术的发展概况,总结出微网目前的控制结构与并网策略。通过对比微网中光伏逆变器与常规电网中的同步发电机的性能,得出了光伏逆变器具有容量小、惯性小、过流能力差的缺点。为了使光伏逆变器克服这些缺点,具有同步发电机的外特性,本文重点介绍了一种微网逆变器接口—虚拟同步发电机(virtual synchronous generator,VSG)的控制策略。详细阐述VSG的基本原理及其实现方法,根据同步发电机的定子电气数学模型与转子机械数学模型与并网运行和孤岛运行时微网对光伏逆变电源的技术要求,设计了功频控制器和励磁控制器。在MATLAB/SIMULINK环境中搭建系统仿真模型,验证所提出的虚拟同步发电机控制策略的并网特性,并对仿真结果进行详细的分析。根据仿真结果,对其硬件电路和软件进行设计。仿真与实验结果表明,具有虚拟同机特性的光伏微网逆变技术,可以满足并网运行和孤岛运行时微网对光伏逆变电源的技术要求,同时也满足大电网对微网的稳定性要求。更多还原

【Abstract】 In recent years, with the rapid development of global economy and population expanding, energy shortage and environmental pollution become global problems Development and utilization of new energy become imperative. Photovoltaic power generation as the most promising new green energy power generation mode has been extended and supported in recent years.Because of Solar energy’s uneven geographical distribution, the photovoltaic power generation need access to the grid as a distributed power supply. With the high penetration rate of distributed power supply, the capacity of the conventional synchronous generator gradually reduced in the proportion, the spinning reserve capacity of power system and the moment of inertia relative reduced. Due to the primary energy has the uncontrollable and intermittent characteristic, and distributed power generally connecting to the grid with inverter.It has no inherent which the conventional power system has while using this mode parallel in grid.That makes the stability problem of power grid becoming more and more serious. Distributed power supply and load compose microgrid, which has the characteristic of distributed power access and the nearest output. Microgrid gives full play to the advantages of the new energy power generation. In this paper, using the photovoltaic inverter as the research object, the inverter control strategy in microgrid and application are studied.First of all, the structure of grid connected photovoltaic is introduced by this paper briefly, mainly about BOOST converter, the DC/AC inverter and the energy storage unit. Then introduces the control strategy of each part of the system.There are mainly Maximum PowerPoint Tracking control and space vector.Secondly, this paper briefly introduces the general development of micro grid technology, summarizes the micro grid control structure and grid connected strategy. Comparing the property of the synchronous generator with photovoltaic inverter, the result shows photovoltaic inverter with small capacity, small inertia and low capacity of current-carrying.Thirdly, the control principle of a micro grid inverter interface----virtual synchronous generator is introduced by this paper, then this paper describes the basic principle of VSG and its realization method. According to the stator electrical model and rotor mechanical model of synchronous generator, and the technical requirements of grid connected and island operation mode, this paper designs a power frequency controller and excitation controllert.Finally, build simulation model in the MATLAB/SIMULINK environment, virtual synchronous generator’s grid connected characteristics are presented. Then gives a detailed analysis of the simulation results. According to the simulation results, the hardware circuit and software are designed. The simulation and experimental results show that, VSG can meet the requirements both of grid operation and isolated operation mode, and it also can meet requirements of the stability of microgrid to large power grid.更多还原