光伏并网逆变器的研究及可靠性分析概要

光伏并网逆变器的研究及可靠性分析

【中文摘要】随着环境污染和能源短缺题目的日趋严重,寻找一种储备大、无污染的新能源已经上升到世界各国的议事日程。太阳能作为当今最理想环保的能源之一,已经得到了人类越来越广泛的应用。本文以光伏(Photovoltaic-PV)并网发电系统为研究对象,以最大限度利用太阳能、无污染回馈电网为主要目标,开展了光伏并网发电系统的理论研究和仿真,具有重要的现实意义。光伏并网逆变器是光伏并网发电系统中必不可少的设备之一,其效率的高低、可靠性的好坏将直接影响整个光伏发电系统的性能和投资。本文主要研究适用于并网型光伏发电系统的逆变器。本文以一个完整的光伏并网发电系统为研究对象,重点对单相光伏并网系统进行了全面的分析,并从并网系统的主电路拓扑、控制策略、孤岛效应以及系统的可靠性分析几个方面做了具体的分析和仿真实验。首先,先容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先容,对光伏并网发电系统建立了总体熟悉。其次,讨论研究了逆变器主电路的拓扑形式,并根据实际情况,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,两部分通过DClink连接。前级的DC/DC模块采用Boost拓扑结构,后级的DC/AC逆变器采用逆变全桥实现逆变,向电网输送功率。讨论确定了逆变器输出电流的控制方式,并终极确定了光伏并网发电系统的总体方案。高性能的数字信号处理器芯片(Digital Signal Processor-DSP)的出现,使得一些先进的控制策略应用于光伏并网的控制成为可能。本文以TI公司的数字信号处理器芯片TMS320F2812为核心,设计了控制电路并给出了驱动电路、保护电路的设计以及系统的电磁兼容设计思想。应用MATLAB/Simulink中的工具箱搭建了整个电路模型,进行了仿真实验研究。再次,我们已经知道孤岛效应题目关系到光伏并网发电系统的安全题目。本文分析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。根据本文涉及的光伏并网发电系统的特点,采用了电压前馈正反馈检测孤岛的方法,然后具体先容了该方法的原理和实现过程,并给出了逆变器的反孤岛效应模型和仿真实验结果。

仿真结果证实,该方法是可行的,并且达到了IEEE Std.2000-929标准的规定。光伏系统的可靠性研究对整个系统的经济运行乃至投资决策产生了重要影响。本论文以光伏并网发电系统的基本组成为线索,对各部分进行可靠性分析,对满足一定可靠性水平的光伏并网发电系统进行分析,从而对其的推广使用起到了理论指导作用。');

【Abstract】 With an increasingly serious problem of environmental pollution and energy shortages, looking for a large reserve, clean new energy has risen to the world\\'s agenda. As one of the best environmentally-friendly energy sources, solar energy has been applied more and more widely by human. This *** deeply researches the grid-connected photovoltaic (PV) system and does simulations with the main objection of transforming the solar energy into electrical energy maximum and no pollution. It has realistic significance to do researches and experiments on the grid-connected PV system. And the grid-connected PV inverter is one of the necessary equipments of the grid-connected PV system. The efficiency and reliability of inverter will influence the performance of the whole system. So an effective inverter suited to the grid-connected PV system is presented in this thesis.This *** bases on grid-connected PV system as research object and focuses on single-phase grid-connected PV systems to conduct a comprehensive analysis, and then does a detail analysis and simulation from the main circuit topology of grid-connected system, control strategies, system parameters, anti-island effect as well as reliability 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 overall understanding of the system is set up naturally.Secondly, this *** discusses the topology of the main circuit of the

inverter. In accordance with the actual situation, it is better to choose two stages transform structure, DC/DC converter with Boost topology structure and DC/AC inverter with full-bridge inverter, this two parts are connected by DClink. This *** discusses control mode of output current of the inverter and then determines the overall program of grid-connected PV system. With the development of digital signal processors (DSP), it is possible that some advanced control strategies can be applied to the grid-connected PV system. This *** takes digital signal processor TMS320F2812 from TI Company as core cell of control circuits. The design of driver and protection circuits and system\\'s EMC are introduced in detail. MATLAB/Simulink toolboxes are used to build the whole circuit model and the simulation study.Then as we know islanding effect relates to the security issues of the grid-connected PV system. The *** analyzes the causes and effects as well as detection methods used now, such as passive and active and external islanding detection methods. According to the features of the system designed this ***, the voltage feed forward position feedback disturbance method is used to solve the problem, and then this *** builds the MATLAB model based on the method and carries out the simulation. The simulation result shows that the method is feasible and up to the demand of IEEE Std.2000-929.Reliability study of PV system has an important impact on the economic operation and *** investment decision to the entire system. This *** does reliability analysis of the grid-connected PV system according to the basal components. Doing analysis on the grid-connected PV system meeting a certain level reliability has played a guiding role to its use.