低压微网中并网逆变器谐振问题的研究

发布时间：2018-05-04 15:45

本文选题：微电网 + 并网逆变器　；参考：《电子科技大学》2014年硕士论文

【摘要】：近年来分布式发电得到了大力的发展,但其本身也存在着一些不足,为了弥补和克服分布式发电系统并网运行时引起的电能质量变差及可靠性降低等问题,同时发挥出分布式电源的价值和其效益优势,微电网技术作为一个非常前沿的研究领域,在未来的几年将会得到大力的研究和发展。目前微电网的发展还处于初级阶段,针对现阶段微电网研究存在的问题:分布式发电并网的电能质量,微电网中多逆变器并联的建模以及各个并网逆变器之间相互作用的机理。本文对微网中并网逆变器谐振问题以及多个逆变器并联系统的建模和谐振问题进行了深入的研究。(1)分析了并网逆变器的拓扑结构和基于同步旋转坐标系的数学模型,简要的分析了LCL滤波器的原理和数学模型,在此基础上给出了并网逆变器的电流内环控制结构,为之后的分析提供理论基础。(2)分别在连续域和离散域对单个并网逆变器的谐振抑制策略进行了深入研究。对于无源阻尼策略,分析了阻尼电阻位置不同时对系统高频特性和低频特性的影响,深入分析了阻尼电阻的大小对系统稳定性和滤波特性的影响;对于有源阻尼策略,基于最根本的电容电压和电容电流反馈的有源阻尼法,在连续域和离散域分析了采用不同方法时的系统稳定性;在此基础上,进一步分析了电网阻抗对有源阻尼和无源阻尼的影响。(3)对于微电网中多逆变器并联系统,建立了三相并网逆变器的Norton等效模型,在此基础上,把单逆变器的Norton等效模型推广到了多逆变器并联系统,建立了多逆变器的Norton等效模型;对于多逆变器并联系统,在离散域分析了逆变器内部谐振、各逆变器之间的并联谐振以及电网和逆变器之间的串联谐振,并且分析了加入有源阻尼策略之后的谐振抑制效果。(4)在Matlab/simulink中搭建了单个并网逆变器和多逆变器并联系统的仿真模型,对本文之前的理论分析进行了仿真验证,仿真结果验证了理论分析的正确性。
[Abstract]:In recent years, distributed generation has been greatly developed, but it also has some shortcomings. In order to make up for and overcome the problems such as the deterioration of power quality and the decrease of reliability caused by the grid connection of distributed generation system, and so on. At the same time, the value and benefit advantage of distributed power generation are brought into play. As a very advanced research field, microgrid technology will be greatly researched and developed in the next few years. At present, the development of microgrid is still in the primary stage. Aiming at the problems existing in the research of microgrid at the present stage, such as the power quality of distributed generation and grid connection, the modeling of multi-inverters in microgrid and the mechanism of interaction between grid-connected inverters. In this paper, the resonant problem of grid-connected inverter in microgrid and the modeling and resonance of parallel inverter system are deeply studied. The topology of grid-connected inverter and the mathematical model based on synchronous rotating coordinate system are analyzed. The principle and mathematical model of LCL filter are analyzed briefly. On this basis, the current inner loop control structure of grid-connected inverter is given. To provide a theoretical basis for the subsequent analysis. (2) the resonant suppression strategies of a single grid-connected inverter in the continuous domain and discrete domain are studied in depth. For the passive damping strategy, the influence of the position of damping resistance on the high frequency and low frequency characteristics of the system is analyzed, and the influence of the damping resistance on the stability and filtering characteristics of the system is analyzed. Based on the most fundamental capacitive voltage and capacitive current feedback active damping method, the stability of the system using different methods is analyzed in the continuous and discrete domains. The influence of impedance on active damping and passive damping is further analyzed. The Norton equivalent model of three-phase grid-connected inverter is established for multi-inverter parallel system in microgrid. The Norton equivalent model of single inverter is extended to multi-inverter parallel system, and the Norton equivalent model of multi-inverter is established, and the internal resonance of inverter is analyzed in discrete domain for multi-inverter parallel system. The parallel resonance between the inverters and the series resonance between the power grid and the inverter, And the resonance suppression effect after the active damping strategy is analyzed. The simulation models of single grid-connected inverter and multi-inverter parallel system are built in Matlab/simulink, and the theoretical analysis before this paper is verified by simulation. The simulation results verify the correctness of the theoretical analysis.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM464

【参考文献】