微电网的建模及其谐波检测方法研究

发布时间：2018-02-02 18:20

本文关键词： 分布式电源微电网谐波检测希尔伯特-黄变换　出处：《南京理工大学》2014年硕士论文　论文类型：学位论文

【摘要】：微电网是一个新型电网结构,由分布式电源、负荷、储能系统和控制装置等组成。微电网技术充分发挥了分布式电源的优势,同时协调了分布式电源与大电网之间的矛盾。随着对微电网的研究不断深入,其电能质量问题也受到越来越多的关注。谐波是衡量电能质量的重要标准,对微电网中的谐波进行准确的检测和分析是研究谐波问题的首要任务。微电网中的谐波具有随机性、非平稳性等特点,传统谐波检测方法在分析时均存在不同程度的局限。希尔伯特-黄变换法是一种自适应的信号分析方法,被广泛应用于非线性、非平稳信号的分析,它可以克服传统检测方法在处理非平稳信号时的不足,但同时自身也存在包络线拟合和模态混叠等问题。论文对光伏发电系统和风力发电系统进行了分析和建模,以Matlab/Simulink为仿真平台,搭建了适用于谐波检测的微电网并网模型,奠定了谐波分析的基础。针对HHT方法本身的包络线拟合问题,论文提出了改进的包络线拟合思路；针对HHT方法在谐波检测中遇到的模态混叠现象,论文设计了用于滤去基波分量的数字高通滤波器。综合分析两种改进思路,论文提出了HHT的改进方法,仿真结果表明改进的HHT方法可以取得良好的谐波检测效果。利用Matlab GUI设计平台,论文设计了基于改进方法的谐波检测平台,实现了谐波信号绘制、谐波检测和谐波瞬时参数计算等功能,提高了改进方法的实用性。论文应用设计的谐波检测平台,对微电网中的光伏发电系统和风力发电系统的并网电流进行了谐波检测分析,仿真结果验证了改进方法的准确性；然后,运用改进方法对不同情况下微电网的并网公共点电流进行了检测与分析,仿真结果表明,改进方法能够准确地检测出微电网谐波信号中存在的各次谐波分量,而且对于非平稳的谐波信号,改进方法能够体现谐波信号发生突变的时间点,检测效果良好。
[Abstract]:Microgrid is a new type of power network structure, which is composed of distributed generation, load, energy storage system and control device, etc. Microgrid technology has brought the advantage of distributed generation into full play. At the same time, the contradiction between distributed generation and large power grid has been coordinated. With the further research on microgrid, more and more attention has been paid to the power quality problem. Harmonics is an important standard to measure power quality. Accurate detection and analysis of harmonics in microgrid is the primary task of harmonic research. The harmonic in microgrid has the characteristics of randomness and non-stationarity. The traditional harmonic detection method has some limitations in analysis. Hilbert-Huang transform is an adaptive signal analysis method. It is widely used in the analysis of nonlinear and non-stationary signals. It can overcome the shortcomings of traditional detection methods in processing non-stationary signals, but it also has some problems such as envelope fitting and modal aliasing. Based on the analysis and modeling of photovoltaic system and wind power system, a grid-connected model for harmonic detection of micro-grid is built based on Matlab/Simulink. It lays the foundation of harmonic analysis. Aiming at the envelope fitting problem of HHT method, an improved envelope fitting method is put forward in this paper. Aiming at the phenomenon of modal aliasing encountered in harmonic detection by HHT method, a digital high-pass filter for filtering fundamental wave components is designed in this paper. Two improved ideas are analyzed synthetically, and the improved method of HHT is put forward in this paper. Simulation results show that the improved HHT method can achieve good harmonic detection results. Using the Matlab GUI design platform, this paper designed the harmonic detection platform based on the improved method. The functions of harmonic signal rendering, harmonic detection and harmonic instantaneous parameter calculation are realized, and the practicability of the improved method is improved. In this paper, the harmonic detection and analysis of grid-connected current of photovoltaic system and wind power system in micro-grid are carried out by using the designed harmonic detection platform. The simulation results verify the accuracy of the improved method. Then, the improved method is used to detect and analyze the common point current of microgrid under different conditions, and the simulation results show that. The improved method can accurately detect the harmonic components in the harmonic signal of microgrid, and for the non-stationary harmonic signal, the improved method can reflect the time point of the harmonic signal mutation. The detection effect is good.
【学位授予单位】：南京理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM711

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