基于ZFFT加窗多谱线插值法的谐波分析及应用研究

发布时间：2019-06-02 05:21

【摘要】：随着非线性负荷和电力电子设备的普及与使用,电网被谐波污染的程度不断增加,而准确地谐波分析与谐波电能计量在减小谐波影响的研究工作中显得尤为重要。谐波参数的准确检测与分析是研究谐波问题的前提,而谐波参数分析的准确性为谐波电能的高准确度计量提供了科学依据。谐波参数分析最普遍的方法是FFT(Fast Fourier Transform,快速傅里叶变换),但其受频谱泄漏和栅栏效应的影响较为严重,使得谐波参数分析的准确度相对较低。由于谐波信号具有不确定性等因素,如出现间谐波等,也会对准确地谐波分析结果产生很大的影响。因此,本文提出基于ZFFT(Zoom-FFT,复调制细化法)加窗多谱线插值的谐波分析方法,并结合Budeanu功率分解原理完成谐波的电能计量。并与传统FFT谐波分析方法进行仿真对比验证,仿真结果表明本文算法更具有准确性和优越性。主要研究内容包括以下几个方面:(1)分析基于加窗多谱线插值法的谐波分析及应用研究的背景和意义,并介绍其发展现状。研究傅里叶变换理论,分析其存在问题的原因及现象,并提出相应的解决办法。通过这些阐述与分析为后续理论研究奠定基础。(2)分析典型窗函数及其频域特性,研究窗函数的选取标准。将窗函数作时域卷积和改变窗函数系数法进行结合,提出新型梯形自卷积窗函数,并分析其频域特性。研究并构建基于2阶梯形自卷积窗四谱线插值的谐波分析方法,推导并建立谐波参数的修正公式。分析传统复调制细化法原理,提出并建立基于复解析带通滤波器的复调制细化分析方法。(3)研究电能计量的基本理论,分析谐波对电能计量的影响及电能计量误差产生的原因。根据Budeanu功率分解原理,结合基于ZFFT加2阶梯形自卷积窗四谱线插值法分析出的谐波参数进行谐波电能计量。(4)通过采用直接FFT法、加梯形窗四谱线插值法、加2阶梯形自卷积窗四谱线插值法、基于ZFFT加2阶梯形自卷积窗四谱线插值法进行对比分析,以验证本文提出方法的准确性与可行性。
[Abstract]:With the popularization and use of nonlinear load and power electronic equipment, the degree of harmonic pollution in power grid is increasing, and accurate harmonic analysis and harmonic energy measurement are particularly important in the research work of reducing harmonic influence. The accurate detection and analysis of harmonic parameters is the prerequisite for the study of harmonic problems, and the accuracy of harmonic parameter analysis provides a scientific basis for the high accuracy measurement of harmonic energy. The most common method of harmonic parameter analysis is FFT (Fast Fourier Transform, fast Fourier transform (FFT), but it is seriously affected by spectrum leakage and fence effect, which makes the accuracy of harmonic parameter analysis relatively low. Due to the uncertainty of harmonic signal, such as the occurrence of interharmonic and so on, it will also have a great influence on the accurate harmonic analysis results. Therefore, this paper proposes a harmonic analysis method based on ZFFT (Zoom-FFT, complex Modulation thinning method) windowed multi-spectral line interpolation, and combines the Budeanu power decomposition principle to complete the harmonic energy metering. The simulation results show that the proposed algorithm is more accurate and superior than the traditional FFT harmonic analysis method. The main research contents include the following aspects: (1) the background and significance of harmonic analysis and application based on windowed multi-spectral line interpolation method are analyzed, and its development status is introduced. The Fourier transform theory is studied, the causes and phenomena of its existing problems are analyzed, and the corresponding solutions are put forward. Through these explanations and analysis, it lays a foundation for the following theoretical research. (2) the typical window function and its frequency domain characteristics are analyzed, and the selection criteria of window function are studied. Combining the window function with the method of changing the window function coefficient in time domain, a new ladder self-convolution window function is proposed, and its frequency domain characteristics are analyzed. The harmonic analysis method based on two-step self-convolution window four-spectral line interpolation is studied and constructed, and the correction formula of harmonic parameters is derived and established. The principle of traditional complex modulation refinement method is analyzed, and a complex modulation refinement analysis method based on complex analytical band-pass filter is proposed and established. (3) the basic theory of electric energy metering is studied. The influence of harmonics on electric energy metering and the causes of electric energy metering error are analyzed. According to the principle of Budeanu power decomposition, the harmonic parameters analyzed by ZFFT and 2-step self-convolution window four-spectral line interpolation method are used to measure harmonic energy. (4) by using direct FFT method and ladder window four-spectral line interpolation method, The four-spectral line interpolation method of 2-step self-convolution window is added, and the four-spectrum interpolation method of 2-step self-convolution window is compared and analyzed based on ZFFT and 2-step self-convolution window four-spectrum interpolation method to verify the accuracy and feasibility of the proposed method.
【学位授予单位】：兰州交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM711

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