改进型加窗插值法对谐波检测精度提升的研究  

Improvement of harmonic detection accuracy by improved windowed interpolation method

作　　者：张成林 张新燕[1] ZHANG Chenglin;ZHANG Xinyan(School of Electrical Engineering,Xinjiang University,Urumqi 830046,China)

机构地区：[1]新疆大学电气工程学院,新疆乌鲁木齐830046

出　　处：《现代电子技术》2021年第23期138-142,共5页Modern Electronics Technique

基　　金：国家自然科学基金资助项目(51667018)。

摘　　要：由于检测频谱泄漏和栅栏效应的存在,采用传统FFT法对谐波参数进行检测会使其检测精度不高。针对上述问题,提出了一种改进型加窗插值算法,即六项余弦二阶自卷积窗函数插值FFT算法。该算法具有优良的旁瓣性能,而旁瓣性能的优劣直接影响着谐波抑制的效果。在上述窗函数对谐波信号做截断处理以后,为了更好地抑制栅栏效应,采用曲线拟合与三谱线插值法对谐波信号参数进行在线修正,最终得出高精度谐波参数。从三个不同方面进行仿真验证,首先在不加任何干扰的情况下,加窗插值函数将谐波精度提升到10^(-9),其次在电网频率发生波动时,谐波精度提升10^(-6),最后加入白噪声干扰信号,谐波精度提升10^(-5)。Due to the existence of spectrum leakage and fence effect,the detection accuracy of the traditional FFT(fast Fourier transform)method in the detection of harmonic parameters is low.In order to solve the above problem,an improved windowed interpolation algorithm,that is,the 6-term cosine second-order self-convolution window function interpolation FFT algorithm,is proposed.This algorithm has excellent side lobe performance,which directly affects the effect of harmonic suppression.After the above window function truncates the harmonic signals,the parameters of the harmonic signals are modified online by curve fitting and three spectral line interpolation method to finally obtain the high-precision harmonic parameters,so as to better suppress the fence effect.The simulation was carried out in three different aspects.When there is no interference,the harmonic accuracy can be increased to 10^(-9) by the windowed interpolation function;when the grid frequency fluctuates,the harmonic accuracy can be increased to 10^(-6);when the white noise interference signals are added in,the harmonic accuracy can be increased to 10^(-5).

关 键 词：六项余弦自卷积窗 电力系统 谐波检测 频谱泄漏 三谱线插值 快速傅里叶变换 栅栏效应 白噪声 

分 类 号：TN911.7-34[电子电信—通信与信息系统]