基于双窗全相位FFT双谱线插值的谐波和间谐波分析算法

在利用传统快速傅里叶变换进行谐波和间谐波分析时,由于非同步采样或非整周期截断,容易影响谐波和间谐波的检测精度。本文提出了一种基于双窗全相位快速傅里叶变换双谱线插值的电力谐波和间谐波分析算法。该算法利用双窗全相位快速傅里叶变换主谱线相位值来估计信号初相位,选择紧邻峰值频点的左右两根谱线进行频率和幅值的插值校正,结合多项式拟合函数推导出典型窗函数下全相位快速傅里叶变换的实用修正公式。通过与传统快速傅里叶变换双谱线插值法、全相位快速傅里叶变换比值法及全相位快速傅里叶变换相位差法的仿真对比实验,验证了所提出的新算法在密集频谱分析、谐波和间谐波的高精度检测及克服白噪声污染等方面的准确性与有效性。

Harmonics and Interharmonics Analysis Algorithm Based on Double-spectral-line Interpolation of Double-window All-phase FFT

When the traditional fast Fourier transform(FFT)is used to analyze the harmonics and interharmonics of power system,the corresponding detection accuracy will be easily affected by non-synchronous sampling or non-integral period truncation.In this paper,an analysis algorithm for power harmonics and interharmonics based on the doublespectral-line interpolation of all-phase FFT is proposed,which estimates the initial phase of a signal by using the phase values of the main spectral line of double-window all-phase FFT,and selects the left and right spectral lines immediate?ly adjacent to the peak frequency point to correct the frequency and amplitude.At the same time,a practical correction formula under the typical window function of all-phase FFT is derived by combining the polynomial fitting function.Compared with the traditional FFT double-spectral-line interpolation method,all-phase FFT ratio method,and allphase FFT phase difference method,the accuracy and effectiveness of the novel algorithm are verified in terms of dense spectrum analysis,high-precision detection of harmonics and interharmonics,and overcoming the white noise pollution.