Blackman-Harris窗的插值FFT谐波分析与应用

快速傅里叶变换在非同步采样和非整数周期截断的情况下存在较大的误差,无法得到准确的谐波参数。加窗插值快速傅里叶变换算法广泛用于电力系统谐波,可改善因非同步采样和非整数周期截断造成的频谱泄露,提高分析精度。文章分析了Blackman-Harris窗的频谱特性,提出了基于Blackman-Harris窗插值的分析算法,运用多项式拟合求出实用的插值修正公式。仿真结果表明,Blackman-Harris窗插值FFT方法设计实现灵活,抑制频谱泄露效果好。

Harmonic Analysis Based on Blackman-Harris WindowInterpolationFFT and Its Application

The fast Fourier transform(FFT) will have a greater error in the cases of non-synchronous sampling and in a truncated non-integral period,thus accurate harmonic parameter values can not be obtained.Widely used for harmonic analysis in the electric power system,the windowed interpolation fast Fourier transform(FFT) algorithms could compensate the spectral leakage in frequency domain caused by non-coherent sampling and non-integral period truncation,and subsequently the accuracy of harmonic parameters measurement couldbe improved.The spectral characteristics of Blackman-Harris window were analyzed and an approach for harmonic analysis based on Blackman-Harris window interpolation FFT was proposed.The applicable rectification formulas of the interpolation were obtained by using polynomial curve fit functions.The simulation results indicate that the approach based on Blackman-Harris window interpolation FFT can be designed and realized easily and restrain spectral leakage effectively.