基于加窗插值FFT和APFFT的谐波检测算法

摘要

Application of the cosin-window and interpolated FFT and APFFT to harmonic analysis of power system is studied, the effect of spectrum leakage to the accuracy of the measurement is discussed.To the numerical analysis, there has high accuracy in the signal amplitude and frequency by using interpolated FFT window, but large error in phase.APFFT has the fe ature of phase invariance, so APFFT can get the phase exactly.As this reason, using cosin-window and interpolated FFT to detect amplitude and frequency of the signal and using APFFT to detect the phase.Simulation result demonstrates that by using the results above the estimation, accuracy of harmonic frequencies, amplitudes and phases reaches the national standards.%研究加窗插值傅里叶变换(加窗插值FFT)和全相位傅里叶变换(APFFT)在电网谐波分析中的应用.详细分析了频谱泄漏效应对测最精度的影响.通过数值模拟,发现加窗插值FFT对信号的幅值和频率的检测精度很高,但对相位的检测还存在着比较大的误差,而APFFT具有相位不变性的特征,能精确地提取相位信号.将加窗捅值FFT用于幅值、频率的检测,将APFFT用于相位的检测,通过试验仿真运行表明,以上的分析结果,电网谐波的频率、幅度、相位精度都很高,达到了国家标准.