基于双插值FFT算法的间谐波分析

为了减小频谱泄漏的影响，提高间谐波分析精度,提出了加余弦窗双插值FFT算法来分析间谐波。该算法通过选取合适的窗函数，对采样信号进行加窗后，用FFT计算出离散频谱，再利用多项式逼近的方法得到频率和幅值的修正公式来对谐波分析结果进行修正。修正谐波幅值时，选择距频点最近的左右两根谱线进行加权，对两根谱线采用的权重与它们各自的幅值成正比。该算法能够有效地降低泄漏和噪声干扰，提高了间谐波和谐波分析的准确性。仿真结果证实了算法的正确性与易实现性。

Inter-harmonics analysis based on double interpolation FFT algorithm

To reduce disturbance by the frequency leakage and improve the accuracy of inter-harmonics analysis,the poly-cosine window and double interpolation FFT algorithm is presented. The windowed FFT transform is applied to the sampling signal choosing a suitable window function. Then a further amendment is made to the harmonic analysis results using double interpolation algorithm. The formulae for frequency and amplitude correction are obtained by means of the polynomial approximation method. The double interpola...