基于四阶牛顿插值法同步化的FFT谐波分析方法

FFT harmonics analysis based on fourth order Newton interpolation synchronization

提出了一种实时检测谐波的分析方法,利用高阶的牛顿插值法推导了同步化公式,该公式对固定采样频率得到的采样数据重新推导与跟踪,再从算法上调整采样周期对重现的信号曲线进行重新采样,最后对重新采样序列进行快速傅里叶(FFT)谐波分析。即使是在工频波动比较大的情况下以及采用较少量的采样数据,新采样序列依然能够利用FFT算法准确地获得被分析曲线所包含的高阶谐波分量的幅值和相位。仿真结果和实际应用证明,该方法对于实时性要求比较高、电压频率变化比较大的情况具有良好的鲁棒性。

A real- time harmonics detection method is proposed. The synchronization formula is derived from high order Newton interpolation,which represents the signal curve according to the signals sampled in fixed frequency,then re-samples the signal curve with adjusted sampling frequency and carries FFT（Fast Fourier Transform） analysis for the re-sampled data sequences. The accurate amplitude and phase of high order harmonics can thus be obtained even when base frequency fluctuates greatly or less data are sampled. Simulation results and actual application prove that this method has good robustness in case with high real-time performance requirement or great power frequency fluctuation.