基于Flat-top窗的双谱线相位差频率测量算法

以Flat-top窗为例,分析了它的旁瓣频谱特性,并提出了基于双谱线相位加权的加窗插值校正算法求取谐波频率偏移量。该算法首先采样N点信号,提取N/2奇数点和N/2偶数点信号进行FFT,分别得到谐波附近最大谱线和次最大谱线的相位,再通过对相位差加权得到谐波的频率。仿真结果表明,该算法能有效减小电力系统中相量参数估计的偏差,提高了谐波的检测精度。

Frequency measurement algorithm of two spectral phases difference based on Flat-top window

Taking Flat-top window for a example,this paper analyzed its spectral characteristics of sidelobes and made a double-line phase based on the weighted harmonic correction algorithm to obtain the frequency offset.Firstly,it sampled N point signal,then extracted N/2 odd and N/2 even point signal to run FFT,which could get the phase of the maximum line and sub-maximum line spectra respectively.Lastly,it obtained frequency of harmonic with the phase-weighted difference.The simulation results show that the algorithm can effectively reduce estimation error in phasor parameters and improve detection accuracy of the harmonic.