基于FFT的间谐波优化检测算法研究

Interharmonics Optimization Detection Algorithm Based on FFT

由于间谐波成分与电网基频不同步,利用快速傅里叶变换进行检测时往往会出现频谱泄漏和栅栏效应,而加窗插值算法在无噪声干扰时能修正误差、提高检测精度。针对此现状给出一种组合小波阈值去噪和快速傅里叶变换的优化检测算法方案。尤其对小波阈值去噪进行改进,提高其算法适应性并实现更精确的信噪分离。通过仿真对比,得到实现间谐波幅频信息准确测量的优化方案。

Because the components of interharmonics are not synchronized with the fundamental frequency of the power grid,the spectrum leakage and fence effect are often detected when using fast Fourier transform. However,the windowed interpolation algorithm can correct the error and improve the detection accuracy in noiseless condition. In the view of this situation,an optimal detection algorithm based on combination wavelet threshold denoising and fast Fourier transform was proposed. Especially,wavelet threshold denoisingwas improved to enhance the adaptability of the algorithm and to achieve more accurate signal-noiseseparation. Through simulation comparison,an optimized scheme for realizing accurate measurement of interharmonic amplitude frequency information was obtained.