谐波检测的抗混叠小波包滤波器设计

传统小波滤波器注重总体抗混叠和信号精确重建，而忽略分解分量中的混叠抑制，导致不能有效分析谐波信号。该文利用内插优化技术设计了一种抗混叠小波包滤波器。通过分析传统小波滤波器结构上的抗混叠局限，在既有的滤波器结构上增加一些内插的高低通滤波器，可以有效消除小波混叠，并可利用优化算法来求解内插滤波器系数。设计的抗混叠滤波器，同时兼顾了信号保持与混叠抑制两方面因素，克服了传统小波滤波器设计时仅考虑信号精确重建和总体抗混叠而带来的固有缺陷。仿真实验表明，所设计的小波包滤波器可以有效抑制小波混叠，能精确提取谐波特征，从而为电力系统谐波精确检测提供了一种有效手段。

ANTI-ALIASING WAVELET PACKET FILTERS DESIGN FOR HARMONIC DETECTION

Traditional wavelet fdters often emphasize total anti-aliasing and perfect reconstruction, but omit aliasing reduction in decomposition components, so it can not effectively analyze harmonics for serious wavelet aliasing error. This paper designed an anti-aliasing wavelet packet filters bank by using optimal interpolation technique. Through analyzing anti-aliasing limitation of traditional wavelet filters structure, some low-pass or high-pass filters were inserted into existing traditional wavelet filters structure, so it can reduce wavelet aliasing, and an optimal algorithm was developed to compute the interpolation filters coefficients. This devised wavelet packet filters give both attention between signal preservation and aliasing reduction, it overcomes the inherent bug of traditional wavelet filters rooted from just only concerning perfect reconstruction and total anti-aliasing. Simulation results reveal that the proposed wavelet packet filters can effectively eliminate wavelet aliasing, can precisely extract harmonic information, so it provides a vigorous means for power system harmonic detection.