一种滤除衰减直流分量的全波傅里叶相角修正算法

提出了一种滤除衰减直流分量的全波傅里叶改进算法,适用于电力系统故障电流中含有多个衰减直流分量以及恒定直流分量的情况.通过比全波傅里叶算法增加2个采样点,利用3次相邻的周期的数据之和,在排除恒定直流分量的干扰的前提下计算出衰减直流分量的幅值和时间常数.只需对采样数据进行一次DFT运算,后一次的数据可以利用前一次的数据,大大减小了原有的计算量,加快了运算速度.自动判断相角是否需要增加180°,防止出现波形反向.本文详细分析了全波傅里叶算法,讨论了其它改进算法,给出了本改进算法的推导过程以及仿真结果,证明该算法计算精度高,数据窗短,易于实现.

A High Accuracy Full-wave Fourier Algorithm for Filtering Decaying DC Component

A refined full -wave Fourier algorithm for filtering decaying DC component was proposed , which is suitable for the system with a few decaying DC components and constant DC components .The amplitude and time constant of a decaying DC component were calculated using the sum of three adjacent data to eliminate the disturbing of constant DC components through adding two sampling points .The data of next calculation can use the those of the former , so that only one time of calculation is needed in this method , which the calculation is reduced and the speed is accelerated obviously .It is judged automatically that if a phase angle of 180°is nee-ded to prevent the reverse wave shape .It is proved by simulation results that the refined algorithm is of many ad-vantages such as high accuracy , short data window and easy realization .