电网信号高准确度频谱插值测量算法

在非同步采样条件下,利用快速傅里叶变换算法分析电网谐波时将出现由长范围频谱泄漏、短范围频谱泄漏、负频点频谱泄漏等造成的测量误差.为了提高测量准确度,推导了频谱泄漏误差的表达式.针对工频交流正弦信号,提出了一种能够同时消除短范围频谱泄漏和负频点频谱泄漏的插值算法.仿真结果和实际的测量实验结果表明:与已有的插值算法相比,所提算法不需要对信号施加特殊的窗函数,在非同步采样程度较大的情况下,利用较少的采样样本便可准确地获得信号的频率、幅值和相位,适用于对准确度要求很高的精密测量领域.

Spectral interpolation measurement algorithm of high accuracy on signals in power network

In the condition of asynchronous sampling, the long-range spectral leakages, short-range spectral leakages and negative frequency spectral leakages will be caused by using Fourier transforms to analyze the harmonics in power network. To improve the measurement accuracy, the spectrum leakage error expressions were derived. For power frequency alternating current signals, a new error correction algorithm based on interpolation was presented to eliminate both of the short-range spectral leakage errors and the negative frequency spectral leakage errors at the same time. Compared with the previous interpolation algorithms, the simulations and practical measurements show the new algorithm need not weight the samples by special windows and can measure out the accurate frequency, amplitude and phase of the signals even if the asynchronous sampling is very serious. It is applicable for the precise measurement fields requiring a higher accuracy.