基于FFT的电网谐波检测误差分析与研究

Harmonic detection has an important significance to the research and design of harmonic compensation devices,but in all kinds of harmonic detection algorithms, harmonic detection algorithm of basing on Fourier transformation is widely used. But standard FFT harmonic detection algorithm require the whole cycle of synchronous sampling, otherwise it will produce spectrum leakage and fences effect so that harmonic detection cause greater errors. This paper analyzes spectrum leakage and fences effect concretely, research and analyze the existence of the errors in standard FFT harmonic amplitude detection algorithm of asynchronous sampling, and propose add window interpolation FFT algorithm harmonic parameters detection algorithm. Deduced related formulas based on amplitude, phase and frequency of Blackman window interpolation FFT algorithm amplitude, and use MATLAB to simulate and obtain conclusions.