Accurate Algorithm for Harmonic Analysis Based on Minimize Sidelobe Window

Errors caused by spectral leakage and picket fence effect can be reduced by the windowed interpolation FFT algorithm in the electric power harmonic analysis. In this paper, the spectral characteristics of minimize sidelobe window were analyzed and the interpolation FFT algorithms for electrical harmonic analysis based on the minimize sidelobe window were proposed. The applicable formulas of the interpolation were obtained by using polynomial curve fit functions, and subsequently calculating burden was dramatically reduced. The simulation results indicate that, with non-synchronized sampling and non-integral period truncation, the proposed method gave the accurate results for weak harmonic extraction and complicate harmonic analysis. The proposed method was applied in the three phase multiply function power energy meter, which verified the usefulness of the proposed method.