Harmonic analysis algorithm based on sixterm cosine window interpolation FFT
ZHOU Li
(Department of Equipment Technology, Management Institute of Automobile, Bengbu 233011，China)
Abstract:  It is very difficult to achieve synchronous sampling and integratedcycle truncation when power system harmonics are analyzed. Therefore, there inevitably exists spectral leakage and fence effect. The windowed interpolation FFT algorithm is the effective method to reduce spectral leakage and fence effect. In order to reduce long range leakage, a 6term cosine window function was applied to harmonics analysis of power system. The interpolation estimation formulas of harmonics parameters were derived, moreover its interpolation coefficient has explicit expression and computation load is low. Comparison with the Hanning and BlackmanHarris interpolation FFT method was conducted by Matlab simulation. The result verifies the higher analysis accuracy of the proposed algorithm. The analysis results to testing data of microwave oven current further demonstrate the validity of the proposed algorithm.
Key words: harmonic; synchronous sampling; 6term cosine window; interpolation fast Fourier transform(FFT); power system