摘要

The signal spectral leakage and fence effect are prone to take place during the power harmonic analysis by fast Fourier transform (FFT) under non-synchronous sampling. Although the signal spectral leakage can be effectively inhibited by weighted window function, however the inhibiting ability of classical window function is restricted by the behavior of sidelobe. Based on the analysis on spectrum characteristic of Nuttall window, a new type of window function, namely the Nuttall self-convolution window, is obtained by several Nuttall window self-convolution operations. Analyzing the behaviors of mainlobe and sidelobe of Nuttall self-convolution window, an improved FFT harmonic analysis method adopting weighted Nuttall self-convolution window is developed. The excellent sidelobe performance of Nuttall self-convolution window can effectively suppress the influcence of signal spectral leakage than classical window function and the improved FFT algorithm can effectively remedy the defect in frquency resolution reduction brought about by convolution. Simulation results show that Nuttall self-convolution window can well suppress frequency spectral leakage; the improved FFT algorithm can effectively modify the results; and the accuracy of harmonic parameter estimation by the proposed method is better than that by classical window function.

  • 出版日期2011

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