NCAFI: Nuttall convolution window all-phase FFT interpolation-based harmonic detection algorithm for infrared imaging detection

Abstract

Harmonic problems seriously restrict the development of power electronics technology. This condition may provoke multiple results, as follows: (i) reduced efficiency of electric energy production, transmission, and utilization; (ii) overheating; (iii) possible failure of electrical equipment; (iv) confusion in electric energy measuring. In this study, we propose a novel harmonic detection method for the increasingly severe harmonic problem by Nuttall convolution window all-phase FFT interpolation in infrared imaging condition. This method selects a convolution window with four terms of third-order Nuttall and four terms of fifth-order Nuttall, with a lower sidelobe level and faster decay speed. Our method derives the correction formulae for frequency domain and amplitude, using four adjacent spectral lines, combined with the polynomial fitting method. Simulated and real experiments demonstrate that the proposed method achieves a significant improvement in calculation accuracy. Furthermore, our algorithm can better suppress spectral leakage, which is suitable for parameter estimation of low harmonic components. Finally, the feasibility and effectiveness of our algorithm are validated.