Advanced spectrum estimation methods for signal analysis in power electronics

Abstract — Modern frequency power converters generate a wide spectrum of harmonics components. Standard tools of harmonic analysis based on the Fourier transform assume that only harmonics are present and the periodicity intervals are fixed, while periodicity intervals in the presence of interharmonics are variable and very long. A novel approach to harmonic and interharmonic analysis, based on the “subspace” methods, is proposed. The Prony method as applied for signal analysis was also tested for this purpose. Both the high-resolution methods do not show the disadvantages of the traditional tools and allow exact estimation of the interharmonics frequencies.