Abstract—Modern frequency power converters
generate a wide spectrum of harmonic components.
Large converter systems can also generate noncharacteristic
harmonics and interharmonics.
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. In the case of frequency
converters the periods of the main component are
unknown. The Prony method as applied for signal
analysis in power frequency converter was tested in the
paper. The method does not show the disadvantages of
the traditional tools and allow exact estimation the
frequencies of all or dominant components, even when
the periodicity intervals are unknown. To investigate
the appropriateness of the method several experiments
were performed. For comparison, similar experiments
were repeated using the FFT. The comparison proved
the superiority of the Prony method.