Advanced Spectrum Estimation Methods for Signal Analysis in Power Electronics
Leonowicz, Z (Wroclaw University of Technology, Poland) ; Lobos, T (Wroclaw University of Technology, Poland) ; Rezmer, J (Wroclaw University of Technology, Poland)
Abstract: Modern frequency power converters generate a wide spectrum of harmonics components. Large converters systems can also generate non-characteristic 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. A novel approach to harmonic and interharmonic analysis, based on the subspace methods, is proposed. Min-norm harmonic retrieval method is an example of high-resolution eigenstructure-based methods. 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. To investigate the methods several experiments were performed using simulated signals, current waveforms at the output of a simulated frequency converter and current waveforms at the output of an industrial frequency converter. For comparison, similar experiments were repeated using the FFT. The comparison proved the superiority of the new methods. However, their computation is much more complex than FFT.
Keyword(s): AC motor drives ; Discrete Fourier Transform ; power system harmonics ; Prony method ; spectral analysis ; subspace methods
Note: IEEE Transactions on Industrial Electronics, vol. 50, no. 3, pp.514-519, 2003.
Fulltext : http://zet10.ipee.pwr.wroc.pl/record/3/files/
Cited by: try citation search for ENY-ARTICLE-2008-003
Record created 2008-03-05, last modified 2008-03-09
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