Abstract

GOMEZ-LUNA, Eduardo; CUARTAS-BERMUDEZ, Juan Sebastián  and  MARLES-SAENZ, Eduardo. Obtaining the electrical impedance phase using Wavelet transform and Fourier transform from transient signals. Part 1: Theoretical analysis. Dyna rev.fac.nac.minas [online]. 2017, vol.84, n.201, pp.138-144. ISSN 0012-7353.  https://doi.org/10.15446/dyna.v84n201.58694.

This paper presents how to get the phase of the electrical impedance from the analysis of transient signals, using Fourier Transform and Wavelet Transform. Traditionally, Fourier Transform has been used for these analysis, however, Fourier Transform is mainly oriented to the analysis of periodic signals and not to the analysis of transient signals. Therefore, this paper proposes a new method based in the Wavelet Transform, which uses as wavelet mother, the Morlet modified that is an adaptation of the traditional complex Morlet, to obtain a better representation of the phase in the frequency domain. Such improvement is valid taking as reference the results obtained by the software "MATLAB" from the impedance of an RLC circuit in response to the impulse of the voltage signal, managing to improve the limitations of the Fourier Transform for the analysis of this type of signals. The study has been divided into two parts, the first part includes what has been done theoretically and through simulation, the second part is to present the experimental results of a real case validating the method developed. For both cases the same two mathematical methods were used, where the potential of the Wavelet Transform for the analysis of transient shown in the obtaining of the electrical impedance front Fourier Transform.

Keywords : Wavelet Transform; Discrete Fourier Transform; Time Domain signals; Complex Frequency Domain signals; non-periodical transients.

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