Resumen

BANUELOS CABRAL, Eduardo Salvador; GUTIERREZ ROBLES, José Alberto  y  NAREDO VILLAGRAN, José Luis. Identification of parameters with numerical methods for the modelling of electrical systems with frequency dependence. Energética [online]. 2015, vol.36, n.2, pp. 155-167. ISSN 1815-5901.

This paper provides a detailed description of the rational fitting techniques that are most used to approximate frequency domain functions. The techniques are: Bode asymptotic approximations, Ordinary Least-Squares, Iteratively Reweighted Least-Squares, Vector Fitting and Levenberg-Marquardt. These techniques are compared by approximating of an analytic function. Then, the techniques are applied to the rational-fitting of the frequency-dependent parameters corresponding to a single-phase transmission line. The effect of the rational representations is evaluated considering transients on cases of open-ended, short-circuited and perfectly matched lines. The numerical Laplace transform technique (NLT) is used as reference for the evaluations. It follows that the proper implementation of each fitting technique depends on various factors; the type of function being adjusted, the desired frequency range, an others. Moreover, one cannot guarantee that there is one of these techniques that will always yield the best fitting. The paper provides guidelines for selecting the most convenient one for a particular application.

Palabras clave : bode; least-squares; vector fitting; levenberg-marquardt; transmission lines.

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