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The Numerical Analysis of the Elementary, Fractional Order, Interval Transfer Function

Oprzędkiewicz Krzysztof

Pomiary Automatyka Robotyka

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2023

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R. 27, nr 4

45--51

EN

In the paper the analysis of the impact of the interval uncertainty of parameters on the behaviour of the elementary Fractional Order (FO) transfer function is investigated. The fractional order and quasi time constant are defined as intervals describing deviation from nominal values. Such an analysis has not be considered yet. The proposed elementary, interval model can be applied in modeling of different, uncertain-parameters elements and physical phenomena. For the considered transfer function the methodology of its numerical analysis is proposed and illustrated by simulations. Results of numerical tests point that the best robustness of the model is achieved for relatively lower values of its parameters.

PL

W pracy zaprezentowano analizę wpływu przedziałowej niepewności parametrów na zachowanie się elementarnej transmitancji niecałkowitego rzędu. Parametry modelu: rząd ułamkowy i pseudo-stała czasowa są zdefiniowane jako przedziały opisujące odchyłki od wartości nominalnych. Tego typu analiza nie była do tej pory rozważana. Proponowany elementarny model przedziałowy może znaleźć zastosowanie do opisu różnych elementów i zjawisk fizycznych, dla których wartości parametrów są opisane jedynie w sposób przybliżony. Dla rozważanej transmitancji zaproponowano metodologię jego analizy numerycznej i zilustrowano ją symulacjami. Wyniki testów numerycznych wskazują, że model jest najbardziej odporny na niepewność parametrów dla ich relatywnie niskich wartości.

2

Problems with modeling of fractional electrical circuits containing supercapacitors

Piotrowska Ewa

Poznan University of Technology Academic Journals. Electrical Engineering

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2020

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No. 104

65--74

EN

For proper operation, diagnostics or control, it is required to know the parameters of the supercapacitor replacement model (relationship between current and voltage at the terminals). The paper describe the bahavior of the eletrical circuit (RC) containing the supercapacitor were used the fractional derivatives of Caputo definiton and Conformable Fractional Derivative definition. Verification of the correctness of the suggested electrical circuit models was carried out a series of measurements of the system response to the given control signal. The measurement data were compared by fractionalorder derivatives: classical case, Caputo definition and CFD definition. Conducting a series of experiments with charging a supercapacitor in an RC circuit, constant control voltage from 2 V to 5 V with an exchanged external resistor, it was shown that none of the three mathematical models reflects the real behavior of the supercapacitor. It has been shown that the behavior of supercapacitor requires the use of different mathematical than fractional derivatives.

3

Analysis of fractional electrical circuit with sinusoidal input signal using Caputo and conformable derivative definitions

Piotrowska Ewa

Poznan University of Technology Academic Journals. Electrical Engineering

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2019

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No. 97

155--167

EN

This paper presents the fractional electrical circuit in the transient state described by the fractional-order state-space equations. General solutions to the fractional state-space equations containing two types of definitions of fractional derivative: Caputo definition and the conformable fractional derivative definition are given the solutions in the case of: 1) control in the form of sine function at zero initial states 2) control in the form of cosine function at zero initial states 3) control in the form of the sine function with phase shift at zero initial states. The solutions are shown for capacitor voltages for fractional derivative orders of 0.7; 0.8; 1.0. The results were compared using graphs.

4

Analysis of fractional electrical circuit with rectangular input signal using Caputo and conformable derivative definitions

Piotrowska E.

Archives of Electrical Engineering

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2018

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Vol. 67, nr 4

789--802

EN

An analysis of a given electrical circuit using a fractional derivative. The statespace equation was developed. The dynamics of tensions described by Kirchhoff’s laws equations. The paper used the definition of the integral derivative Caputo and CDF conformable fractional definition. An electrical circuit solution using Caputo and CDF definitions for rectangular with zero initial conditions was developed. The results obtained using the Caputo and CDF definitions were compared. The solutions are shown for capacitor voltages, for fractional derivative orders of 0.6, 0.8, 1. The results were compared using graphs.