Elementary Derivation of the Nyquist Criterion for Fractional-Order Feedback Systems

It is shown that the classic Nyquist criterion can be extended in a straightforward way to feedback systems of fractional order. The proof of this extension merely requires basic notions of vector analysis and of closed-loop system transfer functions. The criterion can be used not only to ascertain...

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Main Authors: Daniele Casagrande, Wieslaw Krajewski, Umberto Viaro
Format: Article
Language:English
Published: IEEE 2021-01-01
Series:IEEE Open Journal of Circuits and Systems
Subjects:
Online Access:https://ieeexplore.ieee.org/document/9275299/
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author Daniele Casagrande
Wieslaw Krajewski
Umberto Viaro
author_facet Daniele Casagrande
Wieslaw Krajewski
Umberto Viaro
author_sort Daniele Casagrande
collection DOAJ
description It is shown that the classic Nyquist criterion can be extended in a straightforward way to feedback systems of fractional order. The proof of this extension merely requires basic notions of vector analysis and of closed-loop system transfer functions. The criterion can be used not only to ascertain the stability of a fractional-order system but also to detect the presence of closed-loop poles inside any given sector of the complex plane. The test is finally applied to three examples of didactic value.
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spelling doaj.art-75c554151f484f8b9f60d0e1612260222024-12-11T00:07:06ZengIEEEIEEE Open Journal of Circuits and Systems2644-12252021-01-012162210.1109/OJCAS.2020.30400499275299Elementary Derivation of the Nyquist Criterion for Fractional-Order Feedback SystemsDaniele Casagrande0https://orcid.org/0000-0001-6651-1012Wieslaw Krajewski1Umberto Viaro2https://orcid.org/0000-0001-8400-7397Polytechnic Department of Engineering and Architecture, University of Udine, Udine, ItalyPolish Academy of Sciences, Systems Research Institute, Warsaw, PolandPolytechnic Department of Engineering and Architecture, University of Udine, Udine, ItalyIt is shown that the classic Nyquist criterion can be extended in a straightforward way to feedback systems of fractional order. The proof of this extension merely requires basic notions of vector analysis and of closed-loop system transfer functions. The criterion can be used not only to ascertain the stability of a fractional-order system but also to detect the presence of closed-loop poles inside any given sector of the complex plane. The test is finally applied to three examples of didactic value.https://ieeexplore.ieee.org/document/9275299/Fractional-order systemsfeedback systemsstabilityroot clusteringNyquist plot
spellingShingle Daniele Casagrande
Wieslaw Krajewski
Umberto Viaro
Elementary Derivation of the Nyquist Criterion for Fractional-Order Feedback Systems
IEEE Open Journal of Circuits and Systems
Fractional-order systems
feedback systems
stability
root clustering
Nyquist plot
title Elementary Derivation of the Nyquist Criterion for Fractional-Order Feedback Systems
title_full Elementary Derivation of the Nyquist Criterion for Fractional-Order Feedback Systems
title_fullStr Elementary Derivation of the Nyquist Criterion for Fractional-Order Feedback Systems
title_full_unstemmed Elementary Derivation of the Nyquist Criterion for Fractional-Order Feedback Systems
title_short Elementary Derivation of the Nyquist Criterion for Fractional-Order Feedback Systems
title_sort elementary derivation of the nyquist criterion for fractional order feedback systems
topic Fractional-order systems
feedback systems
stability
root clustering
Nyquist plot
url https://ieeexplore.ieee.org/document/9275299/
work_keys_str_mv AT danielecasagrande elementaryderivationofthenyquistcriterionforfractionalorderfeedbacksystems
AT wieslawkrajewski elementaryderivationofthenyquistcriterionforfractionalorderfeedbacksystems
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