Modeling of a Fractional Order Element Based on Bacterial Cellulose and Ionic Liquids

2021 ◽  
Vol 143 (7) ◽  
Author(s):  
R. Caponetto ◽  
S. Graziani ◽  
E. Murgano ◽  
C. Trigona ◽  
A. Pollicino ◽  
...  
Keyword(s):  
Ionic Liquids ◽  
Frequency Domain ◽  
Bacterial Cellulose ◽  
Fractional Order ◽  
Wide Frequency Range ◽  
Complex Frequency ◽  
Frequency Range ◽  
Time Stability ◽  
Order Element ◽  
Lumped Circuit Model

Abstract In this paper, a novel fractional-order element (FOE) is modeled in a wide frequency range. The FOE is based on a green biopolymer, i.e., bacterial cellulose (BC), infused with ionic liquids (ILs). The modeling is performed in the frequency domain and a lumped-circuit model is proposed. The model is an evolution with respect to a simpler one already introduced by the authors, for a narrower frequency range. Results show that ILs generate a quite complex frequency domain behavior, which can be described in the framework of FOEs. Furthermore, results on the time stability of the device under investigation are given.

scholarly journals Design of Cascaded and Shifted Fractional-Order Lead Compensators for Plants with Monotonically Increasing Lags

2020 ◽  
Vol 4 (3) ◽  
pp. 37
Author(s):  
Guido Maione
Keyword(s):  
Fractional Order ◽  
Transfer Functions ◽  
Wide Frequency Range ◽  
Frequency Range ◽  
Robust Controller ◽  
Simulation Experiments ◽  
Rational Transfer ◽  
Serial Connection ◽  
Efficiency Performance ◽  
Two Stages

This paper concerns cascaded, shifted, fractional-order, lead compensators made by the serial connection of two stages introducing their respective phase leads in shifted adjacent frequency ranges. Adding up leads in these intervals gives a flat phase in a wide frequency range. Moreover, the simple elements of the cascade can be easily realized by rational transfer functions. On this basis, a method is proposed in order to design a robust controller for a class of benchmark plants that are difficult to compensate due to monotonically increasing lags. The simulation experiments show the efficiency, performance and robustness of the approach.

Green Fractional Order Elements Based on Bacterial Cellulose and Ionic Liquids

2020 ◽  
Author(s):  
Riccardo Caponetto ◽  
Giovanna Di Pasquale ◽  
Salvatore Graziani ◽  
Emanuele Murgano ◽  
Antonino Pollicino ◽  
...  
Keyword(s):  
Ionic Liquids ◽  
Bacterial Cellulose ◽  
Fractional Order

scholarly journals Frequency Response Based Curve Fitting Approximation of Fractional–Order PID Controllers

2019 ◽  
Vol 29 (2) ◽  
pp. 311-326 ◽  
Author(s):  
Kishore Bingi ◽  
Rosdiazli Ibrahim ◽  
Mohd Noh Karsiti ◽  
Sabo Miya Hassam ◽  
Vivekananda Rajah Harindran
Keyword(s):  
Frequency Response ◽  
Frequency Domain ◽  
Fractional Order ◽  
Curve Fitting ◽  
Order Approximation ◽  
Frequency Range ◽  
Approximation Techniques ◽  
Integer Order ◽  
The Best Approximation ◽  
Fractional Order Pid

Abstract Fractional-order PID (FOPID) controllers have been used extensively in many control applications to achieve robust control performance. To implement these controllers, curve fitting approximation techniques are widely employed to obtain integer-order approximation of FOPID. The most popular and widely used approximation techniques include the Oustaloup, Matsuda and Cheraff approaches. However, these methods are unable to achieve the best approximation due to the limitation in the desired frequency range. Thus, this paper proposes a simple curve fitting based integer-order approximation method for a fractional-order integrator/differentiator using frequency response. The advantage of this technique is that it is simple and can fit the entire desired frequency range. Simulation results in the frequency domain show that the proposed approach produces better parameter approximation for the desired frequency range compared with the Oustaloup, refined Oustaloup and Matsuda techniques. Furthermore, time domain and stability analyses also validate the frequency domain results.

LOW FREQUENCY MODES PROBED BY TIME-DOMAIN OPTICAL KERR EFFECT SPECTROSCOPY

1996 ◽  
Vol 10 (11) ◽  
pp. 1229-1272 ◽  
Author(s):  
S. KINOSHITA ◽  
Y. KAI ◽  
T. ARIYOSHI ◽  
Y. SHIMADA
Keyword(s):  
Frequency Domain ◽  
Time Domain ◽  
Kerr Effect ◽  
Low Frequency ◽  
Great Accuracy ◽  
Wide Frequency Range ◽  
Optical Kerr Effect ◽  
Spectroscopic Techniques ◽  
Frequency Range ◽  
Debye Relaxation

The principle and application of ultrafast optical Kerr effect (OKE) spectroscopy have been reviewed. This spectroscopy is shown to be very useful to investigate low frequency modes in disordered materials and the obtained data are directly comparable with frequency-domain light scattering spectroscopy. Experimental study to show the consistency between the time- and frequency-domain spectroscopy has been performed for liquid nitrobenzene and the excellent agreement is attained over three orders of magnitude in frequency range. It is also shown that the result obtained by the OKE measurement is consistent with that obtained by four wave mixing spectroscopy. Combination of these spectroscopic techniques is particularly suited for the investigation of low frequency modes because a wide frequency range is covered with great accuracy. Several remarks concerning the OKE spectroscopy are presented such as the breakdown of Debye relaxation model and various interference effects which may distort the time-domain data.

Investigation of Bacterial Cellulose-based Fractional Order Element behaviour

2021 ◽  
Author(s):  
Riccardo Caponetto ◽  
Giovanna di Pasquale ◽  
Salvatore Graziani ◽  
Emanuele Murgano ◽  
Antonino Pollicino ◽  
...  
Keyword(s):  
Bacterial Cellulose ◽  
Fractional Order ◽  
Order Element

Frequency Domain Modal Parameter Identification of High Order Systems in a Numerically Stable Way

1997 ◽  
Vol 119 (2) ◽  
pp. 265-270 ◽  
Author(s):  
K. Q. Xu
Keyword(s):  
Parameter Identification ◽  
Frequency Domain ◽  
Narrow Band ◽  
Wide Frequency Range ◽  
Frequency Range ◽  
Modal Parameter ◽  
Modal Parameter Identification ◽  
Identification Methods ◽  
The Time Domain ◽  
Experimental Data Analysis

Frequency domain modal parameter identification methods have several attractive properties as compared with the time domain methods except for the limitation of low-order-and-narrow-band per analysis. As rule of thumb, a limit of less than ten modes has been observed for several popular frequency domain algorithms. However, this paper will show, that with a proper and thorough use of the orthogonal polynomials in the frequency domain, the number of modes per analysis can be increased to as high as 75 in a comparatively wide frequency range of interest while still retaining numerical stability. Both numerical example (75 modes in 5–1000 Hz) and experimental data analysis (56 modes in 50–5000 Hz) are presented to demonstrate the effectiveness of this innovative approach.

scholarly journals Compact Wide Frequency Range Fractional-Order Models of Human Body Impedance against Contact Currents

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Todd J. Freeborn ◽  
Ahmed S. Elwakil ◽  
Brent Maundy
Keyword(s):  
Least Squares ◽  
Fractional Order ◽  
Human Body ◽  
Nonlinear Least Squares ◽  
Wide Frequency Range ◽  
Frequency Range ◽  
Model Simulations ◽  
Integer Order ◽  
Body Impedance ◽  
Constant Phase Elements

Three circuit models using constant phase elements are investigated to represent the human body impedance against contact currents from 40 Hz to 110 MHz. The parameters required to represent the impedance are determined using a nonlinear least squares fitting (NLSF) applied to the averaged human body impedance dataset. The three fractional-order models with 4, 6, and 7 parameters are compared to an already existing integer-order, 11-parameter model. Simulations of the fractional-order models impedance are presented and discussed along with their limitations.

scholarly journals Application of Kramers-Kronig transformations to increase the bandwidth of small antennas

2019 ◽  
Vol 17 ◽  
pp. 65-70
Author(s):  
Mostafa Bakry ◽  
Ludger Klinkenbusch
Keyword(s):  
Magnetic Material ◽  
Frequency Domain ◽  
Internal Energy ◽  
Electric Energy ◽  
Wide Frequency Range ◽  
Monopole Antenna ◽  
Stored Energy ◽  
Frequency Range ◽  
Small Antennas ◽  
Monopole Antennas

Abstract. The internally stored electric energy (Q-energy) of a disk monopole antenna increases as compared to a monopole antenna without a top disk. Recently it was shown that the Q-energy can be significantly reduced and the bandwidth increased by shielding the disk monopole antenna using a thin magnetic material. In the present paper we consider the same structure to explain another method to increase the bandwidth by using a shield made of dispersive magnetic material. We apply the Kramers-Kronig transforms to derive physically correct real and imaginary parts of the dispersive magnetic material. We do not aim at a reduction of the internal energy but at a compensation of the electric by a magnetic stored energy for a wide frequency range. Disk monopole antennas with shells consisting of such dispersive permeability are finally numerically evaluated by means of a commercial frequency-domain field simulator.

scholarly journals Features of designing line radio interference filter in a wide frequency range, taking into account equivalent circuits for capacitors and inductors

2021 ◽  
Vol 23 (4) ◽  
pp. 85-96
Author(s):  
Vladimir F. Dmitrikov ◽  
Alexander Yu. Petrochenko ◽  
Vyacheslav M. Isaev ◽  
Dmitriy V. Shushpanov
Keyword(s):  
Interference Filter ◽  
Wide Frequency Range ◽  
Dielectric Constants ◽  
Dynamic Processes ◽  
Complex Frequency ◽  
Radio Interference ◽  
Frequency Range ◽  
Electric Circuits ◽  
Parasitic Parameters ◽  
Frequency Properties

Based on the phenomenological equations describing the dynamic processes of magnetization of ferromagnets of inductors and polarization of capacitor dielectrics, taking into account complex frequency-dependent dielectric constants e(jw) of capacitor dielectrics and magnetic permeabilities m(jw) of inductor cores, equivalent electrical structural-parametric and capacitor replacement circuits were obtained. The connection of parasitic elements of equivalent electric circuits of capacitors and inductors with the electrophysical characteristics of the material of the dielectric of the capacitor and the inductor core, which determine their frequency properties, structure and parameters of the elements of the equivalent circuit, is established. The features of the design of line radio interference filter taking into account the parasitic parameters of the inductors and capacitors of line radio interference filter, found as a result of the synthesis of equivalent electric circuits of the inductors and capacitors in a wide frequency range of 150 kHz 30 MHz.

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