Fractional Order: Frequential Parametric Identification of the Skin Effect in the Rotor Bar of Squirrel Cage Induction Machine

2003 ◽  
Author(s):  
Sylvain Canat ◽  
Jean Faucher
Keyword(s):  
Fractional Order ◽  
Frequency Band ◽  
Iterative Procedure ◽  
Skin Effect ◽  
Transfer Functions ◽  
Induction Machine ◽  
Parametric Identification ◽  
Squirrel Cage ◽  
Asynchronous Motors ◽  
Levenberg Marquardt

In this article, the authors propose a method of modeling of the skin effect in the rotor bars of asynchronous motors. Two compact transfer functions with a fractional order were selected to represent the admittance of the bar. The compactness of these transfer functions makes it possible to take into account the diffusive phenomenon of the skin effect on a broad frequency band and is characterized by a small quantity of parameters to identify. The authors carried out an identification by the method of the model associated with an iterative procedure of Levenberg-Marquardt.

Asynchronous machine vector control: PIα controllers for current loops

2018 ◽  
Vol 234 (1) ◽  
pp. 107-117
Author(s):  
Rahma Hammami ◽  
Imène Ben Ameur ◽  
Khaled Jelassi
Keyword(s):  
Vector Control ◽  
Temperature Effect ◽  
Fractional Order ◽  
Induction Machine ◽  
Field Oriented Control ◽  
Electrical Parameters ◽  
Industrial Systems ◽  
Squirrel Cage ◽  
Simulation Results ◽  
Fractional Order Controller

This article deals with field-oriented control of induction machine squirrel cage. A robust fractional-order controller is applied and investigated to control the induction machine currents isd and isq. The fractional-order gives better fit in regulation operation. For this purpose, this controller form is recommended, especially in industrial systems, thanks to his flexibility, robustness and efficiency to solve complex problems such as electrical parameters changes (i.e. uncertain parameter) caused by the temperature effect. Based on frequency specification and several constraints, the fractional-order controller is designed. The fmincon toolbox optimization is used to adjust ki, kp and α values. In order to show the reliability of the developed controller in the induction machine behavior, several simulation results are carried out and illustrated.

scholarly journals Validation of Fractional-Order Lowpass Elliptic Responses of (1 + α)-Order Analog Filters

2018 ◽  
Vol 8 (12) ◽  
pp. 2603 ◽  
Author(s):  
David Kubanek ◽  
Todd Freeborn ◽  
Jaroslav Koton ◽  
Jan Dvorak
Keyword(s):  
Transfer Function ◽  
Least Squares ◽  
Fractional Order ◽  
Frequency Band ◽  
Operational Amplifier ◽  
Transfer Functions ◽  
Second Order ◽  
Experimental Results ◽  
Analog Filters ◽  
Lowpass Filter

In this paper, fractional-order transfer functions to approximate the passband and stopband ripple characteristics of a second-order elliptic lowpass filter are designed and validated. The necessary coefficients for these transfer functions are determined through the application of a least squares fitting process. These fittings are applied to symmetrical and asymmetrical frequency ranges to evaluate how the selected approximated frequency band impacts the determined coefficients using this process and the transfer function magnitude characteristics. MATLAB simulations of ( 1 + α ) order lowpass magnitude responses are given as examples with fractional steps from α = 0.1 to α = 0.9 and compared to the second-order elliptic response. Further, MATLAB simulations of the ( 1 + α ) = 1.25 and 1.75 using all sets of coefficients are given as examples to highlight their differences. Finally, the fractional-order filter responses were validated using both SPICE simulations and experimental results using two operational amplifier topologies realized with approximated fractional-order capacitors for ( 1 + α ) = 1.2 and 1.8 order filters.

scholarly journals Comparative Study of Discrete Component Realizations of Fractional-Order Capacitor and Inductor Active Emulators

2018 ◽  
Vol 27 (11) ◽  
pp. 1850170 ◽  
Author(s):  
Georgia Tsirimokou ◽  
Aslihan Kartci ◽  
Jaroslav Koton ◽  
Norbert Herencsar ◽  
Costas Psychalinos
Keyword(s):  
Comparative Study ◽  
Fractional Order ◽  
High Performance ◽  
Continued Fraction ◽  
Transfer Functions ◽  
Operational Amplifiers ◽  
Current Conveyors ◽  
Continued Fraction Expansion ◽  
Current Feedback ◽  
Discrete Component

Due to the absence of commercially available fractional-order capacitors and inductors, their implementation can be performed using fractional-order differentiators and integrators, respectively, combined with a voltage-to-current conversion stage. The transfer function of fractional-order differentiators and integrators can be approximated through the utilization of appropriate integer-order transfer functions. In order to achieve that, the Continued Fraction Expansion as well as the Oustaloup’s approximations can be utilized. The accuracy, in terms of magnitude and phase response, of transfer functions of differentiators/integrators derived through the employment of the aforementioned approximations, is very important factor for achieving high performance approximation of the fractional-order elements. A comparative study of the accuracy offered by the Continued Fraction Expansion and the Oustaloup’s approximation is performed in this paper. As a next step, the corresponding implementations of the emulators of the fractional-order elements, derived using fundamental active cells such as operational amplifiers, operational transconductance amplifiers, current conveyors, and current feedback operational amplifiers realized in commercially available discrete-component IC form, are compared in terms of the most important performance characteristics. The most suitable of them are further compared using the OrCAD PSpice software.

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