Walter Carpes Jr | Universidade Federal de Santa Catarina - UFSC (Federal University of Santa Catarina) (original) (raw)
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Papers by Walter Carpes Jr
Resumo-Este trabalho apresenta um modelo que associa um código de otimização baseado no método Pa... more Resumo-Este trabalho apresenta um modelo que associa um código de otimização baseado no método Particle Swarm Optimization (PSO) com um algoritmo que implementa a Técnica de Traçado de Raios 2D, para otimizar o posicionamento de antenas de estações radiobase em ambientes interiores. O código PSO otimiza a posição da antena de modo a obter o campo mais uniforme possível em uma dada região de interesse. O desempenho do código PSO foi comparado com o de um código baseado em Algoritmos Genéticos (AG), aplicado ao mesmo problema. Observou-se que o PSO apresentou resultados mais satisfatórios que o AG.
The analytical modeling of a three-core cable system is challenging because of the non-concentric... more The analytical modeling of a three-core cable system is challenging because of the non-concentric configuration of the components involved. Given these limitations, a 2D finite element modeling of the cable is developed in order to obtain the values of the self, mutual and sequence impedances and admittances. To calculate the series impedance, a magnetic vector potential magnetodynamic formulation is used and for the calculation of the parallel admittance, an electric scalar potential electrostatic formulation is applied. By calculating the series impedance of the inner cables, the influence of the mutual impedances in all metallic elements involved is shown. The methodology is applied to a typical cable of 300 mm²-18/30 kV. The numerical results are compared with analytical ones and with values supplied by the manufacturer for each phase, validating the numerical modeling.
This paper presents a methodology for determining the values of magnetic induction and current de... more This paper presents a methodology for determining the values of magnetic induction and current density in the design of transformers and inductors based on planar magnetic elements. From experimental values, datasheet parameters and through an optimization tool based on genetic algorithms, we obtain curves of magnetic induction and current density corresponding to operation with minimal magnetic losses. Hence, from the obtained results, it is possible to design a planar magnetic device operating with minimal losses.
Visión electrónica, 2018
El análisis paramétrico usado en la determinación de los efectos de los parámetros geométricos y ... more El análisis paramétrico usado en la determinación de los efectos de los parámetros geométricos y los asociados al dieléctrico en Superficies Selectivas en Frecuencia (SSF), es una herramienta de uso generalizado debido a la ausencia de formulaciones que permitan evaluar este tipo de efectos. El objetivo de esta clase de análisis es determinar la influencia en la frecuencia de resonancia de un parámetro en particular, bien sea asociado al soporte dieléctrico o a los parámetros geométricos de la superficie selectiva, con la finalidad de orientar el proceso de diseño de la superficie. En este artículo se presenta la aplicación del Modelo de Circuito Equivalente (MCE) actuando en conjunto con una novedosa formulación de la permitividad efectiva del dieléctrico en SSF tipo bucle cuadrado, el cual permite determinar los efectos de los parámetros geométricos y los asociados al dieléctrico en la frecuencia de resonancia de la superficie selectiva, haciendo innecesario el uso de análisis de ...
COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, 2016
Purpose The purpose of this paper is to present the results of a particle swarm optimization (PSO... more Purpose The purpose of this paper is to present the results of a particle swarm optimization (PSO) method applied in the design of a square-loop frequency selective surface (FSS) via the equivalent circuit model (ECM), considering the dielectric effective permittivity as a variable in the optimization problem. Design/methodology/approach In the optimization process considered, besides the FSS square loop geometric parameters, the thickness and relative permittivity of dielectric material used as support are included as variables in the search space, using for this a model of dielectric effective permittivity introduced by the authors in a previous work. Findings Square loops were designed and the obtained results were compared with designs reported in literature for applications in wireless local area network and long-term evolution 4G systems. The low computational cost is remarkable as well as the acceptable accuracy obtained with the proposed approach. The PSO method results were...
Journal of Microwaves, Optoelectronics and Electromagnetic Applications, 2016
The purpose of this article is based on analyzing the use of RTQ3D ("quasi-3D" ray tracing techni... more The purpose of this article is based on analyzing the use of RTQ3D ("quasi-3D" ray tracing technique) to produce the value of the initial electromagnetic fields or fitness for a hundred and sixty receivers according to the possible positions of two antennas to be distributed in a closed environment. The problem variables consist of the values of the magnetic fields for one hundred and sixty receptors depending on the positions of the antennas to the base stations, which serve as input data for the algorithm to the RMLP (Artificial Neural Network, multilayer perceptron with Real backpropagation learning algorithm). The values of the magnetic fields associated with the positions of the antennas are the values to be learned by the network, the teacher of RMLP.
Journal of Control, Automation and Electrical Systems, 2017
A full computer-based methodology is proposed for electromagnetic transient simulations in power ... more A full computer-based methodology is proposed for electromagnetic transient simulations in power cables characterized by an arbitrary cross-section geometry. The frequency-dependent parameters of the cables are calculated using finite element method, and the three-phase cable modeling is carried out using modal decoupling and fitting techniques. The multiconductor representation of a sectorshaped cable is possible from the calculation of a constant and real modal transformation matrix, resulting four independent propagation modes (three phases and cable shield), which are modeled from the inclusion of frequency effect in the classic Bergeron method. The currents and voltages are expressed as a system of differential equations, which are presented as state equations and solved using numerical inte
2008 18th International Conference on Electrical Machines, 2008
ABSTRACT This paper presents a methodology for determining the values of magnetic induction and c... more ABSTRACT This paper presents a methodology for determining the values of magnetic induction and current density for the design of transformers and inductors using planar magnetic elements. From experimental values as well as datasheet parameters and by using an optimization tool based on genetic algorithms, we obtained curves of magnetic induction and current density corresponding to operation with minimal magnetic losses. From the obtained results, it is possible to design a planar magnetic device operating with minimal losses.
This work presents the modeling of the frequency response of a transformer using equivalent netwo... more This work presents the modeling of the frequency response of a transformer using equivalent networks and Genetic Algorithms (GA). The transformer is modeled by an equivalent impedance at its terminals representing resonances occurring in the analyzed frequency response. Initially, the electric parameters of this impedance are coarsely estimated using the theory of band-pass filters. Afterward, these parameters are optimized using GA technique by fitting the frequency response curves acquired by an impedance analyzer to those of the developed model.
2008 18th International Conference on Electrical Machines, 2008
This paper aims at presenting several parameters for the determination of magnetic losses in plan... more This paper aims at presenting several parameters for the determination of magnetic losses in planar magnetic devices. All the figures, equations, and graphics presented were obtained by analytical studies, simulations using finite-element analysis, and mainly through the measurements taken on a magnetic device built for this purpose. From the obtained results, it is possible to design a planar transformer or
… Revista de Automação e Tecnologia da …, 2002
… de Engenharia ElétricaUFSC. Available from World …
IEEE Transactions on Magnetics, 2004
This paper presents the application of genetic algorithms in the optimization of an offset reflec... more This paper presents the application of genetic algorithms in the optimization of an offset reflector antenna. The antenna shape is designed in order to obtain a uniform radiation pattern on the Brazilian territory. Modified genetic operators are proposed with the aim to increase the efficiency of the real coded genetic algorithms used here.
IEEE Transactions on Magnetics, 2004
The parameters set of the Jiles-Atherton hysteresis model is identified by using a real coded gen... more The parameters set of the Jiles-Atherton hysteresis model is identified by using a real coded genetic algorithm. The parameters identification is performed by minimizing the mean squared error between experimental and simulated magnetic field curves. The procedure is validated by comparing experimental and simulated results.
Due to the growing demand for traffic communication, the requirement for reconfigurable antennas ... more Due to the growing demand for traffic communication, the requirement for reconfigurable antennas for future generation of satellites is growing steadily. This article presents designs examples of reconfigurable satellite contour beam reflector antennas via multi-objective evolutionary optimization. One configuration is composed of shaped reflector illuminated by a single feed horn. To explore the concept, we consider the case of a satellite that can be placed in three orbital positions to provide different coverage: Europe, North America and South America. A second example considers a single shaped reflector illuminated by two feed horns to simultaneously provide dual coverage with frequency reuse.
This paper presents a numerical method based on finite elements in both frequency and time domain... more This paper presents a numerical method based on finite elements
in both frequency and time domain for modeling the coupling of an
incident wave with a conducting wire placed inside a metallic cavity having a small aperture. The method uses edge elements on tetrahedra for the electric field representation. The formulation can take into account thin wires as well as lumped elements. In the time-domain approach, the time derivatives are discretized by the Newmark method, which allows obtaining an unconditionally-stable scheme with second-order accuracy. Numerical results are provided to validate the presented method.
Resumo-Este trabalho apresenta um modelo que associa um código de otimização baseado no método Pa... more Resumo-Este trabalho apresenta um modelo que associa um código de otimização baseado no método Particle Swarm Optimization (PSO) com um algoritmo que implementa a Técnica de Traçado de Raios 2D, para otimizar o posicionamento de antenas de estações radiobase em ambientes interiores. O código PSO otimiza a posição da antena de modo a obter o campo mais uniforme possível em uma dada região de interesse. O desempenho do código PSO foi comparado com o de um código baseado em Algoritmos Genéticos (AG), aplicado ao mesmo problema. Observou-se que o PSO apresentou resultados mais satisfatórios que o AG.
The analytical modeling of a three-core cable system is challenging because of the non-concentric... more The analytical modeling of a three-core cable system is challenging because of the non-concentric configuration of the components involved. Given these limitations, a 2D finite element modeling of the cable is developed in order to obtain the values of the self, mutual and sequence impedances and admittances. To calculate the series impedance, a magnetic vector potential magnetodynamic formulation is used and for the calculation of the parallel admittance, an electric scalar potential electrostatic formulation is applied. By calculating the series impedance of the inner cables, the influence of the mutual impedances in all metallic elements involved is shown. The methodology is applied to a typical cable of 300 mm²-18/30 kV. The numerical results are compared with analytical ones and with values supplied by the manufacturer for each phase, validating the numerical modeling.
This paper presents a methodology for determining the values of magnetic induction and current de... more This paper presents a methodology for determining the values of magnetic induction and current density in the design of transformers and inductors based on planar magnetic elements. From experimental values, datasheet parameters and through an optimization tool based on genetic algorithms, we obtain curves of magnetic induction and current density corresponding to operation with minimal magnetic losses. Hence, from the obtained results, it is possible to design a planar magnetic device operating with minimal losses.
Visión electrónica, 2018
El análisis paramétrico usado en la determinación de los efectos de los parámetros geométricos y ... more El análisis paramétrico usado en la determinación de los efectos de los parámetros geométricos y los asociados al dieléctrico en Superficies Selectivas en Frecuencia (SSF), es una herramienta de uso generalizado debido a la ausencia de formulaciones que permitan evaluar este tipo de efectos. El objetivo de esta clase de análisis es determinar la influencia en la frecuencia de resonancia de un parámetro en particular, bien sea asociado al soporte dieléctrico o a los parámetros geométricos de la superficie selectiva, con la finalidad de orientar el proceso de diseño de la superficie. En este artículo se presenta la aplicación del Modelo de Circuito Equivalente (MCE) actuando en conjunto con una novedosa formulación de la permitividad efectiva del dieléctrico en SSF tipo bucle cuadrado, el cual permite determinar los efectos de los parámetros geométricos y los asociados al dieléctrico en la frecuencia de resonancia de la superficie selectiva, haciendo innecesario el uso de análisis de ...
COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, 2016
Purpose The purpose of this paper is to present the results of a particle swarm optimization (PSO... more Purpose The purpose of this paper is to present the results of a particle swarm optimization (PSO) method applied in the design of a square-loop frequency selective surface (FSS) via the equivalent circuit model (ECM), considering the dielectric effective permittivity as a variable in the optimization problem. Design/methodology/approach In the optimization process considered, besides the FSS square loop geometric parameters, the thickness and relative permittivity of dielectric material used as support are included as variables in the search space, using for this a model of dielectric effective permittivity introduced by the authors in a previous work. Findings Square loops were designed and the obtained results were compared with designs reported in literature for applications in wireless local area network and long-term evolution 4G systems. The low computational cost is remarkable as well as the acceptable accuracy obtained with the proposed approach. The PSO method results were...
Journal of Microwaves, Optoelectronics and Electromagnetic Applications, 2016
The purpose of this article is based on analyzing the use of RTQ3D ("quasi-3D" ray tracing techni... more The purpose of this article is based on analyzing the use of RTQ3D ("quasi-3D" ray tracing technique) to produce the value of the initial electromagnetic fields or fitness for a hundred and sixty receivers according to the possible positions of two antennas to be distributed in a closed environment. The problem variables consist of the values of the magnetic fields for one hundred and sixty receptors depending on the positions of the antennas to the base stations, which serve as input data for the algorithm to the RMLP (Artificial Neural Network, multilayer perceptron with Real backpropagation learning algorithm). The values of the magnetic fields associated with the positions of the antennas are the values to be learned by the network, the teacher of RMLP.
Journal of Control, Automation and Electrical Systems, 2017
A full computer-based methodology is proposed for electromagnetic transient simulations in power ... more A full computer-based methodology is proposed for electromagnetic transient simulations in power cables characterized by an arbitrary cross-section geometry. The frequency-dependent parameters of the cables are calculated using finite element method, and the three-phase cable modeling is carried out using modal decoupling and fitting techniques. The multiconductor representation of a sectorshaped cable is possible from the calculation of a constant and real modal transformation matrix, resulting four independent propagation modes (three phases and cable shield), which are modeled from the inclusion of frequency effect in the classic Bergeron method. The currents and voltages are expressed as a system of differential equations, which are presented as state equations and solved using numerical inte
2008 18th International Conference on Electrical Machines, 2008
ABSTRACT This paper presents a methodology for determining the values of magnetic induction and c... more ABSTRACT This paper presents a methodology for determining the values of magnetic induction and current density for the design of transformers and inductors using planar magnetic elements. From experimental values as well as datasheet parameters and by using an optimization tool based on genetic algorithms, we obtained curves of magnetic induction and current density corresponding to operation with minimal magnetic losses. From the obtained results, it is possible to design a planar magnetic device operating with minimal losses.
This work presents the modeling of the frequency response of a transformer using equivalent netwo... more This work presents the modeling of the frequency response of a transformer using equivalent networks and Genetic Algorithms (GA). The transformer is modeled by an equivalent impedance at its terminals representing resonances occurring in the analyzed frequency response. Initially, the electric parameters of this impedance are coarsely estimated using the theory of band-pass filters. Afterward, these parameters are optimized using GA technique by fitting the frequency response curves acquired by an impedance analyzer to those of the developed model.
2008 18th International Conference on Electrical Machines, 2008
This paper aims at presenting several parameters for the determination of magnetic losses in plan... more This paper aims at presenting several parameters for the determination of magnetic losses in planar magnetic devices. All the figures, equations, and graphics presented were obtained by analytical studies, simulations using finite-element analysis, and mainly through the measurements taken on a magnetic device built for this purpose. From the obtained results, it is possible to design a planar transformer or
… Revista de Automação e Tecnologia da …, 2002
… de Engenharia ElétricaUFSC. Available from World …
IEEE Transactions on Magnetics, 2004
This paper presents the application of genetic algorithms in the optimization of an offset reflec... more This paper presents the application of genetic algorithms in the optimization of an offset reflector antenna. The antenna shape is designed in order to obtain a uniform radiation pattern on the Brazilian territory. Modified genetic operators are proposed with the aim to increase the efficiency of the real coded genetic algorithms used here.
IEEE Transactions on Magnetics, 2004
The parameters set of the Jiles-Atherton hysteresis model is identified by using a real coded gen... more The parameters set of the Jiles-Atherton hysteresis model is identified by using a real coded genetic algorithm. The parameters identification is performed by minimizing the mean squared error between experimental and simulated magnetic field curves. The procedure is validated by comparing experimental and simulated results.
Due to the growing demand for traffic communication, the requirement for reconfigurable antennas ... more Due to the growing demand for traffic communication, the requirement for reconfigurable antennas for future generation of satellites is growing steadily. This article presents designs examples of reconfigurable satellite contour beam reflector antennas via multi-objective evolutionary optimization. One configuration is composed of shaped reflector illuminated by a single feed horn. To explore the concept, we consider the case of a satellite that can be placed in three orbital positions to provide different coverage: Europe, North America and South America. A second example considers a single shaped reflector illuminated by two feed horns to simultaneously provide dual coverage with frequency reuse.
This paper presents a numerical method based on finite elements in both frequency and time domain... more This paper presents a numerical method based on finite elements
in both frequency and time domain for modeling the coupling of an
incident wave with a conducting wire placed inside a metallic cavity having a small aperture. The method uses edge elements on tetrahedra for the electric field representation. The formulation can take into account thin wires as well as lumped elements. In the time-domain approach, the time derivatives are discretized by the Newmark method, which allows obtaining an unconditionally-stable scheme with second-order accuracy. Numerical results are provided to validate the presented method.