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匹配条件： “Jorge Pleite” ，找到相关结果约25302条。
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Simple Procedure to Compute the Inductance of a Toroidal Ferrite Core from the Linear to the Saturation Regions
Rosa Ana Salas,Jorge Pleite
Materials , 2013, DOI: 10.3390/ma6062452

Abstract: We propose a specific procedure to compute the inductance of a toroidal ferrite core as a function of the excitation current. The study includes the linear, intermediate and saturation regions. The procedure combines the use of Finite Element Analysis in 2D and experimental measurements. Through the two dimensional (2D) procedure we are able to achieve convergence, a reduction of computational cost and equivalent results to those computed by three dimensional (3D) simulations. The validation is carried out by comparing 2D, 3D and experimental results.

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Transformer Model in Wide Frequency Bandwidth for Power Electronics Systems
Carlos Gonzalez-Garcia,Jorge Pleite
Advances in Power Electronics , 2013, DOI: 10.1155/2013/249146

Abstract:

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Transformer Model in Wide Frequency Bandwidth for Power Electronics Systems
Carlos Gonzalez-Garcia,Jorge Pleite
Advances in Power Electronics , 2013, DOI: 10.1155/2013/249146

Abstract: The development of the smart grids leads to new challenges on the power electronics equipment and power transformers. The use of power electronic transformer presents several advantages, but new problems related with the application of high frequency voltage and current components come across. Thus, an accurate knowledge of the transformer behavior in a wide frequency range is mandatory. A novel modeling procedure to relate the transformer physical behavior and its frequency response by means of electrical parameters is presented. Its usability is demonstrated by an example where a power transformer is used as filter and voltage reducer in an AC-DC-AC converter. 1. Introduction The future trends on the power delivery are focused on the development of a smart grid. This concept implies new challenges as interconnection or treatment of renewable energy resources and the application of technologies such as telecommunication or power electronics whose products and solutions should play an important role in the future of the medium voltage distribution. The power transformer is widely spread in electrical systems providing basic functionalities such as voltage insulation and voltage adaptation. As an essential element on the energy distribution, it must be involved in the new smart grid perspective, and therefore new roles regarding its manufacturing, maintenance, use, and operation must be taken into account. One of these roles consists in the analysis of its behavior in a wide frequency bandwidth, not limited to the 50 or 60？Hz power frequency. Considering the transformer maintenance program, most of routine tests to assess the transformer condition are based on power frequency (50/60？Hz) measurements (load and no load losses, capacitance, and Tan-Delta). However, the FRA test measures the impedance between two terminals of the transformer in the 20？Hz to 20？MHz bandwidth. It has been extensively proven that this procedure allows the detection of failures that are not visible for other techniques [1]. Considering the power delivery, the conventional line-frequency transformers are not able to deal with power quality problems (e.g., sags, swells, flicker, and harmonics). To solve this task, there have been some attempts (although still under development) for the installation of additional equipment as power electronics converter that operates at higher switching frequencies in the medium voltage grid. It is also applied in the LV grid due to the advances in semiconductor technology (faster switching actions, higher blocking voltages, and higher power

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Implementación de un Modelo de un Transformador Eléctrico para el Análisis de su Respuesta en Frecuencia
Aponte,Guillermo; Herrera,Wilder; González,Carlos; Pleite,Jorge;
Información tecnológica , 2011, DOI: 10.4067/S0718-07642011000400008

Abstract: this article presents the implementation of a model for the analysis of the frequency behavior of a transformer. the model is obtained from the frequency response test (fra). this test consists basically of obtaining the characteristics of the transformer and comparing the results with those of a reference transformer, which are previously known and considered as normal- the differences indicate that the transformer has certain damage. the article describes the model, its implementation, the procedure to obtain its parameters and its application in the analysis of the curve variations obtained by the fra tests. this model represents a good tool that can be used as support to identify some type of mechanical problem in the transformer.

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Implementación de un Modelo de un Transformador Eléctrico para el Análisis de su Respuesta en Frecuencia Implementation of an Electric Transformer Model for its Frequency Response Analysis
Guillermo Aponte,Wilder Herrera,Carlos González,Jorge Pleite
Información Tecnológica , 2011,

Abstract: Este artículo presenta la implementación de un modelo para el análisis del comportamiento en frecuencia de los parámetros de un transformador eléctrico. El modelo se obtiene a partir de la curva de la prueba de Respuesta en Frecuencia del transformador (FRA). Esta prueba consiste básicamente en obtener una característica del transformador y comparar el resultado con una referencia del mismo, tomada anteriormente y considerada como normal. Las diferencias pueden indicar algún tipo de da o en el transformador. Se hace la descripción del modelo, de la manera como se realizó su implementación, del procedimiento para obtener sus parámetros y de su aplicación en el análisis de variaciones en las curvas obtenidas en los ensayos de FRA. Este modelo es una herramienta que puede emplearse como ayuda para identificar problemas de tipo mecánico en el transformador. This article presents the implementation of a model for the analysis of the frequency behavior of a transformer. The model is obtained from the Frequency Response Test (FRA). This test consists basically of obtaining the characteristics of the transformer and comparing the results with those of a reference transformer, which are previously known and considered as normal- The differences indicate that the transformer has certain damage. The article describes the model, its implementation, the procedure to obtain its parameters and its application in the analysis of the curve variations obtained by the FRA tests. This model represents a good tool that can be used as support to identify some type of mechanical problem in the transformer.

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Experimentally obtaining on-line FRA in transformers by injecting controlled pulses
Eduardo Gómez-Luna,Guillermo Aponte,Jorge Pleite Guerra,Wilder Herrera
- , 2013,

Abstract: Transformer monitoring based on the operating condition (on-line test) has boomed in recent years because it allows early detection of risk situations or limitations regarding use to make appropriate decisions before a failure occurs. Frequency response analysis (FRA) is one of the most heavily researched techniques for on-line development; it is based on obtaining a transformer’s frequency response (admittance, impedance or transfer function) in a given bandwidth. This paper presents an experimental method for obtaining the frequency response with the transformer in service by injecting controlled pulses of the voltage signal using an external electronic circuit. Once the voltage and current signals had been recorded, the wavelet transform was used via multi-resolution analysis (MRA) for filtering. This led to results being obtained without noise interference from the electrical system. The transfer function was obtained in terms of impedance, using the fast Fourier transform (FFT). The proposed method represented an alternative in solving some problems arising from the on-line FRA technique such as filtering and results’ repeatability. The tests involved a 5-kVA 1150/345 V three-phase transformer and a 3-kVA, 7620/240 V single-phase transformer in the Universidad del Valle’s High Voltage Laboratory

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Analysis of the behavior and 2D modeling of ferrite inductors with E geometry: comparison with 3D model and real measurements
Salas R. A.,Pleite J.
EPJ Web of Conferences , 2013, DOI: 10.1051/epjconf/20134017007

Abstract: In this paper we propose and validate by experiment a practical method to compute by simulations the inductance of a ferrite inductor as a function of the current intensity level from the linear to the saturation regions. Our method combines the use of 2D Finite Element Analysis with experimental measurements taken in a laboratory environment. We also present and analyze results of the convergence and computational cost of the 2D and 3D simulations showing the reduction of computational cost when we chose the 2D simulation.

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Efectos de la liberalización de los mercados agrarios. Valoraciones acerca de las políticas de desarrollo rural implementadas en México
Schwentesius Rindermann, Rita;Martínez-Carrasco Pleite, Federico;Perní Llorente, Angel;
Revista mexicana de ciencias agrícolas , 2012,

Abstract: poverty in rural areas of countries with medium income, as in the case of the mexican economy, is still one of the priorities in their development agendas. the efforts that have been made in the scope of rural development and agrarian policies have been important in the majority of latin american countries, and mexico has been one of the countries in which the largest budgetary effort has been aimed at this purpose. the advances in the growth of the levels of well being of the rural population have been limited, and for this reason, this work suggests the study, by means of a questionnaire sent to experts on the sector, of the impact of market liberalization policies implemented since the 1990's. the analysis of the qualitative information gathered from experts provides their valuable opinions on their assessment of the current structure on local development policies implemented in mexico, with numerous aspects being objects discussion, with the sole purpose of proposing a modest reflection that, in at least some cases, may guide possible suggestions for the modification of policies implemented from their public administrations.

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Efectos de la liberalización de los mercados agrarios. Valoraciones acerca de las políticas de desarrollo rural implementadas en México Effects of the liberalization of agricultural markets, assessments on the rural development policies implemented in Mexico
Rita Schwentesius Rindermann,Federico Martínez-Carrasco Pleite,Angel Perní Llorente
Revista mexicana de ciencias agrícolas , 2012,

Abstract: La pobreza en las zonas rurales sigue siendo en los países de ingresos medianos, como es el caso de la economía mexicana, una de las prioridades en sus agendas de desarrollo. Los esfuerzos realizados en el ámbito de políticas de desarrollo rural y agrario han sido cuantiosos en la mayor parte de los países latinoamericanos, siendo México uno de los países que un mayor esfuerzo presupuestario relativo está destinando a esos fines. Los avances en el desarrollo de los niveles de bienestar de su población rural empobrecida han sido limitados, proponiéndose en este estudio, mediante un cuestionario enviado a expertos del sector, el impacto que las políticas de liberalización de los mercados implementadas desde los a os noventa. El análisis de la información recabada de los expertos, de carácter cualitativo, proporciona valiosas opiniones acerca de la valoración que les merece la actual estructura de las políticas de desarrollo local implementadas en México, siendo numerosos los aspectos que son objeto de discusión con el único objetivo de proponer una modesta reflexión que, al menos en algún caso, pudieran orientar posibles propuestas de modificación en las políticas implementadas desde sus administraciones públicas. Poverty in rural areas of countries with medium income, as in the case of the Mexican economy, is still one of the priorities in their development agendas. The efforts that have been made in the scope of rural development and agrarian policies have been important in the majority of Latin American countries, and Mexico has been one of the countries in which the largest budgetary effort has been aimed at this purpose. The advances in the growth of the levels of well being of the rural population have been limited, and for this reason, this work suggests the study, by means of a questionnaire sent to experts on the sector, of the impact of market liberalization policies implemented since the 1990's. The analysis of the qualitative information gathered from experts provides their valuable opinions on their assessment of the current structure on local development policies implemented in Mexico, with numerous aspects being objects discussion, with the sole purpose of proposing a modest reflection that, in at least some cases, may guide possible suggestions for the modification of policies implemented from their public administrations.

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A Graph-Theoretical Approach to Calculate Vibrational Energies of Atomic and Subatomic Systems [PDF]
Jorge Galvez
Open Journal of Physical Chemistry (OJPC) , 2012, DOI: 10.4236/ojpc.2012.24028

Abstract: One of the challenges still pending in string theory and other particle physics related fields is the accurate prediction of the masses of the elementary particles defined in the standard model. In this paper an original algorithm to assign graphs to each of these particles is proposed. Based on this mapping, we demonstrate that certain indices associated with the topology of the graph (graph theoretical indices) are very effective in predicting the masses of the particles. Specifically, the spectral moments of the graph adjacency matrix weighted by edge degrees play a key role in the excellent correlations found. Moreover, the same topological pattern is found in other well known quantum systems such as the particle in a box and the vibrational frequencies of diatomic molecules, such as hydrogen. The results shown here open a suggestive pathway for the use of graph-theoretical approaches in predicting properties of elementary particles and other physical systems, which seem to match similar topological patterns.

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