Artículos (Ingeniería Electrónica)

URI permanente para esta colecciónhttps://hdl.handle.net/11441/11357

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An efficient ordering algorithm to improve sparse vector methods
(1988-11) Gómez Expósito, Antonio; García Franquelo, Leopoldo; Universidad de Sevilla. Departamento de Ingeniería Electrónica; IEEE Power & Energy Society
This paper presents a new node ordering algorithm to enhance sparse vector methods. The proposed technique locally minimizes the number of non-zero elements of the inverse of the table of factors. It uses the cardinality of the set of nodes which precede each node in the path graph as a tie-break criterion in the minimum degree elimination process. Test results are included showing that the method performs better than previously published methods.
A Neural Controller for quasi-resonant converters
(1991-09-01) Quero Reboul, José Manuel; Carrasco Solís, Juan Manuel; García Franquelo, Leopoldo; Universidad de Sevilla. Departamento de Ingeniería Electrónica
A neural controller implementing an energy feedback control law is proposed to improve the stability and dynamic characteristics of the series resonant converter (SRC). The cnert)' feedback control is introduced and analysed in discrete time domain. A novel formulation of the control law is suggested. The adaptive control law is learnt by an analog neural network (ANN). An easy imple· mentation of this controller is proposed and applied to a SRC circuit. Simulation results show a good improvement in the SRC response and confirm the validity of the controller.
Neural network monitoring of resistance welding processes
(1994) Quero Reboul, José Manuel; Millán Vázquez de la Torre, Rafael Luis; García Franquelo, Leopoldo; Cañas Delgado, José; Universidad de Sevilla. Departamento de Ingeniería Electrónica; Universidad de Sevilla. Departamento de Mecánica de Medios Continuos y Teoría de Estructuras
Control of weld quality is one of the most important and complex processes to be carried out on production lines. Neural networks have shown good results in fields such as modelling and control of physical processes. It is suggested in this article that a neural classifier should be used to carry out non‐destructive on‐line analysis. This system has been developed and installed at resistance welding stations. Results confirm the validity of neural networks used for this type of application.
Integrated solution for induction motor control
(2002-05) Mora Jiménez, José Luis; Barrero, Federico; Galván Díez, Eduardo; Colodro Ruiz, Francisco; Tombs, J. N.; Barranco, M.; Torralba Silgado, Antonio Jesús; García Franquelo, Leopoldo; Universidad de Sevilla. Departamento de Ingeniería Electrónica
The command speed has an 'S' shape, typical in vertical operation systems. The reason for this command speed is that a soft acceleration/deceleration avoids abrupt movements in the elevator cabin, increasing the comfort level. A Fuzzy-logic based controller for the speed and position control based on an ASIC design.
Three-dimensional space vector modulation in abc coordinates for four-leg voltage source converters
(Institute of Electrical and Electronics Engineers (IEEE), 2003) Perales Esteve, Manuel Ángel; Martín Prats, María de los Ángeles; Portillo Guisado, Ramón Carlos; Mora Jiménez, José Luis; León Galván, José Ignacio; García Franquelo, Leopoldo; Universidad de Sevilla. Departamento de Ingeniería Electrónica
Four-leg inverters have been selected as one of the preferred power converter topologies for applications that require a precise control of neutral current, like active filters. The main advantage of this topology lies in an extended range for the zero sequence voltages and currents. However, the addition of a fourth leg extends the space vectors from two to three dimensions, making the selection of the modulation vectors more complex. Most of the algorithms that deal with this problem require an /spl alpha//spl beta//spl gamma/ transformation. This paper presents a new space vector modulation algorithm using abc coordinates (the phase voltages) avoiding the /spl alpha//spl beta//spl gamma/ transformation. Thanks to the use of abc coordinates, the algorithm is much simpler and more intuitive than in /spl alpha//spl beta//spl gamma/ representation, drastically reducing the complexity of modulation algorithm and the computational load associated to it.
Novel control system based in DSPs for 800 KW wind power station
(European Association for the Development of Renewable Energy, Environment and Power Quality (EA4EPQ), 2004) Gallardo, Sergio; Barrero, Federico; Carrasco Solís, Juan Manuel; Universidad de Sevilla. Departamento de Ingeniería Electrónica; Universidad de Sevilla. TIC- 201: Aplicaciones Cibernéticas de la Electrónica a las Tecnologías de la Información; Universidad de Sevilla. TIC-109: Tecnología Electrónica
Wind energy conversion is a very mature technology. Its applications are widely accepted all over the world. Consequently, a tendency to erect more wind turbines can be observed. Therefore, wind turbines may gradually start to replace the output of conventional generators in the future, specially during low load situations with much wind. The wind power has a huge potential to supply electrical power without generating pollution. It has the potential to provide many countries with more of one-third of their electricity demand. A novel control system for a variable speed wind turbine generator has been developed in order to improve the wind turbine behaviour, the hardware is based in two digital signals processors (DSPs) in parallel operation, first one is a TMS320VC33, which manages all the signal analysis, control strategies, the protection systems and mechanical behaviour, and second one is a TMS320LF2407, that controls the PC monitoring program communication, the chopper and inverter PWM devices, temperature measures, encoders velocity and the programmable logic controller communication. The conjunction of the variable speed constant-frequency operation with the digital signal processors capacities improves cost and reliability, low Harmonic distortion (THD), stresses reduction in the drive train, turbine efficiency, audible noise minimization, mechanical design, active power production, reactive production or absorption (leading or lagging power factor) and control strategies (PWM, for example).
A novel space-vector algorithm for multilevel converters based on geometrical considerations using a new sequence control technique
(World Scientific Publishing, 2004) Martín Prats, María de los Ángeles; León Galván, José Ignacio; Portillo Guisado, Ramón Carlos; Carrasco Solís, Juan Manuel; García Franquelo, Leopoldo; Universidad de Sevilla. Departamento de Ingeniería Electrónica
his paper presents a fast and simple space vector modulation algorithm for voltage source multilevel converters for calculating the switching times and the space vectors using simple geometrical considerations. This method provides the nearest switching vectors sequence to the reference vector and calculates the on-state durations of the respective switching state vectors without involving trigonometric functions, look-up tables or coordinate system transformations which increase the computational load corresponding to the modulation of a multilevel converter. The low computational cost of the proposed method is always the same and it is independent of the number of levels of the converter. In addition, a new switching sequence control technique is presented for reducing the ripple of the DC-link voltage approximately in 66%.
Biasing CMOS amplifiers using MOS transistors in subthreshold region
(2004) Bikumandla, Manoj; González Carvajal, Ramón; Ramírez Angulo, Jaime; Urquidi, Carlos; López Martín, Antonio; Universidad de Sevilla. Departamento de Ingeniería Electrónica
The implementation of large-valued floating resistive elements using MOS transistors in subthreshold region is addressed. The application of these elements to bias wideband AC coupled amplifiers is discussed. Simple schemes to generate the gate control voltages for the MOS transistors implementing large resistors so that they remain in high resistive state with large signal variations are discussed. Experimental results of a test chip prototype in 0.5-µm CMOS technology are presented that verify the proposed technique.
Low-voltage wide gm adjustable range highly linear bicmos OTA
(2005) Ramírez Angulo, Jaime; Sawant, Milind S.; López Martín, Antonio; González Carvajal, Ramón; Universidad de Sevilla. Departamento de Ingeniería Electrónica
A low distortion low-voltage BiCMOS OTA with wide gm adjustment range and constant input range is presented. It is based on a highly linear voltage-to-current converter input stage merged with translinear loops that implement linear electronically programmable current mirrors. Experimental results are provided that confirm the characteristics of the proposed OTA with a single 1.7V supply, 1.2V input range, two decades gain adjustment range, and 0.3% THD.
Microprocessor and FPGA interfaces for in-system co-debugging in field programmable hybrid systems
(Elsevier, 2005) Aguirre Echanove, Miguel Ángel; Tombs, J. N.; Baena Lecuyer, Vicente; Mora Jiménez, José Luis; Carrasco Solís, Juan Manuel; Torralba Silgado, Antonio Jesús; García Franquelo, Leopoldo; Universidad de Sevilla. Departamento de Ingeniería Electrónica
Modern trends in technology require efficient control and processing platforms based on connected software-hardware subsystems. Due to their complexity and size, algorithms implemented on these platforms are difficult to test and verify. When these types of solution are being designed, it is necessary to provide information of the internal values of registers and memories of both the software and hardware during the execution of the complete system. The final architecture of the targeted design and its debugging capabilities strongly depends on how the hybrid system is connected and clocked. This article discusses different architectural strategies that have been adopted for a hybrid hardware-software platform, built ready for debugging, and that uses components that can be easily found with a few special features. All the solutions have been implemented and evaluated using the UNSHADES-2 framework.
A true low voltage class-AB current mirror
(2005) Torralba Silgado, Antonio Jesús; González Carvajal, Ramón; Jiménez Fuentes, José Mariano; Muñoz Chavero, Fernando; Ramírez Angulo, Jaime; Universidad de Sevilla. Departamento de Ingeniería Electrónica
Class-AB circuits, which are able to deal with currents which are orders of magnitude larger than their quiescent current, are good candidates for low-power analog design. This paper presents a new, simple, class-AB current-mirror, based on the Flipped Voltage Follower [1]. In the authors knowledge this is the first class-AB current-mirror which operates with a supply voltage smaller than two transistor threshold voltages without an additional clock signal or voltage doubler. Experimental results are provided which show proper operation at 1.5V in a 0.5µm standard CMOS technology.
Herramienta multimedia de ayuda en la impartición de un laboratorio de procesadores digitales de señal (DSPs)
(2005) Gallardo Vázquez, Sergio; Barrero, Federico; Toral, S. L.; Universidad de Sevilla. Departamento de Ingeniería Electrónica
El presente trabajo describe una aplicación multimedia realizada en el Departamento de Ingeniería Electrónica de la Escuela Superior de Ingenieros de Sevilla. La herramienta, un CD interactivo, se ha desarrollado con vistas a su empleo como laboratorio virtual y sistema de ayuda en la impartición de un laboratorio de Procesadores Digitales de Señal (DSPs). El uso de este CD agiliza el proceso de aprendizaje y/o entrenamiento de los estudiantes en la asignatura, fomentando la participación de los alumnos en el mismo. El material didáctico se emplea en la actualidad, con gran éxito, en las clases prácticas de la asignatura "Complemento de Sistemas Electrónicos Digitales", de tercer curso de Ingeniero de Telecomunicación
A digital signal processing teaching methodology using concept-mapping techniques
(IEEE, 2005) Martínez Torres, María del Rocío; Barrero, Federico; Toral, S. L.; Gallardo Vázquez, Sergio; Universidad de Sevilla. Departamento de Administración de Empresas y Comercialización e Investigación de Mercados (Marketing); Universidad de Sevilla. Departamento de Ingeniería Electrónica
The main goal of this study is to develop a scientific method for designing a teaching methodology used in a basic digital signal processing (DSP) course. The proposed method is based on concept-mapping techniques, which applies multivariate statistic analysis to summarize the experience and knowledge of teachers involved in basic DSP teaching. As a result, a set of teaching methodologies is obtained. This result, as well as other information obtained related to the relative importance of the concepts to be covered, has been used to program the course. Moreover, different teaching tools have been developed to implement the proposed teaching methodology. Finally, the reliability of the method has been compared with similar studies to validate the proposed methodology
Implementation of a web-based educational tool for digital signal processing teaching using the technological acceptance model
(2005) Toral, S. L.; Barrero, Federico; Martínez Torres, María del Rocío; Gallardo Vázquez, Sergio; Lillo, Javier; Universidad de Sevilla. Departamento de Administración de Empresas y Comercialización e Investigación de Mercados (Marketing); Universidad de Sevilla. Departamento de Ingeniería Electrónica
This paper presents an exploratory study about the improvement and validation of a Web-based educational tool. The tool, designed with Shockwave and Macromedia Director, is used as a teaching methodology in an undergraduate course using modern microprocessors, architectures, and applications. An information system theory, called the Technological Acceptance Model (TAM), has been applied to detect both the use of the tool and the external variables that have a significant influence over it. The obtained results illustrate the strengths and weaknesses to be reinforced and have been taken into account to implement the final version of the tool. The proposed method may be extended to similar tools and experiments to fill the lack of scientific studies in the validation and acceptance of computer-based educational tools
New space vector modulation algorithms applied to multilevel converters with balanced DC-link voltage
(Holon Academic Institute of Technology, 2005) Martín Prats, María de los Ángeles; Carrasco Solís, Juan Manuel; García Franquelo, Leopoldo; Universidad de Sevilla. Departamento de Ingeniería Electrónica
This work presents a survey of new space vector modulation algorithms for high power voltage source multilevel converters. These techniques provide the nearest switching vectors sequence to the reference vector and calculates the on-state durations of the respective switching state vectors without involving trigonometric functions, look-up tables or coordinate system transformations which increase the computational load corresponding to the modulation of a multilevel converter. These algorithms drastically reduce the computational load maintained permitting the on-line computation of the switching sequence and the on-state durations of the respective switching state vectors. The on-state durations are reduced to a simple addition. In addition, the low computational cost of the proposed methods is always the same and it is independent of the number of levels of the converter. The algorithms have been satisfactorily implemented in very low-cost microcontrollers.
Power-electronic systems for the grid integration of renewable energy sources: a survey
(Institute of Electrical and Electronics Engineers (IEEE), 2006) Carrasco Solís, Juan Manuel; García Franquelo, Leopoldo; Bialasiewicz, Jan T.; Galván Díez, Eduardo; Portillo Guisado, Ramón Carlos; Martín Prats, María de los Ángeles; León Galván, José Ignacio; Moreno-Alfonso, Narciso; Universidad de Sevilla. Departamento de Ingeniería Electrónica; Universidad de Sevilla. Departamento de Ingeniería Eléctrica; Universidad de Sevilla. TIC109: Tecnología Electrónica
The use of distributed energy resources is increasingly being pursued as a supplement and an alternative to large conventional central power stations. The specification of a powerelectronic interface is subject to requirements related not only to the renewable energy source itself but also to its effects on the power-system operation, especially where the intermittent energy source constitutes a significant part of the total system capacity. In this paper, new trends in power electronics for the integration of wind and photovoltaic (PV) power generators are presented. A review of the appropriate storage-system technology used for the integration of intermittent renewable energy sources is also introduced. Discussions about common and future trends in renewable energy systems based on reliability and maturity of each technology are presented.
Determinación de las variables de diseño en el desarrollo de una herramienta de elearning
(Secretariado de Publicaciones de la Universidad de Sevilla, 2006) Toral, S. L.; Barrero, Federico; Martínez Torres, María del Rocío; Gallardo Vázquez, Sergio; Cortés Martínez, Francisco Javier; Arias Oliva, M.; Rallo, Robert; Carpeño, Antonio; Ruiz, Mariano; Peñarrocha, Rodrigo; Castro, Manuel; Díaz, Gabriel; Ruiz, Elio; Universidad de Sevilla. Departamento de Administración de Empresas y Comercialización e Investigación de Mercados (Marketing); Universidad de Sevilla. Departamento de Ingeniería Electrónica; Ministerio de Educación y Ciencia (MEC). España
En este artículo se muestran, a través de mapas bidimensionales, los resultados procedentes de un proyecto de investigación mediante el cual se han identificado las variables externas a tener en cuenta en el diseño de una herramienta de eLearning para conseguir evaluar, posteriormente, su uso real. La técnica empleada para ello es la "Elaboración de mapas conceptuales". Asimismo, se observa la necesidad de tener en cuenta cómo llevar a cabo la gestión de la herramienta por parte del usuario. Finalmente, se ha analizado la fiabilidad de nuestros mapas
Planning a master's level curriculum according to career space recommendations using concept mapping techniques
(2006) Toral, S. L.; Martínez Torres, María del Rocío; Barrero, Federico; Gallardo Vázquez, Sergio; Vargas, Enrique; González Ayala, Vicente; Universidad de Sevilla. Departamento de Administración de Empresas y Comercialización e Investigación de Mercados (Marketing); Universidad de Sevilla. Departamento de Ingeniería Electrónica
Nowadays the European Universities are worried about how to adapt higher education to the new European Higher Education Area, as proposed in the Bologna Magna Charta Universitatum of 1998, and signed by 32 European Education Ministers. One of the key points in this higher education reform was the introduction of new Master’s level curricula. These Masters will look for the professional specialization and they will have to be adapted to the specific skills demanded by the society. This paper presents the results from a cooperation project – funded by the AECI (International Cooperation Spanish Agency) and developed between the University of Seville (Spain) and the Catholic University of Asuncion (Paraguay) – by about the planning of a new master’s level curriculum in digital signal processing (DSP) area, taking into account the Bologna principles and the conclusions obtained by the Career Space Consortium. A scientific method from social science, known as concept mapping techniques, was used to perform this planning. Basically, the idea of concept mapping consists of compiling the opinion from actors belonging to different environments (lecturers, researchers, workers, businessmen, etc.) related to DSP applications. The compiled data were statistically computed to cluster the opinions of the different agents. The result will be a master’s level curricula adapted to the environment requirements and the social settings
Empleo de las tecnologías móviles en la enseñanza práctica de asignaturas técnicas. Un caso real: el laboratorio de instrumentación electrónica
(Secretariado de Publicaciones de la Universidad de Sevilla, 2006) Gallardo Vázquez, Sergio; Barrero, Federico; Toral, S. L.; Martínez Torres, María del Rocío; Universidad de Sevilla. Departamento de Administración de Empresas y Comercialización e Investigación de Mercados (Marketing); Universidad de Sevilla. Departamento de Ingeniería Electrónica
Hoy día nuestra sociedad está involucrada en el continuo desarrollo de tres importantes pilares de conocimiento, la electrónica, la informática y las telecomunicaciones. Este documento describe la introducción de estos tres pilares tecnológicos del conocimiento en la enseñanza práctica de carreras técnicas, particularizando sobre un laboratorio de instrumentación electrónica. El sistema propuesto, desarrollado en el Departamento de Ingeniería Electrónica de la Universidad de Sevilla, muestra la implementación de una maqueta de un sistema de seguridad para vehículos que emplea un teléfono móvil convencional como sistema de telecontrol, mejorando el proceso de enseñanza de los estudiantes y fomentando la participación de los mismos
Space Vector Modulation Techniques for Multilevel Converters – a survey
(Holon Academic Institute of Technology (HAIT), 2006) García Franquelo, Leopoldo; León Galván, José Ignacio; Martín Prats, María de los Ángeles; Portillo Guisado, Ramón Carlos; Universidad de Sevilla. Departamento de Electrónica y Electromagnetismo
This paper presents a survey of most recent, simple and efficient Space Vector Modulation algorithms for multilevel converters. These algorithms avoid trigonometric and other complex operations, leading to more simple and cost efficient implementations. They can be applied to multilevel topologies and present freedom degrees that can be Exploited in order to optimize system parameters in the system like: capacitors voltages balancing or voltage/current ripples. Experimental results are presented to show the good performance of the algorithms.

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