EPIC - Energy Processing and Integrated Circuits
Total activity: 993
Type
Research group
Type of group
UPC research group
Acronym
EPIC
URL
http://www.eel.upc.edu/investigacion/grupos-de-investigacion-1/electronica-industrial-y-de-pontencia/epic-energy-processing-and-integrated-circuits?set_language=es Open in new window
Objectives
- Modelling, design (voltage and current modes), implementation and characterisation of analogue integrated circuits such as amplifiers, oscillators, automatically-tuned filters, communication circuits, etc.
- Modelling, design, control (linear control, current-mode control, sliding-mode control and fuzzy control), implementation and characterisation of switching power converters. Application to DC-DC and DC-AC conversions and to the series-parallel connection of converters.
- Fuzzy modelling of nonlinear dynamic systems.
- Microelectronic design of neuro-fuzzy processors and switching power converter controllers.
Keywords
convertidors de potencia conmutats,disseny VLSI,Disseny VLSI analògic en mode de corrent,modelat no lineal i control,processat fuzzy.,sintonia on-chip

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  • Design and comparison of flipped active inductors with high quality factors

     Saberkari, Alireza; Ziabakhsh, Soheil; Martínez García, Herminio; Alarcon Cot, Eduardo Jose
    Electronics Letters
    Vol. 50, num. 13, p. 925-927
    DOI: 10.1049/el.2014.0488
    Date of publication: 2014-05-19
    Journal article

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    A new design based on the flipped-structure for RF active inductors is presented. The conventional flipped-active inductor (FAI) composed of only two transistors is considered as a starting structure. However, it suffers from low-voltage swing, which increases the nonlinearity. Additionally, it requires high power consumption to achieve adequate inductance and quality factor values. A circuit topology named cascoded FAI (CASFAI) based on the basic FAI is proposed. A common-gate transistor added in the feedback path of the proposed CASFAI results in an increase of the voltage swing and linearity as well as the feedback gain. The performance metrics of such active inductors are benchmarked by analytical models and validated in the ADS using a 0.18 µm CMOS process. The results indicate that the CASFAI can achieve a notably higher quality factor and higher inductance values while consuming less power in comparison to the basic FAI.

    A new design based on the flipped-structure for RF active inductors is presented. The conventional flipped-active inductor (FAI) composed of only two transistors is considered as a starting structure. However, it suffers from low-voltage swing, which increases the nonlinearity. Additionally, it requires high power consumption to achieve adequate inductance and quality factor values. A circuit topology named cascoded FAI (CASFAI) based on the basic FAI is proposed. A common-gate transistor added in the feedback path of the proposed CASFAI results in an increase of the voltage swing and linearity as well as the feedback gain. The performance metrics of such active inductors are benchmarked by analytical models and validated in the ADS using a 0.18 µm CMOS process. The results indicate that the CASFAI can achieve a notably higher quality factor and higher inductance values while consuming less power in comparison to the basic FAI.

  • Some limits in peer assessment

     Domingo Peña, Joan; Martínez García, Herminio; Gomariz Castro, Spartacus; Gamiz Caro, Juan
    Journal of technology and science education
    Vol. 4, num. 1, p. 12-24
    Date of publication: 2014-03-25
    Journal article

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    Nowadays, the educational methodology known as `peer assessment¿ constitutes one of the pillars of formative assessment at the different levels of the educational system, particularly at the University level. In fact, in recent years, it has been increasingly used to enhance students' meaningful learning, as it is considered to be an element of social learning, in which students benefit from the lessons learned by other classmates, and draw upon the ability to assess the quality of the learning, contrasting it with the level of knowledge that each has about the subject/course being evaluated, and using common evaluation criteria. In this regard, this paper represents the experience of two groups of students. It allows us to determine how many peer assessments should be required of students in a particular course in order to constitute a serious, reliable activity. On the other hand, from the point of view of the student, the assessments are evaluated to the extent that they are seen as a required and mandatory exercise that must be carried out by students simply to pass the course. In the latter case, the activity can become extremely trivial and banal. Statistical analysis of the results indicates that three peer assessments per student appraised represents an adequate number. On the other hand, more than thirty peer assessments fail to contribute to learning, nor do they represent serious activities.

  • Global MPPT scheme for photovoltaic string inverters based on restricted voltage window search algorithm

     Boztepe, Mutlu; Guinjoan Gispert, Francisco; Velasco Quesada, Guillermo; Silvestre Berges, Santiago; Chouder, Aissa; Karatepe, Engin
    IEEE transactions on industrial electronics
    Vol. 61, num. 7, p. 3302-3312
    DOI: 10.1109/TIE.2013.2281163
    Date of publication: 2014-07-01
    Journal article

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    String inverter photovoltaic (PV) systems with bypass diodes require improved global maximum power point tracking (GMPPT) algorithms to effectively reach the absolute maximum power operating point. Several GMPPT algorithms have been proposed to deal with this problem, but most of them require scanning wide voltage ranges of the PV array from nearly zero voltage to open-circuit voltage that increases the scanning time and, in turn, causes energy loss. This paper presents a novel GMPPT method which significantly restricts the voltage window search range and tracks the global power peak rapidly in all shading conditions. Simulation tests and experimental comparisons with another GMPPT algorithm are presented to highlight the features of the presented approach.

    String inverter photovoltaic (PV) systems with bypass diodes require improved global maximum power point tracking (GMPPT) algorithms to effectively reach the absolute maximum power operating point. Several GMPPT algorithms have been proposed to deal with this problem, but most of them require scanning wide voltage ranges of the PV array from nearly zero voltage to open-circuit voltage that increases the scanning time and, in turn, causes energy loss. This paper presents a novel GMPPT method which significantly restricts the voltage window search range and tracks the global power peak rapidly in all shading conditions. Simulation tests and experimental comparisons with another GMPPT algorithm are presented to highlight the features of the presented approach.

  • Cooperative signal amplification for molecular communication in nanonetworks

     Abadal Cavalle, Sergi; Llatser Marti, Ignacio; Alarcon Cot, Eduardo Jose; Cabellos Aparicio, Alberto
    Wireless networks
    Vol. 20, num. 6, p. 1611-1626
    DOI: 10.1007/s11276-014-0696-z
    Date of publication: 2014-08-01
    Journal article

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    Nanotechnology is enabling the development of devices in a scale ranging from a few to hundreds of nanometers. Communication between these devices greatly expands the possible applications, increasing the complexity and range of operation of the system. In particular, the resulting nanocommunication networks (or nanonetworks) show great potential for applications in the biomedical field, in which diffusion-based molecular communication is regarded as a promising alternative to EM-based solutions due to the bio-stability and energy-related requirements of this scenario. However, molecular signals suffer a significant amount of attenuation as they propagate through the medium, thus limiting the transmission range. In this paper, a signal amplification scheme for molecular communication nanonetworks is presented wherein a group of emitters jointly transmits a given signal after achieving synchronization. This is achieved by means of quorum sensing (QS), a method used by bacteria to both sense their population and coordinate their actions. By using the proposed methodology, the transmission range is extended proportionally to the number of synchronized emitters. An analytical model of QS is provided and validated through simulation. This model is the main contribution of this work and accounts for the activation threshold (which will eventually determine the resulting amplification level) and the delay of the synchronization process.

  • N3Sim: Simulation framework for diffusion-based molecular communication nanonetworks

     Llatser Marti, Ignacio; Demiray, D.; Cabellos Aparicio, Alberto; Altilar, D. Turgay; Alarcon Cot, Eduardo Jose
    Simulation modelling practice and theory
    Vol. 42, p. 210-222
    DOI: 10.1016/j.simpat.2013.11.004
    Date of publication: 2014-03-01
    Journal article

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    Diffusion-based molecular communication is a promising bio-inspired paradigm to implement nanonetworks, i.e., the interconnection of nanomachines. The peculiarities of the physical channel in diffusion-based molecular communication require the development of novel models, architectures and protocols for this new scenario, which need to be validated by simulation. N3Sim is a simulation framework for nanonetworks with transmitter, receiver, and harvester nodes using Diffusion-based Molecular Communication (DMC). In DMC, transmitters encode the information by releasing molecules into the medium, thus varying their local concentration. N3Sim models the movement of these molecules according to Brownian dynamics, and it also takes into account their inertia and the interactions among them. Harvesters collect molecules from the environment to reuse them for later transmissions. Receivers decode the information by sensing the particle concentration in their neighborhood. The benefits of N3Sim are multiple: the validation of channel models for DMC and the evaluation of novel modulation schemes are just a few examples. (C) 2013 Elsevier B.V. All rights reserved.

  • Maximum power point tracking based on slidingmode control for output-series connected converters in photovoltaic systems

     Cabal, Cédric; Martínez Salamero, Luis; Séguier, Lionel; Alonso, Corinne; Guinjoan Gispert, Francisco
    IET power electronics
    Vol. 7, num. 4, p. 914-923
    DOI: 10.1049/iet-pel.2013.0348
    Date of publication: 2014-04-01
    Journal article

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    A perturb and observe algorithm based on both the power-current characteristic of a photovoltaic (PV) panel and the sliding-mode control of the input inductor current of an associated converter is investigated in a static application. A single ended primary inductance converter (SEPIC) converter charging a battery from a PV generator illustrates the procedure whose effectiveness is proved with experimental results. The reported technique is appropriate for distributed maximum power point tracking of PV systems with output series connected DC-DC switching converters. In these systems, each converter is supplied by an independent PV panel at the input port whereas its output port is connected in series with the output ports of the other converters. The proposed converter interconnection is based on a transformer-less SEPIC because of the capability of this converter to step-up or step-down the input voltage. The resulting system allows maximum power extraction from each PV source even in cases of non-uniform irradiance. © The Institution of Engineering and Technology 2014.

    A perturb and observe algorithm based on both the power-current characteristic of a photovoltaic (PV) panel and the sliding-mode control of the input inductor current of an associated converter is investigated in a static application. A single ended primary inductance converter (SEPIC) converter charging a battery from a PV generator illustrates the procedure whose effectiveness is proved with experimental results. The reported technique is appropriate for distributed maximum power point tracking of PV systems with output series connected DC-DC switching converters. In these systems, each converter is supplied by an independent PV panel at the input port whereas its output port is connected in series with the output ports of the other converters. The proposed converter interconnection is based on a transformer-less SEPIC because of the capability of this converter to step-up or step-down the input voltage. The resulting system allows maximum power extraction from each PV source even in cases of non-uniform irradiance. © The Institution of Engineering and Technology 2014.

  • Temperature gradient sensor from pulsed power supply duty cycle in ultra-low-power energy harvesting system

     Jove Casulleras, Roger; Ramos Castro, Juan Jose; Corimanya, H; Camps Carmona, Adriano Jose; Alarcon Cot, Eduardo Jose; Amezaga Sarries, Adria; Bou Balust, Elisenda
    Electronics Letters
    Vol. 50, num. 11, p. 826-828
    DOI: 10.1049/el.2014.0399
    Date of publication: 2014-05-22
    Journal article

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    Directly interfacing sensors that link sensors to micro-controllers without a signal conditioning circuit or an analogue-to-digital converter on the one side and energy harvesting systems on the other side are two key enabling technologies to create self-powered autonomous low-cost and low-maintenance sensor networks. In this reported work, both technologies are concurrently combined in such a way that the duty cycle of the pulsed power supply provided by the harvesting system itself yields in turn a temperature gradient sensor functionality. Originally conceived to power a low-power satellite beacon in a CubeSat project, it has found application, among other applications, in automatic air conditioning and heating systems aiming smart buildings.

  • Design-oriented analysis of quantization-induced limit cycles in a multiple-sampled digitally controlled buck converter

     Bradley, Mark; Alarcon Cot, Eduardo Jose; Feely, Orla
    IEEE transactions on circuits and systems I: regular papers
    Vol. 61, num. 4, p. 1192-1205
    DOI: 10.1109/TCSI.2013.2283671
    Date of publication: 2014-04-01
    Journal article

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    Digital control of switching power converters is an area which has seen increased attention in recent years. However, quantization in the feedback loop from the analog-to-digital (A/D) converter and the digital pulse width modulator (DPWM) may cause limit cycle oscillations to manifest, which are generally seen as being undesirable. This paper presents an analysis of the limit cycle behavior found in a multiple-sampled digitally controlled buck converter. The limit cycles which may arise in the system are characterized and conditions to prevent these oscillations from occurring are presented. © 2004-2012 IEEE.

    Digital control of switching power converters is an area which has seen increased attention in recent years. However, quantization in the feedback loop from the analog-to-digital (A/D) converter and the digital pulse width modulator (DPWM) may cause limit cycle oscillations to manifest, which are generally seen as being undesirable. This paper presents an analysis of the limit cycle behavior found in a multiple-sampled digitally controlled buck converter. The limit cycles which may arise in the system are characterized and conditions to prevent these oscillations from occurring are presented. © 2004-2012 IEEE.

  • Transferencia de energía inalámbrica: acoplamiento inductivo resonante

     Poveda López, Alberto; Vidal Lopez, Eva Maria; Martínez García, Herminio; Alarcon Cot, Eduardo Jose
    Competitive project

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  • On the Scalability Limits of Communication Networks to the Nanoscale  Open access

     Llatser Marti, Ignacio
    Universitat Politècnica de Catalunya
    Theses

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    Los nanosistemas, sistemas integrados con un tamaño total de unos pocos micrómetros, son capaces de interactuar en la nanoescala, pero su corto radio de acción limita su utilidad en escenarios prácticos. Las nanoredes, que surgen de la interconexión de nanosistemas, amplían su ámbito de operación permitiendo la comunicación entre nanosistemas, aumentando de esta forma sus aplicaciones potenciales. Con el fin de dotar de capacidades de comunicación a los nanosistemas, su subsistema de comunicación debe reducirse a unos pocos micrómetros. Existen dudas sobre la viabilidad de miniaturizar las antenas metálicas actuales a un tamaño tan pequeño, especialmente porque su frecuencia de resonancia sería extremadamente alta (en el espectro óptico), lo que causaría a una gran atenuación de las ondas radiadas. Como alternativa, se han propuesto dos nuevos paradigmas para implementar comunicaciones inalámbricas entre nanosistemas: las comunicaciones moleculares y las comunicaciones inalámbricas basadas en grafeno. Por un lado, las comunicaciones moleculares consisten en el intercambio de moléculas entre nanosistemas, inspirado en la comunicación entre células vivas. En las comunicaciones moleculares basadas en difusión (DMC), las moléculas emitidas se propagan por el medio mediante un proceso de difusión hasta que alcanzan el receptor. Por otro lado, el grafeno (una lámina de átomos de carbono de un átomo de espesor) permite implementar antenas de grafeno plasmónicas, o grafenas. Debido a efectos plasmónicos, grafenas con un tamaño de unos pocos micrómetros radian ondas en la banda de terahercios, dando lugar al paradigma de las comunicaciones inalámbricas basadas en grafeno (GWC). Para averiguar cómo escalan las redes de comunicación a medida que se reducen sus dimensiones, esta tesis se presenta un análisis de la escalabilidad de las redes de comunicaciones hacia la nanoescala, siguiendo un modelo general con la menor cantidad posible de hipótesis. Hemos propuesto dos esquemas de detección en DMC: detección de amplitud y detección de energía. Hemos identificado importantes métricas de rendimiento y calculado su escalabilidad con respecto a la distancia de transmisión, que difiere significativamente respecto a las comunicaciones inalámbricas tradicionales. Estas nuevas tendencias de escala requieren el diseño de nuevos protocolos de red especialmente adaptados a las redes de DMC. El análisis de la propagación de ondas plasmónicas en grafenas permite determinar sus propiedades de radiación. En particular, la frecuencia de resonancia de las grafenas no sólo es más baja que en antenas metálicas, sino que también aumenta más lentamente a medida que reducimos su longitud. Por otra parte, la frecuencia de resonancia de las grafenas puede ser ampliamente controlada en función de parámetros como las dimensiones de la grafena, el tiempo de relajación del grafeno y el potencial químico. Además, proponemos un montaje experimental que permite la medición de grafenas alimentadas con una fuente fotoconductora. También hemos analizado los efectos de la absorción molecular en el canal de terahercios a corto alcance, el escenario de operación de las grafenas. La absorción molecular es un proceso por el cual moléculas presentes en la atmósfera absorben parte de la energía de las ondas radiadas por las grafenas, degradando su rendimiento. Hemos cuantificado esta degradación derivando parámetros de rendimiento en este escenario, que muestran novedosas tendencias de escalabilidad en función de la distancia de transmisión. Por último, hemos encontrado que la capacidad de canal de GWC escala mejor a medida que el tamaño de la antena se reduce con respecto a las comunicaciones inalámbricas tradicionales. En consecuencia, las GWC requerirán una potencia de transmisión más baja para lograr un cierto rendimiento. Estos resultados establecen un marco general que puede servir de guía para diseñar las futuras redes de comunicaciones inalámbricas entre nanosistemas.

    Nanosystems, integrated systems with a total size of a few micrometers, are capable of interacting at the nanoscale, but their short operating range limits their usefulness in practical macro-scale scenarios. Nanonetworks, the interconnection of nanosystems, will extend their range of operation by allowing communication among nanosystems, thereby greatly enhancing their potential applications. In order to integrate communication capabilities into nanosystems, their communication subsystem needs to shrink to a size of a few micrometers. There are doubts about the feasibility of scaling down current metallic antennas to such a small size, mainly because their resonant frequency would be extremely high (in the optical domain) leading to a large free-space attenuation of the radiated EM waves. In consequence, as an alternative to implement wireless communications among nanosystems, two novel paradigms have emerged: molecular communication and graphene-enabled wireless communications. On the one hand, molecular communication is based on the exchange of molecules among nanosystems, inspired by communication among living cells. In Diffusion-based Molecular Communication (DMC), the emitted molecules propagate throughout the environment following a diffusion process until they reach the receiver. On the other hand, graphene, a one-atom-thick sheet of carbon atoms, has been proposed to implement graphene plasmonic RF antennas, or graphennas. Graphennas with a size in the order of a few micrometers show plasmonic effects which allow them to radiate EM waves in the terahertz band. Graphennas are the enabling technology of Graphene-enabled Wireless Communications (GWC). In order to answer the question of how communication networks will scale when their size shrinks, this thesis presents a scalability analysis of the performance metrics of communication networks to the nanoscale, following a general model with as few assumptions as possible. In the case of DMC, two detection schemes are proposed: amplitude detection and energy detection. Key performance metrics are identified and their scalability with respect to the transmission distance is found to differ significantly from the case of traditional wireless communications. These unique scaling trends present novel challenges which require the design of novel networking protocols specially adapted to DMC networks. The analysis of the propagation of plasmonic waves in graphennas allows determining their radiation performance. In particular, the resonant frequency of graphennas is not only lower than in metallic antennas, but it also increases more slowly as their length is reduced to the nanoscale. Moreover, the study of parameters such as the graphenna dimensions, the relaxation time of graphene and the applied chemical potential shows the tunability of graphennas in a wide frequency range. Furthermore, an experimental setup to measure graphennas based on feeding them by means of a photoconductive source is described. The effects of molecular absorption in the short-range terahertz channel, which corresponds to the expected operating scenario of graphennas, are analyzed. Molecular absorption is a process in which molecules present in the atmosphere absorb part of the energy of the terahertz EM waves radiated by graphennas, causing impairments in the performance of GWC. The study of molecular absorption allows quantifying this loss by deriving relevant performance metrics in this scenario, which show novel scalability trends as a function of the transmission distance with respect to the case of free-space propagation. Finally, the channel capacity of GWC is found to scale better as the antenna size is reduced than in traditional wireless communications. In consequence, GWC will require lower transmission power to achieve a given performance target. These results establish a general framework which may serve designers as a guide to implement wireless communication networks among nanosystems.

  • Observation of chaotic behavior in automatic tuning loops for continuous-time filters

     Martínez García, Herminio; Cosp Vilella, Jordi; Manzanares Brotons, Manuel
    IEEE International Midwest Symposium on Circuits and Systems
    p. 742-745
    DOI: 10.1109/MWSCAS.2013.6674756
    Presentation's date: 2014-08
    Presentation of work at congresses

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    he appropriate linear dynamic modeling of continuous-time filters (CTFs) with automatic tuning loops should be obtained to assure stability in case an improved design of the loop controllers is to be carried out. With this aim, starting from a general and systematic analysis in order to obtain an equivalent small-signal linearized incremental model, from which transfer functions between output variables and control voltages are derived, the subsequent design of compensated loops with enhanced stability and dynamic performance is required. This systematic procedure allows obtaining improved controllers for the two involved control loops. However, CTFs with automatic tuning loops are nonlinear feedback systems with potential instability. What is more, nonlinear phenomena, which cannot be predicted by a design-oriented small signal modeling approach, are observed in this kind of tuning systems. The purpose of this work is to highlight that when control parameters are varied, the system could present different kinds of dynamical nonlinear phenomena such as bifurcations and chaotic behavior, which cannot be predicted by the small signal design-oriented model.

    he appropriate linear dynamic modeling of continuous-time filters (CTFs) with automatic tuning loops should be obtained to assure stability in case an improved design of the loop controllers is to be carried out. With this aim, starting from a general and systematic analysis in order to obtain an equivalent small-signal linearized incremental model, from which transfer functions between output variables and control voltages are derived, the subsequent design of compensated loops with enhanced stability and dynamic performance is required. This systematic procedure allows obtaining improved controllers for the two involved control loops. However, CTFs with automatic tuning loops are nonlinear feedback systems with potential instability. What is more, nonlinear phenomena, which cannot be predicted by a design-oriented small signal modeling approach, are observed in this kind of tuning systems. The purpose of this work is to highlight that when control parameters are varied, the system could present different kinds of dynamical nonlinear phenomena such as bifurcations and chaotic behavior, which cannot be predicted by the small signal design-oriented model.

  • Simulación mediante ¿hardware in the loop¿ de un convertidor buck

     Velasco Quesada, Guillermo; Casellas Beneyto, Francisco; Guinjoan Gispert, Francisco; Esteban, Jordi; Martínez García, Herminio; Pique Lopez, Robert
    Seminario Anual de Automática, Electrónica Industrial e Instrumentación
    p. 6007.1-6007.5
    Presentation's date: 2014-06-26
    Presentation of work at congresses

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  • Access to the full text
    De la teoría a la práctica: cinco años después de la integración de la competencia genérica de sostenibilidad en el Grado en Ingeniería Informática  Open access

     Garcia Almiñana, Jordi; Sanchez Carracedo, Fermin; Lopez Alvarez, David; Vidal Lopez, Eva Maria; Cabre Garcia, Jose Maria; García García, Helena; Alier Forment, Marc
    Jornadas de Enseñanza Universitaria de la Informática
    p. 253-260
    Presentation's date: 2014-07-09
    Presentation of work at congresses

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    La sostenibilidad es una de las competencias trans- versales básicas que todo ingeniero debería adquirir durante su formación. De hecho, seguir desarrollando ciencia y tecnología de espaldas a la sostenibilidad provocaría en poco tiempo un colapso de nuestro planeta. La puesta en marcha del Espacio Europeo de Educación Superior (EEES) ha propiciado una opor- tunidad única para replantearse diferentes aspectos educativos, entre los cuales destaca la inclusión de esta competencia en los planes de estudio. Existe literatura abundante sobre estrategias y pro- puestas teóricas para incluir esta competencia en las ingenierías. Sin embargo, pocos trabajos han sido llevados a cabo desde una perspectiva más práctica. La Facultat de Informàtica de Barcelona (FIB) posee amplia experiencia en el diseño de titulaciones adap- tadas al EEES y ha integrado la sostenibilidad en su plan de estudios de Grado en Ingeniería Informática. En este trabajo se revisa el proceso de diseño del plan de estudios de Grado en Ingeniería Informática de la FIB, aprobado en el año 2009, y se analiza la experiencia de integración de la sostenibilidad tras cinco años de funcionamiento del grado. Se comentan los mecanismos de organización y coordinación entre las asignaturas implicadas y, finalmente, se extraen las lecciones aprendidas.

    La sostenibilidad es una de las competencias transversales básicas que todo ingeniero debería adquirir durante su formación. De hecho, seguir desarrollando ciencia y tecnología de espaldas a la sostenibilidad provocaría en poco tiempo un colapso de nuestro planeta. La puesta en marcha del Espacio Europeo de Educación Superior (EEES) ha propiciado una oportunidad única para replantearse diferentes aspectos educativos, entre los cuales destaca la inclusión de esta competencia en los planes de estudio. Existe literatura abundante sobre estrategias y propuestas teóricas para incluir esta competencia en las ingenierías. Sin embargo, pocos trabajos han sido llevados a cabo desde una perspectiva más práctica. La Facultat de Informàtica de Barcelona (FIB) posee amplia experiencia en el diseño de titulaciones adaptadas al EEES y ha integrado la sostenibilidad en su plan de estudios de Grado en Ingeniería Informática. En este trabajo se revisa el proceso de diseño del plan de estudios de Grado en Ingeniería Informática de la FIB, aprobado en el año 2009, y se analiza la experiencia de integración de la sostenibilidad tras cinco años de funcionamiento del grado. Se comentan los mecanismos de organización y coordinación entre las asignaturas implicadas y, finalmente, se extraen las lecciones aprendidas.

  • Banco de pruebas para verificar el rendimiento estático y dinámico del MPPT

     Velasco Quesada, Guillermo; Casellas Beneyto, Francisco; Guinjoan Gispert, Francisco; Pique Lopez, Robert
    Seminario Anual de Automática, Electrónica Industrial e Instrumentación
    p. 3016.1-3016.6
    DOI: -
    Presentation's date: 2014-06-26
    Presentation of work at congresses

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  • Performance analysis of dual-frequency buck converter for integrated power management

     Shirmohammadli, V.; Saberkari, Alireza; Alarcon Cot, Eduardo Jose
    Power Electronics, Drive Systems and Technologies Conference
    p. 402-407
    DOI: 10.1109/PEDSTC.2014.6799409
    Presentation's date: 2014-02
    Presentation of work at congresses

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    The use of dual-frequency (DF) buck converter architecture consisting of a merged structure of high and low frequency buck cells is presented as a candidate topology for integrated power management to obtain favorable tradeoffs in terms of efficiency, switching ripple, and bandwidth. It is shown that having two degrees of freedom in designing the DF buck helps to achieve high efficiency and low output ripples, simultaneously. A comparison analysis is done with regards to the aforementioned performance indexes with the standard and three-level buck converters and the results are validated in HSPICE in a 0.35 µm CMOS process.

    The use of dual-frequency (DF) buck converter architecture consisting of a merged structure of high and low frequency buck cells is presented as a candidate topology for integrated power management to obtain favorable tradeoffs in terms of efficiency, switching ripple, and bandwidth. It is shown that having two degrees of freedom in designing the DF buck helps to achieve high efficiency and low output ripples, simultaneously. A comparison analysis is done with regards to the aforementioned performance indexes with the standard and three-level buck converters and the results are validated in HSPICE in a 0.35 µm CMOS process.

  • Class E2 resonant non-radiative wireless power transfer link: a design-oriented joint circuit-system co-characterization approach

     Bou Balust, Elisenda; Nagashima, Tomoharu; Sekiya, Hiroo; Alarcon Cot, Eduardo Jose
    International Multi-Conference on Systems, Signals and Devices
    p. 1-4
    DOI: 10.1109/SSD.2014.6808902
    Presentation's date: 2014-02-11
    Presentation of work at congresses

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    Resonant Inductive CouplingWireless Power Transfer is a key technology to provide an efficient and harmless wireless energy channel to consumer electronics, biomedical implants and wireless sensor networks. Many applications have been proposed for this technology, but the interplay between the Resonant Inductive Coupling magnetic link and the power electronics front-end is still unclear. In this paper, we propose a design-oriented joint circuit-system approach to design a high-efficiency resonant inductive coupling wireless power transfer link embedded in a class E2 DC-DC converter. © 2014 IEEE.

    Resonant Inductive CouplingWireless Power Transfer is a key technology to provide an efficient and harmless wireless energy channel to consumer electronics, biomedical implants and wireless sensor networks. Many applications have been proposed for this technology, but the interplay between the Resonant Inductive Coupling magnetic link and the power electronics front-end is still unclear. In this paper, we propose a design-oriented joint circuit-system approach to design a high-efficiency resonant inductive coupling wireless power transfer link embedded in a class E2 DC-DC converter. © 2014 IEEE.

  • Power adaptor device for domestic DC microgrids based on commercial MPPT inverters

     Valderrama Blavi, Hugo; Bosque, J.M.; Guinjoan Gispert, Francisco; Marroyo, L.; Martínez Salamero, Luis
    IEEE transactions on industrial electronics
    Vol. 60, num. 3, p. 1191-1203
    DOI: 10.1109/TIE.2012.2198038
    Date of publication: 2013
    Journal article

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    This paper presents a power adaptor device, referred to as smart panel device, allowing the connection of additional energy sources and storage elements to a domestic photovoltaic (PV) grid-connected system. The adaptor output port is designed to behave as a power source/sink, thus enabling its hot-swap parallel connection to renewable power sources without modifying their maximum power point (MPP). Moreover, the adaptor device features a power characteristic with a single controllable MPP and allows the control of the injected power within the operating range of the dc¿ac grid-connected inverter. The work presents the design principles of such device by describing the operation of a sliding- mode controlled quadratic-boost converter. The proper operation of the device is experimentally verified for several scenarios in a small PV-based microgrid system including a fuel-cell stack, a 1-kW three-phase wind turbine, a battery charger¿discharger, and commercial grid-connected PV inverters

    This paper presents a power adaptor device, referred to as smart panel device, allowing the connection of additional energy sources and storage elements to a domestic photovoltaic (PV) grid-connected system. The adaptor output port is designed to behave as a power source/sink, thus enabling its hot-swap parallel connection to renewable power sources without modifying their maximum power point (MPP). Moreover, the adaptor device features a power characteristic with a single controllable MPP and allows the control of the injected power within the operating range of the dc–ac grid-connected inverter. The work presents the design principles of such device by describing the operation of a sliding- mode controlled quadratic-boost converter. The proper operation of the device is experimentally verified for several scenarios in a small PV-based microgrid system including a fuel-cell stack, a 1-kW three-phase wind turbine, a battery charger–discharger, and commercial grid-connected PV inverters

  • Introduction to the special section on smart devices for renewable energy systems

     Cecati, Carlo; Guinjoan Gispert, Francisco; Siano, Pierluig; Spagnuolo, Giovanni
    IEEE transactions on industrial electronics
    Vol. 60, num. 3, p. 1119-1121
    DOI: 10.1109/TIE.2012.2219472
    Date of publication: 2013-03
    Journal article

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    The papers in this special section focus on the topics of smart devices and applications for renewable energy systems.

    The papers in this special section focus on the topics of smart devices and applications for renewable energy systems.

  • High slew rate current mode transconductance error amplifier for low quiescent current output-capacitorless CMOS LDO regulator

     Fathipour, Rasoul; Saberkari, Alireza; Martínez García, Herminio; Alarcon Cot, Eduardo Jose
    Integration. The VLSI journal
    Vol. 47, num. 2, p. 204-210
    DOI: 10.1016/j.vlsi.2013.10.005
    Date of publication: 2013-11-08
    Journal article

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    This paper presents a CMOS low quiescent current output-capacitorless low-dropout regulator (LDO) based on a high slew rate current mode transconductance amplifier (CTA) as error amplifier. Using local common-mode feedback (LCMFB) in the proposed CTA, the order of transfer characteristic of the circuit is increased. Therefore, the slew rate at the gate of pass transistor is enhanced. This improves the LDO load transient characteristic even at low quiescent current. The proposed LDO topology has been designed and post simulated in HSPICE in a 0.18 µm CMOS process to supply the load current between 0-100 mA. The dropout voltage of the LDO is set to 200 mV for 1.2-2 V input voltage. Post-layout simulation results reveal that the proposed LDO is stable without any internal compensation strategy and with on-chip output capacitor or lumped parasitic capacitances at the output node between 10-100 pF. The total quiescent current of the LDO including the current consumed by the reference buffer circuit is only 3.7 µA. A final benchmark comparison considering all relevant performance metrics is presented.

  • Energy-balance control of PV cascaded multilevel grid-connected inverters for phase-shifted and level-shifted pulse-width modulations

     Chavarria Roe, Javier; Biel Sole, Domingo; Guinjoan Gispert, Francisco; Meza Benavides, Carlos; Negroni Vera, Juan José
    IEEE transactions on industrial electronics
    Vol. 60, num. 1, p. 98-111
    DOI: 10.1109/TIE.2012.2186108
    Date of publication: 2013-01
    Journal article

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    This paper presents an energy-balance control strategy for a cascaded single-phase grid-connected H-bridge multilevel inverter linking n independent photovoltaic (PV) arrays to the grid. The control scheme is based on an energy-sampled data model of the PV system and enables the design of a voltage loop linear discrete controller for each array, ensuring the stability of the system for the whole range of PV array operating conditions. The control design is adapted to phase-shifted and level-shifted carrier pulsewidth modulations to share the control action among the cascade-connected bridges in order to concurrently synthesize a multilevel waveform and to keep each of the PV arrays at its maximum power operating point. Experimental results carried out on a seven-level inverter are included to validate the proposed approach.

    This paper presents an energy-balance control strategy for a cascaded single-phase grid-connected H-bridge multilevel inverter linking n independent PV arrays to the grid. The control scheme is based on an energy-sampled data model of the PV system and enables the design of a voltage loop linear discrete controller for each array ensuring the stability of the system for the whole range of PV arrays operating conditions. The control design is adapted to Phase-Shifted and Level-Shifted Carrier PWM to share the control action among the cascadeconnected bridges in order to concurrently synthesize a multilevel waveform and to keep each of the PV arrays at its maximum power operating point. Experimental results carried out on a 7-level inverter are included to validate the proposed approach.

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    La sostenibilidad en los proyectos de ingeniería  Open access

     Garcia Almiñana, Jordi; García Gómez, Helena; Lopez Alvarez, David; Sanchez Carracedo, Fermin; Vidal Lopez, Eva Maria; Alier Forment, Marc; Cabre Garcia, Jose Maria
    ReVisión
    Vol. 6, num. 2, p. 91-100
    Date of publication: 2013-09
    Journal article

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    El Trabajo de Fin de Grado representa la última prueba para que el estudiante de grado demuestre que está preparado para ejercer como ingeniero, elaborando y defendiendo un proyecto de envergadura. El proyecto debe cumplir todos los requisitos que se exigen a un proyecto de ingeniería, desde el análisis del problema hasta la presentación de una solución. Los autores del presente trabajo pensamos que todo proyecto de ingeniería debe incorporar un informe de sostenibilidad que demuestre que el proyecto es sostenible en los ámbitos social, ambiental y económico. Existe poca experiencia en este tema, tanto en la empresa como en la universidad, ya que las empresas (algunas) hace pocos años que han incorporado la sostenibilidad como uno de los criterios de realización de sus proyectos y las universidades apenas han comenzado a trabajar en esa dirección. En este trabajo se presentan algunas reflexiones sobre cómo debería ser tratada la sostenibilidad en un proyecto de ingeniería, y en particular cómo se pueden aplicar estas ideas al Trabajo de Fin de Grado.

    El Trabajo de Fin de Grado representa la última prueba para que el estudiante de grado demuestre que está preparado para ejercer como ingeniero, elaborando y defendiendo un proyecto de envergadura. El proyecto debe cumplir todos los requisitos que se exigen a un proyecto de ingeniería, desde el análisis del problema hasta la presentación de una solución. Los autores del presente trabajo pensamos que todo proyecto de ingeniería debe incorporar un informe de sostenibilidad que demuestre que el proyecto es sostenible en los ámbitos social, ambiental y económico. Existe poca experiencia en este tema, tanto en la empresa como en la universidad, ya que las empresas (algunas) hace pocos años que han incorporado la sostenibilidad como uno de los criterios de realización de sus proyectos y las universidades apenas han comenzado a trabajar en esa dirección. En este trabajo se presentan algunas reflexiones sobre cómo debería ser tratada la sostenibilidad en un proyecto de ingeniería, y en particular cómo se pueden aplicar estas ideas al Trabajo de Fin de Grado.

  • Fast transient current-steering CMOS LDO regulator based on current feedback amplifier

     Saberkari, Alireza; Alarcon Cot, Eduardo Jose; Shokouhi, Shahriar B.
    Integration. The VLSI journal
    Vol. 46, num. 2, p. 165-171
    DOI: 10.1016/j.vlsi.2012.02.001
    Date of publication: 2013-03
    Journal article

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    This paper presents a current-steering approach to implement a fast transient response low-dropout regulator (LDO) based on a current feedback amplifier (CFA) topology. The circuit does not require any internal compensation capacitor, being stable for a wide range of output load currents [0¿100 mA] and a 1 µF output capacitor. The CFA consists of an open-loop voltage follower with output local current¿current feedback based on a level-shifted flipped voltage follower (LSFVF) which is instrumental to achieve high regulation and fast transient response. The inverting output buffer stage of the CFA together with current-mirror-based driving of the power pass transistor results in high PSRR. Post-layout simulation results for a 0.35 µm CMOS process design reveal that the proposed LDO requires 59 µA quiescent current at no-load condition and at full-load condition has a current efficiency of 99.8%. For a 1 µF output capacitor, the maximum output voltage variation to a 0¿100 mA load transient with rise and fall times of 10 and 100 ns is only 3 mV, and the PSRR is smaller than -56 dB over the entire load current range.

    This paper presents a current-steering approach to implement a fast transient response low-dropout regulator (LDO) based on a current feedback amplifier (CFA) topology. The circuit does not require any internal compensation capacitor, being stable for a wide range of output load currents [0–100 mA] and a 1 μF output capacitor. The CFA consists of an open-loop voltage follower with output local current–current feedback based on a level-shifted flipped voltage follower (LSFVF) which is instrumental to achieve high regulation and fast transient response. The inverting output buffer stage of the CFA together with current-mirror-based driving of the power pass transistor results in high PSRR. Post-layout simulation results for a 0.35 μm CMOS process design reveal that the proposed LDO requires 59 μA quiescent current at no-load condition and at full-load condition has a current efficiency of 99.8%. For a 1 μF output capacitor, the maximum output voltage variation to a 0–100 mA load transient with rise and fall times of 10 and 100 ns is only 3 mV, and the PSRR is smaller than −56 dB over the entire load current range.

  • An asynchronous finite-state-machine-based buck-boost converter for on-chip adaptive power supply

     Fernández, Daniel; Madrenas Boadas, Jordi; Alarcon Cot, Eduardo Jose
    Analog integrated circuits and signal processing
    Vol. 74, num. 1, p. 227-238
    DOI: 10.1007/s10470-012-9975-8
    Date of publication: 2013-01
    Journal article

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    In this paper we present an asynchronous finite-state machine digital controller co-integrated with an on-chip non-inverting buck-boost power converter with dynamic signal-tracking capabilities. The mostly-digital controller functionally implements a non-PWM zone-wise control law through asynchronous circuitry, thus exhibiting self-timed minimum latency and ultra low power operation due to gate switching activity. Experimental results on a 0.35 µm CMOS technology demonstrate an efficiency up to 80 % with a switching frequency of 2.86 MHz.

    In this paper we present an asynchronous finite-state machine digital controller co-integrated with an on-chip non-inverting buck-boost power converter with dynamic signal-tracking capabilities. The mostly-digital controller functionally implements a non-PWM zone-wise control law through asynchronous circuitry, thus exhibiting self-timed minimum latency and ultra low power operation due to gate switching activity. Experimental results on a 0.35 lm CMOS technology demonstrate an efficiency up to 80 % with a switching frequency of 2.86 MHz

  • A study on multi-level PWM and asynchronous Sigma Delta modulations for enhanced bandlimited signal tracking in switching power amplifiers

     Garcia Tormo, Albert; Poveda Lopez, Alberto; Alarcon Gallo, Eduardo; Guinjoan Gispert, Francisco
    IEEE transactions on circuits and systems I: regular papers
    Vol. 60, num. 6, p. 1621-1634
    DOI: 10.1109/TCSI.2012.2220463
    Date of publication: 2013-06
    Journal article

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    This work deals with multi-level switching amplifiers, in the context of high-efficiency power amplification for signal tracking applications. In particular, this paper evaluates the reduction in the error signal's power due to multi-level power amplification (compared to conventional two-level amplifiers) and compares the performance of two multi-level pulse modulations: PWM and Asynchronous Modulation. First the intrinsic bandwidth limits of multi-level switching amplifiers are inferred, to clearly state the advantages and limitations of multi-level power amplification. From the existing analyses of Pulse Width Modulation already reported in the literature, PWM is herein extended to multiple levels based on an equivalent representation, which allows to derive a closed expression for the power spectrum of multi-level PWM in bandlimited signal tracking. The Asynchronous Modulation is extended to multiple levels and the resulting multi-level encoding algorithm is analyzed in both time and frequency domains. The performance of both modulations is characterized and compared at different operating frequencies and using different number of levels. The main outcomes of this in-depth characterization show that, if the switching frequency is high enough, the tracking error is independent of the modulation and the switching frequency, i.e., it only depends upon the number of levels, which points out the suitability of asynchronous modulations for relatively low switching frequencies (compared to the number of levels).

    This work deals with multi-level switching amplifiers, in the context of high-efficiency power amplification for signal tracking applications. In particular, this paper evaluates the reduction in the error signal's power due to multi-level power amplification (compared to conventional two-level amplifiers) and compares the performance of two multi-level pulse modulations: PWM and Asynchronous ${{Sigma}} {{Delta}}$ Modulation. First the intrinsic bandwidth limits of multi-level switching amplifiers are inferred, to clearly state the advantages and limitations of multi-level power amplification. From the existing analyses of Pulse Width Modulation already reported in the literature, PWM is herein extended to multiple levels based on an equivalent representation, which allows to derive a closed expression for the power spectrum of multi-level PWM in bandlimited signal tracking. The Asynchronous ${{Sigma}} {{Delta}}$ Modulation is extended to multiple levels and the resulting multi-level encoding algorithm is analyzed in both time and frequency domains. The performance of both modulations is characterized and compared at different operating frequencies and using different number of levels. The main outcomes of this in-depth characterization show that, if the switching frequency is high enough, the tracking error is independent of the modulation and the switching frequency, i.e., it only depends upon the number of levels, which points out the suitability of asynchronous modulations for relatively low switching frequencies (compared to the number of levels).

  • El concepto de Smart Metering en el nuevo escenario de distribución eléctrica

     Casellas Beneyto, Francisco; Pique Lopez, Robert; Velasco Quesada, Guillermo; Guinjoan Gispert, Francisco
    Electro noticias
    num. 174-175, p. 36-43
    Date of publication: 2013-11
    Journal article

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  • Detection techniques for diffusion-based molecular communication

     Llatser Marti, Ignacio; Cabellos Aparicio, Alberto; Pierobon, Massimiliano; Alarcon Cot, Eduardo Jose
    IEEE journal on selected areas in communications
    Vol. 31, num. 12, p. 726-734
    DOI: 10.1109/JSAC.2013.SUP2.1213005
    Date of publication: 2013-12-01
    Journal article

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    Nanonetworks, the interconnection of nanosystems, are envisaged to greatly expand the applications of nanotechnology in the biomedical, environmental and industrial fields. However, it is still not clear how these nanosystems will communicate among them. This work considers a scenario of Diffusion-based Molecular Communication (DMC), a promising paradigm that has been recently proposed to implement nanonetworks. In a DMC network, transmitters encode information by the emission of molecules which diffuse throughout the medium, eventually reaching the receiver locations. In this scenario, a pulse-based modulation scheme is proposed and two techniques for the detection of the molecular pulses, namely, amplitude detection and energy detection, are compared. In order to evaluate the performance of DMC using both detection schemes, the most important communication metrics in each case are identified. Their analytical expressions are obtained and validated by simulation. Finally, the scalability of the obtained performance evaluation metrics in both detection techniques is compared in order to determine their suitability to particular DMC scenarios. Energy detection is found to be more suitable when the transmission distance constitutes a bottleneck in the performance of the network, whereas amplitude detection will allow achieving a higher transmission rate in the cases where the transmission distance is not a limitation. These results provide interesting insights which may serve designers as a guide to implement future DMC networks. © 1983-2012 IEEE.

  • On Modified Wien¿Bridge Oscillator and Astable Oscillator

     Martínez García, Herminio
    Analog integrated circuits and signal processing
    Vol. 75, num. 1, p. 179-194
    DOI: 10.1007/s10470-013-0032-z
    Date of publication: 2013-02
    Journal article

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    The present article is related to the recently published paper given in (Abuelma¿atti and Khalifa, Analog Integr Circuits Signal Process, 73:989¿992, 2012), which depicts the possible relation between the modified Wien-bridge circuit used by the authors of references (Singh, Analog Integr Circuits Signal Process 48:251¿255, 2006; Singh, Analog Integr Circuits Signal Process, 50:127¿132, 2007; Singh, Analog Integr Circuits Signal Process, 62:327¿332, 2010; Wangenheim, Analog Integr Circuits Signal Process, 66:139¿141, 2011; Martinez-Garcia et al., Analog Integr Circuits Signal Process, 70:443¿449, 2012), and the comparator-based relaxation oscillator. In particular, in the referenced Mixed Signal Letter (Abuelma¿atti and Khalifa, Analog Integr Circuits Signal Process, 73:989¿992, 2012), the authors assert that the modified Wien-bridge oscillator circuit under discussion, used previously in the aforementioned referenced articles, can behave as a sinusoidal oscillator only at relatively high frequencies when the operational amplifier can be considered non-ideal. In addition, at relatively low frequencies, when the operational amplifier can be considered ideal, the same circuit would behave as a relaxation oscillator with a square wave output rather than a sinusoidal output. However, this paper reveals that this assertion is not strictly correct, because in both cases (in low and high frequencies), the generated waveform at the circuit output is a sinusoidal signal, with the possibility of be cut out, depending on proper circuit dimensioning (according to the oscillation criterion) as well as the oscillation frequency and the properties of the amplifier (slew rate, and frequency response).

  • Technologies for electric current sensors

     Velasco Quesada, Guillermo; Conesa Roca, Alfonso; Roman Lumbreras, Manuel
    Date of publication: 2013-08-01
    Book chapter

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    Within the field of study of classical physics, we can find the branch concerned with electromagnetic phenomena: electromagnetism. Electromagnetism describes the interaction between electric charges through the concepts of electric and magnetic fields. The formulation of the electromagnetic theory principles has enabled the engineering sciences, such as electricity and electronics, to develop applications related to the treatment of energy and information using electric charges as physical support. Most operations performed on the processing of energy or information supported by electric charges involve the movement of these charges, and there are two basic electric magnitudes to represent this movement: electric voltage (also called potential difference or voltage) and electric current. Regardless the scope of the developed application, many electric or electronic systems need to measure the value of either of these two magnitudes. This chapter is devoted to reviewing the various techniques currently available to measure or sensing the electric current intensity.

  • Technologies for electric current sensors

     Velasco Quesada, Guillermo; Conesa Roca, Alfonso; Roman Lumbreras, Manuel
    Date of publication: 2013-05-22
    Book chapter

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  • Chaos in switching converters for power management: designing for prediction and control

     Rodriguez Vilamitjana, Enric; El Aroudi, Abdelali; Alarcon Cot, Eduardo Jose
    DOI: 10.1007/978-1-4614-2128-3
    Date of publication: 2013-01-15
    Book

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  • Engineering Education. REDU. Revista de Docencia Universitaria

     Pique Lopez, Robert
    Vol. 11, num. 2. Octubre 2013
    Collaboration in journals

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  • IEEE Journal on Photovoltaics

     Pique Lopez, Robert
    Collaboration in journals

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  • 1st European award for best practices for the integration of Sustainable Human Development (SHD) into technology/engineering education

     Alier Forment, Marc; Cabre Garcia, Jose Maria; Franquesa Griso, David; Garcia Almiñana, Jordi; García García, Helena; Lopez Alvarez, David; Sanchez Carracedo, Fermin; Vidal Lopez, Eva Maria
    Award or recognition

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  • Premi al Millor Projecte de Final de Carrera CETIB 2013

     Martínez García, Herminio
    Award or recognition

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  • 8th Google Reserach Award

     Alarcon Cot, Eduardo Jose
    Award or recognition

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  • MACHREK ENERGY DEVELOPMENT

     Martínez García, Herminio; Pique Lopez, Robert; Velasco Quesada, Guillermo; Casellas Beneyto, Francisco; Guinjoan Gispert, Francisco
    Competitive project

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    `Bang-Bang¿ technique in supply modulation for linear wideband RF power amplifiers  Open access

     Martínez García, Herminio; Turkson, Richard; Silva-Martínez, José
    Conference on Design of Circuits and Integrated Systems
    p. 16-19
    Presentation's date: 2013-11-27
    Presentation of work at congresses

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    This paper deals with the design techniques of power efficient switching regulators intended for linear power amplifiers employing envelope tracking techniques in wideband wireless standards. The bottlenecks involve a tradeoff between ripple voltage, slew rate and bandwidth. The slew rate limitation is identified as the main challenge, then a `bang-bang¿ slew enhancement technique is proposed. This approach enables the use of efficient supply modulators in wideband power amplifiers. The proposed scheme does not significantly degrade PA efficiency and preserves the stability of the switching regulator. The prototype has been implemented using the TSMC 0.18 µm technology; schematic simulation results in Cadence® are presented to prove the concept.

    This paper deals with the design techniques of power efficient switching regulators intended for linear power amplifiers employing envelope tracking techniques in wideband wireless standards. The bottlenecks involve a tradeoff between ripple voltage, slew rate and bandwidth. The slew rate limitation is identified as the main challenge, then a ‘bang-bang’ slew enhancement technique is proposed. This approach enables the use of efficient supply modulators in wideband power amplifiers. The proposed scheme does not significantly degrade PA efficiency and preserves the stability of the switching regulator. The prototype has been implemented using the TSMC 0.18 µm technology; schematic simulation results in Cadence® are presented to prove the concept.

  • SiC Power JFET Electrothermal Macromodel

     Massana, Francisco; Chavarria Roe, Javier; Biel Sole, Domingo; Poveda Lopez, Alberto; Guinjoan Gispert, Francisco
    International Conference Mixed Design of Integrated Circuits and Systems
    p. 444-447
    Presentation's date: 2013-06-21
    Presentation of work at congresses

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  • Design of a 4.5-V, 450-mA low-dropout voltage linear regulator based on a cascoded OTA

     Martínez García, Herminio; Grau Saldes, Antoni; Bolea Monte, Yolanda
    Annual Conference of the IEEE Industrial Electronics Society
    p. 2242-2247
    Presentation's date: 2013-11-13
    Presentation of work at congresses

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    This article aims to present the design of a 4.5-V 450-mA low drop-out (LDO) voltage linear regulator based on a two-stage cascoded operational transconductance amplifier (OTA) as error amplifier. The aforementioned two-stage OTA is designed with cascoded current mirroring technique to boost up the output impedance. The proposed OTA has a DC gain of 101 dB under no load condition. The designed reference voltage included in the LDO regulator is provided by a band gap reference with the temperature coefficient (T¿) of 0.025 mV/ºC. The proposed LDO regulator has a maximum drop-out voltage of 0.5 V @ 450 mA of load current, and has the worst case power supply rejection ratio (PSRR) of [54.5 dB, 34.3 dB] @ [100 Hz, 10 kHz] in full load condition. All the proposed circuits are designed using a 0.35 µm CMOS technology. The design is checked in order to corroborate its performance for wide range of input voltage, founding that the circuit design works fine meeting all the initial specification requirements.

  • On chaotic behavior in automatic tuning loops for continuous-time filters

     Cosp Vilella, Jordi; Martínez García, Herminio
    European Conference on Circuit Theory and Design
    p. 1-4
    DOI: 10.1109/ECCTD.2013.6662232
    Presentation's date: 2013-09-10
    Presentation of work at congresses

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    Continuous-time filters (CTFs) with automatic tuning loops are nonlinear feedback systems with potential instability. Thus, their appropriate linear dynamic modeling should be obtained to assure stability in case of an improved design of the loop controllers is to be carried out. A systematic approach using a small signal model would allow obtaining these controllers. However, bifurcations and nonlinear phenomena may appear which cannot be predicted by this analysis. This leads to potential instability, semiperiodic or chaotic behavior and, thus, circuit malfunction. The aim of this paper is to show by means of simulations and experimental results that nonlinear phenomena, which cannot be predicted by the common small signal analysis, may appear in this kind of circuits when circuit parameters are varied.

    Continuous–time filters (CTFs) with automatic tuning loops are nonlinear feedback systems with potential instability. Thus, their appropriate linear dynamic modeling should be obtained to assure stability in case of an improved design of the loop controllers is to be carried out. A systematic approach using a small signal model would allow obtaining these controllers. However, bifurcations and nonlinear phenomena may appear which cannot be predicted by this analysis. This leads to potential instability, semiperiodic or chaotic behavior and, thus, circuit malfunction. The aim of this paper is to show by means of simulations and experimental results that nonlinear phenomena, which cannot be predicted by the common small signal analysis, may appear in this kind of circuits when circuit parameters are varied.

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    The Machreck Energy Development - Solar project MED-Solar  Open access

     Velasco Quesada, Guillermo; Guinjoan Gispert, Francisco; Pique Lopez, Robert; Roman Lumbreras, Manuel; Vallvé, Xavier; Tarragó, J.; Bugatti, N.
    International Multi-Conference on Systems, Signals and Devices
    p. 6-13
    Presentation's date: 2013-03-19
    Presentation of work at congresses

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    The aim of this communication is to introduce the project MED-Solar, acronym of Machrek Energy Development. This project is part of the new European Neighborhood Policy (ENP), policy that seeks to reinforce relations with neighboring countries to the east and south in order to promote prosperity, stability and security at its borders. The main objective of this project is the promotion and implementation of innovative technologies and know-how transfer in the field of solar energy, including that stemming from private sector, and that may be implemented in particular or public facilities through public procurement processes.

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    Design of an on-chip linear-assisted DC-DC voltage regulator  Open access

     Cosp Vilella, Jordi; Martínez García, Herminio
    IEEE International Conference on Electronics, Circuits and Systems
    p. 353-356
    Presentation's date: 2013-12-10
    Presentation of work at congresses

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    This article shows the design of an on-chip CMOS linear-assisted DC-DC regulator. It results a good alternative topology to classic switching DC-DC power converters. In the presented technique, an auxiliary linear regulator is used to cancel the output voltage ripple and provides fast responses for load and line variations. On the other hand, a switching converter, connected in parallel, allows supplying almost the whole output current demanded by the load. The objective of this linear-assisted regulator or hybrid topology is to achieve a high efficiency of switching converters, with suitable load and line regulation features, typical of linear regulators. In this kind of on-chip applications, CMOS is the current prevailing technology. Thus, in order to implement on-chip power supply systems and on-chip power management systems with low-to-medium current consumption, this structure has good features.

    This article shows the design of an on-chip CMOS linear-assisted DC-DC regulator. It results a good alternative topology to classic switching DC-DC power converters. In the presented technique, an auxiliary linear regulator is used to cancel the output voltage ripple and provides fast responses for load and line variations. On the other hand, a switching converter, connected in parallel, allows supplying almost the whole output current demanded by the load. The objective of this linear-assisted regulator or hybrid topology is to achieve a high efficiency of switching converters, with suitable load and line regulation features, typical of linear regulators. In this kind of on-chip applications, CMOS is the current prevailing technology. Thus, in order to implement on-chip power supply systems and on-chip power management systems with low-to-medium current consumption, this structure has good features.

    Postprint (author’s final draft)

  • Diseño de una plataforma docente para el estudio de los sistemas de recolección de energía (energy harvesting) en los grados de ingeniería

     Martínez García, Herminio
    Spanish-Portuguese Conference on Electrical Engineering
    p. 1-4
    Presentation's date: 2013-07-04
    Presentation of work at congresses

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    El presente artículo presenta el diseño e implementación física de una plataforma docente recolectora y acondicionadora de energía práctica para aplicaciones de energy harvesting. Concretamente, muestra la realización de un sistema de acondicionamiento de energía solar fotovoltaica a partir de un modelo concreto de panel solar. Con el fin de conseguir una plataforma lo más eficiente posible, se ha implementado un sistema de seguimiento del punto de máxima potencia (MPPT) del panel fotovoltaico que optimiza el rendimiento del mismo, adentrando, a su vez, al estudiante de Ingeniería en este tipo de algoritmos. Además, la plataforma recolectora posee regulación de salida, ofreciendo así una tensión de salida constante, independientemente tanto de variaciones de carga como de la tensión de entrada.

  • La gestión de la calidad: algunas reflexiones sobre los procesos de calidad que se implantan en los centros docentes universitarios

     Perez Gracia, Maria de La Vega; Lopez Lopez, Jose; Buenestado Caballero, Pablo; Garcia-Alzórriz Pardo, Juan Antonio; Torres Camara, Ricardo; Martinez Sanchez, Joan; Velasco Quesada, Guillermo
    Congreso Universitario de Innovación Educativa en las Enseñanzas Técnicas (CUIEET)
    p. 117-124
    Presentation's date: 2013-07-12
    Presentation of work at congresses

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    Resumen. Tras diseñar un sistema interno de garantía de calidad se inició el proceso de implantación. Sin embargo, este proceso se ha dilatado en el tiempo y no se ha podido finalizar todavía. Es posible que muchos de los problemas con los que nos hemos encontrado sean fallos del sistema diseñado, que no fueron previstos por el centro ni detectados por los revisores externos. La discusión sobre nuestra experiencia, contrastándola con la de otros centros puede ser una herramienta valiosa para mejorar un sistema complejo. Abstract. After the quality system design, implementation was the second step. However, several difficulties caused the delay in the implementation process and the system is not yet finalized. It is possible that some of the problems in the process were due to a non appropriate design or evaluation of the quality system. In our opinion, the discussion about the experience, contrasted to the other centres¿ experiences could help in the improvement of the system.

  • Supply modulator for linear wideband RF power amplifiers

     Turkson, Richard; Silva-Martínez, José; Martínez García, Herminio
    Seminario Anual de Automática, Electrónica Industrial e Instrumentación
    p. 1-4
    Presentation's date: 2013-07-11
    Presentation of work at congresses

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    This paper deals with the design techniques of power efficient switching regulators intended for linear power amplifiers employing envelope tracking techniques in wideband wireless standards. The bottlenecks involve a tradeoff between ripple voltage, slew rate and bandwidth. The slew rate limitation is identified as the main challenge, then a `bang-bang¿ slew-enhancement technique is proposed. This approach enables the use of efficient supply modulators in wideband power amplifiers. The proposed scheme does not significantly degrade PA efficiency and preserves the stability of the switching regulator. The prototype has been implemented using the TSMC 0.18 µm technology; schematic simulation results in Cadence ® are presented to prove the concept.

  • Envelope tracking technique with bang-bang slew-rate enhancer for linear wideband RF PAs

     Turkson, Richard; Prakash, Suraj; Silva-Martínez, José; Martínez García, Herminio
    IEEE International Midwest Symposium on Circuits and Systems
    p. 629-632
    Presentation's date: 2013-08-06
    Presentation of work at congresses

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  • Maximizing efficiency through impedance matching from a circuit-centric model of non-radiative resonant wireless power transfer

     Bou Balust, Elisenda; Sedwick, Raymond; Alarcon Cot, Eduardo Jose
    IEEE International Symposium on Circuits and Systems
    p. 29-32
    DOI: 10.1109/ISCAS.2013.6571774
    Presentation's date: 2013-05-21
    Presentation of work at congresses

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    Recent research in wireless power transfer (WPT) using resonant inductive coupling has demonstrated very high efficiencies (above 40%) at large distances compared to the transmitting element dimensions, thereby exponentially increasing the number of potential applications of WPT. Since resonant inductive coupling is a very multidisciplinary field, different approaches have been proposed to predict the behaviour of these systems from the physical theory of resonators (coupled-mode theory), reflected load theory and circuit theory. Also, there is in this field a heterogeneous definition of metrics without a clear optimization process. In this article we unify the different metrics and demonstrate how to maximize the power transfer efficiency in a non-radiative resonant wireless power transfer link from a circuit-centric point of view providing design guidelines in terms of optimal load impedance, optimal source impedance and optimal distance between coils.

  • Magnetic characterization of interfering objects in resonant inductive coupling wireless power transfer

     Bou Balust, Elisenda; Vidal, D.; Sedwick, Raymond; Alarcon Cot, Eduardo Jose
    Progress in Electromagnetics Research Symposium
    p. 1554-1559
    Presentation's date: 2013-08-16
    Presentation of work at congresses

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    Resonant Inductive Coupling (RIC) Wireless Power Transfer is a key technology to provide an efficient and harmless wireless energy channel to consumer electronics, biomedical implants and wireless sensor networks. However, there are two factors that are limiting the applicability of this technology: the effects of distance variation between transmitter and receiver and the effects of interfering objects. While distance variation in WPT has been thoroughly studied, the effects of conductive interfering objects in resonant inductive coupling links are still unclear. When a conductive element is in the vicinity of a RIC link, both the transmitter and the receiver can experiment a change on their resonant frequencies as well as their impedances. This can greatly affect the effciency of such WPT link causing it to a) make the transmitter and/or receiver act as a pass-band filter and b) loose part of the transmitter magnetic field through coupling to the interfering object. Depending on the natural resonant frequency of the object and the distances between this object and the transmitter and receiver antennas, this can affect significantly the RIC wireless power transfer link. In this article, we characterize the Magnetic behavior of a resonant inductive coupled link in the presence of a conductive interfering object using a Finite Element Field Solver (FEKO). Several distances between interference and transmitter/receiver are analyzed providing a design space exploration and applicability study of this link.

  • Access to the full text
    Chaotic behaviour in on-chip automatic tuning loops for continuous-time filters  Open access

     Martínez García, Herminio; El Aroudi, Abdelali; Alarcon Cot, Eduardo Jose; Poveda Lopez, Alberto
    Seminario Anual de Automática, Electrónica Industrial e Instrumentación
    p. 1-4
    Presentation's date: 2013-07-11
    Presentation of work at congresses

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    Continuous-time filters (CTF) with automatic tuning loops are nonlinear feedback systems with potential instability. While an appropriate small signal linear dynamic modeling of the tunable filter should be obtained for design purpose, its ability to predict the real nonlinear dynamic behavior of the system is limited. In order to overcome this problem, a general and systematic procedure is used to obtain a large signal nonlinear model. The obtained model can accurately predict nonlinear phenomena such as bifurcations and chaotic behavior. From this model, some numerical simulations results are presented in this paper. As far as the authors know, the observation of these phenomena in CTF with tuning loops has not been previously presented. Thus, the results obtained in this work can provide some help to obtain improved controllers (with higher bandwidth and better performance) for the two involved control loops.

  • La sostenibilidad en los proyectos de ingeniería

     Cabre Garcia, Jose Maria; Garcia Almiñana, Jordi; García Gómez, Helena; Lopez Alvarez, David; Sanchez Carracedo, Fermin; Vidal Lopez, Eva Maria; Alier Forment, Marc
    Jornadas de Enseñanza Universitaria de la Informática
    p. 317-324
    DOI: 10.6035/e-TIiT.2013.13
    Presentation's date: 2013-07-12
    Presentation of work at congresses

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    El Trabajo de Fin de Grado representa la última prueba para que el estudiante de grado demuestre que está preparado para ejercer como ingeniero, elaborando y defendiendo un proyecto de envergadura. El proyecto debe cumplir todos los requisitos que se exigen a un proyecto de ingeniería, desde el análisis del problema hasta la presentación de una solución. Los autores del presente trabajo pensamos que todo proyecto de ingeniería debe incorporar un informe de sostenibilidad que demuestre que el proyecto es sostenible en los ámbitos social, ambiental y económico. Existe poca experiencia en este tema, tanto en la empresa como en la universidad, ya que las empresas (algunas) hace pocos años que han incorporado la sostenibilidad como uno de los criterios de realización de sus proyectos y las universidades apenas han comenzado a trabajar en esa dirección. En este trabajo se presentan algunas reflexiones sobre cómo debería ser tratada la sostenibilidad en un proyecto de ingeniería, y en particular cómo se pueden aplicar estas ideas al Trabajo de Fin de Grado.