Browsing by Author "Pereda Torres, Javier Eduardo"

Now showing 1 - 20 of 59
  • No Thumbnail Available
    Item
    23-Level Inverter for Electric Vehicles Using a Single Battery Pack and Series Active Filters
    (IEEE, 2012) Pereda Torres, Javier Eduardo; Dixon, Juan
    Cascaded H-bridge (CHB) multilevel inverters have been conceived as an alternative to reduce total harmonic distortion (THD) in medium-voltage drives. The reduced THD makes them useful for electric vehicle (EV) applications, but the main problem with the CHB is the large amount of isolated power sources required to feed each of the H-bridges. An improved variant known as the asymmetrical CHB (ACHB) inverter uses H-bridges of different sizes and then needs fewer isolated power sources than the CHB. However, in battery-powered EVs, only one power supply (fuel cell or battery pack) is desirable. This work presents a solution to solve the problem, operating some of the small H-bridges (Aux-bridges) as series active filters and using a small high-frequency link (HFL). With this solution, only one dc source is required to feed the inverter, and if the control is adjusted to work at particular switching points, more than 98% of power is transferred through the larger H-bridges (MAIN bridges). The proposed ACHB topology can produce any number of levels, and the M AIN bridges always commutate at fundamental frequency. As the number of levels must remain constant for all output voltages, a variable dc source is required to control the amplitude of the motor voltage. This work shows some simulations and experiments on a 2-kW 27-level ACHB working with only 23 levels. The concept is being implemented in a small EV with an ACHB drive of 18 kW.
  • Thumbnail Image
    Item
    27-level converter for electric vehicles using only one power supply
    (IEEE, 2010) Dixon Rojas, Juan; Pereda Torres, Javier Eduardo
    The main advantage of asymmetrical multilevel inverters is the optimization of levels with a minimum number of power supplies. However, this optimized multilevel system still needs a large number of isolated and floating DC supplies, which makes these converters complicated to implement in electric vehicles (EVs), because the system will require many independent battery packs. In this paper, a very simple scheme, based on a small and cheap high frequency link (HFL), allows the utilization of only one power supply for the complete multilevel inverter drive, with an inherent regulation of the voltages supplied among the H-bridges. It also allows voltage control with full number of levels if the DC power supply is of variable voltage characteristic. This work is focused on a 27-level asymmetric inverter but the strategy, using only one power supply, can be applied to converters with any number of levels. In particular, an asymmetrical 27-level converter needs nine isolated power supplies and the proposed system reduces these nine sources to only one: the battery car. The topology also permits full regenerative braking working as a three-level converter. The proposed system is intended for application in electric vehicles from power ratings up to 150 kW. Simulations and experimental results show the feasibility to implement this “one-source†multilevel system.
  • Thumbnail Image
    Item
    A Design Methodology of Multiresonant Controllers for High Performance 400 Hz Ground Power Units
    (2019) Rojas, Félix; Cárdenas, Roberto; Clare, Jon; Díaz, Matías; Pereda Torres, Javier Eduardo; Kennel, Ralph
  • Thumbnail Image
    Item
    A Methodology to Obtain a Synthetic Driving Cycle through GPS Data for Energy Analysis
    (IEEE, 2015) Naranjo Lourido, W.; Munoz, L. E.; Pereda Torres, Javier Eduardo
    This paper proposes a methodology to obtain a synthetic driving cycle by using GPS data as input. The aim is to obtain a driving cycle that is representative of a given condition when used for energy consumption studies. The methodology begins with a data acquisition phase, where an adequate sampling frequency is proposed. Velocity raw data are processed and clustered to capture a mobility global pattern. A synthetic driving cycle is generated from the clustered information using a two level energy model optimization. For a case study, a representative synthetic driving cycle was determined for a Bus Rapid Transit (BRT) route.
  • No Thumbnail Available
    Item
    A Novel Three-Port NPC Converter for Grid-Tied Photovoltaic Systems with Integrated Battery Energy Storage
    (IEEE, 2020) Neira Castillo, Sebastian Felipe; Lizana Gajardo, Alonso Javier; Pereda Torres, Javier Eduardo
    The variable behaviour of the photovoltaic (PV) generation arises as the main drawback of this technology. Therefore, Battery Energy Storage (BES) units appear as a promising solution to overcome the inherent intermittent generation profile of PV systems. BES can be implemented separated from the PV generation units or integrated within a single power system. The latter option gives a better dynamic response, as the variable generation can be directly complemented with the BES, controlling the power flow between both elements with the grid. Thus, there is a need for power converters with capability of interface both PV and BES with the grid in a reliable and efficient way. This paper proposes a Three-Port NPC converter to connect a PV array and a BES unit with the ac grid using a single power processing stage. The converter is based in the H-NPC inverter and allows the connection of a low voltage battery to act as a power buffer ensuring a firm energy dispatch to the grid. Furthermore, simulation results show that the proposed topology maintains the good performance of the H-NPC in terms of efficiency, voltage harmonic distortion and reduced leakage current.
  • Thumbnail Image
    Item
    A Novel Three-Port NPC Converter for Grid-Tied Photovoltaic Systems with Integrated Battery Energy Storage
    (IEEE, 2020) Neira, Sebastián; Lizana Gajardo, Alonso Javier; Pereda Torres, Javier Eduardo
    The variable behaviour of the photovoltaic (PV) generation arises as the main drawback of this technology. Therefore, Battery Energy Storage (BES) units appear as a promising solution to overcome the inherent intermittent generation profile of PV systems. BES can be implemented separated from the PV generation units or integrated within a single power system. The latter option gives a better dynamic response, as the variable generation can be directly complemented with the BES, controlling the power flow between both elements with the grid. Thus, there is a need for power converters with capability of interface both PV and BES with the grid in a reliable and efficient way. This paper proposes a Three-Port NPC converter to connect a PV array and a BES unit with the ac grid using a single power processing stage. The converter is based in the H-NPC inverter and allows the connection of a low voltage battery to act as a power buffer ensuring a firm energy dispatch to the grid. Furthermore, simulation results show that the proposed topology maintains the good performance of the H-NPC in terms of efficiency, voltage harmonic distortion and reduced leakage current
  • Thumbnail Image
    Item
    An Overview of Microgrids Challenges in the Mining Industry
    (2020) Gómez, Juan S.; Rodriguez, Jose; Garcia, Cristian; Tarisciotti, Luca; Flores-Bahamonde, Freddy; Pereda Torres, Javier Eduardo; Nuñez Retamal, Felipe Eduardo; Cipriano, Aldo; Salas, Juan Carlos
    The transition from fossil fuels to renewable energies as power sources in the heavy industries is one of the main climate change mitigation strategies. The carbon footprint in mining is related to its inherent extraction process, its high demand of electric power and water, and the use of diesel. However, considering its particular power requirements, the integration of microgrids throughout the whole control hierarchy of mining industry is an emergent topic. This paper provides an overview of the opportunities and challenges derived from the synergy between microgrids and the mining industry. Bidirectional and optimal power flow, as well as the integration of power quality have been identified as microgrid features that could potentially enhance mining processes. Recommendations pertaining to the technological transition and the improvement of energy issues in mining environments are also highlighted in this work.
  • Thumbnail Image
    Item
    Análisis costo beneficio de la adopción de la electromovilidad en la Región Metropolitana
    (2023) Yunis Ebner, Constanza Daniela; Pereda Torres, Javier Eduardo; Pontificia Universidad Católica de Chile. Escuela de Ingeniería
    En Chile, el transporte representa un alto consumo de energía y emisiones de Gases de Efecto Invernadero. Ante esta situación, el Gobierno ha planteado una meta ambiciosa: lograr que el 100% de las ventas de vehículos livianos, medianos y transporte público urbano sean cero emisiones el 2035. La presente actividad de graduación tiene como objetivo evaluar el impacto de la adopción de la electromovilidad en la Región Metropolitana para el periodo 2023-2050, con foco en el transporte urbano, mediante un análisis costo-beneficio (ACB). La evaluación de los impactos se realiza comparando la diferencia entre un escenario con políticas, que considera una adopción acelerada que permita alcanzar la meta planteada y mantenerla hasta el 2050, y un escenario business as usual, que considera la adopción en base al precio de los vehículos y la capacidad económica de las personas. Los principales resultados muestran que, aunque existen beneficios asociados a la implementación de la electromovilidad acelerada en la RM, la razón total de beneficios/costos es de 0,64, indicando que los beneficios no son suficientes para cubrir los costos. Cabe destacar que en el caso de taxis la proporción beneficio/costo es de 0,96, cercano a 1, y en el caso de buses se obtiene una razón de 4,53. Dado que los resultados anteriores están inevitablemente sujetos a incertidumbre, se sensibilizan las variables claves, teniéndose que para los valores optimista de estas variables el panorama es más alentador, obteniéndose una razón beneficio/costo de 1,14. Los resultados para valores pesimista de las variables claves muestran un panorama desafiante, ya que los beneficios esperados no superan los costos de manera significativa, obteniéndose una proporción de 0,41. Finalmente, se concluye que, con una planificación cuidadosa y la consideración de los impactos económicos, ambientales y sociales, la electromovilidad tiene el potencial de contribuir a sistemas de transporte urbano más sostenibles y resilientes.
  • Thumbnail Image
    Item
    Arm link enhanced modular multilevel converter for low voltage and variable frequency applications
    (2023) Aguilar Villaseca, Rodrigo Ignacio; Pereda Torres, Javier Eduardo; Pontificia Universidad Católica de Chile. Escuela de Ingeniería
    El Conversor Multinivel Modular (MMC) ha tomado mucho interés por parte de la investigación y la industria debido a todos sus beneficios. Su modularidad, escalabilidad, calidad de formas de onda y eficiencias han mostrado claras ventajas sobre otras topologías multinivel, y lo hacen ideal para aplicaciones de medio y alto voltaje. Sin embargo, no está exento de desafíos: su gran cantidad de capacitores requiere un control complejo para balancear la energía, además de necesitar un gran espacio debido a las altas capacitancias. Debido a esto, el MMC no es considerado para aplicaciones de bajo voltaje, donde además el gran número de semiconductores no justifican su costo. Este trabajo presenta un análisis más profundo y la validación de una nueva topología propuesta, llamada Arm Link Enhanced MMC (ALE-MMC). Esta extiende el MMC a aplicaciones de bajo voltaje y de frecuencia variable mediante el uso de Dual Active Bridges (DAB) para permitir el flujo de potencia entre submódulos (SM) de una misma pierna. Se presenta la nueva topología y se estudia su operación considerando la supresión de la corriente circulante, mostrando que no se necesita emplear medición de voltaje para funcionar adecuadamente y la capacitancia del SM puede ser reducida. A continuación, se estudian todos los problemas a considerar debido a la implementación del DAB entre SMs. Se hace énfasis en la corriente que debe manejar y en los efectos de la frecuencia variable en la topología, con y sin control de corriente circulante. Para validar el esquema propuesto y el análisis teórico desarrollado, se simula el ALE-MMC trifásico para probar el correcto funcionamiento, evaluando su comportamiento ante distintos escenarios y comparando con el esquema propuesto. Seguido, se emplea un prototipo experimental del ALE-MMC monofásico para validar su operación en la práctica, también ante distintos escenarios para poder confirmar en análisis hecho. Finalmente, se comentan los resultados además de proponer mejoras para futuros trabajos con el conversor.
  • No Thumbnail Available
    Item
    Asymmetrical Multilevel Inverter for Traction Drives Using Only One DC Supply
    (2010) Dixon Rojas, Juan; Pereda Torres, Javier Eduardo; Castillo Tamayo, Carlos Ignacio; Bosch Castro, Sebastián Andrés
    The main advantage of asymmetrical multilevel inverters is the optimization of levels with a minimum number of power supplies. However, this optimized multilevel system still needs a large number of isolated and floating dc supplies, which makes these converters complicated to implement in electric vehicles (EVs), because the system will require many independent battery packs. In this paper, a very simple scheme, based on a small and cheap high-frequency link (HFL), allows the utilization of only one power supply for the complete multilevel inverter drive, with an inherent regulation of the voltages supplied among the H-bridges. It also allows voltage control with the full number of levels if the dc source is of a variable voltage characteristic. This paper is focused on a 27-level asymmetric inverter, but the strategy, using only one power supply, can be applied to converters with any number of levels. In particular, an asymmetrical 27-level converter needs nine isolated power supplies, and the proposed system reduces these nine sources to only one: the battery car. The topology also permits full regenerative braking working as a three-level converter. The proposed system is intended for application in EVs from power ratings up to 150 kW. Simulations and experimental results show the feasibility to implement this “one-source†multilevel system.
  • No Thumbnail Available
    Item
    Asymmetrical Triangular Current Mode (ATCM) for Bidirectional High Step Ratio Modular Multilevel Dc–Dc Converter
    (IEEE, 2020) Pineda Fornerod, Cristian Andrés; Pereda Torres, Javier Eduardo; Rojas, Félix; Cerda, Carlos; Zhang, Xiaotian; Watson, Alan J.
    Direct current (Dc) networks have proven advantages in high voltage direct current (HVDC) transmission systems, and now they are expanding to medium- and low-voltage distribution networks. One of the major challenges is to develop reliable dc-dc voltage transformation achieving high efficiency and performance, especially at high voltage and high step ratio. New resonant modular multilevel topologies have arisen as an alternative, mainly because of advantages such as optional use of transformers, natural voltage balance, simple control, and soft-switching capability. However, this type of operation generates a high peak current, does not allow control of power flow in all power range, and has a limited range of voltage variation. This article proposes an asymmetrical triangular current mode applied to high step ratio modular multilevel dc-dc converters. The proposed modulation increases the efficiency and achieves bidirectional control of the power, soft-switching, and a natural balance of the voltage in the cell capacitors. The experimental results show the bidirectional operation and the capacitor voltage balance of the converter under different operating conditions with higher efficiency (97.72%) and lower peak current compared to previous reports of this topology using resonant operation.
  • Thumbnail Image
    Item
    Cascaded converters for EVs with single power source and increased power quality
    (2013) Pereda Torres, Javier Eduardo; Dixon Rojas, Juan
  • Thumbnail Image
    Item
    Cascaded Multilevel Converters: Optimal Asymmetries and Floating Capacitor Control
    (IEEE, 2013) Pereda Torres, Javier Eduardo; Dixon, Juan
    Cascaded multilevel (CM) converter is a series connection of several inverters that together generate multiple voltage levels with controllable frequency, phase, and amplitude. Its main advantages are high power, reliability, and power quality. However, it has considerable drawbacks such as high number of components, many isolated power sources, decreasing voltage quality with the modulation index, and regeneration in some series inverters at specific modulation indexes, even when the machine is motoring. The authors propose to improve any CM topology through two solutions: use optimal voltage asymmetries (ratios), higher than conventional ones; replace the voltage sources by floating capacitors balanced with a new control (PI controller) and/or a high-frequency link. This paper presents theoretical analysis and experimental results of CM converters with increased voltage-quality (levels), some of them keeping this high quality and avoiding regeneration in motor mode at any motor operation point, using the proposed voltage asymmetries and simplifying or eliminating some voltage sources. Experimental results show a reduction of components, an improved voltage quality, and a satisfactory behavior in stationary and dynamic operation.
  • Thumbnail Image
    Item
    Consensus-Based Distributed Control of a Multilevel Battery Energy Storage System
    (IEEE, 2020) Neira Castillo, Sebastian Felipe; Poblete Durruty, Pablo Martín; Pereda Torres, Javier Eduardo; Nuñez Retamal, Felipe Eduardo
    Battery Energy Storage Systems (BESS) based on modular multilevel cascaded topologies allow splitting the battery array into the converter sub-modules, improving efficiency and reliability of the solution. Modular converters can perform active balance of the battery packs and regulation of the output power through the use of multi-objective controllers commanding the power of each sub-module accordingly. However, despite the hardware modularity of multilevel BESS, the controller is usually based on centralized designs, which present issues in terms of computational load and scalability. This paper proposes a two-layer distributed control scheme, based on a high-level consensus algorithm to perform the State of Charge (SoC) balance and low-level individual multi-variable controllers to regulate the operation of the converter sub-modules. The controller was implemented in a cascaded topology, where each sub-module determines and regulates its output power considering the information of its neighbours. The proposed solution allows to fully exploit the modularity of the converter, distributing the control units in the power modules to improve the overall flexibility and scalability of the system. Simulations results validate the operation of the proposed system, showing how the converter sub-modules distribute its power outputs to equalize the SoC levels. Furthermore, the distribution of the multi-variable controllers reduces the computational burden, as each unit just regulates the operation of the respective sub-module.
  • Thumbnail Image
    Item
    Control híbrido para conversor multinivel con múltiples capacitores flotantes
    (2016) Aldunate Fernández, José Santiago; Pereda Torres, Javier Eduardo; Pontificia Universidad Católica de Chile. Escuela de Ingeniería
    Los convertidores de potencia son fundamentales para el desarrollo y globalización puesto que juegan roles tan diversos que van desde el cargador de baterías más pequeño hasta sistemas DC de alta corriente que interconectan países. Un problema con ellos es que introducen contaminación indeseable en la red eléctrica, lo cual se hace cada vez más perjudicial dada la masificación en aplicaciones como electrónica del hogar y energías alternativas. Es por esto que hoy en día se requiere el desarrollo de tecnologías que reduzcan la contaminación producida por estos, para mitigar los problemas que puedan causar estos en el futuro. Los conversores multinivel han surgido como una tecnología capaz de suplir los conversores convencionales, con operación a alta potencia y baja distorsión. Un problema con ellos es su complejidad para mayor número de niveles, el cual supone un obstáculo para competir con los convertidores convencionales. Aún así, en los últimos años los conversores multinivel han aumentado su número de aplicaciones y su investigación resulta importante dadas las soluciones que ofrecen.El siguiente trabajo propone un sistema de control que permita reemplazar múltiples fuentes flotantes por capacitores, a implementarse en un conversor multinivel en cascada. El control propuesto disminuye la complejidad y el costo, mejora la eficiencia, y permite una operación de baja distorsión en todo el rango de voltaje y frecuencia. Para llevarlo a cabo, la investigación desarrolla una formulación matemática, una serie de simulaciones y una implementación experimental de estas en un conversor puente-H en cascada para posterior análisis. Las soluciones y procedimientos elaborados son aplicables a cualquier tipo de topología de conversor multinivel en cascada, con especial énfasis en conversores puente-H en serie. El conversor puede ser utilizado en múltiples aplicaciones, como control de motores, generación de potencia y FACTS.
  • Thumbnail Image
    Item
    Control intra-cluster para M2C de bajo voltaje con almacenamiento parcial y tolerancia a fallas en las baterías
    (2022) Rubio Barros, Francisco Javier; Pereda Torres, Javier Eduardo; Pontificia Universidad Católica de Chile. Escuela de Ingeniería
    Los sistemas de almacenamiento de energía conectados a la red poseen un rol fundamental en la integración de energías renovables variables a la matriz energética, debido a que pueden proveer servicios complementarios, tales como regulación de frecuencia y gestión de carga. En la actualidad, la integración sistemas de almacenamiento de segunda vida, que naturalmente poseen una probabilidad de falla mayor a las baterías nuevas, depende crucialmente de como una eventual falla puede impactar la capacidad del sistema de almacenamiento. Los sistemas de almacenamiento de energía comerciales se basan en gigantescos paquetes baterías que se conectan a la red a través de inversores, careciendo de modularidad y generando grandes barreras de entrada al uso de baterías de segunda vida. Los Conversores Modulares Multinivel en Cascada con almacenamiento integrado surgen como una opción interesante a esta problemática. Esta tesis propone un conversor modular multinivel con almacenamiento parcialmente embebido utilizando baterías de segunda vida. Además de un control adecuado y la conexión de clusters en paralelo para aplicaciones de bajo voltaje y alta corriente. Primero se presenta una revisión y un análisis profundo de las aplicaciones, topologías, distribución del almacenamiento, ventajas y desventajas. Este análisis concluyó que la mayoría de los M2C-BESS con almacenamiento parcial propuestos en la literatura son para aplicaciones de HVDC, por lo que no se han desarrollado controladores ni topologías adaptadas que usen una etapa de modulación que permita balancear los estados de carga de las baterías sin inyectar armónicos no determinísticos de voltaje a la red en aplicaciones de bajo voltaje. En base a la revisión y análisis realizado, esta tesis posee dos propuestas: 1) una nueva topología M2C-BESS, con paralelización de clusters para aplicaciones de alta corriente, 2) un nuevo controlador capaz de controlar la topología propuesta y el M2C-BESS con cualquiera de sus SMs operando con o sin unidad de almacenamiento conectado a su DClink, de modo que este se pueda usar en aplicaciones de alta potencia, bajo voltaje. Finalmente, la propuesta 1) se valida mediante simulaciones al no contar con el hardware para su validación experimental, mientras que la propuesta 2) se implementa en un M2C-BESS experimental en el laboratorio, adaptado especialmente para probar las propuestas de esta tesis.
  • Thumbnail Image
    Item
    Control predictivo de motor de inducción accionado por un conversor de tres puertos para un vehículo eléctrico con celda de combustible
    (2023) Lizana Gajardo, Alonso Javier; Pereda Torres, Javier Eduardo; Pontificia Universidad Católica de Chile. Escuela de Ingeniería
    Los vehículos electricos más fabricados en la actualidad utilizan baterías, pero estas poseen una densidad energética media, lo que los hace poco competitivos en ciertas aplicaciones que manejan grandes cargas y/o que requieren de muy alta autonomía. Este nicho puede ser ocupado por los vehículos de celda de combustible híbridos, que poseen una alta densidad energética debido a su fuente de energía principal. Por este motivo, se hace importante el desarrollo de sistemas de almacenamiento de energía híbridos eficientes que puedan facilitar la integracion de este tipo de vehículos. En esta tesis se desarrolla un controlador predictivo de corriente para un conversor de tres puertos, el cual acciona un motor de induccion, con el objetivo de analizar la aplicabilidad de este conversor en vehículos electricos de celda de combustible híbridos. Ademas, se diseña un inductor acoplado para el conversor de tres puertos con el fin de reducir las corrientes AC circulantes de este. El controlador propuesto fue implementado en un banco de pruebas, utilizando el inductor acoplado, y se simuló computacionalmente el sistema utilizando modelos de fuentes de poder reales para analizar su rendimiento en condiciones típicas de un vehículo eléctrico como aceleración, desaceleración y frenado regenerativo.
  • Thumbnail Image
    Item
    Decoupled PI Controllers Based on Pulse-Frequency Modulation for Current Sharing in Multi-Phase LLC Resonant Converters
    (2021) Moreno, M.; Pereda Torres, Javier Eduardo; Rojas, F.; Dominguez-Lopez, I.
    The LLC series resonant converter has emerged as a solution to applications requiring power conversion with isolation, reduced volume and high efficiency, such as PV systems and EV chargers. However, the LLC resonant converter is limited in power, so it requires a multi-phase configuration in order to provide higher currents. This configuration connects the outputs of two or more LLC converters in parallel, increasing the output current but introducing imbalance and circulating currents due to the mismatch and tolerance values of components in each resonant tank. This paper proposes a simple PI control scheme to compensate the current imbalance and eliminate circulating currents generated when several LLC resonant converters are connected in parallel. Unlike reported current sharing methods, the proposed control scheme is based on multiple current control loops operating independently, using the switching frequency of each parallel-connected unit as a degree of freedom of the overall converter. The proposed control scheme has been successfully validated under simulations and experimental assessment, implementing two resonant tanks with ±5% tolerance of parameters, providing excellent steady-state and transient performance.
  • Thumbnail Image
    Item
    Denoising and Voltage Estimation in Modular Multilevel Converters Using Deep Neural-Networks
    (2020) Langarica Chavira, Saúl Alberto; Pizarro Lorca, Germán Eduardo; Poblete Durruty, Pablo Martín; Radrigán Sepúlveda, Felipe Ignacio; Pereda Torres, Javier Eduardo; Rodriguez, Jose; Núñez Retamal, Felipe Eduardo
    Modular Multilevel Converters (MMCs) have become one of the most popular power converters for medium/high power applications, from transmission systems to motor drives. However, to operate properly, MMCs require a considerable number of sensors and communication of sensitive data to a central controller, all under relevant electromagnetic interference produced by the high frequency switching of power semiconductors. This work explores the use of neural networks (NNs) to support the operation of MMCs by: i) denoising measurements, such as stack currents, using a blind autoencoder NN; and ii) estimating the sub-module capacitor voltages, using an encoder-decoder NN. Experimental results obtained with data from a three-phase MMC show that NNs can effectively clean sensor measurements and estimate internal states of the converter accurately, even during transients, drastically reducing sensing and communication requirements.
  • Thumbnail Image
    Item
    Design of Electric Buses of Rapid Transit Using Hybrid Energy Storage and Local Traffic Parameters
    (2017) Naranjo Lourido, W.; Muñoz Camargo, L.; Pereda Torres, Javier Eduardo; Cortés Guerrero, C.