Publicaciones académicas

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Esta colección incluye artículos de profesores de la Pontificia Universidad Católica de Chile, publicados en revistas nacionales y extranjeras.

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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.
3D Microstructured Inorganic Perovskite Materials for Thermal Neutron Detection
(2022) Caraveo-Frescas, Jesus A.; Reyes-Banda, Martin G.; Fernandez-Izquierdo, Leunam; Quevedo-Lopez, Manuel A.
A combination of novel techniques such as a solvent-free thin-film deposition, perovskite patterning, and B-10 back-fill technique enables the high neutron detection efficiency in a perovskite-based microstructured thermal neutron detector. High-efficiency cesium lead bromide (CsPbBr3) perovskite-based microstructured detectors are demonstrated here. Trenches up to 10 mu m deep are etched into the CsPbBr3 thin films using a novel dry etching process involving a combination of HBr and Ar plasma. The microstructured diodes are then backfilled with isotopically enriched boron as neutron conversion material via a sedimentation process to preserve the perovskite integrity. The fabricated microstructured CsPbBr3 thermal neutron detectors show an efficiency of 4.3%. This represents >1.2x efficiency improvement over planar silicon (3.5%) and >2x efficiency improvement over planar CsPbBr3 (2.1%) detectors, respectively. More importantly, gamma-ray discrimination of 10(7) is measured in CsPbBr3-based microstructured neutron detectors.
450 d of Type II SN 2013ej in optical and near-infrared
(OXFORD UNIV PRESS, 2016) Yuan, Fang; Jerkstrand, A.; Valenti, S.; Sollerman, J.; Seitenzahl, I. R.; Pastorello, A.; Schulze, S.; Chen, T. W.; Childress, M. J.; Fraser, M.; Fremling, C.; Kotak, R.; Ruiter, A. J.; Schmidt, B. P.; Smartt, S. J.; Taddia, F.; Terreran, G.; Tucker, B. E.; Barbarino, C.; Benetti, S.; Elias Rosa, N.; Gal Yam, A.; Howell, D. A.; Inserra, C.; Kankare, E.; Lee, M. Y.; Li, K. L.; Maguire, K.; Margheim, S.; Mehner, A.; Ochner, P.; Sullivan, M.; Tomasella, L.; Young, D. R.
We present optical and near-infrared photometric and spectroscopic observations of SN 2013ej, in galaxy M74, from 1 to 450 d after the explosion. SN 2013ej is a hydrogen-rich supernova, classified as a Type IIL due to its relatively fast decline following the initial peak. It has a relatively high peak luminosity (absolute magnitude M-V =-17.6) but a small 56Ni production of similar to 0.023 M-circle dot. Its photospheric evolution is similar to other Type II SNe, with shallow absorption in the H a profile typical for a Type IIL. During transition to the radioactive decay tail at similar to 100 d, we find the SN to grow bluer in B - V colour, in contrast to some other Type II supernovae. At late times, the bolometric light curve declined faster than expected from Co-56 decay and we observed unusually broad and asymmetric nebular emission lines. Based on comparison of nebular emission lines most sensitive to the progenitor core mass, we find our observations are best matched to synthesized spectral models with a M-ZAMS = 12-15 M-circle dot progenitor. The derived mass range is similar to but not higher than the mass estimated for Type IIP progenitors. This is against the idea that Type IIL are from more massive stars. Observations are consistent with the SN having a progenitor with a relatively low-mass envelope.
8-hydroxyquinolinato lithium nano-interlayer in tandem OPV devices
(SPRINGER, 2022) Neculqueo, Gloria; Angel, Felipe A.
8-hydroxyquinolinato lithium (Liq) nano-interlayer was evaluated as part of the interconnection layer (ICL) system Liq|Al|MoO3 to produce tandem organic photovoltaic (OPV) devices. First, the thickness dependence of Liq on the performance of single-stack OPV devices was studied, along with its stability by exposing the devices to different degradation conditions. The results confirmed the benefits of incorporating Liq, providing even further stability, particularly to devices exposed to air. Then, symmetrical tandem OPV devices were prepared by optimizing the thickness of the Al interlayer to obtain an efficient ICL. Although limited power conversion efficiencies were obtained due to the symmetry of the device architecture, electrical, optical, and lifetime measurements confirmed Liq|Al|MoO3 as a suitable ICL to achieve tandem OPV devices.
A charge optimized many-body potential for iron/iron-fluoride systems
(2019) Tangarife Franco, Edwin; Romero, A. H.; Mejía López, José Félix
A clean four-quadrant sinusoidal power rectifier using multistage converters for subway applications
(2005) Dixon, Juan; Morán, Luis
A special 27-level four-quadrant rectifier for subway applications is analyzed. The arrangement uses only three H-bridges per phase, common dc bus, and independent input transformers for each H-bridge. The transformers allow galvanic isolation and power escalation to obtain high-quality voltage waveforms, with total harmonic distortion of less than 1%. Some advantages of this 27-level rectifier are: 1) only one of the three H-bridges, called the main converter, manages more than 80% of the total active power in each phase and 2) it switches at fundamental frequency, reducing the switching losses at a minimum value. The rectifier analyzed in this paper is a current-controlled voltage-source type, with a conventional feedback control loop. Some simulations in a rectifier substation, including power reversal at full load are displayed (750 Vdc, 1200 A). The rectifier shows the ability to produce clean ac and dc waveforms without any ripple, and fast reversal of power. Some experimental results with a small prototype, showing voltage and current waveforms, are finally displayed.
A compact ultrafast capillary plasma discharge as an intense XUV source
(2014) Valenzuela, J. C.; Wyndham, Edmund
A comparative study of Ir(III) complexes with pyrazino[2,3-f][1,10]phenanthroline and pyrazino[2,3-f][4,7]phenanthroline ligands in light-emitting electrochemical cells (LECs)
(2015) Gonzalez, I.; Dreyse, Paulina A.; Cortes, D.; Sundararajan, M.; Morgado, C.; Brito, I.; Roldan, C.; Bolink, H.; Loeb Luschow, Bárbara
A Comparison of Energy Efficiency Certification in Housing: A Study of the Chilean and Spanish Cases
(2019) Sanhueza Durán, Francisco; Gómez Soberón, José M.; Valderrama Ulloa, Claudia; Ossio Castillo, Felipe Antonio
Faced with implementing policies that seek to improve the energy efficiency of housing and reduce the impact of CO2 emissions, several countries are introducing (unilaterally or by international agreement) energy certification systems that allow the effects of these policies to be evaluated. This study aims to compare the energy efficiency certification systems in Spain and Chile, identifying convergent and divergent parameters, enabling the existing gaps to be identified and improvements noted for both systems. To do so, 20 sample dwellings in Santiago de Chile were evaluated, along with the local calculating tools in both countries. The analysis considered the aspects of regulation, its reach, the characterization of the models and the necessary indicators. The comparison identified, among others, differences such as obligatory implementation of the system, a study of the existing buildings in the focus area, the prevailing indicators for evaluating the effects of the buildings, the low incidence of mixed energy systems in the Chilean system and the possibility of proposing and evaluating improvements in the Spanish system. As a result, higher energy requirements and greater CO2 emissions were identified in the Chilean system, reaching differences of 42 kWh/m2/year in consumption and 14 kgCO2/ m2/year in emissions with regard to the Spanish qualification. The results of this comparison have facilitated the identification of improvements that will increase the evaluation standards of the Chilean system.
A comparison of packed-bed flow topologies for high-temperature thermal energy storage under constrained conditions
(2024) Ignacio Calderón-Vásquez; Cardemil Iglesias, Jose Miguel
A Compound Real Option Approach for Determining the Optimal Investment Path for RPV-Storage Systems
(The Energy Journal, 2022) Hassi, Benjamín A.; Reyes Torres, Tomas Hernan; Sauma Santis, Enzo Enrique
The use of residential Photovoltaic-Storage systems may produce large benefits to owners and has expanded rapidly in recent years. Nonetheless, large uncertainties regarding the profitability of these systems make it necessary to incorporate flexibilities in their economic evaluations. This paper offers a new method to evaluate the compound flexibility of both the option of delaying investments and the option of further expanding the capacity of solar photovoltaic modules and batteries during the investment horizon. Flexibility is modeled as a compound real option, whose value is computed using a novel method that we call Compound Least Squares Monte Carlo (CLSM). The model is applied to the investment decisions associated to a residential Photovoltaic-Storage system. Results suggest that investors should use the proposed CLSM method in the economic valuation of multi-stage projects, since considering only a single flexibility could promote sub-optimal decisions. Moreover, in our case study, we show that it is optimal to break the investment down into two steps or more in 36% of future scenarios, on average.
A comprehensive review on expansion planning: models and tools for energy policy analysis
(2018) Gacitúa Rocha, Leonardo Esteban; Gallegos Garay, Pablo Ignacio; Henríquez Auba, R.; Lorca Gálvez, Álvaro Hugo; Negrete Pincetic, Matías Alejandro; Olivares Quero, Daniel; Valenzuela, A.; Wenzel, George
A convex chance-constrained model for reactive power planning
(2015) Lopez, Julio; Pozo, David; Contreras, Javier; Mantovani, J. R. S.
A data analysis of the Chilean housing stock and the development of modelling archetypes
(2020) Molina Carvallo, Constanza del Pilar; Kent, M; Hall, I; Jones, B
A decoupled Nearest Level Control for a Modular Multilevel Cascade Converter based on Triple Star Bridge Cells (MMCC-TSBC)
(2021) Shamshuddin, Mohammed Azharuddin; Arancibia, David; Rojas, Felix; Pereda Torres, Javier; Kennel, Ralph
A delicate balance in South America
(2008) Rudnick, Hugh; Barroso, Luiz; Mocarquer, Sebastian; Bezerra, Bernardo
This article deals with the challenges of balancing the need for hydroelectricity with the impact on the environment. Economic efficiency, energy security, and environmental sustainability are concerns that must be considered in any energy policy in any given country. These key aspects remain challenged currently in South America. High energy consumption growth worldwide rising fossil fuels prices, strong environmentalist pressure toward reducing greenhouse gas effects, and promotion of renewable energy production have been a common challenge in South American energy markets. The development of vast unexploited hydroelectric resources is also at the center of attention, where its renewable character is being confronted with its environmental impact.
A DESGW Search for the Electromagnetic Counterpart to the LIGO/Virgo Gravitational-wave Binary Neutron Star Merger Candidate S190510g
(2020) Garcia, A.; Morgan, R.; Herner, K.; Palmese, A.; Soares Santos, M.; Annis, J.; Brout, D.; Vivas, A. K.; Drlica Wagner, A.; Quirola Vásquez, Jonathan Alexander; Santana Silva, L.; Tucker, D. L.; Allam, S.; Wiesner, M.; Garcia Bellido, J.; Gill, M. S. S.; Sako, M.; Kessler, R.; Davis, T. M.; Scolnic, D.; Casares, J.; Chen, H.; Conselice, C.; Cooke, J.; Doctor, Z.; Foley, R. J.; Horvath, J.; Howell, D. A.; Kilpatrick, C. D.; Lidman, C.; Olivares, E. F.; Paz Chinchon, F.; Pineda G., J.; Rest, A.; Sherman, N.; Abbott, T. M. C.; Aguena, M.; Avila, S.; Bertin, E.; Bhargava, S.; Brooks, D.; Burke, D. L.; Rosell, A. C.; Kind, M. C.; Carretero, J.; Costanzi, M.; da Costa, L. N.; Desai, S.; Diehl, H. T.; Dietrich, J. P.
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
A design tool and fabrication guidelines for small low cost horizontal axis hydrokinetic turbines
(2014) Muñoz, A.; Chiang Sánchez, Luciano Eduardo; De La Jara, E.
A DFT/TDDFT Study of Porphyrazines and Phthalocyanine Oxo-Titanium Derivatives as Potential Dyes in Solar Cells
(2011) Zarate, Ximena; Schott Verdugo, Eduardo Enrique; Arratia Pérez, Ramiro

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