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48 results on '"Villar, Irma"'

1. Electro-thermal modeling of an induction heating process of 42CrMo4 steel probe.

Author

Mendi-Altube, Amaiur, Villar, Irma, Carretero, Claudio, and Acero, Jesús

Subjects
*STEEL, *COMPUTATIONAL electromagnetics, *CURIE temperature, *INDUCTION heating
Abstract

This paper describes the procedure of electromagnetic and thermal modeling of an induction hardening load of 42CrMo4 steel. In addition to the temperature and field level dependent physical properties of the material, the magnetic behavior of the load is captured by means of some kind of non-linear impedance boundary condition which simplifies the computational cost of the simulation. The numerical results show the critical behavior around Curie temperature. Finally, a comparison between several simulation results and experimental measurements are provided to assess the usefulness of the proposed electro-thermal simulation. [ABSTRACT FROM AUTHOR]

Published
2024
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8. Design Space Analysis of the Dual-Active-Bridge Converter for More Electric Aircraft

Author

Fernández Hernández, Alejandro, González-Hernando, Fernando, García Bediaga, Asier, Villar, Irma, Abad, Gonzalo, Fernández Hernández, Alejandro, González-Hernando, Fernando, García Bediaga, Asier, Villar, Irma, and Abad, Gonzalo

Abstract

In the literature, different DC/DC power electronic converters (PECs) have been found to interconnect high-voltage DC and low-voltage DC grids in the electric power distribution networks of aircraft. In this scenario, the dual-active-bridge (DAB) converter has been shown to be one of the most promising topologies. The main disadvantages of this PEC are the large output capacitance required to satisfy more electric aircraft (MEA) requirements and the high conduction losses produced in low-voltage power devices of (LV). Therefore, this paper proposes analytical models to determine the voltage ripple and root-mean-square (RMS) current in DC bus capacitors of DABs considering different modulation strategies. Moreover, an analysis of the design space in an MEA case study is performed to evaluate the influence of the design variables in power losses of power devices and peak-to-peak voltage ripple in DC bus capacitors. These models are useful for the design stage of this PEC, as well as to enable multi-objective optimization procedures by reducing the computational cost of these methodologies. Furthermore, the exploration of the switching frequency and limit of the modulation angle aid in reducing the resulting volume of the low-voltage DC capacitor.

Published
2022

12. Analysis of Interleaved Input-Parallel Output-Parallel Dual-Active-Bridge Converter for More Electric Aircraft

Author

Fernández Hernández, Alejandro, García Bediaga, Asier, Villar, Irma, Abad, Gonzalo, Fernández Hernández, Alejandro, García Bediaga, Asier, Villar, Irma, and Abad, Gonzalo

Abstract

Dual-Active-Bridge (DAB) converter is one of the most proposed topologies when considering DC/DC bidirectional isolated power conversion. In these applications, the power density of the converter is one of the main optimization goals. To improve power density, interleaved Input-Parallel Output-Parallel (IPOP) DAB configurations are analyzed in this paper. This configuration helps to reduce voltage and current ripple in input and output capacitors, whose contribution in the converter volume and weight is critical in aircraft applications. To this aim, an analytical model to determine the voltage and current waveforms in these components is proposed in this work. These equations are validated through a simulation model developed in PLECS. Finally, a comparison is presented to find the optimal IPOP configuration in a More Electric Aircraft case study.

Published
2021

13. From the Measurement of COSS–VDS Characteristic to the Estimation of the Channel Current in Medium Voltage SiC MOSFET Power Modules

Author

Rabkowski, Jacek, Zdanowski, Mariusz, Kopacz, Rafal, Gonzalez-Hernando, Fernando, Villar, Irma, and Larranaga, Uxue

Abstract

This article presents a novel method for the dynamic measurement of $C_{\mathrm {OSS}}$ – $V_{\mathbf {DS}}$ characteristic of SiC MOSFET power modules based on the process of charging the output capacitance of the transistors. This technique has been used to determine the $C_{\mathrm {OSS}}$ – $V_{\mathrm {DS}}$ characteristics of medium voltage SiC MOSFET modules, which allows for the extraction of the capacitive current while switching off the transistor. Based on this measurement method, the influence of the turn-off gate voltage $V_{\mathrm {GS-OFF}}$ on the $C_{\mathrm {OSS}}$ – $V_{\mathrm {DS}}$ characteristics has been studied, exhibiting an impact on the output capacitance at low drain–source voltages. However, it is shown that the effect of $V_{\mathrm {GS-OFF}}$ on the capacitive current and power loss is limited in this area. Finally, the channel current and the capacitive current distribution within the drain current were determined based on the determined $C_{\mathrm {OSS}}$ – $V_{\mathrm {DS}}$ in the experimental test at various switched currents and switching speeds. According to the capacitive charge calculations for several cases, the method’s accuracy is high enough to perform switching power loss estimations for medium voltage power modules to be employed in the design of the state-of-the-art power converters. Furthermore, the method is very simple, based on basic capacitance equations, and the required experimental setup is very similar to one used in double-pulse tests.

Published
2023
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47. Multiphysical Characterization of Medium-Frequency Power Electronic Transformers

Author

Villar, Irma and Rufer, Alfred

Subjects
Power Electronic Transformer, Non-Sinusoidal Transformer Characterization, Medium-Frequency Transformer, Transformateur d'Électronique de Puissance, Transformateur de Moyenne Fréquence, Méthode de Conception des Transformateurs, Transformer Design Methodology, Caractérisation Non-Sinusoïdal
Abstract

Europe is currently making a great effort in order to improve the sustainability and reduce the environmental impact of its energy and transportation systems. A key role on these initiatives is played by efficient generation systems, like cogeneration, and clean or renewable energies, like wind or solar energy, as well as, by efficient and improved transportation technologies. In the evolution of these energy and transport systems, the development of Power Electronic Converters with greater functionality, higher reliability, higher efficiency, lower cost, and more sophisticated control will be essential. The main goal of future Power Electronic Converters will be to increase power density, reduce cost and improve reliability. This way, volume, weight and material reduction as well as reliability will gain the future market. A great contribution of these goals will be made by new high-power semiconductor devices, which permit the extension of the frequency range of power converters, and consequently the reduction of magnetic components. A good example of one of these systems are medium-frequency power conversion systems, also known as Power Electronic Transformers, which are able to convert electric power as convectional transformers but with increased features: volume and weight reduction, power transfer and quality control etc. The present work introduces a complete characterization of a medium-frequency power transformer, suitable for efficient Power Electronic conversion systems. The motivation of the present work stems out from the need to evaluate the constraints of conventional transformer characterization and design methodologies. The proposed expressions are able to successfully address the problematic related to non-sinusoidal waveforms, typical of medium-frequency power transformers. Moreover, a design methodology for the optimal design of medium-frequency power transformers is introduced. The characterization, as well as the design methodology, are verified by means of finite element simulations and measurement results.

48. Analytical Models of Multiphase Isolated Medium-Frequency DC-DC Converters

Author

Garcia-Bediaga, Asier, Villar, Irma, Rujas, Alejandro, Etxeberria-Otadui, Ion, and Rufer, Alfred

Subjects
high-power density, parametric models, medium frequency (MF), DC-DC power converters, soft-switching
Abstract

This paper presents new analytical equations, parametrized with respect to the number of converter phases, for multiphase isolated dc-dc topologies. This paper describes five multiphase isolated converter models, as well as their level of accuracy. Based on these new parametric models, a thorough comparative among various common high-power converter topologies is carried out, highlighting the best topology regarding efficiency, cost, and power density. The analytical results are firstly compared and verified using PLECS simulation software, and validated finally by experimental measurements with a 10-kW/20-kHz/500-V configurable laboratory prototype. Due to the low computation cost and accuracy, the developed analytical models provide important insights for optimization-based design methodologies. Furthermore, this paper highlights, depending on the targeted application and objectives, the benefits of each analyzed converter configuration.

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