Publications de Irma Villar | EPFL Graph Search

Multiobjective Optimization of Medium-Frequency Transformers for Isolated Soft-Switching Converters Using a Genetic Algorithm

Alfred Rufer, Alejandro Rujas, Irma Villar, Asier Garcia Bediaga

The main challenge of medium-frequency transformers is the number of design parameters, constraints and objectives, and the difficulty of handling them on a particular design. This paper presents a novel computer-aided optimal design for MF transformers us ...

Ieee-Inst Electrical Electronics Engineers Inc2017

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

Alfred Rufer, Alejandro Rujas, Irma Villar, Asier Garcia Bediaga

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 o ...

Ieee-Inst Electrical Electronics Engineers Inc2017

New Parametric Model of Medium-Frequency Single-Active-Bridge Converters

Alfred Rufer, Philippe Barrade, Alejandro Rujas, Irma Villar, Asier Garcia Bediaga

This paper presents a new parametric model of a single-active-bridge (SAB) converter with a variable number of phases. The soft-switching behavior and the design of snubbers are also analyzed. The analytical study is validated using PLECS simulation softwa ...

2013

Proposal and Validation of Medium-Frequency Power Transformer Design Methodology

Alfred Rufer, Irma Villar

Power electronics is continuously evolving toward higher power densities. Consequently, volume, weight, and material reduction are becoming major design issues, which lead the research focus toward high/medium-frequency power conversion systems. This paper ...

2011

Multiphysical Characterization of Medium-Frequency Power Electronic Transformers

Irma Villar

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 ...

EPFL2010

Description and Efficiency Comparison of Two 25 kVA DC/AC Isolation Modules

Alfred Rufer, Frédéric Zurkinden, Daniel Siemaszko, Lukas Fleischli, Irma Villar

In the frame of the European project UNIFLEX-PM, two AC/AC converter topologies hove been studied and implemented. Both converters, rated for 25 kVA, are isolated by a medium-frequency power transformer. The first topology is based on a dual active bridge ...

2009

Global Loss Evaluation Methods for Nonsinusoidally Fed Medium-Frequency Power Transformers

Alfred Rufer, Irma Villar

Medium-voltage conversion systems, such as traction and grid-connected converters, are continuously evolving toward higher power densities. Consequently, volume, weight, and material reductions are becoming major design issues, which lead the research focu ...

2009

Transient Thermal Model of a Medium Frequency Power Transformer

Alfred Rufer, Irma Villar

Nowadays medium voltage conversion systems, like traction and energy distribution systems, aim to increase power density. Volume, weight and material reduction are gaining the market today. Due to the development of new high power semi-conductor devices a ...

2008

Analysis of Empirical Core Loss Evaluation Methods For Non-Sinusoidally Fed Medium Frequency Power Transformers

Alfred Rufer, Frédéric Zurkinden, Irma Villar

Nowadays medium voltage conversion systems, like traction and energy distribution systems, aim to increase power density. Volume, weight and material reduction are gaining the market today. Due to the development of new high power semiconductor devices a n ...

2008