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Alfred Rufer

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Publications associées (215)

Isolated DC/DC Structure Based on Modular Multilevel Converter

Alfred Rufer, Stephan Kenzelmann, Drazen Dujic

In the future, new aspects from decentralized generation using different dc voltage levels are expected to influence the general concept of power exchange. Converter are needed to adapt the voltage between low voltage (LV), medium voltage (MV), and high vo ...

Ieee-Inst Electrical Electronics Engineers Inc2015

Comparison of Multistage Stacked Boost Architecture Topologies in Regards of the Relation between Duty Cycle, Number of Stages and Efficiency

Alfred Rufer, Gina Kristin Steinke

A step-up DC-DC converter (non-isolated) based on the current diverter principle is shown. This converter is intended for renewable energy sources or distribution networks for elevating the voltage from LV to MV levels. The relationship of stage number, du ...

2015

Configurable Modular Multilevel Converter (CMMC) for Flexible EV

Alfred Rufer, Rosa Martel Danoary Tsirinomeny

Today, there is a long-term trend towards bi-directional and flexible charger functions for not only drawing current from the grid but also feeding excess energy back into it. The Configurable Modular Multilevel Converter (CMMC) offers a large flexibility ...

2015

High-Order Vector Control of Grid-Connected Voltage Source Converters with LCL-Filters

Alfred Rufer, Behrooz Bahrani, Michail Vasiladiotis

This paper proposes a vector control strategy for LCL-filter-based grid-connected voltage source converters (VSCs). The proposed control strategy is inherently capable of attenuating the resonance phenomenon of such systems. This is an advantage over the e ...

Institute of Electrical and Electronics Engineers2014

Configurable Modular Multilevel Converter (CMMC) for a universal and flexible integrated charging system

Alfred Rufer, Rosa Martel Danoary Tsirinomeny

Electric Vehicle (EV) owners are confronted by the limited compatibility of available charging infrastructures. Therefore, this paper is focused on presenting a Configurable Modular Multilevel Converter (CMMC) for a universal and flexible integrated chargi ...

2014

Modular Converter Architecture for Medium Voltage Ultra Fast EV Charging Stations: Dual Half-Bridge-based Isolation Stage

Alfred Rufer, Behrooz Bahrani, Niklaus Burger, Michail Vasiladiotis

The concept of ultra fast charging of Electric Vehicles (EVs) is expected to contribute significantly to their widespread utilization in long-distance travels. Towards this direction, emerging power electronic topologies will be the key components of the d ...

2014

On The Strategies Towards Isothermal Gas Compression And Expansion

Alfred Rufer, Sylvain Lemofouet-Gatsi, Mahbod Heidari

Isothermal compression/expansion is regarded as the most promising process in many applications and many researchers and inventors have tried different methods to achieve this goal. The current article first studies the gradual roadmap from adiabatic towar ...

2014

Bond Graph Model Representation of a New Reciprocating Finned Air Compressor

Alfred Rufer, Mahbod Heidari

A new finned reciprocating air compressor model is developed recently for compressed air energy storage. First the mechanism of operation of the new compressor is described. The complexity of the design encouraged us to develop the model based on the bond ...

2014

Optimal Energy Management Strategy of an Improved Elevator With Energy Storage Capacity Based on Dynamic Programming

Alfred Rufer, Philippe Barrade

Efficiency and energy consumption reduction are becoming a key issue in elevation applications. Energy Storage Systems (ESS) can play a significant role in this field, together with their associated Energy Management Strategy (EMS) to optimize the overall ...

Institute of Electrical and Electronics Engineers2014

Thermo-Electric Analogy Method for Computing Transient Heat Transfer in a New Reciprocating Finned Piston Compressor

Alfred Rufer, John Richard Thome, Mahbod Heidari

In the framework of Isothermal Compressed Air Energy Storage (CAES), a new finned piston compressor has been designed and realized at LEI laboratory in EPFL. This system comprises a series of concentric annuli’s fitting into each other compressing the air ...

2014

Accurate Capacitor Voltage Ripple Estimation and Current Control Considerations for Grid-Connected Modular Multilevel Converters

Alfred Rufer, Nicolas Cherix, Michail Vasiladiotis

In this paper the analytical solution for the submodule voltage ripple equations of a Modular Multilevel Converter (MMC) is derived, based on the knowledge of the external voltage/current magnitudes, and enhancing a concept previously presented in literatu ...

Ieee-Inst Electrical Electronics Engineers Inc2014

Dynamic Analysis and State Feedback Voltage Control of Single-Phase Active Rectifiers with DC-Link Resonant Filters

Alfred Rufer, Michail Vasiladiotis

Single-phase active rectifiers exhibit an inherent strong second-order current harmonic on their DC-link. The latter is often undesirable from a load point of view and is therefore chosen to be eliminated. A common method is the use of a resonant passive L ...

Ieee-Inst Electrical Electronics Engineers Inc2014

Optimizing EV driving-recharge time ratio a under limited grid connection

Alfred Rufer, Hardi Hõimoja

An evident issue for electric vehicle (EV) is the limited average speed while driving long distances. This paper will provide a better understanding of EV requirements in order to make the electric vehicles more compatible for long distance driving. Batter ...

2014

Fluid Flow Analysis of a New Finned Piston Reciprocating Compressor Using Pneumatic Analogy

Alfred Rufer, Mahbod Heidari

The goal of this paper is to investigate the fluid flow analysis in a novel multilayered finned reciprocating compressor, adopting a so-called “pneumatic-Electric” analogy using a lumped methodology. This machine includes two sets of concentric annular fin ...

2014

Non-Isolated DC-DC Converters for High Power Appli-cations - Control of the Capacitive Voltage Divider

Alfred Rufer, Philippe Barrade

A non-isolated DC-DC converter is presented, based on the current diverter principle. The converter is foreseen for large power electronic applications where normally the converters are fed from DC supplies at a typical voltage level of around one or two k ...

2014

Voltage Step-Up Converter based on Multistage Stacked Boost Architecture (MSBA)

Alfred Rufer, Philippe Barrade, Gina Kristin Steinke

A non-isolated DC-DC converter is presented, based on the current diverter principle. The converter is foreseen for larger photovoltaic plants or other DC collection networks for renewable energy sources. The topology allows the DC-DC conversion as step-up ...

2014

Fluid Flow Analysis of a New Finned Piston Reciprocating Compressor Using Pneumatic Analogy

Alfred Rufer, Mahbod Heidari

2014

Multivariable Control of Single-Inductor Dual-Output Buck Converters

Alfred Rufer, Alireza Karimi, Behrooz Bahrani

Cross regulation is the main technical challenge of a Single-Inductor Multiple-Output (SIMO) dc-dc converter. This paper proposes a multivariable digital controller to suppress the cross regulation of a Single-Inductor Dual-Output (SIDO) buck converter in ...

Ieee2014

Operation of Modular Multilevel Converters Under Grid Asymmetries

Alfred Rufer, Daniel Siemaszko, Nicolas Cherix, Michail Vasiladiotis

The Modular Multilevel Converter is very likely to operate in a grid-connected mode under asymmetric conditions. Such a converter features several unique characteristics, which make its analysis different from other types of power converters in similar cas ...

2013

Fail-safe Modular Control Platform for Power Electronic Applications in R&D Environments

Alfred Rufer, Philippe Barrade, Simon Delalay, Nicolas Cherix

This paper presents a modular control platform which is tailored for teaching and research applications. It aims at being entirely “student-proof” and features software-independent safety mechanisms, extensive signal conditioning and easy-to-use interfaces ...

2013

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