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Alfred Rufer

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Related publications (215)

A Flexible, High Efficiency, VSI-based HVDC Transmission System with Reduced Harmonics

In this paper a High Voltage Direct Current (HVDC) transmission system is proposed, based on using three level three phase (3L3P) converters, coupled through a specific transformer connection in order to benefit from natural and selective harmonic cancella ...

2008

Advanced Integration of Multilevel Converters into Power System

Alfred Rufer, Stephan Kenzelmann

The paper introduces an advanced multilevel-based power converter structure for flexible power management of future electricity networks. The structure is then analysed so that appropriate control approaches are proposed in order to overcome technical chal ...

2008

Benefits of Short- and Long-Term Energy Storage in the context of renewable energies and sustainable management of energy resources

Alfred Rufer

Potential solutions for energy storage are presented, in the context of renewable energies and in relation with new opportunities in the domain of the use of classical resources as fossils. From the classical pumped hydro storage to smaller energy quantiti ...

2008

Energy storage systems

Daniel Favrat, Alfred Rufer, Philippe Barrade

Different types of energy storage systems are described, in particular hydro-pneumatic storage systems. In one, energy is stored by compressing gas in a chamber (44,45,54,55) with a liquid piston and released by gas expansion. A spray head or grid at the t ...

2008

A novel 60 MW Pulsed Power System based on Capacitive Energy Storage for Particle Accelerators

Alfred Rufer, Claude Fahrni

Large physics experimentation as in particle accelerators or in nuclear fusion is often characterised by a strong and modulated power demand, incompatible with the power availability of the grid. Therefore, large facilities for short-term energy storage ha ...

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

Multiphysic Modeling of a Hybrid Propulsion System for a Racecar Application

Alfred Rufer, Philippe Barrade

A hybrid propulsion system has been designed for an optional use in the Formula S2000, based on supercapacitive energy storage coupled to an ICE engine via a Synchronous PM machine. Because of the high level specification of the weight penalty in competiti ...

2008

Sizing of a Supercapacitive Tank: Finite Elements Thermal Modelling

Alfred Rufer, Philippe Barrade

The sizing process of a supercapacitive tank is today a well-known procedure. It enables the identification of the number of cells needed to match energy requirements. In some cases, this number must be increased, in order to match the power needs of the a ...

2008

Dynamic Behaviour of a Series – Connected Multilevel Converter with Interleaved Switching

Alfred Rufer, Claude Fahrni

This paper presents an analysis and design method for the current control of a series connected multilevel converter with interleaved switching. Based on a conventional design method for the parameters of a PI controller, the variable response of a current ...

2008

Multiphysics and Energetic Modeling of a Vanadium Redox Flow Battery

Alfred Rufer, Christian Blanc

Vanadium redox flow batteries (VRB) are large stationary electricity storage systems; their performance is enhanced when they are operating under optimal conditions. The multiphysics model developed in this paper offers a good understanding of the VRB oper ...

2008

Introducing the Common Cross Connected Stage (C3S) for the 5L ANPC Multilevel Inverter

Alfred Rufer

This paper proposes a novel multilevel Power Electronics Building Block (PEBB) for the 5 level ANPC multilevel voltage source inverter [7]. The PEBB is composed of 6 switches in a crossed configuration [8] and one capacitor. It is common to the 3 phases of ...

2008

Device for feeding a charge including integrated energy storage

Alfred Rufer, Claude Fahrni

The feeding device enables a charge (1) to be fed with relatively weak medium power on the one hand, and strong power points on the other, due to energy storage condensers (21) placed in a series. Each of said energy storage condensers (21) is linked to an ...

2008

En route avec un train hybride diesel-électrique

Alfred Rufer, Blaise Destraz, Philippe Barrade

Le surcoût d'une locomotive hybride équipée de supercondensateurs peut être amorti en dix ans, grâce à l'économie d'énergie réalisée, qui est d'environ 40%. ...

2008

Caractérisation de cellules photovoltaïques avec prise en compte de l’ombrage pour un dirigeable stratosphérique

Alfred Rufer, Philippe Barrade, Yannick Louvrier

Suite à la prise de conscience collective du réchauffement climatique, les domaines d’application des cellules photovoltaïques se sont diversifiés donnant naissance à des projets dont la complexité aboutit logiquement à la conception de nouveaux moyens d’a ...

2008

Application de supercondensateurs dans le transport individuel Etude expérimentale d’un scooter électrique avec assistance en puissance

Alfred Rufer, Blaise Destraz, Philippe Barrade

La plupart des véhicules électriques utilisent des accumulateurs électrochimiques qui sont sollicités par des puissances instantanées élevées. Ces derniers posent le problème de leur longévité et du rendement énergétique. Cet article présente une approche ...

2008

Three-Level Quadratic Non-Insulated Basic DC-DC Converters

Alfred Rufer

This paper presents a family of three transformerless converters (buck, boost and buck-boost) with two specific characteristics: the quadratic static gain as a function of the duty cycle ratio, and the division of the higher voltage level between the two s ...

2007

Today's and tomorrow's meaning of power electronics within the grid interconnection

Alfred Rufer

Power Electronics is expected to become a major component in the field of the global electric power management, as it is already today within most of electric power applications like variable speed drives or other conventional user applications. From the e ...

2007

The Active Self-controlled Free-wheeling Management Principle Applied to Reverse Recovery Losses Reduction

Alfred Rufer, Philippe Barrade, Daniel Siemaszko

Several works suggest the imminent appearance of bidirectional active devices. The promised performances go in the direction of a reverse recovery effects reduction and efficiency improvement. Our purpose is the study of an active management for switches t ...

2007

Stockage d'énergie par air comprimé. Un défi pour les circuits d'électronique de puissance

Alfred Rufer, Sylvain Lemofouet-Gatsi

The principle of air compression can be utilized for the storage of electrical energy, with variable properties from the point of view of the energy efficiency. For the involved thermodynamic phenomena different approaches and realized systems lead to more ...

2007

Efficiency Considerations and Measurements of a Hybrid Energy Storage System based on Compressed Air and Supercapacitors

Alfred Rufer, Sylvain Lemofouet-Gatsi

This paper presents the study and experimentation of a hybrid energy storage system based on Compressed Air, where the storage and discharge are done within maximum efficiency conditions for the volumetric machine. As these maximum efficiency conditions im ...

2007

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