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Alfred Rufer

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Related publications (215)

Page 4 of 11

Re-generative Asymmetrical Multi-level Converter for Multi-Megawatt Variable Speed Drives

Alfred Rufer

This paper is focused on the design, modulation and control of a re-generative non-symmetrical multi-level converter for high-power applications such as oil and gas or mining. The converter is based on standard IGBT modules and the DC-link voltages are cho ...

2010

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

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

Study and Simulation of the Energy Balance of an Urban Transportation Network

Alfred Rufer, Philippe Barrade

This paper proposes and studies new strategies for an increase of the energetic efficiency of an urban transportation network fed with catenaries. A simulation tool has been developed to determine the energy efficiency on the global transportation system ( ...

2007

Performance Evaluation of Static and Dynamic Compressed Air Reservoirs for Energy Storage

Alfred Rufer

The concept of static and dynamic reservoirs is presented, and their performances are evaluated. The static reservoir is a simple reservoir with constant volume, and the dynamic one has a volume which varies as a function of the position of an internal pis ...

MDPI AG2025

Multilevel two quadrant DC/DC converter for regenerative braking in mobile applications

Alfred Rufer

In this paper different cascaded and multilevel topologies are compared for regenerative braking systems using supercapacitors (SC). It shows that the multilevel buck derived topology can beneficiate from both reduced voltage across the inductor and increa ...

2011

Single Phase Resonant LC Circuit Using a Bank of Self-Switched Capacitors

Alfred Rufer, Daniel Siemaszko, Christian Rod

This paper presents a preliminary work on the feeding of an AC dipole using a resonant circuit with a varying resonant frequency. A single phase LC oscillator containing a variable capacitor is fed by a wide band amplifier or a voltage source inverter. For ...

Institute of Electrical and Electronics Engineers2011

Controlled Resonant Circuit with Commutated Capacitors using Self-Switching Power Devices

Alfred Rufer, Daniel Siemaszko, Christian Rod

This paper presents a preliminary work on a resonant circuit, also called AC-dipole. The resonance frequency of the circuit is changed by the mean of a variable capacitor connecting an inductor. For this purpose, a bank of switched capacitors of different ...

Ieee Service Center, 445 Hoes Lane, Po Box 1331, Piscataway, Nj 08855-1331 Usa2009

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

Alfred Rufer, 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

Operation and Control of Single-to-Three-Phase Direct AC/AC Modular Multilevel Converters under Asymmetric Grid Conditions

Alfred Rufer, Michail Vasiladiotis, Nicolas Cherix

Single-to-three-phase direct AC/AC Modular Multilevel Converters have gained a significant interest in the field of railway interties. The use of such an MMC-based structure implies more advanced control techniques as well as design requirements, especiall ...

2015

Multilevel Modular DC/DC Converter for Regenerative Braking Using Supercapacitors

Alfred Rufer

Regenerative braking is presented in many electric traction applications such as electric and hybrid vehicles, lifts and railway. The regenerated energy can be stored for future use, increasing the efficiency of the system. This paper outlines the benefits ...

2012

Use of a DC-DC step up converter in photovoltaic plants for increased electrical energy production and better utilization of covered surface area

Alfred Rufer, Gina Kristin Steinke

An important parameter for the economy of a photovoltaic plant is the coefficient of generated power to needed surface. An analysis of this relationship is done for different solar plants and losses generated by the transmission within such a plant are cal ...

2015

Design and Control of a Modular Multilevel DC/DC Converter for Regenerative Applications

Alfred Rufer

This paper compares different cascaded and multilevel topologies to interface supercapacitors to a dc bus in regenerative braking applications. It is shown that the modular multilevel dc/dc converter (MMC) can benefit from both reduced voltage and increase ...

2013

High-Power High-Voltage Isolated DC-DC Converters using an NPC Balanced Capacitive Divider

Alfred Rufer

A new isolated DC-DC converter is presented suited for high voltage applications. It is based on the series connection of NPC inverter cells, using semiconductor devices with lower voltage blocking capability than the total input voltage. The galvanic isol ...

2015

A fully analytical PEM fuel cell system model for control applications

Alfred Rufer, Félix Grasser

Maintaining a fuel cell system in correct operating conditions when subjected to fast load changes requires good system control. Best results are typically achieved using model based control strategies. This paper elaborates a control oriented PEM fuel cel ...

2006

A versatile DC/DC converter based on Modular Multilevel Converter for energy collection and distribution

Drazen Dujic, Alfred Rufer, Stephan Kenzelmann

A topology based on the Modular Multilevel Converter (MMC) is presented, using two MMC linked by a medium frequency transformer. The back to back structure proves to have effective circuit breaker properties and reduced passive components. Due to the adopt ...

2011

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

Fictive Axis Emulator-based State Feedback Vector Current Control for Single-Phase Voltage Source Converters

Alfred Rufer, Michail Vasiladiotis

This paper presents a vector current control method tailored for single-phase voltage source converters. In order to imitate the behavior of a three-phase system, the Fictive Axis Emulation (FAE) concept is employed. The latter is able to synthesize the ro ...

2013

Analysis and Control of Modular Multilevel Converters with Integrated Battery Energy Storage

Alfred Rufer, Michail Vasiladiotis

Multilevel Converters and battery energy storage systems (BESS) are key components in present and future medium voltage networks, where an important integration of renewable energy sources takes place. The Modular Multilevel Converter (MMC) offers the capa ...

Ieee-Inst Electrical Electronics Engineers Inc2015

Modular DC/DC Converter: Comparison of Modulation Methods

Drazen Dujic, Alfred Rufer, Stephan Kenzelmann

This paper presents a bidirectional modular DC/DC converter. It consists of two Modular Multilevel Converters (MMC) linked by a transformer to achieve galvanic isolation. This topology serves as “DC transformer” interfacing low and medium voltage DC grids. ...

2012