Publications by Stephan Kenzelmann

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

Modular DC/DC Converter: Comparison of Modulation Methods

Alfred Rufer, Stephan Kenzelmann, Drazen Dujic

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

Modular DC/DC Converter for DC Distribution and Collection Networks

Stephan Kenzelmann

A major change in the electrical transmission and distribution system is taking place in Europe at the moment. The shift from a centralised energy production to a distributed generation profoundly changes the behaviour of the grid. Environmental or social ...

EPFL2012

Study on the Reversible DC-DC Converter as Interface between Low and Medium Voltage DC Networks

Alfred Rufer, Stephan Kenzelmann, Carlo Arrioja

This paper introduces an isolated reversible DC-DC converter with a particular topology, which benefits from both the NPC (neutral point clamped) structure and the series-parallel connection of converters. The key property of the proposed topology is the o ...

2012

Vector Control of Single-Phase Voltage-Source Converters Based on Fictive-Axis Emulation

Alfred Rufer, Stephan Kenzelmann, Behrooz Bahrani

This paper presents an alternative way for the current regulation of single-phase voltage-source dc-ac converters in direct-quadrature (dq) synchronous reference frames. In a dq reference frame, ac (time varying) quantities appear as dc (time invariant) on ...

Institute of Electrical and Electronics Engineers2011

A Versatile DC-DC Converter for Energy Collection and Distribution using the Modular Multilevel Converter

Alfred Rufer, Stephan Kenzelmann, Michail Vasiladiotis, Drazen Dujic

The drawbacks of conventional Modular Multilevel Converters (MMC) are described in terms of short-circuits. The configuration of MMC-transformer-MMC proves to handle short-circuits at the input and output without the need for additional DC or AC circuit br ...

Ieee2011

Power and DC Link Voltage Control Considerations for Indirect AC/AC Modular Multilevel Converters

Alfred Rufer, Stephan Kenzelmann, Nicolas Cherix, Michail Vasiladiotis

A highly interesting application field of the Modular Multilevel Converter is the interconnection of the European three-phase 50 Hz industrial grid with the single-phase 16 2/3 Hz railway supply. Contrary to existing technologies, the utilization of a bulk ...

Ieee2011

Multivariable-PI-based DQ Current Control of Voltage Source Converters with Superior Axes Decoupling Capability

Alfred Rufer, Stephan Kenzelmann, Behrooz Bahrani

This paper presents a linear direct-quadrature (dq) current control strategy for voltage source converters (VSCs) in a rotating reference frame (RRF). The described method is based on Multivariable proportional-integral (PI) regulators and provides fast dy ...

Institute of Electrical and Electronics Engineers2011

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

Alfred Rufer, Stephan Kenzelmann, Drazen Dujic

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

Reversible DC/DC Converter as interface between Low and Medium Voltage DC Networks

Alfred Rufer, Stephan Kenzelmann, Carlo Arrioja

This paper introduces an isolated reversible DC/DC converter with a particular topology, which benefits from both the Neutral Point Clamped (NPC) structure and the series-parallel connection of converters. The key property of the proposed topology is the o ...

2011

Control Challenges and Solutions for a Multi-cellular Converter for Use in Electricity Networks

Alfred Rufer, Stephan Kenzelmann

This paper presents the concept of a multi-cellular power converter, structure targeted towards use in future electricity networks. Control of such a converter is challenging because of the distributed energy storage intrinsic to concept If the energy flow ...

2009

A Novel Multilevel Converter Structure Integrated into Power Systems and its Performance Evaluation

Alfred Rufer, Stephan Kenzelmann

The paper introduces an advanced multicellular power converter structure for flexible power management in future electricity networks. The power converter structure is analysed and the control approaches required in order to overcome the technical challeng ...

2009

The Monophasor Theory: Analytical Development and Practical Demonstration on a Single Phase Voltage Source Inverter

Alfred Rufer, Philippe Barrade, Yannick Louvrier, Stephan Kenzelmann

A method for simplifying the analytical treatment of single phase systems is introduced. This method, called monophasor theory, makes it possible to apply the same calculation methods and control strategies used for three-phase systems. This way, the spaci ...

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

Vector Control of Single-Phase Voltage Source Converters based on Fictive Axis Emulation

Alfred Rufer, Stephan Kenzelmann, Behrooz Bahrani

This paper presents an alternative way for controlling the current of single-phase voltage source dc-ac inverters in a dq synchronous reference frame. In a dq reference frame, ac (time varying) quantities appear as dc (time invariant) quantities allowing t ...

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

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