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Drazen Dujic

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Publications associées (208)

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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

Arbitrary order generalized state space average modeling of switching converters

Drazen Dujic, Uzair Javaid

Generalized State Space Average Modeling (GSSAM), of switching converters, offers an opportunity to improve fidelity of a model by inclusion of different harmonic components. Yet, the inclusion of each frequency component contributes to an increase in the ...

IEEE2015

Design Optimization of a MW-level Medium Frequency Transformer

Drazen Dujic, Nikolina Djekanovic

Nowadays, with the increased interest in applications dealing with high-power medium-voltage conversion, there is a strong need to master the design of medium-frequency transformers, which are one of the key components of modern DC transformers. The paper ...

2022

A Multiport Isolated DC-DC Converter

Drazen Dujic, Yan-Kim Tran

This paper presents a multi-port isolated DC-DC converter for DC applications. A three-port structure is presented, characterized with full bidirectional power flow and simple control. Galvanic isolation is achieved by means of a multi-winding medium frequ ...

IEEE2016

Comparison of two Modular Multilevel Converter Internal Energy Balancing Methods

Drazen Dujic, Stefan Milovanovic, Miodrag Basic

Although challenging, control of the modular multilevel converter internal variables has been addressed using several different approaches so far. With the aim of maintaining the submodules’ energies within a predefined band, the socalled circulating curre ...

IEEE2019

Flexible Medium Voltage DC Source Utilizing Series Connected Modular Multilevel Converters

Drazen Dujic, Stefan Milovanovic, Milan Utvic

This paper presents the converter configuration acting as a medium voltage DC source. In order to obtain desired voltage across the DC terminals, two series connected modular multilevel converters are used. The use of modular multilevel converters results ...

IEEE2019

Solid-State Technology for Shipboard DC Power Distribution Networks

Drazen Dujic, Seongil Kim, Gabriele Ulissi

The use of DC shipboard power distribution networks has been shown to offer several advantages over their AC counterparts. The reduction of the size and number of system components, the increased simplicity of operation and fuel efficiency of the system an ...

2021

A Multiport Medium Voltage Isolated DC-DC Converter

Drazen Dujic, Yan-Kim Tran

A multiport medium voltage (MV) isolated DC-DC converter with integrated energy storage, suited for connection of low voltage (LV) and medium voltage (MV) DC grids is presented. A multi-stage structure, adapted for MV ratings, is composed of multiple ident ...

2016

Insulation Coordination for a Modular Multilevel Converter Prototype

Drazen Dujic, Alexandre François Christe, Émilien Luc Henri Coulinge

This paper provides a detailed overview of the dielectric design and insulation coordination applied to a medium voltage modular multilevel converter prototype. The complete system has ratings of 0.5 MVA and is designed for connection to a 10 kVdc supply w ...

Ieee2016

Power Losses Measurement Method for High Efficiency MV Oil-Insulated DC-DC Converter

Drazen Dujic

The concept of MVDC collection network for renewable applications requires a high efficiency DC-DC converter to connect low voltage sources to the medium voltage network. The accurate measurement of low power losses is not possible with traditional electri ...

Institute of Electrical and Electronics Engineers2025

Evaluation of 1.7 kV SiC MOSFETs for a Regenerative Cascaded H-Bridge Multilevel Converter Cell

Drazen Dujic, Marko Petkovic, Nicolai Hildebrandt

High fidelity AC grid emulators allow early testing and qualification of various equipment under conditions close to those expected in reality. Realizing this at medium voltage high power level is associated with certain challenges, some of which are discu ...

2018

Virtual Submodule Concept Applied to the Modular Multilevel Converter

Drazen Dujic, Alexandre François Christe

The design phase of a modular multilevel converter (MMC) needs to be supported by suitable tools for the submodule loss evaluation. This paper proposes a fast MMC cell loss calculation based on the virtual submodule (VSM) concept. Compared to other propose ...

VDE VERLAG GMBH, 20172017

Gate unit for a gate-commutated thyristor and integrated gate-commutated thyristor

Drazen Dujic, Jakub Kucka

The invention relates to a gate unit (22) for controlling a gate commutated thyristor (21), comprising: - a voltage selector (26) for selectively applying a high supply potential (Vpos), a middle supply potential (Vmid), and a low supply potential (Vneg); ...

2023

Thermal Design of a Medium Voltage Modular Multilevel Converter Cell

Drazen Dujic, Yanick Patrick Frei

This paper presents the cooling concept for a medium voltage modular multilevel converter cell. To optimize power density, the metallic enclosure is used to dissipate the heat generated by semiconductor losses, while maintaining maximum temperatures below ...

New York2023

Method for operating a power converter and power converter

Drazen Dujic, Jakub Kucka

The present invention relates to a method for operating a resonant power converter (1) having a primary stage (2) and a secondary stage (3) at least one of which is actively operated and includes a half-bridge or full-bridge inverter (21) having a pull-up ...

2023

Analysis of the Effectiveness of the Series Inductor Integration Into the MFT for SST Applications

Drazen Dujic, Marko Mogorovic

This paper analyzes the effectiveness of the integration of the series inductor into the medium frequency transformer used for series resonant or dual active bridge converters - galvanically isolated DC-DC converters for high-power medium-voltage (solid st ...

2020

Marine MVDC Multi-Phase Multi-Pulse Supply

Drazen Dujic, Francisco Daniel Freijedo Fernández, Uzair Javaid

This paper presents comparative evaluation and explores the different technologies suitable for the implementation of the Medium Voltage Direct Current (MVDC) electrical supplies for the marine on-board electrical distribution network. To realize the MVDC ...

2017

Centralized Short-Circuit Protection of SiC Modules Connected in Parallel

Drazen Dujic

Due to the low short circuit withstanding time, short-circuit protection (SCP) for SiC devices is challenging. The SCP is more difficult when multiple devices are connected in parallel, as the turn-off of one device locally may lead to the overstressing of ...

Institute of Electrical and Electronics Engineers Inc.2024

Comprehensive Analysis and Design of a Quasi Two-Level Converter Leg

Drazen Dujic, Stefan Milovanovic

Quasi two-level operation of voltage source converters, intended to operate either within high/medium voltage DC networks or low output frequency applications, has caught the attention of both academia and industry. Sequential insertion of the so-called su ...

2019

Medium Voltage Impedance-Admittance Measurement System Based on the Cascaded H-Bridge Multilevel Converter

Drazen Dujic, Francisco Daniel Freijedo Fernández, Marko Petkovic, Nicolai Hildebrandt

Recent trends in power system design such as an increasing share of renewable energy sources and smart grids are creating different subsystem interactions that require proper investigation, understanding, describing and estimating global system stability t ...

2018