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Drazen Dujic

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Publications associées (208)

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Direct Current Transformer Impact on the DC Power Distribution Networks

Drazen Dujic, Renan Pillon Barcelos

The latest developments in dc transformer technology are enabling larger and more complex dc power distribution systems. However, the literature is scarce regarding the investigation and quantification of its impact on the dc grid. Therefore, this paper an ...

2022

Inductive Power Transfer System for Auxiliary Power Supply in Medium Voltage Converters

Drazen Dujic, Chengmin Li, Xiaotong Du

Inductive power transfer technology is an attractive solution for medium voltage applications by eliminating the need for high voltage cables or wired connections in general. This paper introduces an inductive power transfer system which has multiple indep ...

2022

Extending Protection Selectivity in DC Shipboard Power Systems by Means of Additional Bus Capacitance

Drazen Dujic, Seongil Kim

DC shipboard power systems have been connsidered as a promising solution for stricter environmental regulations on ships due to their main benefits in fuel savings with variable speed engines and easy integration of energy storage systems. In order to empl ...

2020

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 ...

2019

Dc-Link Ripple Suppression of Cascaded H-Bridge Based MV Grid Emulator Apparatus for Analysis and Testing of Grid-Tied Converters in Distribution System

Drazen Dujic, Chengmin Li

The medium-voltage grid emulator is gaining popularity for testing grid-code compliance of large-capacity converters for renewable energy resources. The cascaded H-bridge converter based on active-front-ends is a promising candidate for high-power grid emu ...

2023

Experimental investigation of a FSFC variable speed pump-turbine prototype - Part2: runner fatigue reduction

Drazen Dujic, Daniel Biner

The demonstration of flexibility technologies to enhance ancillary services of Hydropower Plants (HPPs) is showcased by the XFLEX HYDRO H2020 European Project. The potential of Full Size Frequency Converters (FSFC) is numerically and experimentally assesse ...

IOP Publishing2024

On Power Scalability of Modular Multilevel Converters: Increasing Current Ratings Through Branch Paralleling

Drazen Dujic, Stefan Milovanovic

The modular multilevel converter (MMC) presented in Figure 1 found its place within highvoltage and medium-voltage (MV) applications owing to the possibility of effortlessly meeting the imposed voltage requirements by stacking the so-called submodules (SMs ...

2020

Open-Loop Power Sharing Characteristic of a Three-Port Resonant LLC Converter

Drazen Dujic, Francisco Daniel Freijedo Fernández, Yan-Kim Tran

The Solid State Transformer (SST) is an attractive solution for highly flexible, cost-effective, compact and efficient power transfer among different grids. Furthermore, a three-port topology is proven as a suitable solution to integrate energy storage res ...

2019

Active Voltage Balancing with Seamless Integration into Dual Gate Driver for Series Connection of SiC MOSFETs

Drazen Dujic, Rui Wang

The versatility of half-bridge configuration of silicon carbide (SiC) metal-oxide-semiconductor field-effect transistor (MOSFET) power module contributes to its widespread adoption, highlighting the popularity and significance of its corresponding dual gat ...

2024

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

Performance Analysis of Energy Balancing Methods for Matrix Modular Multilevel Converters

Drazen Dujic, Stefan Milovanovic, Philippe Alexandre Bontemps

Modular multilevel converters achieve voltage scalability through the series connection of cells, each with its own capacitance. However, this converter structure using floating energy storage elements increases the control complexity significantly. The vo ...

2022

Numerical study on pressure fluctuations in a variable speed pump-turbine with head variations

Drazen Dujic, Daniel Biner

Grid regulation capacities of Pumped Storage Hydropower Plants (PSHPs) are of great importance for today’s and future power supply systems. In this context, variable speed technologies provide solutions for enhanced operational flexibility of PSHP units. E ...

IOP Publishing2025

Breakerless Protection for Voltage Source Converter-Based Marine DC Power Supply Systems

Drazen Dujic, Seongil Kim

DC power supply systems utilising voltage source converters offer several advantages compared with their counterparts in marine low-voltage DC power distribution networks. In case of a two-level voltage source converter fed by a synchronous generator which ...

IEEE2021

Dynamics analysis for DC transformers integration in hybrid AC‐DC power distribution networks

Drazen Dujic, Andrea Cervone, Renan Pillon Barcelos, Jules Christian Georges Macé, Max Dupont

In AC/DC power distributions networks, power converters are interfacing buses to ensure DC voltage regulation and power distribution. Active front ends are used between AC and DC buses and two typical control schemes that can be implemented are voltage reg ...

2023

Static and Dynamic Voltage Balancing for an IGCT-Based Resonant DC Transformer

Drazen Dujic, Renan Pillon Barcelos, Nikolina Djekanovic

This paper focuses on the operational characteristics of a medium voltage resonant DC transformer based on a split capacitor IGCT 3L-NPC leg. The study delves into both the dynamic and static balancing aspects of the 3L-NPC when operating in a two-level, 5 ...

2024

Interactions Between Bandwidth Limited CPLs and MMC Based MVDC Supply

Drazen Dujic, Francisco Daniel Freijedo Fernández, Alexandre François Christe, Uzair Javaid

With the improvement in the power electronic technologies, medium voltage dc (MVDC) electrical distribution systems are being considered for on-shore and off-shore applications. These future MVDC electrical distribution systems are expected to provide the ...

2017

Conformal Mapping of Impedance Stability Models for System-Level Dynamics Assessments

Drazen Dujic, Francisco Daniel Freijedo Fernández, Uzair Javaid

Impedance stability methods are suitable for assessing the dynamics of power converters controllers, but also for ac/dc microgrids system level studies. This work proposes the combination of impedance modeling and conformal mapping for the identification o ...

2017

Scalable Solid State Bus Tie Switch for Flexible Shipboard Power Systems

Drazen Dujic, Gabriele Ulissi

The need to increase efficiency and reduce operating cost of shipboard DC power distribution networks results in a desire to increase the operating voltage of such installations to the medium voltage levels. Devices such as solid state bus-tie switches are ...

2020

Direct Arm Energy Control in Modular Multilevel Converter Under Unbalanced Grid Conditions

Drazen Dujic, Milan Utvic

This paper studies the behaviour of the gridconnected modular multilevel converter under unbalanced grid conditions in terms of the energy imbalances within the converter, and proposes a novel approach for dealing with imbalances. Since the energy content ...

IEEE2020

Input-Admittance Passivity Compliance for Grid-Connected Converters With an LCL Filter

Drazen Dujic, Francisco Daniel Freijedo Fernández

This work presents a design methodology and its experimental validation for the input-admittance passivity compliance of LCL grid-connected converters. The designs of the LCL filter parameters and discrete controller are addressed systematically, and suita ...

2019