Publications de Drazen Dujic | EPFL Graph Search

Publications associées (208)

Design Trade-offs of Second Harmonic Minimization in Solid-State Transformers

In two-stage solid-state transformers (SSTs) equipped with LLC DC/DC converters for galvanic isolation, fixed-frequency open-loop operation of LLC stages has been a straightforward and prevailing design choice. Meanwhile, with a closed-loop-operated LLC co ...

Institute of Electrical and Electronics Engineers (IEEE)2025

Multi-Variable High-Frequency Input-Admittance of Grid-Connected Converters: Modeling, Validation and Implications on Stability

Drazen Dujic, Francisco Daniel Freijedo Fernández

Modern grids are facing a massive integration of power electronics devices, usually associated to instability issues. In order to assess the likelihood and severity of harmonic instability in the high frequency region, this work develops a multi-variable i ...

2019

Comprehensive Spectral Analysis of PWM Waveforms With Compensated DC link Oscillations

Drazen Dujic, Stefan Milovanovic

In the available literature, including reference books on the topic, the spectral analysis of voltage waveforms obtained through the use of pulse-width modulation relies on the assumption of an ideally flat voltage across the DC link of a considered switch ...

2020

Advanced Dual-Channel Gate Driver with Short-circuit Protection for Series Connected Medium-Voltage SiC MOSFETs

Drazen Dujic, Rui Wang

The dual-channel gate driver (D-GD) is widely employed in the industry to support the extensive adoption of half-bridge power modules. With the growing popularity of silicon-carbide (SiC) devices in medium-voltage scenarios known for their superior switchi ...

Institute of Electrical and Electronics Engineers (IEEE)2025

Turbine mode start-up simulation of a variable speed Francis pump-turbine prototype - Part II: 3-D unsteady CFD and FEM

Drazen Dujic, François Avellan

The Z'Mutt pumping station, part of the Grande Dixence hydroelectric scheme, is one of the demonstrators of the XFLEX HYDRO project. A 5 MW reversible pump-turbine prototype equipped with a full-size frequency converter (FSFC) is used to investigate dynami ...

IOP Publishing2021

Modeling and Design Optimization of Loosely Coupled PCB Spiral Coils in Inductive Power Transfer Systems

Drazen Dujic, Xiaotong Du

There are various possibilities to realize coil winding designs for an inductive power transfer system. In order to achieve high power transfer efficiency and power density and explore trade-offs between the two, design optimization around the coil link is ...

2023

Leakage Flux Modeling of Multi-Winding Transformers for System-Level Simulations

Drazen Dujic, Min Luo

In multiwinding transformers, different geometry of the individual windings leads to unbalanced leakage flux paths. The unbalance affects the behavior of the power electronic converters, where these transformers are used. This paper proposes an approach to ...

Ieee-Inst Electrical Electronics Engineers Inc2018

Stable and Passive High-Power Dual Active Bridge Converters Interfacing MVDC Grids

Drazen Dujic, Francisco Daniel Freijedo Fernández

Dual active bridge (DAB) is a topology that is receiving more and more attention as a potential solution to interface dc grids of different voltage levels. From a system level, the implications of DABs on the stability of complex power systems are addresse ...

2018

Open-Loop Power Sharing of Three-Port DC-DC Resonant Converters

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

Multi-port DC-DC converters are an attractive solution for highly flexible and efficient interface of different elements of DC grids (e.g., sources, loads, energy storage). This paper provides an analytic solution for the natural power sharing characterist ...

2019

Modularized Diode Rectifiers: A New Family of Solid-State Transformers

Drazen Dujic, Andrea Cervone, Zhenchao Li

Solid-State Transformers are conventionally based on a multi-stage architecture, with an input and/or an output AC/DC converter (for interfacing with the AC grid and/or the load), and with an isolated DC/DC conversion stage (to provide insulation and volta ...

Institute of Electrical and Electronics Engineers (IEEE)2024

Terminal Characteristics Measurements and Analysis of the Three-Phase Active Front End Converter Building Block

Drazen Dujic, Marko Petkovic

The safe and reliable operation of modern power system imposes the need to describe and estimate the system stability through impedance-admittance measurement and identification. The integration and operation of medium voltage equipment in existing infrast ...

Wiley2021

Permeance Based Modeling of Magnetic Hysteresis with Inclusion of Eddy Current Effect

Drazen Dujic, Min Luo

Magnetic hysteresis together with eddy current effects are typically present in metal based core materials and contribute significantly to the nonlinearity and power loss of the magnetic components operating in power electronic converters. In order to inve ...

IEEE2018

Computationally Efficient Estimation of the Electric-Field Maximums for the MFT Insulation Coordination

Drazen Dujic, Marko Mogorovic

This paper proposes a methodology for computationally-efficient estimation of the local E-field maximums within the transformer winding insulation material for design optimization purposes, where besides the estimation accuracy, the computational cost repr ...

IEEE2019

Smooth Power Direction Transition of a Bidirectional LLC Resonant Converter for DC Transformer Applications

Drazen Dujic, Jakub Kucka

The bidirectional LLC resonant converter operated at fixed switching frequency is a preferable candidate for a true dc transformer that does not actively control the power flow. This is due to its naturally stiff voltage ratio regardless of the imposed loa ...

2020

Permeance Based Modelling of the Core Corners Considering Magnetic Material Nonlinearity

Drazen Dujic, Min Luo

Lumped magnetic circuit provides possibility for fast transient simulation of magnetic component together with power electronics circuit. The simplified geometry representation however is not able to completely reflect the real field distribution, especial ...

2015

Discretization Uncertainties of Flow and Fatigue Damage Simulations of a Reversible Francis Pump-Turbine at Off-Design Operation in Turbine Mode

Drazen Dujic, Daniel Biner, Philippe Alexandre Bontemps

In the framework of the XFLEX HYDRO H2020 European Project, a 5 MW reversible Francis pump-turbine prototype, equipped with an industrial full size frequency converter, is investigated to demonstrate enhanced grid regulation capacities of variable speed hy ...

SPRINGER INTERNATIONAL PUBLISHING AG2022

High-Power DC–DC Converter Utilising Scott transformer Connection

Drazen Dujic, Stefan Milovanovic

To obtain a resilient and flexible DC grid, reliable means for interfacing its parts operating under different voltage levels must be ensured. This paper proposes bidirectional, isolated, DC–DC converter designed to connect either high/medium voltage bipol ...

2019

Current Limiting in Overload Conditions of an LLC-Converter-Based DC Transformer

Drazen Dujic, Jakub Kucka

The dc transformers based on an LLC converter operated in open loop near resonant frequency have several crucial advantages compared to other topologies. These advantages are the stiff voltage ratio with a natural power flow, the dc grid isolation via medi ...

2021

High Frequency Operation of Series-Connected IGCTs for Resonant Converters

Drazen Dujic, Gabriele Ulissi

Series connected IGCTs find application in hard-switched commercial power converters at the MW power levels. Expanding the application of these devices to medium voltage dc-dc resonant converters is of great interest due to the IGCTs low conduction losses. ...

2021

Scalable Marine Bus-Tie Switch for Switchboard Interconnections

Drazen Dujic, Gabriele Ulissi

DC power distribution systems in marine applications are in the process of being established as the preferred solution for shipboard power distribution systems. This paper presents a bus-tie switch topology for the protection of such systems. The device is ...

2020