Publications by Francisco Daniel Freijedo Fernández

Stability Analysis of Multi-Port MVDC Distribution Networks for All-Electric Ships

Uzair Javaid, Drazen Dujic, Francisco Daniel Freijedo Fernández, Wim Van der Merwe

2020

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

Drazen Dujic, Francisco Daniel Freijedo Fernández, Marc Ferrer Duran

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

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

Drazen Dujic, Francisco Daniel Freijedo Fernández, Enrique Rodriguez Diaz

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

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

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

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

An Approach to Increase the Bandwidth of Current Controllers for Grid-tied Converters with LCL Filter

Francisco Daniel Freijedo Fernández

This This article discusses the design of a current controller for a converter system connected to the electrical grid through a LCL filter. A form of compensation is proposed and implemented to mitigate the effects of the computational delay in the discre ...

IEEE2019

Multiport Energy Gateway

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

2019

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

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

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

Analysis and Comparison of Notch Filter and Capacitor Voltage Feedforward Active Damping Techniques for LCL Grid-Connected Converters

Francisco Daniel Freijedo Fernández, Enrique Rodriguez Diaz

The use of LCL filters is a well-accepted solution to attenuate the harmonics created by the pulsewidth modulation. However, inherently LCL filters have a resonance region where the unwanted harmonics are amplified, which can compromise stability. Several ...

IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC2019

Full Discrete Modeling, Controller Design, and Sensitivity Analysis for High-Performance Grid-Forming Converters in Islanded Microgrids

Federico De Bosio, Francisco Daniel Freijedo Fernández

Recent works have shown that the state-feedback decoupling of capacitor voltage allows for drastic bandwidth enlarging of current controllers for grid-forming converters in islanded microgrids. Furthermore, Smith predictor and lead compensation have been a ...

2018

Cascaded H-Bridge Multilevel Converter for a High-Power Medium-Voltage Impedance-Admittance Measurement Unit

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

Recent trends in power system design and inclusion of renewable energy sources and smart grids are creating different subsystem interactions that require proper investigation, understanding, describing and estimating global system stabilitythrough impedanc ...

2018

Power Supply System with Integrated Energy Storage for Superconducting Magnets

Émilien Luc Henri Coulinge, Drazen Dujic, Francisco Daniel Freijedo Fernández, Maria Papamichali

2018

MVDC Supply Technologies for Marine Electrical Distribution Systems

Uzair Javaid, Drazen Dujic, Francisco Daniel Freijedo Fernández, Wim Van der Merwe

The increase in the popularity of the medium voltage dc (MVDC) electrical distribution, as a possible evolution of the medium voltage ac (MVAC) electrical distribution for the ship on-board power systems, arises a need for a comparative evaluation and demo ...

2018

An Approach for the Emulation of DC Grid Admittances: Implementation on a Buck Converter

Drazen Dujic, Francisco Daniel Freijedo Fernández, Enrique Rodriguez Diaz

2018

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

Drazen Dujic, Francisco Daniel Freijedo Fernández, Enrique Rodriguez Diaz

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

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

Marko Petkovic, Drazen Dujic, Francisco Daniel Freijedo Fernández, 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

A Root-Locus Design Methodology Derived From the Impedance/Admittance Stability Formulation and Its Application for LCL Grid-Connected Converters in Wind Turbines

Francisco Daniel Freijedo Fernández, Enrique Rodriguez Diaz

This paper presents a systematic methodology for the design and the tuning of the current controller in LCL grid-connected converters for wind turbine applications. The design target is formulated as a minimization of the current loop dominant time constan ...

Ieee-Inst Electrical Electronics Engineers Inc2017

Dynamic Assessment of Source–Load Interactions in Marine MVDC Distribution

Uzair Javaid, Drazen Dujic, Francisco Daniel Freijedo Fernández, Wim Van der Merwe

Medium-voltage direct-current (MVDC) distribution is a possible replacement due to the advancements in power electronic technologies, for existing medium-voltage ac distribution on ships. The new systems based on MVDC are expected to increase fuel efficien ...

Institute of Electrical and Electronics Engineers2017

Discrete-Time Domain Modeling of Voltage Source Inverters in Standalone Applications: Enhancement of Regulators Performance by Means of Smith Predictor

Federico De Bosio, Francisco Daniel Freijedo Fernández

The decoupling of the capacitor voltage and inductor current has been shown to improve significantly the dynamic performance of voltage source inverters in standalone applications. However, the computation and pulse width modulation delays still limit the ...

Ieee-Inst Electrical Electronics Engineers Inc2017

Marine MVDC Multi-Phase Multi-Pulse Supply

Uzair Javaid, Drazen Dujic, Francisco Daniel Freijedo Fernández, Wim Van der Merwe

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

Interactions Between Bandwidth Limited CPLs and MMC Based MVDC Supply

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

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