Publications by Francisco Daniel Freijedo Fernández

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

Drazen Dujic, Francisco Daniel Freijedo Fernández, Uzair Javaid, 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

Drazen Dujic, Yan-Kim Tran, 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

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

2019

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

Drazen Dujic, Yan-Kim Tran, 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

Francisco Daniel Freijedo Fernández, Federico De Bosio

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

Drazen Dujic, Francisco Daniel Freijedo Fernández, Marko Petkovic, 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