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Preda Ioana

Professeure HES associée

Hauptkompetenzen

polymer, resins, insulating systems

Finite element modeling (Comsol)

Hauptvertrag

Professeure HES associée

Telefon-Nummer: +41 26 429 65 58

Büro: HEIA_C20.11

Haute école d'ingénierie et d'architecture de Fribourg
Boulevard de Pérolles 80, 1700 Fribourg, CH

Institut
iPrint - Institut de printing

BSc HES-SO en Génie électrique - Haute école d'ingénierie et d'architecture de Fribourg

Electricité 1 (Introduction to electrodynamics)
Matériaux de l'électrotechnique (Materials science for electrical engineers)
Systèmes énergétiques (Energy and electricity generation / Smart Energy Systems 1)
Modélisation et simulation (Modeling and numerical simulations)
MEMS Design (HES-SO Master in Micro and Nano technology)

BSc HES-SO en Génie électrique - Haute école d'ingénierie et d'architecture de Fribourg

Matériaux et fiabilité des semi-conducteurs

MSc HES-SO en Engineering - HES-SO Master

High Voltage Engineering

Laufend

BRIDGE Discovery - A3P

Rolle: Mitgesuchsteller/in

Financement: FNS Bridge

Description du projet :

Automated Photonic-pulses Processing for Thin Solar Energy Devices (A3P) - BRIDGE 40B2-0_203626 / 1

Forschungsteam innerhalb von HES-SO: Preda Ioana , Buccella Pietro , Hennebert Jean , Donato Laurent , Birbaum Yves

Partenaires académiques: EPFL; CSEM

Durée du projet: 15.03.2022 - 31.12.2025

Montant global du projet: 1'557'977 CHF

Statut: Laufend

Laboratoire de recherche sur les piles à combustibles H2

Rolle: Mitgesuchsteller/in

Financement: FR - EIA - Général école pilier 01

Description du projet :

Montage en cours d'un laboratoire de recherche et développement sur les piles à combustibles H2 de type PEM. Le but de ce laboratoire est de maîtriser la production verte d'hydrogène par électrolyse membranaire et de produire de l'énergie électrtique par pile à combustible à hydrogène. La maîtrise technique de toute cette chaîne permettra d'ajouter ces compétences dans le département du génie électrique et de l'HEIA-FR tant pour la formation de nos étudiants que pour la Ra&D.

Une validation de la sécurité des installations laboratoire a également été faite par la Suva.

Forschungsteam innerhalb von HES-SO: Oberson Daniel , Preda Ioana

Durée du projet: 04.01.2021

Statut: Laufend

GreenSKHy - Green Skills and Knowledge for Hydrogen

Rolle: Mitgesuchsteller/in

Description du projet :

The aim of our project is to promote the development of the clean hydrogen sector by reducing the
obstacles to the European recognition of skills and related systems through joint action plans and by
promoting careers that can contribute to the energy transition through new practical training
schemes. This ambition involves networking the actors in charge of skills and certifications,
developing and testing specific training and acculturation modules, and implementing campaigns to
promote the hydrogen sector and its opportunities. By bringing together within the consortium
companies, public authorities as well as the main actors of initial and continuous training, the project
should therefore support the development of a key sector for the energy transition by ensuring the
empowerment of a large audience

Forschungsteam innerhalb von HES-SO: Preda Ioana

Partenaires professionnels: Interreg - ARE

Montant global du projet: 500'000 CHF

Statut: Laufend

Abgeschlossen

Développement d'un capteur utilisant la polarisation diélectrique pour le suivi de la fermentation et du niveau d'extraction durant la production des vins

AGP

Rolle: Mitgesuchsteller/in

Requérant(e)s: 425 - Oenologie

Financement: HES-SO Rectorat

Description du projet : Aujourd'hui, le suivi de fermentation pour la production du vin est réalisé principalement par la mesure de densité, de manière manuelle ou automatique. Pour la production du vin rouge, une étape déterminante pour la qualité du vin final ' l'extraction des composés d'intérêt présents dans la pellicule du raisin (principalement des polyphénols ou « anthocyanes et tanins ») ' a lieu également pendant la phase fermentaire. Actuellement, à part la dégustation, il n'existe pas d'outil performant d'aide à la décision afin de déterminer le moment d'écoulage à cause de la difficulté d'obtenir des informations fiables d'un milieu complexe par une analyse rapide et simple à manipuler. Afin de développer une alternative analytique sensible pour le suivi du niveau d'extraction et d'avancement de la fermentation, un partenariat interdisciplinaire est formé, regroupant les personnels de HES-CHANGINS et de la HEIA-FR, avec des compétences en procédés oenologiques, analyse chimique, électronique appliquée et spectroscopie. Ensemble, les partenaires du projet ont identifié une approche innovante et prometteuse pour la problématique du suivi de fermentation : l'utilisation de la spectroscopie diélectrique. Ayant la possibilité d'utiliser un large spectre d'ondes électromagnétiques, la spectroscopie diélectrique est une technique couramment employée pour la caractérisation électrique (isolants, matériaux avec une haute capacité de stockage d'énergie, '). Depuis quelques années, l'agro-alimentaire bénéficie également du potentiel offert par cette technique, que ce soit pour l'évaluation de la qualité des fruits ou lors de la pasteurisation du jus de pomme. Comme les tests sont rapides et ne détruisent pas la matière, la spectroscopie s'est avérée un outil expérimental adaptée aux mesures en ligne ainsi qu'au suivi de longue durée. Basée sur l'excitation des dipôles (chaines polymères ou molécules) ou des ions en rapport avec les caractéristiques d'un faible champ électrique externe, cette méthode permet la mesure de la permittivité complexe des matériaux polarisables, chaque composant ayant un moment dipolaire caractéristique. Dans ce contexte, nous proposons le projet «WinE-index» («WineExtraction-index ») pour la mise en place d'une corrélation entre les propriétés diélectriques et d'autres caractéristiques ou propriétés physico-chimiques du jus de raisin en phase de fermentation. L'objectif principal du projet est de proposer une technique permettant de tirer à partir d'une évaluation rapide et non destructive des vrais indicateurs par rapport à la composition du vin, pendant la fermentation. Le défi du projet sera la différentiation entre la réponse diélectrique des marqueurs significatifs (éthanol, anthocyanes et tannins condensés) et l'évaluation de l'impact des éléments externes ayant une grande influence sur les propriétés diélectriques, par exemple, des ions (K+), des acides organiques ou des particules solides. En vue de remplir au mieux notre mission - fournir aux oenologues des indicateurs quantitatifs pour compléter leurs analyses sensorielles, afin de leur apporter une réelle aide à la décision - nous proposons le développement d'un capteur innovant, ayant un fort potentiel de marché. Utilisable offline aussi bien qu'intégrable dans des systèmes en ligne, celui-ci permettra de suivre l'avancement de la fermentation en même temps que le niveau d'extraction.

, , , , , , , , , , , , , , , , , , , , , , , Forschungsteam innerhalb von HES-SO: Galé Benjamin Claude Bircher Fritz Cléroux Marilyn Kuster Joël Giorgi Luca Roth Samuel Schneuwly Vincent Bourrier Hervé Monnard Jacques Scheurer Laurence Gomez-Von Allmen Sophie Preda Ioana Froidevaux Lucas Bapst Nicolas Sahli Benoît Trevisani Sandro Gugler Gilbert Carrie Natalia Siebert Priscilla Zeng Liming Pernet Arnaud Balestra Gioele Brodard Patricia Mertenat Muriel

Partenaires académiques: 425 - Oenologie; FR - EIA - Institut ENERGY; FR - EIA - Institut IPRINT

Durée du projet: 17.02.2020 - 17.05.2022

Montant global du projet: 219'980 CHF

Statut: Abgeschlossen

DCHVA Innosuisse 35013.1 IP-ENG

Rolle: Mitgesuchsteller/in

Financement: Innosuisse

Description du projet :

Elements of a high voltage capacitor produced by an additive manufacturing technology are being developed in order to meet the industry 4.0 strategy of the company. Intensive technology exploration and innovative research are needed to meet the strategic roadmap.

Forschungsteam innerhalb von HES-SO: Preda Ioana , Gugler Gilbert

Durée du projet: 01.01.2019 - 31.12.2021

Montant global du projet: 1'119'550 CHF

Statut: Abgeschlossen

2023

Development of distillation sensors for spirit beverages production monitoring based on impedance spectroscopy measurement and partial least-squares regression

Wissenschaftlicher Artikel ArODES

Liming Zeng, Arnaud Pernet, Marilyn Cléroux, Benoît Bach, Lucas Froidevaux, Ioana Preda

ACS Omega, 2023, 8, 17, 15323-15333

Link zur Publikation

Zusammenfassung:

During spirit beverages production, the distillate is divided into three parts: the head, the heart, and the tail. Acetaldehyde and ethanol are two key markers which allow the correct separation of distillate. Being toxic, the elimination of the head part, which contains a high concentration of acetaldehyde, is crucial to guarantee the consumer’s health and security. Plus, the tail should be separated from the heart based on ethanol concentration. Nowadays, online or in-line sensors for acetaldehyde monitoring during distillation do not exist, and the online sensors for alcohol monitoring, based on density measurement, remain expensive for producers. In this work, we demonstrate the development of distillation monitoring sensors based on electrical impedance spectroscopy (EIS) measurements, combined with PLS-R (partial least-squares regression) modeling. Four types of sensors are proposed and tested with wine-based distillates. Using PLS-R, the best correlations were found for one electrode, named “SpotsSym”. With an R2 up to 89.9% for acetaldehyde concentration prediction and an R2 up to 86.8% for ethanol, the obtained results indicate the promising potential of the proposed approach. To our knowledge, this is the first report of sensors capable of simultaneously measuring ethanol and acetaldehyde concentrations. Furthermore, these sensors offer the advantages of being low cost and nondestructive. Based on these results, the development of an in-line distillation monitoring system is possible in the near future, providing a promising tool for spirit beverages producers.

2021

Review of technologies and materials used in high-voltage film capacitors

Wissenschaftlicher Artikel ArODES

Olatoundji Georges Gnonhoue, Amanda Velazquez-Salazar, Éric David, Ioana Preda

Polymers, 2021, vol. 13(5), no. 766

Link zur Publikation

Zusammenfassung:

High-voltage capacitors are key components for circuit breakers and monitoring and protection devices, and are important elements used to improve the efficiency and reliability of the grid. Different technologies are used in high-voltage capacitor manufacturing process, and at all stages of this process polymeric films must be used, along with an encapsulating material, which can be either liquid, solid or gaseous. These materials play major roles in the lifespan and reliability of components. In this paper, we present a review of the different technologies used to manufacture high-voltage capacitors, as well as the different materials used in fabricating high-voltage film capacitors, with a view to establishing a bibliographic database that will allow a comparison of the different technologies.

2022

Low-cost impedance analyzer and IDC sensors :

Konferenz ArODES

an imperfect tool for dielectric condition monitoring

Ioana Preda, M. Colautti, Arnaud Pernet, Liming Zeng

2022 IEEE Conference on Electrical Insulation and Dielectric Phenomena (CEIDP), 30 October- 2 November 2022, Denver, CO, USA

Link zur Konferenz

Zusammenfassung:

Low voltage (LV) cables, like medium or high voltage ones, are prone to ageing. However, as they are usually exposed to lower electrical stresses, they are seldom monitored. In this work, an IDC (Inter-Digital Capacitive) sensor combined with two different commercial impedance analyzers (Hioki IM3570 and AD5940) is evaluated. The sensitivity and the penetration of the electric field are calculated using Comsol Multiphyisics simulations and measurements performed on low voltage PVC cables help comparing the two systems and assessing their performance. It was found that, for low capacitive samples, such as a LV cable’s insulation, the variation found between consecutive measurements is too important to consider the AD5940 as a reliable tool for dielectric condition monitoring.

Dry-type high voltage capacitors

Konferenz ArODES

Amanda Velazquez-Salazar, Georges O. Gnonhoue, Éric David, Ioana Preda

Proceedings of 4th International Conference on Dielectrics, 3rd-7th July 2022, Palermo, Italy

Link zur Konferenz

Zusammenfassung:

High voltage capacitors are important components of electrical network. The current technology is based foil-laminar coil impregnated in a liquid dielectric. However, there is an interest to develop technologies allowing to replace mineral or synthetic oil due both to health and environmental issues. The feasibility of replacing the impregnating liquid by a solid encapsulating material for HV capacitors is presented in this paper.

Inkjet printing :

Konferenz ArODES

a new technique for manufacturing solid insulation systems

Ioana Preda, Dominique Rolle, Sebastian Filliger, Natalia Carrie, Gilbert Gugler

Proceedings of 4th International Conference on Dielectrics, 3rd-7th July 2022, Palermo, Italy

Link zur Konferenz

Zusammenfassung:

This work investigates several dielectric coatings, of different thicknesses, applied over metalized layers. More precisely, acrylate-based dielectric materials were fabricated using two different additive manufacturing techniques: spincoating and inkjet. While microscope imaging showed that uniform layers could be achieved by both techniques, breakdown strength, along with partial discharge measurements showed that microstructural defects were present in the bulk and that the quality of the printed layers decreases as the thickness of the layers increases. Nevertheless, it is shown that lacquer insulating layers, of variable thickness, can be easily obtained by inkjet printing. Even without any process optimization, they exhibit good dielectric properties, which shown their potential for electrical engineering applications.

2021

Investigation of ink-jet printed lacquer systems for coating applications

Konferenz ArODES

Ioana Preda, Sebastian Filliger, Natalia Carrie, Gilbert Gugler

Proceedings of European Coating Symposium (ECS) 2021, 7-9 September 2021, Brussels, Belgium

Link zur Konferenz

Zusammenfassung:

This work presents a material screening study conducted while researching an 100% UV lacquer for an ink-jet coating application. In the first part of the study, spin-coating was used for creating a uniform coating of 7 μm over a metallic substrate. The uniformity and the defect-free characteristics of the coating were confirmed by FIB microscopy and by electrical tests, which were found to be a reliable tool for ensuring the preparation of defect-free coatings over metallic substrates. In the second part of the study, the manufacturing process was switched to ink-jet. The best jetting and UV curing parameters were found to ensure good wetting between consecutive coating layers while having sufficient curing. Although thicker coatings of about 20 μm/layer were produced using ink-jet, the defect-free characteristics were conserved up to 50 consecutive layers, confirming that thicker yet uniform coatings could be obtained by ink-jet. The new testing method was helpful during the material screening. Furthermore, we have shown that lacquer systems can be easily obtained by ink-jet printing and could be very useful for electrical engineering applications.

2020

Dielectric properties of a semicrystalline supramolecular polymer

Konferenz ArODES

Ioana Preda, Diana Kay Hohl, Christoph Weder

Proceedings of IEEE 2020 International Conference on Dielectrics, 6th-31st July 2020, Valencia, Spain

Link zur Konferenz

Zusammenfassung:

Supramolecular polymers (SPs) are assemblies of monomers that bind to another through non-covalent interactions. The reversible nature of these interactions permits one to temporarily disassemble SPs “on command” by applying an appropriate stimulus, which is advantageous for processing and recycling and allows creating stimuli-responsive materials. Here we report on the dielectric properties of an SP network assembled from monomers based on polypropylene oxide (PPO) cores, functionalized with UPy groups. In this work, we measured the DC breakdown strength, dielectric relaxation and electrical conductivity and show that the dielectric properties are similar to those of silicones or silicon-based adhesives. However, the material is reprocessable, thus has a potential for medium voltage applications, within the context of a circular economy.

Characterization of dielectric walls of capacitors

Konferenz ArODES

O. G. Gnonhoue, A. Velazquez-Salazar, L. Millard, S. Joncas, E. David, L. Cormier, R. Poudret, Ioana Preda

Proceedings of IEEE 2020 International Conference on Dielectrics, 6th-31st July 2020, Valencia, Spain

Link zur Konferenz

Zusammenfassung:

This work presents the preliminary results of a study that proposes the development of capacitors with similar or better performance in terms of reliability and partial discharges (PD) level than their oil-impregnated counterparts. It presents the comparison of several configurations and technologies of layered dielectric films capacitors impregnated with a commercial polymeric resin, with the aim to improve the properties of its inner dielectric wall. To find a suitable match between the different dielectric film arrangements and technologies with the polymeric resin used, tests on different sample configurations were carried out. These tests also covered the impact of the surface treatment prior to impregnation and the final enhancement of dielectric properties of the system due to the encapsulating polymeric resin. To ensure a reliable fabrication process, the Vacuum Pressure Impregnation (VPI) technique was used. The results show that rough polypropylene (PPR) films with prior surface treatment and set in polymeric resin may be the best candidate to compete with current technologies to carry out oil-free capacitors.

2018

Lightning breakdown voltage of dielectric oil :

Konferenz ArODES

discussion on measuring setups and standards

Ioana Preda, José-Luis Bermudez, Thomas Heid

Proceedings of the 36th Electrical Insulation Conference (EIC), San Antonio, TX, USA, 17-20 June 2018

Link zur Konferenz

Zusammenfassung:

Nowadays, more and more studies present the results obtained while testing the lightning impulse breakdown behavior of newly developed, innovative dielectric oils. As showed for industrial frequencies, clear standardized test conditions are mandatory to allow the interpretation of test results without uncertainties. This paper addresses the characteristics of the measuring cell suggested by ASTM and IEC standards and their influence on performing impulse breakdown measurements. As an addition to the results recently published by other research teams, this work intends to discuss several aspects that could be further investigated in a working group. The joint research could provide the ASTM and the IEC standards organizations with a broader view of lightning impulse breakdown (LI) and withstand data that can benefit and improve their regulation.

A digital robust control scheme for dual half-bridge DC-DC converters

Konferenz ArODES

Maxime Tissières, Iman Askarian, Majid Pahlevani, André Rotzetta, Andy Knight, Ioana Preda

2018 IEEE Applied Power Electronics Conference and Exposition (APEC)

Link zur Konferenz

Zusammenfassung:

This paper presents a digital control scheme used in the control system of a bi-directional Dual Half-Bridge (DHB) converter over a wide range of operating conditions (load variations, input voltage changes). The proposed control scheme is a nonlinear current controller, where it enforces the current error of the high frequency transformer to converge to zero in a geometric progression. It offers higher stability, improved transient performance and increased robustness compared to the conventional control methods in DHB converters. Moreover, the proposed control scheme is a simple structure technique, which is easy to implement on digital microprocessors (e.g. DSP, FPGA). Simulation and experimental results show the superior performance of the GSC compared to other conventional control techniques.

Errungenschaften

2022

Automated Photonic-pulses Processing for Thin Solar Energy Devices (A3P)

2022 ; Bridge - Discovery

Collaborateurs: Preda Ioana

Link zur Errungenschaft

According to the Shell Sky Scenario, photovoltaics (PV) will need to reach a production capacity of 1000 GW per year from the year 2035 onwards to follow the Paris agreement and stay below 2 degrees of increase in global temperatures. This represents a phenomenal growth rate compared to today´s total installed capacity of about 600 GW (for reference, the capacity added last year was about 140 GW). In this project, we will bring our flash infrared annealing (FIRA) technique for the curing of thin-film materials to the next level by demonstrating a rapid and continuous process with low environmental impact for the production of high-efficiency PV devices. We will apply our method to upscale and accelerate process time of perovskite-silicon tandem solar cells, a solar cell technology that has the potential to accelerate the deployment of PV thanks to its potential for high performance and low fabrication costs. However, our photonic pulse method will remain applicable to other technologies, notably dye-sensitized solar cells (DSSCs) and electrode materials for solar fuel production.With this project, we aim to build on a promising base: our photonic sintering method currently enables the curing of perovskite films in less than 2 seconds and yields single-junction solar cell efficiencies up to 20%. Importantly, our approach has about only 10% of the environmental impact compared to the most established antisolvent (AS) method based on life cycle assessments. FIRA has hence a unique potential for industrial manufacturing since it can be adapted for both plate-to-plate and roll-to-roll (R2R) processing, and it replaces hour-long annealing steps. In the project, we will upgrade and generalize our FIRA method to manufacture large-scale perovskite single-junction and perovskite-silicon tandem solar cells. We will ensure that our process is rapid, environmentally friendly, cost-effective, and enables the continuous manufacturing process of thin films and devices of high optoelectronic quality. In situ optical characterization coupled to data-driven methods such as machine learning will be implemented to accelerate the search for optimum process parameters.Our consortium involves the Swiss University of Applied Sciences (HEIA-Fribourg) and EPFL (PVLAB and LIMNO). The HEIA team will be in charge of developing the automated photonic pulse annealing system, which will be synchronized with a solution deposition system. Work at EPFL will build on the unique expertise of the consortium partners in highly efficient small-scale (mm2-cm2) single-junction (> 24%) and tandem solar cells (>27%). Combining these strengths, we will develop a process to upscale device dimensions to industrially relevant ones, =239 cm2 for tandems, while ensuring high device efficiencies.

WinE-index

2022 ; Capteurs d'impédance miniaturisés

Collaborateurs: Preda Ioana , Zeng Liming

Link zur Errungenschaft

Aujourd’hui, le suivi de fermentation pour la production du vin est réalisé principalement par la mesure de densité, de manière manuelle ou automatique. Pour la production du vin rouge, une étape déterminante pour la qualité du vin final – l’extraction des composés d’intérêt présents dans la pellicule du raisin (essentiellement des polyphénols ou « anthocyanes et tanins ») – a lieu également pendant la phase fermentaire. Actuellement, à part la dégustation, il n’existe pas d’outil performant d’aide à la décision afin de déterminer le moment d’écoulage à cause de la difficulté d’obtenir des informations fiables d’un milieu complexe par une analyse rapide et simple à manipuler.

Pour développer une alternative analytique sensible pour le suivi du niveau d’extraction et d’avancement de la fermentation, un partenariat interdisciplinaire est formé, regroupant les personnels de HES-CHANGINS et de la HEIA-FR, avec des compétences en procédés œnologiques, automatisation en cave, analyse chimique, électronique appliquée et spectroscopie. Ensemble, les partenaires du projet ont identifié une approche innovante et prometteuse pour la problématique du suivi de fermentation : l’utilisation de la spectroscopie diélectrique. Avec des mesures rapides et qui ne détruisent pas la matière, la spectroscopie diélectrique s’est avérée un outil expérimental adapté aux mesures en ligne ainsi qu’au suivi de longue durée. Basée sur l’excitation des dipôles (chaines, polymères ou molécules) ou des ions en rapport avec les caractéristiques d’un faible champ électrique externe, cette méthode permet la mesure de la permittivité complexe des matériaux polarisables, chaque composant ayant un moment dipolaire caractéristique.

Les objectifs du projet «WinE-Index» (« WineExtraction-index ») sont :

Mise en corrélation entre les propriétés diélectriques et d’autres caractéristiques ou propriétés physico-chimiques du jus de raisin en phase de fermentation ;
Évaluation des influences de la présence des ions (K+), des acides organiques ou des particules solides sur les propriétés diélectriques ;
Développement de plusieurs typologies d’électrodes miniatures : conception, acquisition des données et optimisation.

Ces développements se sont avérés fructueux non seulement pour une application dans le domaine d’œnologie, mais aussi pour la suivie de production des boissons spiritueuses. Utilisables offline aussi bien qu’intégrable dans des systèmes en ligne, ces capteurs aident à la décision à bas coûts présentent un grand potentiel de marché, qui fournissent aux œnologues ou distillateurs des indicateurs quantitatifs pour compléter leurs analyses sensorielles.

https://pubs.acs.org/doi/10.1021/acsomega.3c00481

PEOPLE@HES-SO
Verzeichnis der Mitarbeitenden und Kompetenzen

Preda Ioana

Professeure HES associée

Hauptkompetenzen

Dielectric materials

High voltage insulation

Materials for electrical eng.

polymer, resins, insulating systems

Finite element modeling (Comsol)

Professeure HES associée

PEOPLE@HES-SO Verzeichnis der Mitarbeitenden und Kompetenzen

Preda Ioana

Professeure HES associée

Hauptkompetenzen

Dielectric materials

High voltage insulation

Materials for electrical eng.

polymer, resins, insulating systems

Finite element modeling (Comsol)

Professeure HES associée

PEOPLE@HES-SO
Verzeichnis der Mitarbeitenden und Kompetenzen