Scientific direction Development of key enabling technologies
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PhD : selection by topics

Engineering science >> Electronics and microelectronics - Optoelectronics
19 proposition(s).

Interleaved current source inverters for high power PV converters prototyping

Département des Technologies Solaires (LITEN)

01-09-2019

SL-DRT-19-0061

jeremy.martin@cea.fr

Conventionally, systems for converting electrical energy in the photovoltaic domain are voltage inverter type structures [4] - [7]. In this case, the conversion chain of the photovoltaic energy is composed of two stages: a DC-DC converter followed by a voltage inverter (VSI). These voltage source topologies have short-term disadvantages (link capacitor lifetime problems) [5], [8], [9] and relatively low efficiency (due to a double conversion) [5]. As an alternative solution, the current inverter (CSI) structure can be used. Among the advantages of the CSI structure, can be listed: -A reduction in the number of power components, due to the conversion of energy with a single conversion stage [5] -A longer converter lifetime (compared to conventional structures) due to the suppression of the link capacitor [5], [8], [9] and a voltage in the blocked state seen by the switches lower [11] -Integration of natural short-circuit protection On the other hand, the CSI topology has the following disadvantages: -Relatively high conduction losses due to the series connection of devices (MOSFET + Diode) [4], [6] -Special protection requirements for AC and DC sides [4] For the CSI topology, one possible way to overcome the disadvantage of high switching losses is to use Wide bandgap devices (WBGs). Specifically, SiC semiconductors, because of their higher voltage ranges. The LSPV is currently working on: -The characterization of WBG semiconductors in 1.7kV blocking voltage -The design and building of a 100 kW CSI (using custom modules) -The characterization of the efficiency of the converters by calorimetric methods -The study and building of a high power multi-level CSI converter The subject of the thesis is the logical continuity of this work with an important part relative to the control of the structure, the interleaving of the blocks, the reduction of the size of the input inductor. [1] Jäger-Waldau, A. (2016). PV Status Report 2016. JRC Science for Policy Report (Publications Office of the European Union, 2016). [2] Photovoltaics report. Fraunhofer Institute for Solar Energy Systems-ISE, Freiburg, November 2016. Retieved May 2017. [3] BURGER, Bruno. Power Electronics for Photovoltaics. 2015. [4] Sahan, B., Araujo, S. V., Noding, C., & Zacharias, P. (2011). Comparative evaluation of three-phase current source inverters for grid interfacing of distributed and renewable energy systems. IEEE Transactions on Power Electronics, 26(8), 2304-2318. [5] Bülo, T., Sahan, B., Nöding, C., & Zacharias, P. (2007, September). Comparison of three-phase inverter topologies for grid-connected photovoltaic systems. In Proc. 22nd Eur. Photovolt. Sol. Energy Conf. Exhib., Milan, Italy. [6] Martin, J., Bier, A., Catellani, S., Alves-Rodrigues, L. G., & Barruel, F. (2016, May). A high efficiency 5.3 kW Current Source Inverter (CSI) prototype using 1.2 kV Silicon Carbide (SiC) bi-directional voltage switches in hard switching. In PCIM Europe 2016; Proceedings of (pp. 1-8). VDE. [7] Sahan, B., Vergara, A. N., Henze, N., Engler, A., & Zacharias, P. (2008). A single-stage PV module integrated converter based on a low-power current-source inverter. IEEE Transactions on Industrial Electronics, 55(7), 2602-2609. [8] Wang, H., Liserre, M., & Blaabjerg, F. (2013). Toward reliable power electronics: Challenges, design tools, and opportunities. IEEE Industrial Electronics Magazine, 7(2), 17-26. [9] Yang, S., Bryant, A., Mawby, P., Xiang, D., Ran, L., & Tavner, P. (2011). An industry-based survey of reliability in power electronic converters. IEEE Transactions on Industry Applications, 47(3), 1441-1451. [10] Engler, A., et al. "Design of a 200W 3-phase module integrated PV inverter as part of the European project PV-MIPS." Proceedings of the 21st European Photovoltaic Solar Energy Conference and Exhibition, Dresden, Germany. 2006. [11] Felgemacher, C., Araujo, S. V., Noeding, C., & Zacharias, P. (2016, May). Benefits of increased cosmic radiation robustness of SiC semiconductors in large power-converters. In PCIM Europe 2016; Proceedings of (pp. 1-8). VDE. [12] Rashid, M. H. (2010). Power electronics handbook: devices, circuits and applications. Academic press.

Nonlinear compressive imaging for machine learning

Département Architectures Conception et Logiciels Embarqués (LIST-LETI)

Laboratoire Circuits Intégrés, Intelligents pour l'Image

01-10-2019

SL-DRT-19-0299

william.guicquero@cea.fr

In a context where the deployment of image sensors combined with computer vision tend to grow very quickly, the major challenges lie in information and signal processing. In the field of smart low-power sensors, the emerging breakthrough technology named Compressive Sensing is of major interest. In the case of embedded systems, autonomous decision-making becomes one of the core device feature while available resources (i.e., memory load, computing complexity and power consumption) remain highly limited. Indeed, the power consumption due to the sensor with dedicated signal processing is largely related to the overall data bandwidth and involved signal dimensionality. In particular, recent theoretical results demonstrate that standard Machine Learning approach can be advantageously applied in the compressed signal domain. However, those results are only restricted to the methods said as « linear », i.e. based on linear projections. The first objective of this PhD will thus be to properly identify theoretical limitations related to the combination of advanced Machine Learning with Compressive Sensing. It will aim at providing cutting-edge algorithm principles outperforming state-of-the-art tradeoffs between resources and inference accuracy. Thanks to a solid background in the laboratory on these fields of research, the goal of this thesis will be to evaluate the interest of introducing non-linearity during the acquisition process in order to improve the overall efficiency. This will help to define proper levers for smart sensor design enabling close-to-sensor context recognition (e.g., specific object detection with a highly limited hardware).

Study of 300-GHz electronically reconfigurable transmitarray antennas in monolithic technology

Département Systèmes

Laboratoire Antennes, Propagation, Couplage Inductif

01-12-2018

SL-DRT-19-0320

antonio.clemente@cea.fr

Due to the scarcity of electromagnetic spectrum resources and the need of broad bandwidth for high data-rate communications, the millimetre wave (mm-wave) and sub-THz bands from 30 to 350 GHz are very attractive for 5G and beyond 5G applications. In this context, high gain electronically reconfigurable antennas with beam-steering, multi-beam, and beam-forming capability are required in a huge number of emerging applications for radar, sensing, and communication systems (civil and military) typically ranging from C-band (4-8 GHz) to W-band (75-110 GHz). Typically composed of one or more radiant surfaces operating in transmission mode and illuminated by one or more focal sources, transmitarrays (also called discrete lens) are a recent cutting-edge antenna concept. Transmitarrays are realized using multilayer printed circuit technologies compatible with the integration of the active devices (diodes, MEMS, NEMS, semi-conductors, etc.). These devices can be used to control the electromagnetic field on the array aperture with excellent performances (bandwidth, cross-polarization level). CEA and IETR (university of Rennes I) have a very strong and unique expertise on transmitarray antennas. The previous realized studies form 2006 demonstrated the potentiality of transmitarrays in X-band (8-12 GHz), in Ka-band (28-40 GHz), and in V-band (50-70 GHz). The major scientific & technical innovations beyond the state-of-the-art are the following: first experimental demonstrations ? at world level ? (1) of highly efficient (70%) and highly directive (gain > 43 dBi) flat antennas at 300 GHz, (2) of ultra-flat transmitarray antennas, and (3) of self-alignment techniques for highly-directive flat antennas beyond 80 GHz.

Protecting binary elliptic curve cryptography against Template atttacks and Horizontal attacks

Département Systèmes

Laboratoire Sécurité des Objets et des Systèmes Physiques

01-09-2019

SL-DRT-19-0385

antoine.loiseau@cea.fr

This study takes place in the field of embedded systems security and the asymetric cryptography against Template and Horizontal side channel attacks. Recent studies, applied to the symetric cryptography, have yielded new side channel attacks : by improving the efficiency of Template attacks, these new attacks allow to bypass countermeasures based on desynchronisation and masking. It is time now to study the relevance of those new Machine Learning-based Template and Horizontal attacks to asymetric cryptography, especially for binary elliptic curves. This thesis follows the work of Antoine Loiseau on Binary Edwards Curves (BEC). Those BECs have been proven to have some intrisic properties of security against side channel attacks. However, latest results have shown that the resistance of BECs against the new ML-based Template and Horizontal attacks have yet to be studied. This thesis aims at qualifying the degree of resistance of those BECs to ML-based Template and Horizontal Attacks and at devising, implementing and testing new countermeasures to twarth those lastest générations of side channel attacks.

Miniature and directive antenna design with frequency agility over several octaves

Département Systèmes

Laboratoire Antennes, Propagation, Couplage Inductif

01-09-2019

SL-DRT-19-0423

serge.bories@cea.fr

The 'New Space' sector pushes for innovative solutions concerning on board micro-satellites antenna design. With smaller satellites, the miniaturization of directive and extremely wide band antenna represents a solution to fill the requirements of a lot of services. The double circular polarization needs to be ensure properly over more than 2 octaves. The CEA Leti antenna laboratory proposes to skirt the classical antenna physical limitation (bandwidth / miniaturization) by tuning the antenna on a smaller instant sub-band that can be shifted with reconfigurable RF components. This is the concept of antenna aperture tuning. The novelty of the PhD subject is to extend the tuning range over several octaves thanks to tunable capacitors developed at CEA Leti. The challenge consists to optimize the miniaturization of the antenna structure while limiting the impact of losses introduced by the tunable capacitors and get a performance stability over several octaves. Prototypes will be realized and measured in the CEA Leti or CNES anechoic chamber.

Multi-level inverter based on switched photovoltaic modules

Département Systèmes

Laboratoire Electronique Energie et Puissance

01-10-2019

SL-DRT-19-0470

ghislain.despesse@cea.fr

The thesis aims to develop a power conversion architecture based on switched photovoltaic modules that both optimize the use of each photovoltaic panel and optimize the power transfer to the electrical network. The principle consists to dynamically add / remove modules from a serialization to generate the desired output voltage. This principle has already been evaluated and tested in the case of batteries management and has shown many advantages: switching low voltages (drastic reduction of switching losses), increased flexibility (the average current extracted from each module can be adjusted independently), allows service continuity in the event of a faulty element. We wish, through this thesis, to extend this principle to the case of photovoltaic production, with its whole specificities. A photovoltaic module is rather a source of current than of voltage and the optimization of the module operation require that the current extracted places it in a maximum mode of energy extraction (MPPT: Maximum Power Point Tracking). This optimal point being different for each module due to dust, orientation, defects, shading ... It is necessary to determine the control laws to bring each module to their optimum operating point. This optimization of the operation of each module must be done while following at same time and in real time the mains voltage level at the output of the overall photovoltaic system and this with a sinusoidal current amplitude which maximizes the global output power.

VHF converter incorporating innovative passive components

Département Systèmes

Laboratoire Electronique Energie et Puissance

01-10-2019

SL-DRT-19-0573

sebastien.carcouet@cea.fr

The aim of the thesis is to develop a very high frequency converter (> 10 MHz) and exploiting innovative passive components. The increase in frequency allows the use of smaller passive components in value, size and weight. Indeed, the higher the frequency is, the lower the energy is stored and exchanged per cycle, the lower the volume of the inductor and / or capacity is and the higher the power density of the converter is. Moreover, a high switching frequency allows a faster converter response to operating condition changes (shorter response time). However, when the converters operate at more than 10MHz, commonly used structures, even conventional resonant structures, are no longer suitable even via Zero Voltage Switching (ZVS). This is why a new inverter topology, breaking with half or full bridge topologies is being considered. The objective of the thesis is to design, model and experimentally validate new high frequency DC / DC converter topologies using piezoelectric materials whose quality factor is high. The power level considered is from a few tens to a few hundred watts.

3D Thermomechanical Modeling of Printed Circuit Boards

DLORR

01-09-2019

SL-DRT-19-0623

manuel.fendler@cea.fr

The digital transition is illustrated in the factory of the future by the instrumentation of tools and parts evolving in extremely harsh environments for the Internet of Things. In order to ensure an efficient and robust integration, the study proposed in the context of this thesis aims to acquire knowledge of design constraints, and to implement the modeling and simulation tools that allow the collaborative mechanical and electronical design of future intelligent industrial systems

Electronic packaging by cold spray metallic encapsulation

DLORR

01-09-2019

SL-DRT-19-0624

manuel.fendler@cea.fr

The digital transition is illustrated in the factory of the future by the instrumentation of tools and parts evolving in extremely harsh environments for the Internet of Things. One of the difficulties is to integrate wireless communicating functions inside metallic parts, in particular for purposes of traceability with RFID tags. Due to the difficulties associated with the delicate electromagnetic environment, there are no integration solutions in the state of the art. The aim of this study is to investigate the potentialities offered by the Cold Spray technique, by characterizing the beneficial effects of texture on the metal absorption properties thus implemented to encapsulate the electronic chip.

Tools and methods for securing a memory hierarchy against software side-channel attacks

Département Systèmes

Laboratoire Sécurité des Objets et des Systèmes Physiques

01-10-2019

SL-DRT-19-0625

thomas.hiscock@cea.fr

Nowadays, computing systems execute an important quantity of untrusted software and have to isolate them from other user-trusted applications. For such multi-applications environments, strong process isolation is mandatory for security. Indeed, it prevents malicious processes to read or modify data of legitimate ones. In practice, perfect isolation is very difficult to achieve. Indeed, virtual memory or virtualisation are usually not sufficient: processes still execute on the same hardware and share lots micro-architectural elements. The memory hierarchy, from first level of caches to random access memory (RAM) represents without doubts the most important part of hardware shared between different processes and hence represents a large surface of attack. This is illustrated by many examples like cache attacks, known for more than a decade, software-induced faults in DRAM (Rowhammer) or information leakage through the MMU. Even the famous Spectre and Meltdown attacks revealed in 2018 rely on caches to extract sensible information. Since most of these vulnerabilities are known for years, a large panel of ?vulnerability-specific? countermeasures is available. However, no single solution covers all these vulnerabilities and the interaction of these countermeasures is not really studied. The first objective of this thesis is to develop new tools (statistical and/or simulation based) to reason about the security of the memory management hardware as a whole. These tools will form a solid basis to compare existing countermeasures taken from the state-of-the-art and combine them efficiently. Finally, a key contribution of the thesis will be to propose, design and evaluate possible countermeasures to secure the memory hierarchy.

Hardware security for post-quantum cryptography based on elliptic curve isogenies

DPACA (CTReg)

Autre

01-10-2019

SL-DRT-19-0626

simon.pontie@cea.fr

The main objective of this PhD thesis is to design protections to improve the security of SIKE (Supersingular Isogeny Key Encapsulation) implementations against side-channel and fault attacks. Walks in elliptic curve isogeny graphs can be used to establish a shared secret with a Diffie-Hellman protocol. SIKE is a key encapsulation suite based on this asymmetric cryptography. It is executed on conventional computer and is thought to be secure against an attack by a quantum computer. NIST has initiated a competitive "post-quantum" cryptography standardisation. These algorithms were built to avoid cryptanalysis. But, attackers may explore alternative attack methods that exploit physical access to implementation. Electromagnetic radiation analysis of deciphering or fault injection are examples of such attacks. There exist protections to hide secrets which used by implementations of classical cryptography. But, there are only few counter-measures to protect SIKE implementations and the threat of physical attacks against isogeny-based cryptography is not well known, up to now. This thesis will address these two problems. The PhD student will begin with studying SIKE protocol and existing implementations. He/She will have to identify existing physical attack propositions and to provide new attack methods. To refine the threat characterisation, he/she will build attack demonstrators based on side-channel analysis and/or fault injection. He/She will propose counter-measures that could be algorithmic, software or hardware methods to protect SIKE implementation. The SAS "Secure Architectures and Systems" research group is located close to Marseille (FRANCE). It is a joint CEA and EMSE team with state-of-art equipment to perform side-channel and fault attacks. PhD student supervisors are Nadia El-Mrabet (EMSE/SAS), Luca De Feo (UVSQ/CRYPTO) and Simon Pontié (CEA/SAS).

Stretchability : which impact on printed electronics ?

Département des Technologies des NanoMatériaux (LITEN)

Laboratoire Composants Optiques Imprimés

01-10-2019

SL-DRT-19-0662

mohammed.benwadih@cea.fr

Stretchability is a main challenge that printed electronics has to face in order to integrate printed functions (sensors, actuators, energy harvesters) inside systemes. This integration close to the use imposes strong constraints on device specification : stretchable, wearable, co-integration with elements having a different mechanical behavior (rigid/stretchable). This Phd work aims at studing the impact of this new constraints on technologies printed on the PICTIC Plateform of CEA Grenoble. The study will first focus on building blocks of printed electronics (conductive track, dielectric, capacity, organic semi-conductor). Then it will be applied on few devices already under control in the lab on usual plastic substrate. The study will figure out the materials blocking points and the innovation to provide on stack and archotecture. The last part will focus on the co-integration of stretchable sensors and flexible/semi-rigid elements.

Analysis of mechanical constraints on transmission lines by instrumentation with sensitive materials

Département Architectures Conception et Logiciels Embarqués (LIST-LETI)

Laboratoire Fiabilité et Intégration Capteur

01-09-2019

SL-DRT-19-0683

nicolas.gregis@cea.fr

Reflectometry is as old as electromagnetism itself and share the same principle with radar technologies. CEA LIST has been working on reflectometry to make it available for cable diagnosis through the use of signal processing algorithms and embedded hardware, such as FPGA or SoC. Nowadays, progress in this field opens new possibilities, like transforming cables in distributed sensors, especially for detection of mechanical constraints. This is even more possible by adding to the cable materials with both electromagnetical and mechanical effects, such as magnetostrictive layers. Previous work on the subject has shown great potential for this combination. Thus the objective of this thesis will be to design a new cable integrating materials sensible to mechanical constraints and reflectometry. First the work will focus on the study of the best material combined with signal processing methods and then the new design will be proposed and tested. For this PhD project a sound knowledge in the field of electromagnetics is mandatory. It is also expected that the candidate has some basic knowledge in the fields of reflectometry and magnetostriction which are the core technologies used in this PhD project. Additionnaly, a solid background in signal processing techniques will be necessary for both the modelling and the analysis of experimental results. Those skills will also be useful for preparing a potential technological application. An important part of this thesis will also rely on the design of experimental set-ups. It is therefore expected that the candidate has motivation for experimental work.

Study of DNA origami?surface interactions for application in lithography

Département Technologies Silicium (LETI)

Laboratoire

01-09-2019

SL-DRT-19-0684

raluca.tiron@cea.fr

In nanotechnology in general and semiconductor industry in particular, there is an ever increasing need for smaller and more complex features at an ever lower cost. Some examples of applications are sub-10 nm features for creation of FinFETs, lateral (horizontal) and vertical gate-all around nanowires, single electron transistors and advanced non-volatile memories (STT-RAM, MRAM, OxRAM, etc.). To address the challenge of patterning at sub-10 nm features novel patterning approaches must be envisioned. DNA (deoxyribonucleic acid), by virtue of its inherent small diameter (2 nm), tendency to self-organize into various different morphologies and its possibilities for functionalization, offers the possibility to realize both two- and three dimensional structures at nanometer scale. The goal of this PhD work is to demonstrate the feasibility of nanostructuring the surface of a substrate using DNA origami as a mask, with an ultimate resolution of a few nanometer, with a density that is above the current state of the art in semiconductor industry. The focus of the internship will lie on ever more complex features, while ensuring long-range order by conventional lithography guide patterns. The last part of the thesis consists of the effective transfer of the DNA pattern into the substrate.

Improvement of performance X and gamma-ray imaging by identification of semiconducting detector parameters

Département d'Optronique (LETI)

Laboratoire pour la Visualisation et l'Eclairage

01-10-2019

SL-DRT-19-0796

gmontemont@cea.fr

Our laboratory designs X and gamma-ray imaging systems for medical imaging or luggage control. We use CdTe or CdZnTe-based detectors that are sensitive to five physical parameters of the interaction: deposited energy E, interaction time T and the 3-dimensional position XYZ. These parameters are estimated by real-time analysis of anode electronics signals. These detectors have been significantly improved in recent years but some limits remain, especially those due to the non-uniformity of the response due to physical properties of the material. The goal of this Ph.D. internship is to overcome these limits by a detailed modelling and characterization of the actual detector response. The identification of internal physical parameters of the detector would allow to optimize estimation of interaction location, time and energy. The student should have a background in mathematics, statistics or physics and a high affinity for multi-disciplinary research.

Robustness tests of embedded systems by controlled disturbance in simulation using virtual platforms

Département Ingénierie Logiciels et Systèmes (LIST)

Laboratoire pour la Sûreté du Logiciel

01-10-2019

SL-DRT-19-0857

yves.lhuillier@cea.fr

The development of embedded systems is subject to the consequences of more and more advanced integration. These consequences are manifested by increasingly complex architectures (multi-core ...), but also more and more sensitive (to faults). These systems, which are difficult to test (System On Chip), also have potential security vulnerabilities. All these integration-related impacts must therefore be taken into account in a strict context of information system reliability and security (SSI) requirements. The classical development methods show their limits vis-à-vis these new architectures inducing significant risks in the reliability of the final system. In almost all cases, the software is developed under the assumption of a stable and secure hardware, this being generally ensured by mechanisms of redundancies more and more expensive. To reduce these risks, the use of virtual platforms makes it possible to develop software that is less sensitive to potential errors. The aim of the thesis is to study the testability of embedded systems by an approach based on fault injection by simulation, via virtual platforms. The use of simulation makes it possible to execute a program and to disturb certain data precisely. The analysis of the divergences with a perfect execution, makes it possible to check the level of criticality of each of the operations carried out by an executable and to adapt the development accordingly.

Hybrid approaches in co-located multi-antenna systems for object detection

Département Systèmes

Laboratoire Antennes, Propagation, Couplage Inductif

01-09-2019

SL-DRT-19-0873

raffaele.derrico@cea.fr

The framework of this thesis is that of the detection and imaging of objects in a lossy, and possibly layered, environment using multi-antenna wide-band radar technologies. In these systems, one of the options is to use a large number of antennas to improve the location accuracy, and another one consists in using high-resolution array signal processing approaches. The objective of this thesis is to propose co-located multi-antenna solutions, and their correponding signal processing methods, capable of exploiting MIMO techniques and beamforming in penetrating radar applications, i.e. using wide band signals. The study will start with a state of the art concerning multi-antenna radar systems and the implementation of a (simplified) propagation model, both in the wideband HR localization framework. Then, the PhD student will perform measurement campaigns using the CEA LETI channel sounder. This experimental phase will involve an evolution of the propagation model including the wave sphericity , the polarization the medium heterogeneity and potential dispersivity. The student will propose multi-antenna solutions by optimizing the layout and number of radiating elements, by developping performing signal processing techniques, and will produce a proof of concept. The PhD student will be part of the Antenna, Propagation and Inductive Coupling Laboratory at CEA-LETI, in Grenoble (France). He/she will benefit of the state of the art facilities (channel sounders, emulator, OTA setup, and electromagnetic simulator). The PhD thesis will be carried out in collaboration with Université de Rennes 1, under the supervision of Prof. Laurent FERRO-FAMIL. The student will have the opportunity to spend training periods in both institutes. Application: The position is open to outstanding students with Master of Science, ?école d'ingénieur? or equivalent. The student should have specialization in the field of telecommunications, radar, microwave and/or signal processing. The application must necessarily include a CV, cover letter and grades for the last two years of study.

Study and control of Intermetallic compounds formation in indium based interconnects

Département d'Optronique (LETI)

Laboratoire d'assemblage et de Packaging Photonique

01-09-2019

SL-DRT-19-0899

olivier.mailliart@cea.fr

CEA\LETI\DOPT develops photonic components such as micro-displays, or infrared detectors by 3D integration that is a modern way for electronic packaging, where devices are stacked on top of each other or packaged. The electrical, optical and/or thermal connections are created between the stacks and package with the help of interconnects. The interfacial intermetallic (IMC) layer formed at metal/metal interface plays a crucial role in determining the properties and reliability of the joint/interconnect. In this work, we will focus on IMC formation in indium balls interconnects that becomes an issue (reliability) when fine pitches (below 10µm) are reached. This study will be divided into 3 parts: - Understanding of IMC formation in current configuration - Improvement of the configuration so as to control IMC formation

Design and integration of active EMC filters for power converter

Département de l'Electricité et de l'Hydrogène pour les Transports (LITEN)

Laboratoire Electronique avancée, Energie et Puissance

01-10-2019

SL-DRT-19-0935

xavier.maynard@cea.fr

The specifications of power converters for embedded applications have high constraints (efficiency, weight / power ratio, etc.) while respecting normative EMC constraints. A converter may be upset by its own disturbances (self-immunity) or disturb its environment, usually due to common-mode (CM) currents. Converters (even low-power ones) may also radiate high-frequency electromagnetic energy that can upset nearby equipment (near-field coupling) or radio receivers (far-field coupling). The conventional way of satisfying the EMC requirements is the use of shielding and filtering techniques based on large and heavy passive components (inductors and capacitors) which degrade the specific power of the converter. Passive EMC filters would represent approximately 20% of the cost, weight and volume of a power converter. With the adoption of GaN components allowing higher and higher switching frequencies, active CEM filters appear as a worthy alternative to the classic passive filtering approach. Similar attenuations are possible with reduced mass and bulk. The aim of the thesis is to study the different types of active CEM filters with: - The realization of a state of the art. - The realization of a common mode (CM) and differential mode (DM) noise estimator of switching cells and transformers. - Simulation and comparison of the most relevant solutions (active and passive). - EMC measurement of standard filters and converters. - The design of a model of an active filter for a given converter. - The test of the model with its associated converter. The PhD student will have a background in analog and digital electronics as well as knowledge of electronic simulation software (LTspice, Pspice, PSIM or others), routing software (KiCad, Altium for example) and embedded programming for a programmable digital circuit ( µC, DSP or FPGA).

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