Mohammed Terrah

Le transfert d'énergie sans contact connaît aujourd'hui un développement important dans des domaines variés, allant de l'électronique portable aux véhicules électriques, en passant par les dispositifs biomédicaux implantables. L'extension de cette technologie au domaine des drones constitue une voie prometteuse pour dépasser les limitations actuelles en autonomie énergétique, un enjeu majeur freinant leur déploiement dans des applications telles que la surveillance, la logistique ou l'agriculture de précision. Plutôt qu'une augmentation de capacité batterie, solution qui s'accompagne d'un accroissement de masse et de coût avec moins de d'autonomie d'exécution, la mise en place de plateformes de recharge inductive, fixes ou embarquées, constitue une approche alternative permettant d'assurer des missions prolongées et autonomes.Dans ce contexte, cette thèse porte sur la conception, la modélisation et l'optimisation d'un système de transfert d'énergie sans contact dédié aux drones. Dans un premier temps, un modèle électromagnétique et électrique précis du système est développé, intégrant l'environnement réel d'implantation sur drone ainsi que différents scénarios de désalignement. Ce modèle permet d'identifier les paramètres influençant le rendement, le tolérance aux désalignements et la masse embarquée.Une étude paramétrique approfondie est conduite afin de déterminer une configuration présentant un compromis favorable entre performances énergétiques et contrainte de masse. Sur cette base, une validation expérimentale est réalisée, incluant la caractérisation du coupleur, la mesure du rendement énergétique et l'analyse du champ magnétique rayonné vers l'électronique embarquée du drone. Cette étape permet de confirmer la pertinence du modèle développé et d'établir les fondations pour l'optimisation.Dans une seconde phase, une méthodologie d'optimisation multi-objectif est mise en œuvre pour améliorer la conception du coupleur magnétique. Les algorithmes d'optimisation sont associés à des techniques de méta-modélisation, permettant de réduire significativement les temps de calcul liés aux simulations 3D tout en conservant une précision satisfaisante. Les critères considérés incluent rendement, masse, tolérance au désalignement et rayonnement électromagnétique.

Wireless power transfer (WPT) systems offer a promising solution for automating the charging process and extending the mission duration of unmanned aerial vehicles (UAVs). However, the weight of the WPT system's receiving part mounted on the UAV can significantly impact its energy consumption and overall performance. In this regard, the ferrite plate is a critical component. While it is necessary for improving magnetic coupling and reducing the stray magnetic field, it also increases weight. Topology optimization (TO) is an effective tool for addressing this challenge and identifying the most suitable shape for the ferrite plate. In this study, a multi-objective topology optimization (TO) approach based on the solid isotropic material with penalization (SIMP) method is employed to design an optimized ferrite plate for the receiver side of a WPT system for UAV charging. The multi-objective optimization, implemented through a weighted-sum formulation, identifies ferrite configurations that maximize mutual coupling while minimizing material usage. Three representative Pareto-optimal designs are fabricated and experimentally validated against a full-ferrite reference plate. The results show that the reference configuration is a dominated solution in the Pareto sense, as equivalent mutual coupling can be achieved with approximately 40% less ferrite material. The trade-off between the resulting reduction in charging efficiency and the decrease in the required flight power due to ferrite reduction is analyzed, further demonstrating the potential of TO to substantially reduce system weight without compromising overall system performance.

This paper explores Wireless Power Transfer (WPT) for Unmanned Aerial Vehicles (UAVs) battery recharging. To enhance the performance of WPT various parameters such as frequency, compensation topology, and the number of coils turns are examined. The objective is to identify the most suitable combination in terms of efficiency, weight, and feasibility. The aim of this procedure is to ensure a maximum WPT efficiency while having a minimum additional weight, thereby providing autonomous recharging processes, and extending the duration of the UAV mission. The analysis is carried out through simulations and measurements, taking into account the variations of the coupling factor due to potential lateral misalignment of the parallel coils.

Adopting Wireless Power Transfer (WPT) technology to an Unmanned Aerial Vehicle (UAV) involves adding extra components, which may impact the drone’s overall weight and performance. This paper aims to enhance UAV performance by designing a lightweight WPT system through a parametric design approach. This method explores novel perspectives by identifying the most suitable combination of parameters in terms of efficiency, weight, and feasibility. Various parameters such as the compensation topology, number of turns of coils, and frequency were studied. The system was analyzed through a coupled simulation approach, where electromagnetic modeling of the coupler using the finite element method (FEM) was combined with electrical circuit simulations, providing a more accurate assessment of the overall system efficiency and behavior considering variations in the coupling factor due to misalignment. A prototype of the resulting configuration was designed and tested experimentally versus misalignment at reduced power using a specific test bench. The results show a 70% efficiency level with SP compensation that was improved to 80% with SS compensation.

The efficiency of Dynamic Inductive Power Transfer (DIPT) depends mainly on the coupling coefficient within the coupler. In order to improve this parameter, a novel approach has been introduced that results in a significant increase of between 25% and 36% at minimal additional cost in the case of juxtaposed rectangular coil configuration on the road. This method involves the incorporation of a passive additional short-circuit coil adjacent to the primary coil for obtaining a higher coupling coefficient, as has been theoretically demonstrated. Simulations carried out on Comsol have optimized the dimensions of this additional coil, not only for cost effectiveness and minimal space utilization, but also for optimal efficiency. Experimental validation was performed at reduced power, using a 2 kW test bench, and confirmed the estimation. The efficiency improvement proposed in this paper is crucial for improving the global DIPT efficiency and then facilitating its social acceptance.