Tremendousadvancement inultra-low powerelectronics and radiocommunica tionshas significantly contributed towards the fabrication of miniaturized biomedical sensors capable of capturing physiological data and transmitting them wirelessly. However, most of the wearable sensors require a battery for their operation. The battery serves as one of the critical bottlenecks to the development of novel wearable applications, as the limitations offered by batteries are affecting the development of new form-factors and longevity of wearable devices. In this work, we introduce a novel concept, namely Intra-Body Power Transfer (IBPT), to alleviate the limitations and problems associated with batteries, and enable wireless, batteryless wearable devices. The innovation of IBPT is to utilize the human body as the medium to transfer power to passive wearable devices, as opposed to employingon-boardbatteries for each individual device. The proposed platform eliminates the on-board rigid battery for ultra-low power and ultra-miniaturized sensors such that their form-factor can be flexible, ergonomically designed to be placed on small body parts. The platform also eliminates the need for battery maintenance (e.g., recharging or replacement) for multiple wearable devices other than the central power source. The performance of the developed system is tested and evaluated in comparison to traditional Radio Frequency based solutions that can be harmful to human interaction. The system developed is capable of harvesting on average 217µW at 0.43V and provides an average sleep/high impedance mode voltage of 4.5V.

Ces travaux portent sur la récupération et le stockage d’énergie pour l’alimentation de capteurs sans fil dans un contexte aéronautique. Dans un premier temps, nous présentons la problématique particulière de l’alimentation des capteurs sans fil dans un tel domaine et dressons un état de l’art des différentes technologies de stockage et de récupération pouvant répondre à ce besoin. Dans un deuxième temps, à travers l’étude et la réalisation de deux récupérateurs, nous montrons les possibilités qu’apporte cette technologie et détaillons les contraintes de conception qu’impose le milieu afin d’obtenir une alimentation robuste et fiable. Le premier récupérateur présenté est une alimentation photovoltaïque située sur l’extrados de l’aile d’un A321 alimentant des bandes de capteurs sans fil proches. Le système fournit 2 watts, fonctionne par temps couvert et résiste aux températures fortement négatives (-50°C) et aux basses pressions (200hPa) qui sont rencontrées à l’altitude de croisière de cet appareil. Le deuxième récupérateur est une alimentation thermoélectrique placée dans le mât réacteur d’un A380 pour alimenter un système de capteurs dédié à la surveillance de l’état de structure. Le système résiste aux températures élevées (300°C) et aux importantes vibrations de la zone d’installation et produit l’énergie nécessaire à l’alimentation du système de capteurs. Les choix et les étapes de conception ayant menés aux deux systèmes sont détaillés, tant au niveau de l’assemblage mécanique que des circuits électroniques. / This work deals with energy harvesting and storage to power aircraft embedded wireless sensors. First, we discuss the issue of powering wireless sensors in an aircraft and we present a state of the art of the various energy harvesting and storage technologies that could be used. Then, through the design and construction of two harvesters, we show the possibilities offered by this technology and we explain the design constraints imposed by the application to get a reliable and robust power supply. The first harvester is a photovoltaic power supply located on the upper surface of an A321’s wing supplying a wireless sensors belt nearby. The systems provides 2 watts to the load, works with cloudy weather and is highly resistant to negative temperature (-50°C) and low pressure (200hPa) that are met at aircraft cruising altitude. The second harvester is a thermoelectric power supply located in an A380 pylon supplying a structural health monitoring system. The harvester is highly resistant to high temperature (300°C) and severe vibrations of the installation area and manages to generate the required energy to supply the structural health monitoring sensors. Mechanical and electronic design steps and choices that led to both harvesters are detailed and discussed.

Lågströmskommunikationsprotokoll såsom 6LoWPAN har använts i stor utsträckning för applikationer som kräver mindre energiförbrukning för trådlös kommunikation på korta avstånd, exempelvis IoT-enheter. Eftersom antalet sådana enheter ökar blir det allt viktigare att överväga ambient energy harvesting som en energikälla för att driva sådana enheter. Det framkallar ett behov av att ompröva designen av ett energieffektivt kommunikationsprotokoll som gör det möjligt för sensorer och aktuatorer att använda den utvunna energin för beräkning och kommunikation. Eftersom den utvunna energin från en energikälla är begränsad och det tar tid för en enhet att samla tillräckligt med energi för datahantering och kommunikation, finns det ett behov av att undersöka energibudgeten och bestämma de kritiska parametrarna som påverkar energiförbrukningen för trådlös kommunikation. En analys av energiförbrukningen utfördes genom att anpassa en Python-modell och simuleringar genomfördes för att hjälpa till att förstå påverkan av nyckelparametrar på energiförbrukningen med hänsyn till en lämplig radio frequency energy harvesting (RF-EH) för “zero” energienheter. I examensarbetet föreslås designöverväganden för ett nytt lågströmskommunikationsprotokoll för “zero” energienheter. Resultaten visade att adaptive data rate (ADR) har en stor betydelse för energibesparingar. Med lämpliga överföringsparametrar inställda kan energiförlusterna för omsändningar och kollisioner minskas. Det är också möjligt att införa en schemaläggningsalgoritm för kommunikationsprocessen för förbättrad kollisionsundvikande. De föreslagna designövervägandena kan tillämpas i framtida arbeten för att förbättra kortdistanskommunikationsprotokollet för “zero” energienheter. / Low power communication protocols such as 6LoWPAN have been widely used on applications that require less energy consumption for short-range wireless communication, for example, Internet of Thing (IoT) devices. As the amount of these devices escalates, it becomes increasingly important to consider ambient energy harvesting (EH) as an energy source to power such devices. This induces a need to reconsider the design of an energy-efficient data transfer protocol that enables the sensors and actuators to utilize the harvested energy for computing and communication. As the harvested energy from an energy source is limited and it takes time for a device to accumulate enough energy for data processing and communication, there is a need to investigate the energy budget and determine the critical parameters that affect the energy consumption for wireless communication. An energy consumption analysis was performed by adapting a Python model, and simulations were carried out to help understand the impact of key parameters on energy consumption while considering a suitable range for radio frequency (RF) energy harvesting “zero” energy devices. The thesis project aims to propose the design considerations of a new low-power communication protocol for “zero” energy devices. The results showed that adaptive data rate (ADR) has a major contribution to energy saving. With suitable transmitting parameters set, the energy waste of retransmissions and collisions could be reduced. It is also possible to introduce a scheduling algorithm to the communication process for improved collision avoidance. The proposed design considerations can be applied in future work to improve the shortrange communication protocol for zero-energy devices.