Carlos Augusto BERLITZ defended his PhD on December 20th, 2023.
Place : INSA-Lyon
Jury :
Rapporteurs :
M. Marc COUSINEAU, Maître de Conférences HDR, Univ Toulouse
M. Aleksandar PRODIC, Full Professor, Univ Toronto, Canada
Examinateurs :
M. Jean-Michel VINASSA, Professeur des Universités, Univ Bordeaux
Mme. Romane DUMOND, Docteur ingénieure chez STMicroelectronics, Grenoble
M. Samir OUKASSI, Directeur de Recherches, CEA LETI
Encadrement :
M. Bruno ALLARD, Professeur des Universités, Directeur
M. Gael PILLONNET, Directeur de Recherches, CEA LETI, Co-directeur
Abstract :
With current popularization of portable electronic devices, wireless sensors, and the Internet of Things (IoT), the demand for efficient and adaptable power management solutions has risen to unprecedented heights. Low-power applications, spanning a broad spectrum of domains from healthcare to environmental monitoring, have become integral to our modern way of life. These applications, often operating on limited energy resources, present a unique set of challenges and opportunities in the realm of power electronics.
While traditional DC-DC converters have demonstrated their efficacy in a myriad of scenarios, their conventional designs may no longer suffice to address the distinct and stringent requirements of low- and ultra-low-power systems. This thesis embarks on a comprehensive exploration of this intricate landscape, unveiling a tapestry of challenges, innovations, and solutions that define the domain of low-power DC-DC
converters.
The pursuit of novel switched DC-DC converters specifically tailored to low-power applications is at the heart of this thesis. As technology advances, the call for power-efficient solutions becomes ever more compelling, driven by a confluence of factors that underscore the significance of this research endeavor.
Traditionally DC-DC converters rely on inductors or capacitors for high efficiency conversion. However, despite advances on plenty of domains of power electronics, some physical and intrinsic limitations are still present when dealing with low-power applications, like charge sharing loss or the difficulty of inductor miniaturization. Such constraints call for innovative solutions for this application field.
The manuscript starts by presenting DC-DC converters and the particular challenges that are faced by such solutions at low-power scenarios. It is followed by studying some of the solutions proposed to address such challenges and their limitations, serving as cornerstone to the remaining of the thesis. Having identified that some of the limitations of current solutions are intrinsic to the passive devices used, the next step is to propose a solution tackling this challenge, a new topology family of DC-DC converters based on batteries as flying passive device. This new family topology is then experimentally validated and compared to a more traditional solution at a simple scenario. In a next natural step the concept is further experimented to more advanced converter topologies, including promising control and regulation strategies. Ultimately it leads to exploring different battery chemistries and their impact on the topology but also other passive technologies like fuel cells. A new topology family for low frequency and low-power DC-DC converters is proposed and experimentally validated with advantages against traditional DC-DC converters ate the same conditions. It also opens a new field of study for passive technologies not before explored in this context.
Keywords: switched-capacitor converter, micro-batteries, switched-battery converter