« The HDR presentation summarizes my research work as a doctoral student at LAAS in Toulouse (2005-2008), post-doctoral student at LMP in Tours (2008-2010), and Associate Professor at IMS in Talence (2010-2024). Structured in 3 parts, it begins with my Curriculum Vitae, detailing my teaching, research and collective responsibilities. This is followed by a presentation of my work on the design of new components. The following part deals with the reliability of power components and assemblies, illustrated by various projects. Finally, a conclusion with future prospects in the short, medium and long term. » – Loïc Théolier.