De Dual Active Bridge-omzetter in toekomstige geëlektrificeerde systemen: een vrijheidsgraden- en uitbreidingsbenadering

Future electrified systems will require either or both high efficiency and high power density. Nevertheless, achieving these goals is not limited to nominal power or traditional operating conditions. Instead, maintaining high efficiency across varying load and voltage conditions will be critical, as modern and emerging applications inherently experience power fluctuations. For instance, in renewable energy generation, power levels change due to meteorological variations, while in electrified transportation, optimizing battery energy usage is important because even a small energy saving can significantly impact the performance, influencing driving/flying range and or oil consumption. This requirement becomes even more stringent in hybrid aerospace vehicles, where power density directly affects fuel efficiency. The backbone components of these systems are called power electronic converters. Research and development in this field are essential, as the entire system's efficiency depends on them. Driven by ambitious (if not imperative) targets such as net-zero emissions and the increasing demand for energy-efficient applications, power converters must continue evolving. However, rather than completely replacing existing technologies, improving and optimizing traditional converters can help minimize electronic waste and extend their usability. A highly used converter, the Dual Active Bridge (DAB), was introduced back in the 80s for high-power-density aerospace applications. Its widespread adoption is justified by its performance of minimal switching losses, high voltage gain, and intrinsic safety features enabled by its high-leakage transformer and active bridge implementation. However, when operated using conventional control strategies, the DAB can not maintain its efficiency under light-load conditions. Research efforts have taken two primary approaches to address this issue: developing alternative topologies that compete with the DAB or completely changing its control parameters. Despite various improvements that have been proposed, industrial adoption remains limited due to the mathematical complexity of these approaches and their reliance on nonlinear or discontinuous parameter modifications. This thesis aims to study several degrees of freedom of the DAB and the expansions proposed in the state of the art, aiming to deliver power at different load levels while maintaining high efficiency, even when operating below their optimal operation point. It also proposes modeling strategies based on artificial intelligence and Fourier component generalization, which help speed up the analysis of the converters handling multiple loads and having high degrees of freedom. Finally, certain topological modifications are proposed for study, providing a detailed comparative analysis. Technological improvements are addressed, including the implementation of variable magnetic devices and novel wide band gap devices. The thesis attempts to push the use of this converter and not discard it yet for future applications; the authors are convinced that the DAB and other old technologies can benefit from the methodology proposed to continue using them from a recycling/keep-using perspective in future applications.