This paper presents a 4 kW GaN-based galvanically isolated bidirectional DC/DC converter suitable for on-board auxiliary power supply systems, interconnecting the HV battery with the LV power system. To enable the trend towards higher levels of electrification, a second LV level of 48 V is introduced to supply the high-power consumers, relieving the 12 V grid on the one hand and/or avoiding using additional costly isolated converters connected to the HV batteries on the other. The built converter prototypes aim to ...

Magnetic devices are an important part of electronic converters. They can be used to control some properties of the converters. There are three different control methods using an auxiliary bias-winding. In the presented paper, the impact of the implementation of the auxiliary bias-winding was studied for mixed biasing. Seven different designs were investigated in small signal measurements and 3D-FEM-simulations. The results were proven by calculated results of equivalent diagram circuits, which have been developed. ...

In this dissertation, we investigate the interplay between extremal fixpoints and higher-order constructs. The main Focus here is Higher-Order Modal Fixpoint Logic (HFL), an extension of the modal mu-calculus by a simply typed lambda calculus. The resulting logic is very expressive, yet the interplay of its components has not been systematically investigated so far. Goal of this thesis is to characterize the interplay of the components of HFL. A first characterization is given by converting the denotational semantics ...

The nanoimprint technology realizes already the production of two-dimensional (2D) shaped nanoparticles of different shapes and materials. These nanoparticles can be applied in advanced applications in material engineering, as well as in biology and particularly in drug-delivery systems. This work presents three-dimensional (3D) shaped nanoparticles with T-, L- and step-like cross-sections, implemented by substrate conformal imprint lithography (SCIL) and a manual soft-imprint technique. Further, 2D shaped nanoparticles ...

Computer science has evolved so much that it influences almost every part of human live. A particularly personal part of human live is the selection of a given name for a newborn baby. The name discovery service Nameling is our way to help expectant parents with this decision. It is a web service that helps parents to find a given name for their newborn baby. We want to further improve the user experience of Nameling by personalizing its name results for the current user. We deem this important, because the selection ...

In den letzten zehn Jahren wurde eine große Menge an Daten über menschliche Interaktionen verfügbar, die entweder aus sozialen Online-Netzwerken stammen oder von tragbaren Geräten erfasst wurden. Die klassischen Sozialwissenschaften bieten keine Instrumente für die Durchführung datengetriebener Forschung mit solchen Daten. Die computerorientierte Sozialwissenschaft (Computational Social Science) versucht, diese Lücke zu schließen, indem sie Methoden für Data-Mining und maschinelles Lernen zur Nutzung der Daten aus ...

System inertia is the instantaneous power reserve that stabilizes power systems after large-scale disturbances. It declines with increasing renewable generation, causing an increased risk of black-out unless action is taken. Providing additional inertia will be necessary to maintain security of supply at a reasonable level. To solve the problem of reduced inertia in a reliable and cost-efficient way, this thesis first systematically describes requirements on system level, as basis for the following evaluation of ...

Die vom Fachgebiet Elektrische Energieversorgungssysteme (EVS) am Kompetenzzentrum für Dezentrale Elektrische Energieversorgungstechnik (KDEE) der Universität Kassel durchgeführten und in diesem Bericht vorgestellten Arbeiten haben einen Beitrag zum Verbundvorhaben „Hocheffiziente, langlebige und kompakte Leistungselektronik auf GaN-Basis für die Elektromobilität der Zukunft“ (HELENE) geleistet. Ziel des Gesamtvorhabens war die Untersuchung der Einsatzfähigkeit und die Bewertung und Demonstration von Gewichts- und ...

Almost all power electronic converters require magnetic devices and some properties of the converters can be controlled with magnetics. New magnetic materials enable implementation of magnetic control of converters also in high switching frequency applications. The presented paper gives an overview about controllability of magnetic devices in theory and practice, simulation approaches and examples. The focus is on electrically controllable magnetic devices. This means that an additional control winding is wound on ...

The primary theme in the vehicles industry is the increase in automating and integrating more robust intelligent electronic systems to enhance the safe functioning, flexibility, and to extend the virtual productive age of the vehicular systems. Further, significant efforts focus on developing monitoring systems for the abnormal driving conditions such as wheel spinning and sliding that can increase the hazardous in the operating environment and speed up the wearing off process. Thus, these events play a primary role ...