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Dissertation
Entwicklung einer selbstjustierenden Formgebungsstruktur zur Herstellung formspezifischer 3D-Partikel basierend auf Nanoimprint-Technologie
(2020-11)
Ausgehend vom Soft-Nanoimprint-Verfahren wurde im Rahmen dieser Arbeit die Self-Aligned Molding Technology (SAMT) entwickelt. Die SAMT-Prägetechnologie ermöglicht eine wesentliche Reduzierung des Justieraufwands zur Herstellung echter 3D-Strukturen. Das Konzept basiert auf einem ‚Waffeleisen‘-Prinzip in Mikrometergröße und erlaubt in einem einstufigen Prägeprozess die Erzeugung komplexer 3D-Strukturen und -Partikel. Die SAMT Prägeform wurde in Form von 35 µm breiten V-Gräben im elastischen Polydimethylsiloxan (PDMS) ...
Konferenzveröffentlichung
Interleaved Buck Converter with Coupled Inductors as Auxiliary Bias-Current Source for Controllable Magnetic Devices
(VDE Verlag, 2020-08-26)
This paper presents an Interleaved Buck Converter with Coupled Inductors as a DC-Bias Current Source for Controllable Magnetic Devices, the modular interleaved Buck system supplies a low-ripple current for the auxiliary DC-bias winding of a controllable inductor with different biasing winding disposition in relationship with the main operating flux of the inductor. A 4-phase interleaved Buck converter system was built and inductance measurements where made for different operating current values of the DC-bias and the ...
Preprint
An Overview of Modeling Concepts for Service-Based Software Architectures
(2020)
This document provides an overview of modeling concepts for service-based software architectures (SBSAs). The concepts were extracted during a survey of conceptual frameworks for architecture modeling of SBSAs.
Konferenzveröffentlichung
A GaN-based DC/DC converter for e-vehicles applications
(IEEE, 2020)
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 ...
Konferenzveröffentlichung
Impact of implementation of auxiliary bias-windings on controllable inductors for power electronic converters
(IEEE, 2020)
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. ...
Dissertation
A Self-Organising Multi-Agent Knowledge Base
(2021-12)
Digitale Städte sind zunehmend auf IT- und Kommunikationsinfrastruktur angewiesen. Sie können als große verteilte Systeme betrachtet werden, die aus heterogenen und autonomen Teilnehmern bestehen. Besonders in Notfall- und Krisensituationen muss kritisches Wissen, beispielsweise über verletzte Personen oder beschädigte Infrastruktur, zuverlässig auch unter eingeschränkter Kommunikation erreichbar sein. In einer solchen Umgebung würde eine zentrale Verwaltung des kritischen Wissens einen Engpass verursachen. Daher ...
Dissertation
Long-term voltage stability of electric power systems hosting inverter-interfaced energy sources
(2021)
The study of power system dynamics refers to the motion of electro-mechanical and electro-magnetic quantities such as voltages, currents, rotational speeds, angles and powers under the action of forces caused by system disturbances. For decades, such dynamics have been extensively dominated by large Synchronous Generators (SGs). Not a surprising statement, considering that the power systems that we know today were built based on the SG concept since the closing decades of the 19th century. It all began in 1891, when ...
Dissertation
Development of feedback control for energy policy design to guarantee sustainable solar and wind power investment growth
(2021)
Energy transition in the power sector is one of the main pathways to achieving the climate targets. In order to stimulate renewable power development, regulatory policies play a vital role. However, these policies have so far attained only partial results or unexpected consequences due to the unsuitable designs. Therefore, the study addresses the question, “How do regulatory policies have to be designed in order to create a favorable environment for renewable power development?”
This work proposes to use feedback ...
Dissertation
Towards Service Co-evolution in the Internet of Things
(2021-12)
Nowadays, in the world of technology, where the new technologies are devolved and replace the old ones every single day, any software product in order to maintain its competitiveness, must be updated continually. Updating a software product results from an evolution process, including adding new features, replacing outdated features, repairing bugs, closing security gaps, and improving performance, which requires a lot of effort and knowledge. Therefore, the Internet of Things (IoT) services are no exception.
An ...
Working paper
Verbundvorhaben "HELENE" - Hocheffiziente, langlebige und kompakte Leistungselektronik auf GaN-Basis für die Elektromobilität der Zukunft
(2020)
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 ...