05. - 07.06.2018
Power Electronics | Intelligent Motion | Renewable Energy | Energy Management
Tuesday, 05.06.2018, 15:15 - 17:30 hrs
Ionel Dan Jitaru, Rompower, USA
Implementation of an Adaptive Dead Time in Resonant Converters
A fixed dead time is not always sufficient in any resonant converter design, neither in every operating point to fully charge/discharge the parasitic half-bridge capacitors. An adaptive dead time represents an alternative and more promising approach. To achieve this, a special control logic is needed, which determines the individual turn-on and turn-off events of the input switches.
Modified Basic DC-DC Converters
Changing the position of the output capacitor in such a way that it connects one input and one output terminal modifies a DC-DC converter. This is here demonstrated with the basic buck, boost, and buck-boost topologies. The changes concern the input buffer capacitor C1, caused by a modified input current form and the necessary voltage across the capacitor C2. The dimensioning of the converter is compared. Small signal models and transfer functions are derived and measurements of a converter realized with GaN semiconductor devices are shown.
GaN Based Multilevel Intermediate Bus Converter for 48 V Server Applications
With the power architecture transition from a 12 V to 48 V rack in modern data centers there is an increased interest in improving 48 V power conversion efficiency and power density. In this paper, we explore system optimization of 48 V to 12 V non-isolated, fully regulated, intermediate bus converters (IBC) to maximize efficiency and power density. Two final GaN transistor based experimental prototypes, a traditional buck converter and a three level buck converter are compared.
A FPGA-Based Algorithm for Soft Switched DC-DC Converters with a Variable Transmission Path
An approach for control of resonant switching DC-DC Converters is presented. The aim of the control algorithm is to maintain soft switching for a variable transmission path. Second Order Generalized Integrator (SOGI) and a Frequency Locked Loop  are used for frequency detection. The primary current of the transmission path is the input signal of the SOGI. With the filtered outputs v' & qv' the angle is calculated and the switching time is determined by compensation of propagation delays .
Compact Bidirectional GaN Buck-Boost Converter for Negative Rail Supply in Bipolar DC-Grids
A volume and weight optimized high-frequency bidirectional buck-boost converter for negative rail supply up to -300 V is presented. By use of state-of-the-art eGaN-HEMTs, switching frequencies far beyond the range of similarly rated silicon based converters can be achieved, leading to a significant increase in power density without sacrificing too much of the converter’s efficiency. The proposed converter is able to operate in boundary conduction mode at a switching frequency up to 2 MHz.
Exact Analytical Solution of the Peak Gain for the LLC Resonant Converter
The peak gain is a fundamental value for an efficient design of resonant converters. In some cases it is directly given by the maximum of the transferable power, which is likewise the peak of the gain curve. There is a second limit for the maximal usable output power. It’s the transition from the ZVS to the ZCS region. This paper gives a survey over the solutions for both limits in CCM and DCM for the lossless converter resulting in a fast and accurate optimization process.
GaN Buck Converter in CCM with Optimized High Frequency Inductors
Utilization of wide-bandgap semiconductors such as gallium nitride transistors facilitates the operation at high switching frequencies. Therefore, the volume of filter components like inductors can be reduced which helps to improve the power density of the converter. In continuous conduction mode, the relatively high DC component of the inductor current superimposed by a high frequency component makes high demands in the winding design. Hence, this paper discusses a buck converter with inductors with an alternative, optimized winding concept.
Modelling of a Bi-Directional Converter from a Power Supplying System With Application in Radio Communication Systems
In the paperwork a bi-directional converter for power supplying system of radio communication equipment has been reviewed. The converter provides charging of the energy storage elements (ESE)-supercapacitors (SC) and supplying the equipmnet from the SC when needed. The converter is made of a resonant converter and synchronous rectifier. Each one of the bi-directional converters charges a separate ESE from the battery. The developed models allow studying of the system when the converters are working on a common load.
A Bidirectional Quasi-Z-Source Based DC-DC Converter
This paper presents a novel quasi-Z-source based bidirectional DC/DC converter consisting of a quasi-Z-source inverter, high-frequency transformer, and push-pull converter. Both inputs provide buck/boost functionality by incorporating shoot-through states. Operating principles and modulation techniques are presented.
Friedrich-Alexander-University Erlangen, Erlangen, Deutschland
Markus Barwig received his diploma degree in 2012 at the University of Erlangen-Nuremberg. Since 2012 he is a PhD student at the Chair of Electromagnetic Fields at the University of Erlangen-Nuremberg. His main fields of study focus on the simulation of magnetic components and soft-switching converters.
University of Paderborn, Paderborn, Deutschland
Dipl.-Ing. Sven Bolte studied electrical engineering at the University in Paderborn/Germany. Since 2011 he is with the department of Power Electronics and Electrical Drives at the Paderborn University. His research topics are modeling and optimization of power supplies in regard to efficiency and power density. Presently he is doing research in converters with wide bandgap semiconductors.
University of Applied Sciences Würzburg-Schweinfurt, Thundorf i.UFr., Deutschland
Lukas Göbel did a cooperative study program at the Preh GmbH, Bad Neustadt, and the University of Applied Sciences Wuerzburg-Schweinfurt (FHWS), Germany. In the year 2017, he finished his studies with the Bachelor's Degree (B.Eng. Mechatronics). Since that time, he is doing a Master Resarch Program at the FHWS with resonant DC-DC-Converts as his main research topic. Therefore, he works at the Technology Transfer Center for Electric Mobility at the FHWS
University of Applied Science Vienna, Wien, Österreich
Felix A. Himmelstoss received the Dipl.-Ing. and Dr. (PhD) degrees from Technical University of Vienna, in 1981 and 1990, respectively. Since 1982 he has been working on different projects for Austrian companies developing power supplies and electrical drives. He is author of numerous technical and scientific papers and patents. Dr. Himmelstoss is professor and head of the Energy and Industrial Electronics department of the UAS Technikum Wien.
Macquarie University, Sydney, Australien
Yuba Raj Kafle was born in Chitwan District, Nepal in 1983. He received his B.E. from the Tribhuvan University, Nepal, and Master?s degree from Xi?an Jiaotong Univeristy, China in 2006 and 2013 all in Electrical Engineering. He is currently a PhD student in the School of Electrical Engineering, Macquarie University, Australia. His current research interests include solid state transformer, grid connected photovoltaic inverters, and impedance source converters.
Helmut Schmidt University, Hamburg, Deutschland
Sebastian Klötzer received the Dipl.-Ing. degree in Electrical Engineering from the Technical University of Munich, Germany, in 2011. He is currently pursuing his doctorate at Helmut-Schmidt-University, Hamburg, Germany. His research interest includes wide bandgap devices and EMC of switched-mode power supplies.
University of telecommunications and post, Sofia, Bulgarien
My researches are in the range of power supplying systems with voltage equalization over series connected cells. I have interests in the range of bi - directional converters, energy storage elements (supercapacitors), PV systems, UPS systems.
Friedrich-Alexander University Erlangen, Erlangen, Deutschland
Christian Oeder studied electrical engineering at the Friedrich-Alexander University Erlangen-Nuremberg. Currently he works as research associate at the Friedrich-Alexander University Erlangen-Nuremberg department of electrical engineering, electromagnetic field theory.
Efficient Power Conversion (EPC) Corporation, El Segundo, USA
David Reusch is the Executive Director of Applications Engineering at Efficient Power Conversion Corporation. He received his B.S, M.S. and Ph.D. degrees in electrical engineering from Virginia Tech. While pursuing his Ph.D. degree at the Center for Power Electronics Systems he was the recipient of the Bradley Graduate Fellowship. He has authored over 35 peer reviewed technical publications and given numerous invited presentations related to high frequency, high density power conversion.