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Comparative Evaluation of MVAC-LVDC SST and Hybrid Transformer Concepts for Future Datacenters
(2022)2022 International Power Electronics Conference (IPEC-Himeji 2022- ECCE Asia)A transition from state-of-the-art 400 V AC to 690 V AC or 800 V DC (+/- 400 V DC) distribution improves the overall power conversion efficiency of datacenter power supply systems. The latter requires megawatt-level isolated medium-voltage (MV) AC to low-voltage (LV) DC conversion stages that operate with an efficiency of at least 98 AD. Whereas today's most advanced industrial MVAC-LVDC solid-state transformer (SST) prototypes do achieve ...Conference Paper -
Application of WBG Power Devices in Future 3-Φ Variable Speed Drive Inverter Systems "How to Handle a Double-Edged Sword"
(2020)2020 IEEE International Electron Devices Meeting (IEDM)Latest research results on three-phase wide-bandgap (WBG) inverter systems with full-sinewave output voltage filtering are reported. A new soft-switching modulation scheme for two-level 1200 V SiC inverters is described. Furthermore, a new Figure-of-Merit for determining maximum multi-level (ML) bridge-leg efficiency is defined and low-voltage GaN devices are evaluated considering ML flying capacitor (FC) and multi-cell inverter structures. ...Conference Paper -
High-Bandwidth High-CMRR Current Measurement for a 4.8MHz Multi-Level GaN Inverter AC Power Source
(2021)2021 IEEE Applied Power Electronics Conference and Exposition (APEC)The control of very high switching frequency power electronic converter systems featuring latest generation wide bandgap (WBG) devices requires current measurements with a very high bandwidth (BW) to achieve high closed-loop control dynamics. One example is a ultra-high BW 4.8 MHz parallel-interleaved multi-level GaN inverter AC power source with a target output BW of 100 kHz. This work investigates the combination of state-of-the-art ...Conference Paper -
Comparative Evaluation of Overload Capability and Rated Power Efficiency of 200V Si/GaN 7-Level FC 3-Φ Variable Speed Drive Inverter Systems
(2021)2021 IEEE Applied Power Electronics Conference and Exposition (APEC)Variable speed drive systems in e.g. robotics applications are challenged with discontinuous operation cycles and short-time overload current requirements of 2-3 times nominal load. As the motor itself constitutes a large thermal time constant compared to the semiconductor devices in the inverter, latter create a bottleneck for the increased losses during overload operation. Hence, special focus has to be laid on the inverter overload ...Conference Paper -
Single-Phase Full-Power Operable Three-Phase Buck-Boost Y-Rectifier Concepts
(2021)2021 IEEE Applied Power Electronics Conference and Exposition (APEC)Future electric vehicle chargers should feature full nominal output power in single-phase (1-Phi) and three-phase (3-Phi) operation, such that they can be employed in the USA as well as in Europe. Further, the converter system should have buck-boost capability to cover a wide DC output voltage range in order to provide compatibility with various nominal battery voltage levels. The phase-modular Y-Rectifier consists of three buck-boost ...Conference Paper -
Design and Control of an Active Reset Circuit for Pulse Transformers
(2008)2008 IEEE International Power Modulators and High-Voltage ConferenceIn pulse modulators applying pulse transformers reset circuits are used to achieve optimal utilization of the core material, which results in lower costs, downsized pulse transformer/system volume and therefore in an improved pulse behavior due to the smaller parasitics. Because of its simplicity the most common method to reset the core is a dc reset circuit, where a dc current is used to premagnetize the core. However, the dc reset circuit ...Conference Paper -
Novel AC coupled gate driver for ultra fast switching of normally-off SiC JFETs
(2011)IECON 2010 - 36th Annual Conference on IEEE Industrial Electronics SocietyConference Paper -
Modeling the space elevator - A project oriented approach for teaching experimental power electronics
(2009)2007 European Conference on Power Electronics and ApplicationsConference Paper -
Solid State Modulator for Plasma Channel Drilling
(2008)2008 IEEE International Power Modulators and High-Voltage ConferenceIn addition to conventional mechanical and explosive drilling and demolition, drilling based on the use of pulsed electric power has been investigated intensively and recently commercial applications begin to emerge. With this method, the demolition of the rock is either performed by sonic impulses due to pulse discharges in water or by discharges directly through the rock, called plasma channel drilling (PCD). Due to the direct impact, ...Conference Paper -
A Fast Method for the Calculation of Foil Winding Losses
(2015)2015 17th European Conference on Power Electronics and Applications (EPE '15 ECCE-Europe)Conference Paper