Rm. 303b / 14:00-17:00, Sunday, June 4
The GOOGLE Little Box Challenge - Ultra-Compact GaN- or SiC-Based Single-Phase DC/AC Power Conversion

Prof. Johann W. Kolar

Swiss Federal Institute of Technology
Johann W. Kolaris a Fellow of the IEEE and received his Ph.D. degree (summa cum laude) from the Vienna University of Technology, Austria. He is currently a Full Professor and the Head of the Power Electronic Systems Laboratory at the Swiss Federal Institute of Technology (ETH) Zurich. He has proposed numerous novel PWM converter topologies, and modulation and control concepts and has supervised over 60 Ph.D. students. He has published over 750 scientific papers in international journals and conference proceedings, 3 book chapters, and has filed more than 140 patents. He has presented over 20 educational seminars at leading international conferences, has served as IEEE PELS Distinguished Lecturer from 2012 through 2016, and has received 25 IEEE Transactions and Conference Prize Paper Awards, the 2014 IEEE Power Electronics Society R. David Middlebrook Achievement Award, the 2016 IEEE William E. Newell Power Electronics Award, the 2016 IEEE PEMC Council Award, and the ETH Zurich Golden Owl Award for excellence in teaching. He has initiated and/or is the founder of 4 ETH Spin-off companies. The focus of his current research is on ultra-compact and ultra-efficient SiC and GaN converter systems, wireless power transfer, Solid-State Transformers, Power Supplies on Chip, as well as ultra-high speed and ultra-light weight drives, bearingless motors, and energy harvesting.

Mr. Dominik Bortis

Swiss Federal Institute of Technology
Dominik Bortis (M’09) received the M.Sc. degree in electrical engineering and Ph.D. degrees from the Swiss Federal Institute of Technology (ETH) Zurich, Switzerland, in 2005 and 2008, respectively. During his studies, he majored in communication technology and automatic control engineering. After the internship with ABB Switzerland, Turgi, where he developed a power supply with wide input voltage range for synchronizing system, he carried out his diploma thesis in industry at Levitronix realizing a signal processing unit for magnetically levitated pump systems.
      In May 2005, he joined the Power Electronic Systems Laboratory (PES), ETH Zurich, as a Ph.D. student. During his Ph.D. in collaboration with Siemens Medical, Erlangen, he realized a 20MW pulsed power systems for cancer treatment where he investigated on fast pulse generators, current balancing methods for high power IGBT modules and the design of high step‐up transformers with extremely fast pulse rise times. From 2008 to 2011, he has been a Postdoctoral Fellow and from 2011 to 2016 a Research Associate with PES, co‐supervising Ph.D. students and leading industry research projects.
      During this time he gained comprehensive knowledge in power electronics, e.g. in the design of compact and efficient PFC rectifier systems with soft‐switching TCM modulation, the realization of ultra compact inverter systems for the Google Little Box Challenge where the latest power semiconductor technology (SiC and GaN) are employed, the design of future variable speed motor drive systems with PCB‐integrated power semiconductors for electric cars, the realization of a high temperature automotive inverter system or the design of light weight rotating transformers used for the power transfer in advanced high speed spindles applied for ultrasonic assisted grinding.
      In 2010, he founded the ETH Spin‐off company Enertronics GmbH, a consulting company in the field of power electronics system engineering and prototyping. The collaborations with leading international companies allowed him to set up a wide network of industry partners and to gain deep insight into industry demands which is mandatory for the technology transfer from academia to industry.
      Since January 2016 Dr. Bortis is heading the newly established research group Advanced Mechatronic Systems at PES, which concentrates on ultra‐high speed motors, magnetic bearings and bearingsless drives, new actuator and machine concepts, and machine integrated power electronics. In this context, multi‐objective optimizations concerning weight/volume/efficiency/costs, the analysis of interactions of power electronics and electric machines, and EMI are given special attention. Targeted applications include advanced industry automation and manufacturing, e.g. highly dynamic and precise positioning systems, medical and pharmaceutical systems, e.g. ultra‐high purity pumps, and future mobility concepts, including motors and actuators for hybrid and electric vehicles, more electric aircraft and satellites.

Mr. Dominik Neumayr

Swiss Federal Institute of Technology
Dominik Neumayr (S´10) started his academic education at the University of Applied Sciences (FH) for Automation Engineering in Wels/Austria and received the Dipl.‐Ing. (FH) degree in 2008. Starting as an industry internship, Dominik worked at the Center for Advanced Power Systems (CAPS) in Tallahassee/Florida between 2008 and 2011. As a Research Assistant at CAPS, he worked on Power/Controller Hardware‐in‐the‐Loop simulations and control systems design for AC/DC/AC PEBB based converter systems from ABB. In order to strengthen his knowledge in power electronics and control engineering, he continued his academic education at the Swiss Federal Institute of Technology in Zurich (ETH Zurich) and received the B.Sc. and M.Sc. degrees in electrical engineering and information technology in 2013 and 2015, respectively. During the course of his master thesis, Dominik designed and constructed a 25 kW bidirectional, isolated DC/DC converter system based on SiC technology. Since spring 2015 he is a PhD student at the Power Electronic Systems (PES) Laboratory, ETH Zurich. His current research focuses on high power density converter systems.
The GOOGLE Little Box Challenge was aiming to build the worldwide smallest air-cooled 2kVA DC/AC converter, created a huge interest in the power electronics community, and resulted in a massive performance improvement compared to state-of-the-art technology systems. This seminar explains the approach selected by the authors along with a detailed discussion and comparative evaluation of the concepts presented by other finalists. First, the target specifications of the challenge are explained and basic options available for the realization of the main power circuit topology, the buffering of the power pulsation with twice the output frequency, the EMI filter and the modulation and control of the converter stages are discussed. Subsequently, GaN and SiC power semiconductor technology are evaluated for the power switches including hints for accurate soft-switching loss measurements. Furthermore, the realization of high-frequency inductors with multi-airgap magnetic cores and low high-frequency loss winding arrangements is detailed. In this context also the increase of the core losses by mechanical stress resulting from the cutting process is discussed. In a next step, the mechanical designs of several finalists are presented including details of the heat management. Subsequently, the corresponding power density and efficiency figures are comparatively evaluated. Finally, based on a multi-objective optimization “absolute” performance barriers as e.g. resulting for ideal switches are analyzed and technological requirements concerning active and passive components as well as cooling and integration technologies mandatory for enabling further performance improvements are identified. The seminar would like to convey the main results and findings of the GOOGLE Little Box Challenge and is tailored to serve the interests of a broad audience with academic or industrial background.