Tuesday, 1 September 2020 1:00 PM ET
Presenter: Juan Rivas, Stanford University, USA
Abstract: With the commercialization of wide-bandgap power semiconductors, multi-MHz switching frequencies are more compelling and critical to meet new applications demanding leaps in power density and efficiency. In the past, studies of these converters reported significant gaps between measured and modeled performance, often attributed to dynamic RDS, ON in GaN HEMTs. In particular, the power semiconductors – which often drive thermal constraints – dissipated much more power than expected, rendering designs based on simulated values unusable. In soft-switched converters, which dominate at MHz frequencies, the semiconductor’s output capacitor is resonantly charged and discharged once per switching cycle. Recently, multiple papers have found significant losses from this process in silicon and wide-bandgap devices, explaining the unexpected power dissipation. With these losses known, the MHz-frequency design space can be reopened – if designers are careful about semiconductor selection. In this webinar, we will give the audience the tools to select the right device across material (GaN, SiC, or Si), device technology (super junction or trench), size (lower RDS, ON is not always better), and, in some cases, manufacturer. Further, we showcase how this selection drives thermal design, input voltage selection, and novel circuit topologies in a variety of high-performance demonstrations from 6.78 MHz all the way to 40.68 MHz.
Biography: Juan Rivas is an Assistant Professor at Stanford’s Electrical Engineering department. Before, he served as an Assistant Professor at the University of Michigan and worked for GE Global Research in the high-frequency power electronics group. He has extensive experience in the design of dc-dc power converters working at MHz frequencies. He has published peer-reviewed work on power converters reaching up to 100 MHz using Si and WBG devices. He obtained his doctoral degree from MIT in 2006. His research interests include power electronics, resonant converters, resonant gate drive techniques, high-frequency magnetics, and finding new applications for power converters.
Friday, 11 September 2020 10:00 AM ET
Presenter: Helen Cui, University of Tennessee, USA
Abstract: Magnetic material and component structures that favor the trend towards planarization, chip-scale integration, and novel magnetic packaging become the most promising direction of facilitating the development of future power electronics and RF systems. However, conventional design and modeling of magnetic components largely reply on behavioral-level regression methodologies that are inadequate to provide theoretical guidance and feasibility for advanced applications. This talk starts from the external characteristics of magnetic components, and then shifts from macroscopic performance to microscopic behavior for magnetic materials in order to reveal the hierarchy of interactions between material properties and component applications. The modeling techniques not only provide powerful tools for analyzing magnetic-related issues in the next generation of high-frequency and high-density power electronics with wide-bandgap devices; but also inspire cross-disciplinary applications such as magnetic-molded packaging, ferromagnetic-resonance wireless power transfer, and multiferroic antennas.
Biography: Helen Cui received the B.S. degree in electrical engineering from Tianjin University, Tianjin, China, in 2011, and the M.S. and Ph.D. degrees from Virginia Tech, Blacksburg, in 2013 and 2017, respectively, both in electrical engineering. She is currently an assistant professor at the University of Tennessee since 2020. Before joining UT, she was a postdoctoral scholar in the Department of Electrical and Computer Engineering at UCLA working on RF magnetics. Her research interests include magnetic components for high-density and high-frequency applications; magnetic material modeling in power electronics with wide-bandgap devices.
Advancing Layout Tools to Support High Performance/High-Frequency Electronic Design
Thursday, 24 September 2020 11:00 AM ET
Registration Link coming soon
Presenter: Eckart Hoene, Fraunhofer IZM, Germany
Abstract: Routing power electronic circuits for high-speed switching becomes very tricky, as parasitic effects gain relevance and influence system performance significantly. For example, some parts of the circuit have to be routed with low inductance, others for low coupling capacitance, proximity effects dominate losses, and so on. Although there are tools to calculate these kinds of effects it is not straight forward to use them during the design process. The transfer of the layout data to the calculation tool works seldom without rework and the tools need special knowledge to get the right results. Layout tool integrated evaluation features may offer a way out of this obstruction.In the webinar, the performance relevant parasitics are gathered and ways to handle them in layout tools discussed. Solutions for ohmic losses in arbitrarily formed tracks and inductance are demonstrated.
Biography: Eckart Hoene received his M.S. degree in electrical engineering from Technical University (TU) Berlin, Germany, in 1997. He received his Ph.D. degree on the topic “ EMC of drive systems” from TU Berlin in 2001. He joined the Fraunhofer Institute for Reliability and Micro Integration, Berlin, as a scientific assistant and worked toward his Ph.D. degree simultaneously. He continued at Fraunhofer as a postdoc, group leader, and business development manager. In 2014, he became an adjunct professor at Aalborg University, Denmark, in addition to the courses he chairs for the European Center for Power Electronics and his Fraunhofer affiliation. The technical focus of his work is high switching frequencies in power electronics, packaging semiconductors, and electromagnetic compatibility. His group works mainly under contract with industry customers. He holds more than ten patents and is regularly invited to speak at conferences.
Tuesday, 6 October 2020 11:00 AM ET
Presenter: Jun Wang, University of Nebraska-Lincoln, USA
Abstract: SiC-enabled high-power modular converters for medium-voltage (MV) power distribution systems in naval applications have a great potential to achieve notably higher efficiency and power density than their Si predecessors. Such revolutionary improvement is built upon the resolution of critical challenges comprising gate driving, control and sensing, EMI, high-voltage insulation, and thermal management, in a bottom-up manner from the component level to the power-cell level and finally to the converter level.
This seminar presents systematic design solutions to tackle the aforementioned challenges. Enhanced gate drivers and their power supplies, a bi-directional auxiliary power network, and synchronous distribution control systems have been proposed to address low-power-level concerns; a switching-cycle control approach for passive component reduction, a shielded laminated dc-bus, and a partial-discharge-free insulation design method have been proposed to handle high-power-level issues. The electromagnetic interference, as an ubiquitous issue involved in all the designs above, has been carefully contained and mitigated by proposed shielding and coupling minimization techniques. All the solutions have been successfully validated on converter platforms operating continuously with switching transients up to 100 V/ns.
Biography: Jun Wang (S'13-M'17) received his B.S. and M.S. degrees from Zhejiang University, Hangzhou, China, in 2007 and 2010, respectively; Ph.D. degree from Virginia Polytechnic Institute and State University (Virginia Tech), Blacksburg, VA, USA, in 2017, all in Electrical Engineering.
From 2010 to 2012, Dr. Wang was with GE Power Conversion, Shanghai, on design, integration, and testing of medium-voltage tens-of-megawatt variable-frequency drives and grid-interfaced converters. From 2018 to 2020, he stayed at the Bradley Department of Electrical and Computer Engineering and the Center for Power Electronics Systems (CPES), Virginia Tech, as a Research Assistant Professor. In August 2020, he joined the Department of Electrical and Computer Engineering at the University of Nebraska-Lincoln (UNL) as an Assistant Professor. His research interests include modeling, control, and design of SiC-based medium-voltage modular power conversion systems for grid and transportation applications.
Wednesday, 28 October 2020 8:00 AM ET
Presenter: Wei Xu, Huazhing University of Science and Technology (HUST), China
Abstract: The seminar aims to share the advancements in the linear induction machine topologies, integrated modeling, multi-objective optimization techniques, and high-performance control strategies applied in transportation, such as linear metro, low-speed maglev, and so on. Researchers and engineers from electrical, mechanical, and information fields may find it useful when dealing with transportation motor and drive related design, optimization and control development, etc., which can be extended to other industrial applications.
Biography: Wei Xu (M’09-SM’13) One Full Professor with Huazhong University of Science and Technology (HUST), China. His research topics focus on design and control of linear machines and drive systems. He made Postdoctoral Fellow with UTS, Vice-Chancellor Fellow with RMIT, JSPS Invitation Fellow with Meiji Univ. during 2008-2013, respectively. He has 100+ papers accepted or published in IEEE Transactions Journals, three books published by Springer or China Machine Press, and 130+ Invention Patents granted or pending. He is a Fellow of the Institute of Engineering and Technology (IET), Chapter Chair for IEEE IES Wuhan Chapter, and Associate Editor for 6 IEEE Journals, and will serve as General Chair for LDIA 2021 and PRECEDE 2023, Wuhan, China, respectively.