Zhejiang University  

 Title：Power Electronics for Data Center Industry-Status and Future        

Abstract:

Data centers consume 2% of the world’s electricity with continuing growth. The power supply system plays a significant role in data center energy efficiency and decarbonization. The development of power electronics brings opportunities for more efficient and reliable data centers. An overview of the data center power supply systems will be made by covering the power delivery path from the grid edge to onboard Point-of-Load conversion. The system architectures are introduced with respect to efficiency and reliability. The power conversion stages of the data center power supply system are discussed as AC-DC conversions and DC-DC conversions. State-of-the-art techniques in topology, control, and device are investigated. This presentation hopes to inspire researchers to advance the data center power supply technology to realize sustainable development goals. 

Biography: 

Prof. Mark Dehong Xu received a Ph.D. degree from the Department of Electrical Engineering of Zhejiang University in China in 1989. He used to be a visiting professor at the University of Tokyo, Virginia Tech, and ETH. He is presently a distinguished professor and director of the Power Electronics Institute at Zhejiang University, China. 

His research interest includes modeling and control of power electronics circuits and systems, renewable energy systems, and power supplies for data centers. He has authored 16 books and over 300 IEEE Journal or Conference papers. He holds over 50 patents. He received seven IEEE journal or conference prize paper awards. He is IEEE Fellow in 2013. He is IEEE PELS Distinguish Lecturer from 2015-2016. He received the IEEE Power Electronics Society R. D. Middlebrook Achievement Award in 2016.

He is a Co-Editor-in-Chief of the IEEE Open Journal of Power Electronics and an Associate Editor of IEEE Transactions on Power Electronics. He is the honorable president of the China Power Supply Society. He currently serves as Vice-President Membership of the IEEE Power Electronics Society.

 Texas Instruments            

 Title：Challenges and opportunities in automotive power electronics            

Abstract:

The auto industry is experiencing incredible changes that impact and are impacted by power electronics. Vehicle electrification, automated and assisted driving systems, and infotainment advances are just a few. This presentation provides a high-level overview of challenges and opportunities of automotive power electronics. Auto makers and suppliers often desire to reduce size, decrease cost, and increase performance of power electronics systems. Three examples that demonstrate the challenges and opportunities are explored in further detail. They cover high density, on-board chargers, low EMI isolated bias supplies, and power delivery architectures in current and future vehicles.

Biography: 

Pradeep Shenoy leads Texas Instrument’s Power Design Services team focused on the automotive market. Pradeep has over 15 years of experience in power electronics working on projects ranging from solar energy conversion to electric vehicle battery chargers. He has served in several roles in the IEEE Power Electronics Society and the Applied Power Electronics Conference (APEC) organizing committee. Pradeep obtained the B.S. degree from the Illinois Institute of Technology, Chicago, and the M.S. and Ph.D. degrees from the University of Illinois, Urbana-Champaign. He received various awards including the Illinois International Graduate Achievement Award in 2010, the Jack Kilby Award for Innovation in 2015, and the IEEE Richard M. Bass Outstanding Young Power Electronics Engineer Award in 2020.

 Chongqing University            

 Title：Stability Analysis and Control of Grid-Connected Power Electronic Converters

Abstract:

Power electronic converters (PEC) have been widely used in photovoltaic power generation, wind power generation and other new energy sources, HVDC transmission as well as multi-electric aircraft. A plenty of PECs integrated into the power system show distinct strong nonlinear characteristics such as multi-time scale dynamic and multi-variable interaction, resulting in multiple oscillation accidents, which seriously threaten the safe and stable operation of the power electronic grid-connected system. The oscillations in power electronic grid-connected system are characterized by multi-harmonics, wide band, and time-varying. Relying on the oscillation accidents in the actual projects, this report focuses on the sustained oscillation mechanism and mathematical model, grid-connection adaptability with fluctuating conditions, frequency-coupled broadband impedance measurement and stability control strategy, to explore the stable operation mechanism and control method for power electronics grid-connected system.

Biography: 

Xiong Du received the B.S., M.S., and Ph. D. degrees from Chongqing University, China in 2000, 2002, and 2005 respectively, all in the Electrical Engineering, where he is currently a Full Professor and Vice Dean in the School of Electrical Engineering. He was a recipient of the National Excellent Doctoral Dissertation of P.R. China in 2008. He is currently serving as the Vice Director of China Power Supply Society (CPSS). He was supported by the National Science Foundation of China for Distinguished Young Scholars.

Prof. Du was a recipient of the Provincial/Ministerial Natural Science First Prize, Second Prize and Third Prize respectively and was a recipient of the Distinguished Young Scholars by CPSS. His current research interests include the reliability assessment and stability control for AC/DC hybrid power electronic system. He holds six the National Natural Science Foundation projects. He has published more than 100 academic papers and holds more than 20 issued/pending patents.

 Institute for Systems and Computer Engineering Technology and Science (INESC TEC)          

 Title：Optimizing Multilevel Single-Phase Converters with Cascaded-Transformer Systems         

Discover the advantages of a multilevel single-phase converter based on cascaded-transformer systems.  The integration of well-known multilevel cascaded H-bridge and transformer-based solutions is investigated to optimize the synthesized voltage levels without excessive transformer usage. The proposed converter features six two-level IGBT legs, injection transformers, and dc links, providing reduced semiconductor losses for high-voltage and low-current applications. The proposed configuration is compared with other converter based on cascaded-transformer, showcasing its interesting features. Experimental and simulation results validate the feasibility of the system.      

Biography: 

Nayara Brandão de Freitas is a power electronics researcher from Campina Grande, Brazil. She received her B.S., M.S., and Ph.D. degrees in electrical engineering from the Federal University of Campina Grande (UFCG) in 2015, 2016, and 2020, respectively. From 2020 to 2021, she  

worked as a Postdoctoral Researcher at UFCG. Currently, she holds the position of Assistant  Researcher at the Institute for Systems and Computer Engineering, Technology and Science  (INESC TEC) in Porto, Portugal. Nayara Brandão de Freitas is also the Chair of the IEEE Power  

Electronics Society (PELS) Students and Young Professionals Committee (S&YP) and previously served as the PELS Student Membership Chair from 2018 to 2020. Her research interests primarily  revolve around power electronics and electrical drives.         

 Delta (Shanghai) Power Electronics Design Center         

 Title： LLC-SRC Converter and New Challenges           

Conventional DC/DC converters including PWM converter and resonant converter usually features higher efficiency at lower input voltage but lower efficiency at high input voltage operation condition.  LLC Series Resonant Converter (LLC-SRC) is a very unique converter that can achieve higher efficiency at higher input voltage while operating the primary switch at ZVS condition and operating the secondary rectifier at ZCS condition. With these features, the LLC-SRC converter can achieve the design of a power supply with the highest efficiency at normal operation based regular 2-stage architecture with Boost PFC as pre-stage regulating the dc bus voltage typically at 400Vdc for normal operation condition. and meanwhile it can also achieve high density design of the power supply by increased switching frequency with whole load range soft-switching feature. Thus LLC-SRC converter had been widely used in last decades for switching power design. The author will firstly give an overview of the LLC-SRC converter features and applications for high efficiency and high density design of adapter, server power and automotive chargers and etc. and then discuss the new challenges of LLC-SRC for high frequency operation up to MHZ switching and for extra wide output voltage range application such as PD charger and charger for electric vehicle and etc.

Biography: 

Dr. Alpha J. Zhang is currently the Director of Delta Shanghai Design Center and Delta Hangzhou Design Center.  

He had been with Electrical Engineering Department of Zhejiang University since he received the Ph. D degree in Power Electronics in 1991.  He was a vice-director of Power Electronics Research Institute of Zhejiang University and a vice-director of State Key Lab on Power Electronics at Zhejiang University from 1993 to 1997.  He was a visiting professor of CPES at Virginia Tech. in 1995 and 1998.

He joined Delta Electronics (Shanghai) Co., Ltd. in 1999.  He is the founder and Director of Delta Shanghai Design Center since 2002, and the founder and Director of Delta Hangzhou Design Center since 2007.  His working area includes high frequency power electronics and high efficiency and high density power converter design for adapter, server and data center, to automotive charger and renewable energy system. He owns 108 US patents and 133 China patents.  

He is an IEEE Senior Member and a member of PELS Magazine Advisory Board and a member of PELS Industry Advisory Committee. He is currently a vice-president of China Power Supply Society.

 Power Device Works, Mitsubishi Electric Corp.       

 Title： Development status of upcoming SiC power chips and modules

Abstract: 

This talk provides challenges that SiC devices are facing today and latest development status of the upcoming SiC power chips and modules.  To begin with, SiC features will be addressed. Compared with widely used silicon devices, SiC provides superior performance like lower losses and higher switching capabilities.  To fully utilize these merits, in-depth consideration is required since the nature of compound semiconductor is totally different from that of silicon, like crystals and epitaxial layer defects, strong electric field inside the device, and very high switching speed.  Mitsubishi Electric has a strong SiC experience of overcoming these challenges, resulting in such examples like high-speed bullet trains.  Then, the latest chip development, like high-performance trench MOSFET and SBD-embedded MOSFET will be addressed.  Utilizing these chips, SiC power modules for various applications like industry, renewables, and automotive will also be discussed.

Biography: 

Dr. Kondo received the B.S., M.S., and Ph.D. degrees from Osaka University, JAPAN. 

In 1985, he joined Mitsubishi Electric Corporation. In her LSI R&D Laboratory, he had been engaged in the design of large-scale chips for digital communication like Ethernet.  

In 2003, he moved to the Optical and High-frequency Device Works, where he had been worked on high-speed Optical Transceiver development.

Since 2009, he has been working at Power Device Works for the development of DIPIPM™, Industrial modules, and high-voltage modules for railway and electric power applications including silicon IGBT and SiC MOSFET. 

He is currently the Senior Technical Advisor at Power Device Works, Mitsubishi Electric Corporation.

He is now participating in the IEC white paper project “Power Semiconductors for an Energy-Wise Society” as an expert member.