Pushing the Limits of Power Density and Efficiency: Nanocrystalline Magnetics for Next-Generation Solid-State Transformers

Mr Sheng Ren, City University of Hong Kong

Abstract: As artificial intelligence reshapes the data center, delivering enormous amounts of power efficiently and within a limited footprint is becoming a challenge in its own right. This is driving growing interest in solid-state transformers (SSTs) as a compact and flexible alternative to conventional power delivery solutions. But making an SST smaller and more efficient ultimately comes down to its magnetic components. Ferrite, the workhorse of high-frequency transformers, faces increasing limitations as size is pushed further. Conventional nanocrystalline materials can shrink the magnetics, but rapidly rising core loss at higher frequencies limits their potential. This talk explores how stress-annealed nanocrystalline materials can push beyond this trade-off. We will discuss how their magnetic properties can be translated into medium- and high-frequency transformer designs, from core loss and leakage inductance engineering to magnetic integration, and demonstrate these concepts experimentally in dual-active-bridge converters. Finally, we will discuss their potential for the next generation of compact, high-efficiency SSTs.

Speaker's Bio: Sheng Ren is currently a Ph.D. student in the Department of Electrical Engineering at City University of Hong Kong. He received his M.Sc. degree in Electrical Engineering from the Institute of Power Electronics at Zhejiang University in 2023 and his B.Sc. degree in Electrical Engineering from Hefei University of Technology in 2019. His research focuses on power electronics, nanocrystalline magnetic materials, magnetic component design, and dual-active-bridge converters, with an emphasis on modeling and optimizing high-efficiency, high-power-density power conversion systems.