Phase Shift Regulated Resonant Switched Capacitor Based Intermediate Bus Converter for 48V Data Center Power System

Abstract

In the two-stage architecture of 48V data center power systems, the front-end intermediate bus converter (IBC) needs to adapt to both 48V nominal input voltage and a wide input voltage range of the backup battery (typically 40V-60V). To cope with this design challenge, we propose a phase shift regulated resonant switched-capacitor-based IBC. At nominal input, it achieves a 4n:1 voltage conversion ratio with an n:1 transformer, and the electrical stresses on primary switches are significantly reduced. Furthermore, zero-voltage-switching does not rely on the transformer’s magnetizing current. Therefore, the magnetizing current can be suppressed to optimize the efficiency. When the backup battery is linked, a phase shift is introduced between the stacked bridges to regulate the wide input voltage. Theoretical analysis and design considerations are provided to showcase the advantages of the proposed concept. A hardware prototype operated at 1 MHz, converting 40V-60V input to stable 12V and maximum 20A output, is designed and tested. Experimental results well validate its exceptional soft-switching and voltage regulation performances. The peak efficiency reaches 97.12% at 48V input and 12V/7A output.

Jiawei Liang (梁家伟)

Ph.D. candidate of Power Electronics

My research interests include switched-capacitor converter, point-of-load converter, and magnetic integration in data center applications.