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

In the two-stage architecture of 48 V data center power systems, the front-end intermediate bus converter (IBC) needs to adapt to both 48 V nominal input voltage and a wide input voltage range of the backup battery (typically 40 V–60 V). To cope with this design challenge, we propose a phase shift regulated resonant switched-capacitor-based IBC. At nominal input, it achieves a 4
n
:1 voltage conversion ratio with an
n
:1 transformer, and the electrical stresses on primary switches are significantly reduced. Furthermore, zero voltage switching (ZVS) 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 40 V–60 V input to stable 12 V and maximum 20 A output, is designed and tested. Experimental results well validate its exceptional soft-switching and voltage regulation performances. The peak efficiency reaches 97.12% at 48 V input and 12V/7 A output.