High Frequency Investigation of Wide Bandgap-based PFC and LLC Converters in PSU

Abstract:
The commercial Wide Bandgap based devices, Gallium Nitride (GaN) and Silicon Carbide (SiC), have the capability of faster switching and lower on-state resistance than Si MOSFET, and therefore attract lots of interests in the industry. Both GaN E-HEMT and SiC MOSFET can achieve high power density by using high switching frequency. This paper provides a comparison within WBG devices for a high frequency Power Supply Unit (PSU). The PSU consists of a CCM Bridgeless Totem Pole Power Factor Correction (BTP-PFC) AC/DC stage in conjunction with an LLC resonant DC/DC stage. The efficiency, power density and thermal with high switching frequency are provided for a 3KW PSU design.