28W/cm³ high power density three-port DC/DC converter cell for dual-voltage 12-V/48-V HEV subsystem

Realizing both of compact and low energy consumption is technical issue on development of electricity-rich automotive subsystems. In the present work, a 12-V/48-V dual-voltage subsystem using three-port DC/DC converter cells is proposed, and the high power density cell design is studied to achieve ultra-compact subsystem in hybrid-electric-vehicle. A 500W, 400 kHz prototype is developed with GaN FETs, and its efficiencies are evaluated. The prototype achieves power density of 28W/cm³ at rated power, and its efficiency is measured more than 91% over a wide output power range, with a maximum efficiency of 93.7%.