A Three-Port LCC Resonant Converter for the 380-V/48-V Hybrid DC System

The dc power distribution has become a promising solution to powering datacenters, which can reduce power conversion steps and total power losses. However, both of the two most promising options, 380 V and 48 V dc power distributions, have their own defects that cannot be ignored, such as 380 V dc power distributions have lower reliability and 48 V dc power distributions have lower efficiency. In this article, a three-port
LCC
resonant converter is proposed to eliminate the above-mentioned defects by combining the aforementioned dc distributions to form a 380-V/48-V hybrid dc system. A full-bridge
LCC
converter is used to transfer power to the 380 V load, whereas a bidirectional
LCC
converter is used to charge the 48-V battery packs, and the two are magnetically coupled by a three-port transformer. The converter realizes zero-voltage switching of all switches and zero-current switching of rectifying diodes through resonance. The battery charging current is controlled by changing the frequency of all switches to achieve the switch of constant-current charging and constant-voltage charging, and the phase-shift control is adopted to keep the output voltage constant. Simulations and experiments are carried out to verify the validity of the theory.