Power density and efficiency enhancement in impedance control network resonant DC-DC converters using topology morphing control

This paper introduces a new voltage regulation scheme for impedance control network (ICN) resonant dc-dc converters in which the rectifier of the ICN converter alternates between full-bridge and half-bridge topologies. Compared to the conventional burst-mode control, this topology morphing control approach substantially reduces the output capacitance requirement in ICN converters and improves partial-power efficiencies. A prototype 1-MHz, 120-W step-down ICN resonant converter designed for an input voltage range of 18 V to 36 V, an output voltage of 12 V, and a 10:1 output power range has been designed, built and tested with both burst-mode control and the proposed topology morphing control. The topology morphing control reduces the output capacitance requirement in the prototype ICN converter by over 36%, and reduces converter losses at partial power levels by up to 46.5%.