Abstract-This paper presents the design of a 100kW DC/DC
converter that transfer energy from/to two 125V-supercapacitor
stacks to/from a 560V DC line that is attached to a three-phase
inverter. The converter provides galvanic isolation between the
560V DC line and the supercapacitors. In one power flow
direction, it works as a step-up DC/DC converter that maintains
the DC voltage at 560V by delivering energy from the
supercapacitors, and in the other direction it works as a current
source to charge the supercapacitors. The proposed design is a
two-stage converter: a series resonant converter that raises the
supercapacitor voltage by four and provides isolation, and a halfbridge
converter that maintains the output voltage by adjusting
the step-up process. Experimental results are presented. The
efficiency of the whole converter is higher than 91% at input
currents up to 500A.