Design of a SiC-based LLC Resonant Converter for On-Board Chargers Considering Parasitic Capacitance of Planar Transformer

This paper proposes a resonant parameter design of an LLC converter with a planar transformer for on-board chargers. By comparing three cases of PCB windings, PCB windings to minimize parasitic capacitance are designed. To achieve high efficiency and high power density at the same time, loss of the system and core volume are analyzed considering various combinations of LLC resonant parameters. Moreover, considering the parasitic capacitance of the planar transformer, the minimal value of the turn-off current is designed. A 3.3 kW LLC converter prototype with a planar transformer is built, and the design result is experimentally verified.