Design Methodology of a Planar Transformer in LLC Converters for High Power Density On-Board Chargers

In this paper, a planar transformer design method for an LLC converter of on-board chargers that can increase power density is proposed. Based on an on-board charger (OBC) using a commercial planar transformer core, the parameters of the planar transformer core and the effect of the pattern arrangement are designed and analyzed through FEM simulation. Through the proposed design, the volume of the transformer can be reduced by 9% compared to the planar transformer with the commercial core.