High-Power Planar Transformer Design for Four-Port Converters

This paper analyzes a high-power planar transformer designed for GaN-based bidirectional DC-DC four-port converters. The multiport configuration introduces challenges in achieving uniform magnetic coupling among the windings as their number increases. This study addresses these magnetic design complexities, proposing solutions to enhance power density and magnetic coupling while minimizing core losses. Interleaving and flux path management designs are applied to develop a planar transformer featuring four windings with a 3(400)/800V and 3(5kW)/15kW rating. Finite Element (FE) simulations validate the design's performance, and experimental evaluation of a fabricated prototype confirms its magnetic characteristics.