A Compact 700kHz 1.8kW GaN-based Transistor Low Voltage High Current DC-DC Converter for xEV using Planar Matrix Transformer

This paper presents a technique to achieve a high power density of a 1.8kW low output voltage, high current DC-DC converter for xEV application. Using a GaN-based transistor at 700kHz switching frequency, the size of the passive component can be greatly reduced. The concept of matrix planar transformer with flux cancellation is applied, resulting in a reduction of the transformer size. Topologies evaluation are performed to select the most suitable topology for achieving the size specification, and a phase-shift full-bridge converter with current-doubler rectifier is selected. A 5.63kW/L(92W/in³) power density is achieved. Simulation and experimental results from the proposed converter system prototype are provided.