Circuit Design Techniques for Reducing the Effects of Magnetic Flux on GaN-HEMTs in 5-MHz 100-W High Power-Density LLC Resonant DC–DC Converters
Akinori Hariya ; Tomoya Koga ; Ken Matsuura ; Hiroshige Yanagi ; Satoshi Tomioka ; Yoichi Ishizuka ; Tamotsu Ninomiya


This paper presents circuit design techniques for reducing the effects of magnetic flux, occurred from the planar transformer, on gallium nitride high-electron-mobility transistors (GaN-HEMTs) in 5-MHz 100-W high power-density LLC resonant dc–dc converters. For investigating the effects of magnetic flux on a GaN-HEMT, power device model for finite element method (FEM) simulation is proposed. In order to confirm the validity of the model, the quantitative evaluation is conducted with FEM simulation, and experiment using evaluation boards. Moreover, the optimization of printed circuit board layout is considered using the verified model with FEM simulation, for reducing the effects of magnetic flux on GaN-HEMTs while reducing the area of converter. In the experiments, 5-MHz 48 V/12 V 100 W unregulated LLC resonant dc–dc converter with efficient power conversion GaN-HEMTs is built as the prototype to verify the optimized layout. The maximum power efficiency can be achieved 91.28%, and the power density can be achieved 32 W/cm3.

Published in: IEEE Transactions on Power Electronics ( Volume: 32, Issue: 8, Aug. 2017 )
Page(s): 5953 – 5963

Date of Publication: 11 October 2016

ISSN Information:
Print ISSN: 0885-8993
Online ISSN: 1941-0107
DOI: 10.1109/TPEL.2016.2616439
Publisher: IEEE
Sponsored by: IEEE Power Electronics Society

IEEE Keywords

Magnetic flux, Copper, DC-DC power converters, Finite element analysis, Magnetic noise, Magnetic shielding, Integrated circuit modeling

Author Keywords
planar transformer, Finite element method (FEM), gallium nitride high-electron-mobility transistor (GaN-HEMT), high power-density dc–dc converter, MHz-level switching frequency