Study of the decoupling magnetic integrated high‐frequency transformer for DC/DC converter

Abstract

The isolated DC/DC converter plays an irreplaceable role in the development of the DC microgrid. However, the multiple discrete high‐frequency transformers occupy considerable volume in power converters due to the connection of multiple isolated converters. In order to reduce the number of discrete transformers and increase the power density as well as the reliability of the power converter, a three‐port isolated DC/DC converter with a decoupling magnetic integrated high‐frequency transformer (DMIHFT) is proposed for the DC microgrid in this paper. The semiconductor count of the proposed converter is reduced by combining one DAB converter and two LLC converters. Three discrete transformers are integrated into a single common core, and magnetic decoupling is achieved among each transformer by rational design at the same time. In addition, the magnetic circuit model derivation process of the proposed DMIHFT and the operation principles of the converter are described in detail. The design guidance of the proposed DMIHFT is present. And then, a 15 kW/20 kHz DMIHFT is designed based on the design guideline, and the simulation is carried out. Finally, a 15 kW/20 kHz DMIHFT prototype is fabricated, and the effectiveness of the proposed DMIHFT is verified by experimental results.