Design and implementation of a Central-Tapped Medium Frequency Transformer with nanocrystalline core for high-efficiency DC-DC SAB converters

Abstract

A design methodology for medium frequency transformers, which considers a central tap in its secondary winding, is thoroughly presented in this paper. Topologies such as SAB (Single-Active Bridge), PSFB (Phase Shift Full Bridge), and DAB (Dual Active Bridge) can be implemented using this type of transformer for nowadays applications. The design and implementation of a Central-Tapped Medium Frequency Transformer (CT-MFT) is carried out and it is tested as part of a SAB topology. Differently to other proposals, the equivalent model of the CT-MFT was thoroughly defined and verified in the simulation and a tailor-made design methodology is presented. As result, the CT-MFT prototype achieve 99.49 % efficiency which demonstrate the usefulness and efficacy of the proposed methodology. The experience gained in developing this advanced design procedure opens the possibility of further improving isolated unidirectional and bidirectional DC-DC converter topologies in aspects such as efficiency and reliability.