Non-Traditional Design and Experimental Validation of a Central-Tapped MFT for High-Efficiency DC-DC CT-PSFB Converters

Current applications in photovoltaic power generation and energy storage require isolated, efficient, and reliable DC-DC converter topologies. However, the design of the nanocrystalline-core medium-frequency transformer (MFT), as a key element of these isolated topologies, often overlooks the impact of specific operating conditions, such as non-sinusoidal input signals and variations in total harmonic distortion (THD). This work introduces an innovative design method customized for a high-efficiency Central-Tapped medium-frequency transformer (CT-MFT) integrated into a SiC-based central-tapped phase-shift full-bridge (CT-PSFB) converter. Unlike earlier proposals, this work considers key parameters in the transformer design, including non-sinusoidal excitation waveforms and changes in THD during converter operation. After the CT-MFT is designed, the CT-MFT/CT-PSFB structure is simulated and validated using a tailor-made prototype. The experimental results confirm the structure’s effectiveness: the CT-MFT achieves 99.65% efficiency, and the CT-PSFB achieves 94.7% average efficiency, with THD up to 22.5% and 97.66% peak efficiency.