Evaluation of a high-power three-phase dual active bridge DC-DC converter with three-level phase-legs

Abstract

A three-phase dual active bridge (DAB) converter with three-level phase-legs is analyzed, showing an increased soft-switching region and a reduction in rms current in the ac-link for unequal input and output voltages compared to the conventional two-level circuit. Furthermore, a comparison of the semiconductor losses is carried out for different three-level inverter implementations using commercially available silicon (Si) and silicon-carbide (SiC) power modules. The lowest losses are found for the T-type implementation with a combination of SiC and Si power modules. Experimental results, obtained from a high-power prototype, are included to support the evaluation of the three-level three-phase DAB.