Design of a Novel Medium-Frequency Coaxial Transformer for Modular Isolated DC/DC Converter

This paper proposed a novel medium-frequency coaxial transformer design method to solve the high voltage insulation problem between the high voltage side and low voltage side windings in DC/DC converters. Considering the actual situation in all-DC offshore wind farm, a medium-frequency coaxial transformer for modular isolated DC/DC converter (MIDC) is designed. At first, coaxial transformer structure is analyzed and parameter optimization is made in detail. Then, the optimal solution for the coaxial transformer is obtained. Moreover, simulation of transformer temperature field is done with Ansys software. Finally, a rated 250kVA medium-frequency coaxial transformer is set as a design example. The result shows that the optimal transformer volume is 0.0223m
³
with a weight of 47.11kg, and the maximum temperature is 98.5°C under full load working condition, with both the magnetic inductance and the leakage inductance value meet the design requirements. The simulation proves effectiveness and feasibility of the design method proposed in this paper.