Multi-objective optimization and design of a 500kHz isolated bidirectional DC-DC converter

The performance of the conventional isolated bidirectional DC-DC converters is limited in terms of the power density and efficiency at low voltage high current condition. A scalable multi-core based bidirectional DC-DC converter topology with multiple high frequency transformers and high current low voltage side full bridges is proposed for this application. The converter is switching at 500kHz. To address the performance issue, multi-objective optimization based design approach is used to identify the best topology structure and to obtain the best efficiency and power density, based on a few constraints. The low voltage building block and transformer design, and topological architecture of the converter are optimized. A 400V to 12.8V/100A prototype was build. 5.1kW/L power density and 96.0% peak efficiency were achieved.