High Efficiency High Power Density Cellular 1MHz 380V-12V DCX for Future Data Centers

The requirement for high efficiency high density isolated DC/DC converters with low output voltage and high output current is becoming more and more critical in future performance-driven data center power architectures. To improve the power density of the converters, the switching frequency has been improved to megahertz to reduce the volume of passive components, where the series resonant converter (SRC) is popular for its good soft-switching characteristics. However, the thickness of the transformer core is still large for a 12V/turn design at 1MHz frequency due to the restriction of the core loss density, which restricts the further improvement of the power density. In this paper, a low-profile transformer based on the multi-window EI core is achieved and the winding loss is optimized. A cellular 380V-12V 1MHz DCX prototype using the optimized power transformer is built for verification, where the peak efficiency has attained 98.4% and power density improved to 1.8kW/in3 with 97.0% efficiency at full load in the current experimental results.