Pursuing high power-density and high efficiency in DC-DC converters for automotive application

The paper presents an approach to designing automotive converters with main objectives being high efficiency and high power density. The approach is demonstrated by presenting two case study designs and measurements on converter prototypes. The goals of high efficiency and high power density are reached by an optimal converter design including soft switched SAZZ topology, paralleled mosfets, integrated inductors, interleaved converter modules, advanced thermal management and optimized spatial design. The initial goals of the project were to reach as high efficiency as possible and to exceed power density of 10 kW/litre. The power density goal was exceeded by a large margin reaching the power density of 17.7 kW/litre even for air-cooled system. The measured efficiency of a single converter module operating at 200 kHz is as high as 95.4 % and a larger efficiency is still expected from the complete interleaved converter prototype.