A 98.7% Efficient Composite Converter Architecture With Application-Tailored Efficiency Characteristic

A dc-dc boost composite converter architecture is introduced that can lead to optimized efficiency over a range of operating points dictated by the application requirements. The composite converter system employs dissimilar modules to minimize the ac power losses in the indirect power conversion paths. It is composed of three converter modules: buck converter, boost converter, and a dual active bridge converter that operates as a dc transformer (DCX). Each module processes partial power, with reduced voltage rating. With the same semiconductor area and same magnetics volume, substantial efficiency improvements and reductions in capacitor size are achieved relative to a conventional boost architecture. It is possible to design each module to optimize efficiency over a wide operating range, including pass-through modes that exhibit very low loss. A 10-kW boost composite converter is experimentally demonstrated having 98.7% efficiency at a critical partial power point, with similar very high efficiencies achieved over a wide operating range.