Different Modular Techniques Applied in a Synchronous Boost Converter With SiC MOSFETs to Obtain High Efficiency at Light Load and Low Current Ripple

摘要

This paper is focused on a high-voltage (400 to 800 V) bidirectional converter, which is intended to be used for the interconnection of battery-based energy-storage systems with the cells of a modular multilevel converter, providing distributed energy-storage capability to a solid-state transformer. This converter must have a high efficiency at medium and light load and also a low current ripple due to the charging and discharging processes. This work takes advantage of the use of SiC MOSFETs into a synchronous boost converter to accomplish the previous requirements. First, the adoption of a variable-switching frequency control to keep the efficiency high is analyzed, and second, the use of a modular converter with different control techniques to provide a current ripple reduction is also addressed in this study. An input-parallel-output-parallel synchronous boost converter, made up with three modules (3 kW per module), is used to validate experimentally the advantages of the use of SiC MOSFETs and to compare different control techniques.