Comparison of high power non-isolated multilevel DC-DC converters for medium-voltage battery storage applications

In this paper 4-level neutral-point-clamped (4L-NPC), 4-level flying-capacitor (4L-FC) and 4-level neutral-point-clamped Ćuk (4L-NPC-Cuk) converter topologies for multilevel DC-DC buck-boost converter for medium-voltage battery storage applications are compared with respect to efficiency and power density. The comprehensive comparison is performed with multi domain models and optimization procedures. For the converters, pareto-fronts are calculated for different operating frequencies in order to find the optimal design with respect to the specified minimum efficiency.