Reconfigurable Type I and Type II Buck-Boost Partial Power Converter for EV Fast Chargers

Abstract

This work introduces a reconfigurable topology for AC-link partial power converters (PPC), intended for use as high-frequency transformerless regulated DC-DC converters in fast charging stations for electric vehicles (EV). This new topology allows an AC-link PPC to be reconfigured so that it works as a type I PPC during boost mode and as a type II PPC during buck mode. The converter is able to operate across a wide output voltage range, making it compatible with the different battery voltage configurations found in the electric vehicle industry. The converter is reconfigured using four additional switches. Depending on the operating mode, these switches can be turned on or off to achieve the desired topology. In a type I PPC configuration, the input is connected in parallel, and the output is connected in series with the battery. In a type II configuration, the input is connected in series, and the output is connected in parallel with the battery. This paper presents an analysis of converter operations and control for EV charging systems operating at 400 V and 800 V, incorporating both operation validation and efficiency metrics derived from simulations.