Ultra-Wide Voltage Range Bidirectional EV Charger with Topology Morphing Control

Various fast-charging standards, such as megawatt charging systems (MCS) and CHAdeMO 3.0, have specified charging voltages above 1kV. Also, the growing number of battery pack voltages for fast-charging solutions has driven demand for ultra-wide-voltage-range converters. To meet requirements determined by charging trends, an active-clamped dual-current-fed (ACDCF) series resonant topology has been proposed and designed for wide-voltage-range EV charging/discharging operations. This solution features a combination of an active-clamped current-fed configuration and topology morphing control (TMC), enabling an output voltage range of 150V to 1000V, while keeping the voltage stress within limits and allowing the selection of relatively low-voltage switches with low on-state resistance. The TMC also offers a more cost-effective alternative to the reconfigurable converter that uses multiple expensive breakers to achieve wide voltage ranges while maintaining soft-switching over the entire operating range of the proposed topology. The operational study, converter design, and control are briefly outlined, along with the experimental validation of a 3.3kW proof-of-concept prototype. Moreover, the performance of the proposed topology has been tested for 400V and 800V battery systems, yielding promising time/energy-weighted average efficiencies (T/EWAE) of around 95.7% and 96.5%, respectively. Although this design is primarily intended for EV charging, it can also serve as a DC interface for a different range of energy sources and storage technologies.