Investigating Safe Operation Boundaries of Single-Stage Isolation Based Multi-Outlet EV Fast Charging Architecture

Within the next few decades, the rapid de- carbonization of road transport will be crucial in achieving a carbon-neutral future. Fast charging infrastructures for electric vehicles promise a comparable ‘refuel’ time as ICE vehicles, which makes electric vehicles (EVs) more attractive towards customers. The advancement of power electronics has enabled rapid growth of elec- tric vehicle charging infrastructure (EVSEs) in terms of power levels. However, state-of-the-art EVSEs incorporate multiple galvanically isolated power conversion stages, which result in lower efficiency and significant deployment costs. This work introduces an innovative concept of cost- effective single-stage galvanic isolation based multi-outlet EV fast charging architecture, capable of simultaneous charging. The underlying challenges associated with the proposed architecture, such as insulation measurement and touch current hazards, are investigated while considering the guidelines from international standards (IEC 61851-23:2023, IEC 60479-1,2). Furthermore, a distributed insulation deterioration detection method is provided for the architecture to ensure real-time fault diagnosis. Finally, safe operating boundaries based on the maximum number of simultaneously charging vehicles for different system voltage levels are formulated to further support the applicability of the proposed architecture.