Analysis and Operation of Two-Stage Isolated ISOP Converter with Partial Power Processing for Fast EV Charging

One of the main challenges in the deployment of electric vehicles (EVs) as a sustainable alternative to conventional fossil fuel-powered vehicles is the need for the fast EV charging infrastructure. To meet the high power requirement of a fast charger that exceeds 300 kW, modular topologies are employed for the fast charging power converter. In this paper, a modular two-stage input-series-output-parallel (ISOP) architecture is proposed for the DC Fast charging unit, providing both isolation and control of EV battery charging. Additionally, a partial power processing converter (PPPC) is used to enhance system efficiency and reduce power rating of the non-isolated converter. The self-balancing of ISOP topology and stable operation of PPPC is ensured by an active resonant voltage balancer (ARVB) optimized for the highest efficiency and the operation in open loop. The paper investigates applied control structure and validates the proposed design using a Hardware-In-the-Loop (HIL) real-time testbed.