The commercialization success of heavy-duty electric vehicles (EVs) is predominantly contingent upon the development of a robust and scalable charging infrastructure. Compared with low-frequency transformers (LFT), modular applications of solid-state transformers (SST) offer a more promising solution for achieving MW-level power scalability in the future. In the DC/DC stage of SSTs, the dual active bridge (DAB) converter is a widely adopted topology. And the optimal modulation plays a crucial role in selecting appropriate switching devices and improving overall efficiency. This paper focuses on the specific case of a 33.3 kW module within the modular charging station for heavyduty EVs, presenting a generalized approach to optimize the current stress of MOSFETs and soft-switching performance. The switching performance of the candidate devices for this case has also been quantitatively discussed and verified to achieve soft switching over a wide load range in PSIM simulation.

The electric vehicle (EV) market is expanding rapidly. However, the main barriers to EV adoption are high vehicle costs, range issues, and charging infrastructure. Meanwhile, energy storage systems (ESS) appear as a promising solution to preventing grid overload during charging and reducing infrastructure costs. In this paper, the integration of the battery energy storage system (BESS) in a 450 kW EV charger is designed and investigated via modeling and simulation mainly from the perspective of thermal management. To explore the heat dissipation and the temperature distribution across the pack, the thermal model based on the sub-modeling technique is developed via COMSOL, and a preliminary layout and cooling strategy are determined.