A Futuristic Silicon-Carbide (SiC)-Based Electric-Vehicle Fast Charging/Discharging (FC/dC) Station

Medium-voltage (MV) grid-connected solid-state transformer (SST)-based fast-charging (FC) stations provide several merits in terms of improved efficiency, power density, current limiting capability, etc. In this article, an MV grid-connected public multiport FC/discharging (dC) station is proposed which not only resembles a refueling station's functionality by simultaneously interfacing all three plug-in electric vehicle (PEV) categories (heavy or hPEVs, medium or mPEVs and light or lPEVs) but also facilitates bidirectional power flow for vehicle-to grid (V2G) applications. The modulation, operational and control schemes of the front-end (FE) MVAC-low-voltage DC (LVDC) single-stage conversion and back-end (BE) dc-dc conversion of the proposed architecture are explained in detail. Hardware-in loop (HIL) test results for full-scale 22 kV, 1 MVA architecture's bidirectional operation verifies the proposed operation and control schemes. The architecture facilitates simultaneous FC/dC of one hPEV within 49.5 min, two mPEVs within 28 min and four lPEVs within 16 min. Finally, a proportionally scaled down 1 kV, 13.2 kVA experimental verification validates the architecture's performance during drastic net power flow change conditions and exhibits a peak efficiency of 96.4% with a power density of 3.2 kVA/L. A comprehensive benchmarking of the proposed architecture with commercially available FC products is also presented.

Automated summary

This article proposes a medium-voltage (MV) grid-connected solid-state transformer (SST)-based fast-charging (FC) station, which offers improved efficiency, power density, and current limiting capability. The architecture functions as a refueling station by simultaneously interfacing all three plug-in electric vehicle (PEV) categories and enables bidirectional power flow for vehicle-to-grid (V2G) applications. The modulation, operational, and control schemes of the proposed architecture are explained, and hardware-in-loop (HIL) tests verify its operation and control. The architecture allows for simultaneous FC/DC for different types of PEVs within specified time durations. A scaled-down experimental verification demonstrates the architecture's performance under drastic net power flow change conditions and provides a comprehensive benchmark comparison with commercially available FC products.