SiC based on-board EV power-hub with high-efficiency DC transfer mode through AC port for vehicle-to-vehicle charging

This paper is focused on a high-density, bi-directional, 6.6 kW EV power-hub, designed to operate in four distinct modes: 1) Grid-to-Vehicle (G2V), 2) Vehicle-to-Grid (V2G), 3) Vehicle-to-House (V2H), and 4) the more recent Vehicle-to-Vehicle (V2V) operating mode. This study also investigates sending DC power through a conventional 240 VRMS Level-2 AC power port, with all the associated ratings and constraints from the AC design, in order to achieve higher power transfer and efficiency for V2V operation. Using a digital Hysteretic Current Mode Control (HCMC) scheme, the efficiency and loss distribution of four operating modes are analyzed: 1) dc-ac Boundary Conduction Mode (BCM), 2) dc-ac Continuous Conduction Mode (CCM)/BCM hybrid, 3)dc-dc BCM, and 4) dc-dc CCM. The AC design achieves a peak efficiency of 96.6% and an average THD of 3.2%. The peak efficiency of the power-hub is increased from 96.6% to 98.3%, by operating in DC transfer mode for V2V operation, thus increasing the power capability by 50%. Finally, a new low-frequency output voltage commutation scheme is proposed to reduce the peak junction temperature of MOSFETs when operating in V2V dc-dc mode.