A Capacitor Coupled On-board Bi-directional Vehicle-to-Vehicle Charging System

In recent times, Vehicle-to-Vehicle (V2V) chargers have gained popularity to transfer the energy between two Electric Vehicles (EV). In this paper, a new direct V2V charger is proposed that uses a capacitor coupling and an on-board DC-DC converter in each EV to enable the energy transfer between them. Importantly, this charger differentiates itself from other V2V chargers by eliminating the requirement for motor winding and inverter circuit from an EV. The charger operation is verified through simulation studies (via MATLAB/Simulink) in three operating modes: Forward Boost, Reverse Buck and Forward Buck-Boost mode for EVs with battery voltage of 350 V and 450 V. The simulation studies are validated through the OPAL-RT Real-Time simulator. The proposed charger achieves an efficiency of 96.57 % in the forward boost mode, 96.56 % in the reverse buck mode, and 96.26 % in the forward buckboost mode of operation at a rated power level of 20 kW, while demonstrating a 25 % to 76 % reduction in component count compared to existing topologies. Further, a laboratory proof of concept is developed and tested with battery voltages of 12 V and 25.6 V in all modes of operation. Experimental results under static and dynamic discharge currents are presented.