Direct Electric Vehicle to Vehicle (V2V) Power Transfer Using On-Board Drivetrain and Motor Windings

Abstract

Vehicle to vehicle (V2V) energy sharing is emerging as an alternate solution to range anxiety and limited charging infrastructure challenges associated with electric vehicles (EVs). The existing off-board dc fast charging options for V2V application found in the literature are not effective due to the additional weight, size and cost of the external charger or interface. In this article, a new V2V interface is proposed in which both EV’s motor winding neutrals and negative rails of on-board drivetrains are directly connected to each other. This further helps in forming an integrated dual bidirectional dc–dc converter to control the direction of power flow. The proposed approach does not require reconfiguration of motor winding or mechanical clutch to arrest the motor from rotating and/or the reconfiguration of drivetrain inverter connections. The major hardware requirement for the proposed approach is, access to the already existing neutral connection of the EV motor phase windings. To achieve dc fast charging, all three-legs of voltage source inverter of energy Provider-EV are switched using interleaved pulsewidth modulation. Furthermore, finite element analysis is presented for 150 kW EV motor model and its performance validation with the high frequency dc current flowing in the motor windings during the V2V operation. A scaled lab prototype is developed to demonstrate the energy sharing between two Lithium-ion battery banks through the proposed direct V2V power transfer concept.