A Smooth Mode-Switching Strategy for Bidirectional OBC Base on V2G Technology

Abstract

Vehicle to grid (V2G) technology uses electric vehicles (EVs) as energy storage devices for the power grid along with peak cutting and grain filling function. The bidirectional converter plays an essential part in V2G technology since it allows energy to flow in both directions based on the grid dispatching signal. However, in two-stage bidirectional on-board-charge (OBC) with CLLC circuit, traditional frequency conversion control can not achieve smooth mode-switching, so that the OBC can not response to the power grid dispatching signal quickly. In this paper, a control strategy combining frequency conversion control and phase-shifting control is proposed, which can realize smooth mode-switching of CLLC circuit. The control strategy is validated by a 3kW two-stage OBC prototype integrating Totem-pole and CLLC circuit.