V2G and G2V Using Interleaved Converter for a Single-Phase Onboard Bidirectional Charger

Abstract

This paper presents the design and control of an interleaved buck-boost bidirectional converter for a non-isolated onboard battery charger used in an electric vehicle. The topology of the charger consists of two part: 1) an AC-DC inverter and 2) a DC-DC buck-boost converter. A bidirectional ac-dc converter will work in two modes, rectifying mode for G2V and inverter mode for V2G. The proposed topology of the charger is not only having bidirectional power flow capability but also providing power quality control to the utility grid. The beauty of this is concept is that the vehicle’s battery is not negative impacted while reactive power operation as the energy of the battery is not taken. Emphasized in this paper, a DC-DC converter work in two modes: buck mode for charging the battery and boost mode for discharging the battery power and injecting this power to the grid by the mean of the single-phase inverter. For G2V operation, the bidirectional dc-dc converter is controlled to work in a buck mode to bring down the voltage of the dc-link and to charge on the battery with either a current constant or voltage constant depending on battery’s SoC. In the boost mode-V2G, the converter is working in a boost mode to step up the voltage of the battery and discharge the energy into the dc-link by using interleaved boost converter with 180° phase shift for reducing the current ripple and the inductor size. The bidirectional buck-boost converter has been engineered and its control has been verified through PSIM. The simulation results have shown that the proposed converter and its control work perfectly for the G2V application.