An Improved Bidirectional dc/dc Converter with Split Battery Configuration for Electric Vehicle Battery Charging/Discharging

Abstract

A bidirectional dc/dc on-board chargers for EV battery charging/discharging application provides a better solution of V2G and G2V compatibility. Isolated converter prefer to deal with high power density at wide load range which is useful in EV application. The bidirectional converter performs the step-up and step-down operation at zero voltage switching for all power switches in both directions. Low voltage or battery side converter is chosen as current source converter to limit short circuit current and effective current rating of the converter. The gain of the converter is offered by input boost converter along with transformer. Additional gain is provided by end side converter with voltage double to synchronize voltage with dc grid or high voltage dc During step down mode, The converter allows a low charging current to charge the batteries. To increase charging current of the battery, the voltage has to reduced with two battery system. During charging of batteries, the split of is done to achieve high charging current. The commutation of switches is achieved at ZVS as soft-switching without snubber circuitry and the voltage across switched clamped naturally. The proposed topology is simulated using MATLAB/Simulink for a 350W battery system.