Design and Implementation of a Bidirectional DC-DC Converter for Electric-Vehicle Applications

Electric Vehicles are the future which helps in reducing the carbon emissions and provide a sustainable transport alternative. The feasibility and performance of an Electric Vehicle is affected because of its costly Battery Management System and heavy space consuming battery packs. This paper proposes a cost-efficient and reliable method of replacing the external battery packs with a single 4V cell parallel architecture of a bidirectional buck-boost converter, bucking 48V to 4V and boosting 4V to 48V. Bidirectional DC-DC power converters are used in applications that needs the power to flow in both forward and reverse direction. In this application, the power flows from the battery to motor drive for smooth control of the motor in motoring mode, while in regenerative mode, power is fed back to the battery from the motor and helps in charging the battery with the stored motor energy. The proposed converter is designed for a nominal power rating of 100W and a target efficiency of more than 80%. The conversion is implemented in two cascaded stages to achieve higher efficiency as compared to a single non-isolated converter stage. This paper details the complete design and implementation of the proposed converter. LM5170 controller is used for the application and closed-loop operation is validated at different loading conditions. Results depicting the working of circuit in buck mode are presented.