A Dual Active Bridge based Wireless Power Transfer System for EV Battery Charging Controlled Using High Speed FPGA

In this paper, a Dual Active Bridge (DAB) based fast charging system is designed for multiple port Electric Vehicle (EV) charging which are simultaneously feeding the three EVs rated for different powers using a common DC link voltage. In the proposed system, the transformer coil is operated as inductive coil for wireless power transfer. In which primary coil with capacitive compensation is located at source end and secondary coil with capacitive compensation placed at moving EV. However in the proposed system, the Li-ion batteries of three different duty EV are charged from the combination of Constant Current Constant Voltage (CC-CV) strategy. Based on the sensed State of Charge (SOC) level, the CC-CV mode is controlled through two separate PI controller by controlling the receiver end buck converter. The proposed system delivers 25 kW, 100 kW and 600 kW power to charge the 15.5 kWh (low duty EV), 60 kWh (medium duty EV) and 375 kWh (high duty EV) battery respectively in 30 min from 0 to 80 % SOC. The simulation results obtained using MATLAB are in accordance with the commercial guidelines for the battery charging operation. Detailed simulation results are provided thereby exploiting various aspects of the proposed charger. For hardware controller implementation, FPGA Virtex - 5 is used here.