Design and Control of OBC-LDC Integrated Circuit with Variable Turns Ratio for Electric Vehicles

This paper describes the new design and control of on-board charger (OBC) and low-voltage dc-dc converter (LDC) integrated circuit for electric vehicles (Evs), which operates in three modes. That is, it charges the high-voltage battery (HVB) by grid to vehicle (G2V) operation, and it supplies the energy of HVB to grid by vehicle to grid (V2G) operation. Also, the low-voltage battery (LVB) is charged via HVB. In conventional integrated circuit, the additional control is required to deal with the wide range of voltages for HVB operations in all modes. Moreover, it has the limitation to increase the power efficiency. To solve these problems, the new integrated circuit with variable turns ratio of transformer is proposed. Its main operation and design considerations are firstly analyzed. Then, its performance is evaluated by simulation test, and it is compared with that of conventional integrated circuit.