To meet the charging and discharging requirements of electric vehicles

a bidirectional LC resonant DC-DC converter with a wide voltage range was proposed. Compared with the conventional full-bridge LC resonant converter

an auxiliary Boost bridge arm was added to the proposed topology. Two high-efficiency operating modes were introduced

namely the charging low gain(CLG)mode and the discharging high gain(DHG)mode. In the CLG mode

the converter was operated as a full-bridge resonant PWM converter to achieve step-down conversion. In the DHG mode

the boost arm was employed for energy storage to increase the voltage gain. Soft-switching operation was achieved over the entire load range in both operating modes. In addition

the converter was operated at a fixed switching frequency

which simplifies the design of magnetic components. The proposed converter exhibits low magnetizing current and reactive current

resulting in improved efficiency. The resonant capacitor has low voltage stress

and the gapless transformer features low leakage magnetic flux

which contributes to high power density. An experimental prototype with a battery voltage range of 250-400 V and a high-voltage DC bus of 380 V was built

and the experimental results verify the feasibility of the proposed converter for achieving efficient bidirectional power transfer over a wide voltage range.