A new modulation strategy on isolated battery charger with wide input and output voltage range

Abstract

Abstract A new wide voltage operation range isolated battery charger, which is composed of an asymmetric T‐type AC–DC power rectifier and a modified re‐configurable half bridge DC–DC power converter, is proposed in this paper. The asymmetric T‐type rectifier adopts different modulation strategies under different AC bus voltage amplitudes and different battery voltages for increasing power conversion efficiency. As the isolated DC–DC power stage, a modified re‐configurable half bridge converter applies a three‐winding transformer to achieve a wide output operation range. The proposed battery charger operates over a wide AC input voltage range and wide DC output voltage range. A 3.2 kW hardware battery charger prototype is built to adapt AC voltage between 85 and 265 V. Both constant current and constant voltage modes are implemented experimentally to charge the battery up to 6.5 A from 50 to 500 V. The experimental results prove that the proposed asymmetric T‐type rectifier adopts different modulation strategies under different AC bus voltage amplitudes and different battery voltages can increase the power conversion efficiency, the proposed DC–DC converter can output the DC voltage from 50 to 500 V and the proposed battery charger can achieve around 94% efficiency.

Keywords

• AC–DC power convertors
• battery chargers
• DC–DC power convertors
• modulation