Analysis and application of the bidirectional converter for ReflexTM strategy

In this paper, a reflex charger based on bidirectional converter is proposed. The Reflex charging strategy has a positive pulse interval, a negative pulse interval and a resting time in a complete charging period. In the positive pulse interval, the bidirectional converter is operated as a phase shift full bridge converter (PSFB). The zero voltage switching (ZVS) of the lagging legs of the bidirectional converter can be achieved without additional inductor, so the circulating current problem of the phase shift full bridge converter can be overcome and the conduction losses of the power switches is decreased. Therefore, the PSFB converter is suitable for the constant-current charging. Besides, the Reflex charging is one of the fast charging methods. In order to achieve fast charging, a large output current is needed. Therefore, an improved current doubler rectifier is adopted at the secondary side of the converter. The improved current doubler rectifier is operated as an interleaved boost converter in the negative pulse interval. Finally, a 360-400V input, 60V/12A output Reflex charger will be proposed in this paper.