IEEE Workshop on Wide Bandgap Power Devices and Applications in Asia (WiPDA Asia 2018)

293 / 2017-12-07 20:45:29

A High Efficiency 2.5 kW Bidirectional FB-CLTC Resonant DC–DC Converter with Large Voltage Ratio

SiC,DC-DC converter,high conversion ratio,bidirectional

Plenary track > Very high efficiency and compact converters

A novel high conversion ratio bidirectional flyback-CLTC (FB-CLTC) resonant DC-DC converter is proposed in this paper. Based on the traditional LLC, an auxiliary transformer and a extra resonant capacitance is introduced in the new FB-CLTC structure, which alters the resonant cavity and harvests a broaden voltage gain range within a narrow working frequency. Also, the proposed converter can achieve zero voltage switching (ZVS) on the high voltage side (HVS) and zero current switching (ZCS) on the low voltage side under all load range. Besides, the operating principles of the converter are analysised in both step-up mode and step-down mode. In additional, the relevant voltage gain and working frequency are also analysised. Moreover, combined with the application of wide band gap SiC, the loss mechanism analysis of the converter is given. At last, a 2.5kW prototype is established with the SiC devices to verify the performance of the FB-CLTC converter, and its maximum efficiency reaches 97%.