A novel hybrid converter for 6.6kW on board charger

A novel hybrid on-board charger consisting of a phase shift full bridge (PSFB) and a half bridge LLC resonant converter with shared lagging-leg switches is proposed. The proposed topology adopts an additional switch and a diode in the secondary side of the PSFB converter to guarantee the wide ZVS range of the lagging-leg switches and to eliminate the circulating current. The outputs of the two converters are connected in series and the output voltage is adjusted by controlling the effective duty cycle of the PSFB converter within the desired output voltage range. Since each converter has its own rectifier, the rectifier diodes with a lower voltage rating can be used. The operation principle is detailed and the performance of the proposed converter is verified by implementing a 6.6-kW charger. The experimental results show that the maximum efficiency of the converter is 97.7%.