Design of a secondary side regulated LLC based integrated PEV onboard charger with full ZVS range

This paper proposes an integrated onboard charger architecture for plug-in electric vehicles (PEVs). In this architecture, the phase shifted full bridge topology (PSFB) with voltage doubler rectifier serves to charge the high voltage battery pack. A half-bridge secondary side regulated LLC based topology (SSR-LLC) is employed to supply power to the onboard auxiliary battery. The half-bridge SSR-LLC converter shares its primary side switching network with the PSFB converter. This switches' reuse guarantees that the lagging leg switches of the PSFB converter operate under full zero voltage switching (ZVS) condition. The voltage regulations of the PSFB converter and the SSR-LLC converter are achieved by phase shift and duty cycle modulation of the secondary side switch, respectively. Hence, the outputs of the two converters can be controlled independently. In the integrated onboard charger, all the MOSFETs can achieve full range ZVS and all the power diodes work under zero current switching (ZCS) condition. A 250 kHz, 390 V input, 250-420 V/1 kW, 14 V/300 W outputs converter prototype is designed to verify the proof of concept. The PSFB converter in the integrated architecture demonstrates large efficiency improvement compared with the conventional PSFB converter.