Single- and Three-Phase PHEV Onboard Battery Charger Using Small Link Capacitor

This paper suggests a new onboard charger for plug-in hybrid electric vehicle. It has a cascade structure of a high-frequency resonant converter with a constant switching frequency for electrical isolation and discontinuous-conduction-mode buck-boost converter for charge control and harmonic regulation of input current under universal line input. This structure uses small link capacitors so that high-voltage electrolytic capacitors that are not preferable to be used in automotive applications due to its short lifetime can be removed. The feasibility of the proposed charger has been verified with single-phase and three-phase prototypes.