High efficiency wide range bidirectional DC/DC converter for OBCM application

This paper present a study of the isolated DC/DC stage of Bi-directional on-board battery charger module (OBCM) for electric vehicle (EV) and plug-in hybrid electric vehicle (PHEV) application. The modulated dual active bridge (DAB) converter and boost series resonant converter were thoroughly analyzed for this application. The ZVS boundary conditions, power stage optimization compatible to wide output range were provided including high to light loading. Using digital control schemes, a standard 3.5kW prototype DC/DC converter designed for a high-frequency galvanic isolation of 390Vdc bus was developed with 240V~430V output range. Simulation and experimental result verify the performance of the proposed boost series resonant converter is over 97% efficiency for the whole full power charging / discharging range, peak close to 98%, the design were based on automotive level components, and the designed volume was also comparable to existing unidirectional OBCM as real product application.