Design of High Efficiency High Power Density 10.5kW Three Phase On-board-charger for Electric/hybrid Vehicles

The design of an electric/hybrid automobile oriented 10.5kW, AC-to-DC three phase onboard-charger is presented in this paper. In order to achieve full power ability when plugged into a three phase grid and single phase grid, three single phase AC/DC converters are paralleled together to offer full power delivery from AC grid to DC high voltage battery. Each phase AC/DC converter is composed by a PFC and a LLC resonant converter while the output current of each phase is regulated to an equal reference to get an equal power distribution. Benefiting from the ZVS characteristics of LLC resonant converter, the converter achieves high power efficiency and low volume. The total prototype performs 6L, and a high power density 1.75W/cm(exp 3). Experimental results prove that a peak efficiency of 95.5% is obtained and efficiency is higher than 94% from 1.6kW to 10.5kW.