Three-phase high frequency transformer isolated AC to DC converter for EV battery quick charging

This paper proposed a three phase AC to DC converter, which is isolated by high frequency transformer, for EV battery quick charging. EV battery chargers normally need a transformer to isolate the power grid from battery system for safety. Different types of chargers exist. Some types that are isolated by commercial frequency transformer are of large volume and weight. By increasing frequency, the volume and weight of transformer can be greatly reduced. But the material that is proper for very high frequency can hardly be used for large power applications, by the reason of manufacturing and cost. The principle and design of this converter was studied. The fundamental operations were confirmed by 37 kW experimental results. Weight of transformer is reduced to about 1/7 and total efficiency is higher than 90%. 2-ARM-PWM method is studied for the purpose of loss reduction.