The on-board charger and DC/DC undertake the power conversion function between AC charging of new energy vehicles and low-voltage power supply of the vehicle, which are indispensable parts of the vehicle system. With the rapid development of electric vehicle industry, the current automotive industry has more and more stringent requirements on power system. Lightweight and high power density are more and more important for OEMs. With the increasing popularity of electric vehicles, how to reduce the cost has become one of the most important indicators for OEMs.
In the traditional on-board power supply, the on-board charger and DC/DC are mostly combined as independent parts in the vehicle system. In order to meet the integration requirements of OEMs, the on-board charger and DC/DC are even put on a PCB board or only in a shell, so as to achieve the so-called "integration" requirements. But in terms of cost, lightweight, and power density, this approach doesn't really make a real difference to the system.
In terms of technology, LLC topology is adopted for the rear power conversion of vehicle charters. LLC provides the possibility of high frequency and high efficiency for the system by virtue of its soft switch characteristics. However, LLC and the traditional phase shift full bridge cannot bring great efficiency improvement due to the wide output voltage and large output current of DC/DC.
This paper focuses on introducing the integration scheme of on-board charger and DC/DC for new energy vehicles. The innovative topology architecture is used to fully integrate DC/DC with on-board charger to realize the deep integration at component level so as to meet the requirements of lightweight, low cost and high power density. At the same time, this topology takes into account the characteristics of soft switch, which guarantees the high efficiency of the system.