A Bidirectional 400-12 V Dc-Dc Converter with Improved Dynamics and Integrated Transformer for EV Applications

The core of electric vehicles is the high-voltage battery, which powers the electrical powertrain. However, the transition from conventional combustion cars to electric vehicles relies on the use of a low-voltage port to power electrical loads such as lighting, infotainment, and air conditioning, among others. Classically, the low-voltage port has been powered using a lead-acid battery, and only passive loads have been considered. In contrast, modern EV design trends demand bidirectional power conversion from the high-voltage battery to the low-voltage distribution systems to supply power to active loads, such as suspensions, and to recharge the low-voltage battery using the high-voltage battery. Furthermore, advanced designs are now exploring the possibility of eliminating the low-voltage battery by using fast-dynamic 400-12 V DC-DC converters.In this context, DC-DC converters require high efficiency and power density while achieving bidirectional operation and rapid response. This paper proposes a bidirectional 400-12 V dc-dc converter using a dual-active-bridge structure with fast dynamics and integrated transformer in the PCB. The proposed converter is designed and implemented, and it is tested using a dual-channel 2.2 kW converter.