Low voltage dc-to-dc converter combining flyback and boost converter for charging an auxiliary battery in hybrid electric vehicle

It presents a low voltage dc-to-dc converter (LDC), which needs to charge an auxiliary battery in a hybrid electric vehicle. LDC locates between an inverter and a main battery. Because it is always on board, a small and light design is very important to increase fuel efficiency and performance. The proposed LDC integrates a boost converter into a flyback converter. It substitutes the primary of a transformer for a boosting inductor. When supplying a low dc voltage to electric field systems, LDC operates in a step-down mode. On the other side, when starting, it operates in a step-up mode to supply a high dc voltage. According to operational modes, theoretical analysis is done and proven by computer-aided simulation using PSIM.