HEV/PHEV 용 고효율 2단 LDC 설계

A two-stage LDC(Low Voltage DC-DC Converter) which has the boost converter interleaved between the high voltage battery output and full-bridge converter input is proposed in this paper. This two-stage LDC has the transformer with the high turn ratio in order to decrease the semi-conductor devices losses and increase the entire LDC efficiency finally. Using the synchronous MOSFET instead of the rectifier diode in the secondary is also proposed to maximize the total efficiency. The proposed two-stage LDC was designed to meet the condition of not only the HEV but also the PHEV. It was demonstrated by PSIM simulations and experiments that the two-stage LDC has the increased average efficiency of 94.5% and increased peak efficiency of 95.7% (which were 91.2% and 92.9% respectively in the existing LDC).