An LLC Resonant DC–DC Converter for Wide Output Voltage Range Battery Charging Applications

In this paper, resonant tank design procedure and practical design considerations are presented for a high performance LLC multiresonant dc–dc converter in a two-stage smart battery charger for neighborhood electric vehicle applications. The multiresonant converter has been analyzed and its performance characteristics are presented. It eliminates both low- and high-frequency current ripple on the battery, thus maximizing battery life without penalizing the volume of the charger. Simulation and experimental results are presented for a prototype unit converting 390 V from the input dc link to an output voltage range of 48–72 V dc at 650 W. The prototype achieves a peak efficiency of 96%.