Multiphase resonant converter with output current multiplier for battery charger applications

This paper presents the analysis and design of a multiphase resonant converter suitable for high-current low-voltage battery charger applications. In order to reduce the conduction losses, the inverter stage of the converter is obtained from the parallel connection of N class D LC_p resonant inverters. In the same way, the output stage is based on a current multiplier, obtained through the parallel connection of two current-doubler rectifiers. The regulation of the charging current is implemented at constant frequency, modifying the phase displacement of the drive signals. The battery charger is designed for a high-performance Absorbent Glass Mat (AGM) battery; at present, widely used in micro-hybrid vehicles.