A Reconfigurable Two-stage 11kW DC-DC Resonant Converter for EV Charging with a 150-1000V Output Voltage Range

In this paper, a reconfigurable two-stage DC/DC resonant topology with a wide output voltage range of 150-1000V is proposed for Electric Vehicle (EV) charging with high efficiency over the entire load range. The proposed topology consists of an LLC resonant converter with dual secondary sides; two interleaved triangular current mode buck converters, and three additional auxiliary switches for reconfiguration. Two possible arrangements of the proposed topology are considered and compared. The analytical model of the topology is developed, which is used for the efficiency estimation of different configurations and the design of the prototype converter. An 11kW hardware demonstrator is built and tested. The maximum measured efficiency of the converter is 97.66%, with a >95% efficiency over the complete 150-1000V range at full power. The proposed two-stage converter achieves the widest output voltage range reported in literature for resonant power converters, thereby capable of charging existing and future EVs very efficiently over any charging cycle.