Direct DC-DC electric vehicle charging with a grid connected photovoltaic system

The Electric Vehicle/Photovoltaic Demonstration and Evaluation Program being conducted at the University of South Florida (USF) includes a 20 kW (peak) photovoltaic (PV) system in which PV panels form the roof of a 12 bay carport. A 6 kW (peak) segment of the PV system can be simultaneously distributed between computer controlled direct DC-DC charging and power grid interconnection. The DC-DC charger (DC-DAS) controls the charging current of a battery pack with minimal power waste, by computer control of current flow direction of each of four source circuits. It demonstrates superior efficiency, dependability and safety for DC-DC charging over DC-AC-DC charging and has greater control over the last 20% of charge than traditional PV DC-DC chargers.