A modular battery charger for electric vehicles

The next five years will see a substantial increase in the number of all-electric (EVs) and hybrid electric vehicles (HEVs) utilizing onboard electrochemical energy storage devices (batteries) that require full or part recharging by connection to a low voltage utility network that supply domestic or light industrial users. The utility connection requires a battery charger composed of a uni- or bi-directional power electronic converter that converts the AC supply to DC or vice versa. The expectation for future automotive power electronic converter products is lifetimes of 10 years and over, and operation in arduous temperature environments, factors that compromise existing power converter topologies, in particular those employing electrolytic capacitors. This paper discusses a 7kW battery charger design that is modular, has a balanced three-phase input, is near unity power factor and has no electrolytic capacitors. The paper discusses the charger design concepts and presents test validation results.