Modeling and control of a 50KW electric vehicle fast charger

Modeling and control of a 50KW vehicle battery fast charger prototype, developed at Gamatronic Electronic Industries LTD, is presented in the paper. The charger topology may be referred as a two-stage controlled rectifier. The input stage consists of a three phase full bridge rectifier combined with an active power filter (three single stage power filters are actually employed). The input stage creates an uncontrolled DC bus while complying with the grid codes by keeping the THD and power factor within the permissible limits. The output stage is formed by six interleaved groups of two DC-DC converters, reducing the input and output current ripples. Two independent control boards are employed: active filters control circuitry and the DC-DC control circuitry. The former is operated according to the predetermined grid interfacing behavior, while the operation of the latter is dictated by the requests from the Battery Management System. The charger is capable of operating in any of the two modes: Constant Current and Constant Voltage. Control loops are explained throughout the paper and extended simulation/experimental results are presented.