Design considerations and topology selection for a 120-kW IGBT converter for EV fast charging

Fast charging of electric vehicles (EV's) is a very desirable feature, especially for long-distance travel, For an EV with a battery capacity of 30 kWh, a 15-min charge requires 120-kW charging power, Inductive charging offers a safe and convenient means to accomplish this task, This paper investigates the design criteria of the high-power converter for a 120-kW inductive battery charger, Since insulated gate bipolar transistors (IGBT's) are the devices of choice at this power level, the impact of IGBT tosses on the converter design and topology selection is investigated, A comparison between a zero-voltage-switching (ZVS) and zero-current-switching (ZCS) series-resonant converter (SRC) is presented, Based on the comparison results, a ZCS SRC topology is selected for this application, and an experimental 120-kW/75-kHz unit was built and tested in the laboratory to verify the results.