New EV battery charger PFC rectifier front-end allowing full power delivery in 3-phase and 1-phase operation

Abstract

A new universal front-end PFC rectifier topology of a battery charger for Electric Vehicles (EVs) is proposed, which allows fast charging at rated and/or full power level in case of 3-phase (Europe) as well as 1-phase (USA) mains supply. In this regard, a conventional 3-phase PFC rectifier would facilitate only one-third of the rated power in case of 1-phase operation. The new topology is based on a two-level six-switch (2LB6) 3-phase boost-type PFC rectifier, which is extended with a diode bridge-leg and additional windings of the Common-Mode (CM) chokes of the EMI filter. Besides this extension of the power circuit, the general design of the new converter is explained, and the generated Differential Mode (DM) and Common Mode (CM) EMI disturbances are investigated for 3-phase and 1-phase operation, resulting in guidelines for the EMI filter design. The EMI performance (CISPR 11 class-B QP) is experimentally verified for 1-phase and 3-phase operation at an output power of 4.5kW, using a full-scale hardware prototype that implements the proposed extensions for a 2LB6 3-phase boost-type PFC rectifier and that is designed for output power levels of 22kW and 19kW in case of 3-phase and 1-phase operation, respectively. Compared to a conventional 2LB6 PFC rectifier, the volume of the extended system increases from 2.7dm3 to 3.4dm3, of which 0.5dm3 is due to the additional dc-link capacitance for buffering the power pulsation with twice the mains frequency occurring for 1-phase operation.