22 kW EV Battery Charger Allowing Full Power Delivery in 3-Phase as well as l-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 I-phase (USA) as well as 3-phase (Europe) mains supply. For a conventional 3-phase PFC rectifier, only 1/3 of the rated power would be available in case of I-phase operation. The new topology is based on a two-level six-switch (2LB6) 3-phase PFC rectifier, which is extended with a diode bridge-leg and additional windings of the Common-Mode (CM) chokes of the EMI filter. The focus of the paper is on the analysis of the generated CM and Differential Mode (DM) EMI noise for both operating modes, i.e., I-phase and 3-phase operation, resulting in guidelines for EMI filter design. The suggested topology modifications are also applied to a three-level T- type (Vienna) PFC rectifier structure. The theoretical considerations are verified with simulations. Finally, a 22kW prototype of the new universal PFC rectifier is designed using η-ρ Pareto optimization, targeting an efficiency of 98.4 %, a power density of 6.8kW/dm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> , i.e., a volume of 3.24dm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> , and an EMI filter that ensures compliance with the CISPR class B EMI standard. Compared to a volume-optimized design of a conventional 3-phase topology of same power rating and efficiency, but limited 1-phase power transfer capability, the additional volume required for the proposed extension is less than 0.5dm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> (15%) and therefore clearly justified considering the enabled universal applicability of the converter system.