Electromagnetic Compatibility Assessment of Electric Vehicles during DC-Charging with European Combined Charging System

Abstract

The ongoing energy transition will have a profound impact on future mobility, with electrification playing a key role. Battery electric vehicles (EVs) are the dominant technology, relying on the conversion of alternating current (AC) from the grid to direct current (DC) to charge the traction battery. This process involves power electronic components such as rectifiers and DC/DC converters operating at high switching frequencies in the kHz range. Fast switching is essential to minimise losses and improve efficiency, but it might also generate electro-magnetic interferences (EMI). Hence, electromagnetic compatibility (EMC) testing is essential to ensure reliable system operations and to meet international standards. During DC charging, the AC/DC conversion takes place off-board in the charging station, allowing for better cooling and larger components, resulting in increased power transfer, currently up to 350 kW. The EMC requirements for this charging method are outlined in IEC 61851-21-2. This paper presents possible test setups supporting the standard. Furthermore, it emphasizes the need for measurements not only in controlled laboratories, but also at real charging stations within their specific environments. Therefore, a mobile test setup is introduced and validated. It can be connected to any public DC charging station using a European standard plug CCS-2 (Combined Charging System 2). In addition, the emerging concept of Vehicle to Grid (V2G) is gaining prominence. The objective is to leverage electric vehicles as mobile energy storage for grid optimization and stabilization. The proposed test setup also allows to take these operating states into account concerning conducted interference emissions. As the transition to electric mobility progresses, these investigations contribute ensuring the seamless integration of EVs into the evolving energy landscape.