Development of a Equivalent Impedance Network Reproducing the Impedance of Electric Vehicles During Active DC Charging

Beside the ongoing vehicle electrification, a massive expansion of the charging infrastructure is present. These charging stations are operated at rising power levels and increasing voltages of up to 800V focusing on passenger vehicles and up to 1500V for heavy duty vehicles. Beside the speed up of the charging process these technology trends have a large impact on the electromagnetic emissions of the DC charging process which must fulfill the requirements addressed in the standard IEC 61851-21-2 [1]. For measuring the emissions, the charging station has to be operated in a realistic operation point. Therefore, an adequate load modelling of the impedance of an electric vehicle can be used to gain realistic results. Since the vehicle impedances in the frequency range between 9 kHz respectively 150 kHz and 30 MHz are not known, in this work an inductive decoupled impedance measurement procedure [2], [3] is presented and applied to the DC-charging setup. For data acquisition in total three electric vehicles with different battery capacities are measured during active DC-Charging operation. In a further step the impedance of one vehicle is chosen to design a passive impedance network reproducing its impedance at the DC charging port. Using this impedance network more realistic emission results can be gained during operation of a DC charging station.