Challenges in EMC Testing of EV and EVSE Equipment for Inductive Charging

Due to rising air pollution and acoustic noise emissions especially in city areas the powertrain of more and more vehicles is electrified full or partially. Thus there is a rising amount of usage scenarios for such vehicles especially in urban areas. As the capacity and the energy density of the propulsion batteries used in these vehicles is limited an appropriate charging infrastructure has to be implemented. Currently this recharge process is mainly realized using conducted charging methods. As there are several charging modes for AC and DC charging available often charge spots having several charging cables like the classical petrol pumps. Beside the conductive charging systems currently wireless charging systems are developed and implemented into test vehicles. Using these systems the vehicle can be recharged while parking above the primary coil mounted on the ground. The secondary coil inside the vehicle receives the power which is rectified to charge the battery. In addition inside the vehicle a DC-DC converter is connected to the secondary coil to control the charging current. Considering the EMC, similar to the conductive charging also in wireless charging mode the two worlds of standardization E and CE meet at the charging cable respectively between the primary and the secondary coil. As the on the primary and secondary side power electronic components generating broadband EMI are used. The charging systems, the vehicle and the on-board vehicle devices have to be designed to fulfill the specific EMC requirements. For EMC testing of all these components a suitable peripheral setup has to be realized. Exemplary for testing vehicles with inductive charging functions and vehicle components an appropriate test source generating low EMI is needed. This work presents a source realizing inductive charging for electric vehicles. To reduce the emissions of the system the paper presents an EMI filter system to realize a sufficient interference suppression having low impact on the power transfer.