Experimental Investigation on Magnetic Field Emissions of Wireless Power Transfer Vehicle Charging Systems

Along with an increasing amount of electrified vehicles worldwide, an appropriate charging infrastructure has to be implemented to ensure a successful structural transformation in the transport sector. Commonly, conducted charging is used for fast charging using direct current and charging powers up to 350 kW or alternating current for e.g. private charging with 11 kW. Furthermore, wireless charging technologies are in development for a potentially higher level of automation of the charging process, especially. Thus, this technology has to be considered in context with automated driving functions, to provide a completely autonomous vehicle usage. As these wireless charging systems use two air-coupled, planar coils for energy transmission at an operating frequency between 79 kHz and 90 kHz, the electromagnetic emissions become an important issue. Especially the magnetic field emissions between 9 kHz and 30 MHz are the main focus of the current standardization process. This work focusses on the magnetic field emissions of a wireless charging system considering the disturbance currents, which are responsible for the field generation. Beside this, the impact of the measurement environment on these emissions is investigated. As the measurements are commonly conducted in a semi-anechoic chamber, while for wireless charging systems the typical area of application is e.g. a parking place with nonconductive floor and walls around, comparative measurements are executed to show the effects of the environment on the measurement results