Electromagnetic Dosimetry and Compliance for Wireless Power Transfer Systems in Vehicles

Vehicle electronization has raised compliance concerns regarding safety standards of the electromagnetic fields. The permissible external field level, described in international guidelines/standards, is based on the assumption that humans are exposed to a uniform field in free space, resulting in overconservativeness in practical scenarios for compliance. This study discusses the emitted field strength, dosimetric evaluation, and compliance assessment for a wireless power transfer (WPT) system implemented in a vehicle, which is composed of iron, aluminum, and carbon fiber reinforced plastic (CFRP). The postprocessing of the internal electric field, based on the IEEE C95.1 standard-2019, is discussed to consider the influence of skin-to-skin contact. The computational results revealed that when the body of the vehicle is composed of CFRP, the magnetic field strength leaking into the vehicle is higher than that with other materials. The coupling factor, an index used to facilitate compliance, ranged from 0.027 to 0.076 in the limb. With the corresponding coupling factor and the magnetic field strength observed at the position prescribed in the International Electrotechnical Commission standard, compliance assessment is simpler than the conventional approach.