Dosimetry and Compliance for Wireless Power Transfer Systems in Vehicle

Vehicle electronization has raised compliance concerns regarding standards for the electromagnetic field exposure. The permissible external field levels prescribed in international guidelines/standards are derived from the limit inside the body under the assumption where humans are exposed to a uniform field in free space, resulting in over-conservativeness in most practical scenarios. This study discusses the emitted field strength, dosimetric evaluation, and compliance assessment method for a wireless power transfer (WPT) system implemented in an electric vehicle. The vehicle body is composed of carbon fiber reinforced plastic (CFRP). The effect of post-processing of the internal electric field which is not applied with current crossing skin layers, is mainly discussed, which has been mentioned in the IEEE C95.1 standard-2019. The computational results suggested that the magnetic field strength at the drive's thigh and buttocks and passenger's foot is highest because the magnetic field generated by the WPT leaks directly into the cabin from the floor for bodies made of CFRP. The influence of skin-to-skin contact appears at armpit, buttocks and between thigh and buttocks of human model. When both the exclusion of skin-to-skin contact and 99%itle is applied, the coupling factor of each body parts is not smaller than that of using only 99.9%tile. Therefore, the exclusion of skin-to-skin contact does not warrant conservativeness considering the different body parts.