Assessing Human Exposure With Medical Implants to Electromagnetic Fields From a Wireless Power Transmission System in an Electric Vehicle

Numerical dosimetry with regards to a resonance-based wireless power transfer (RBWPT) system for charging electric vehicles (EVs) has been conducted. The RBWPT system operating at 13.56 MHz frequency with a transferred power of 5.3 kW is placed below the center of the vehicle body. Specific absorption rate (SAR) in anatomically-based human models Duke and Ella with and without a medical implant is evaluated using four exposure scenarios (i.e., Duke and Ella models sitting in the EV without an implant, the Ella model: With an InterStim neurostimulator implant, having a prosthetic hip implant, or having a cardiac pacemaker implant). The results indicate that change in radio frequency (RF) energy absorption occurs when conductive implants are placed in the near field of an RF source. Enhancement of the SAR close to the implants is predicted. The peak averaged SAR over 10 g of tissues exceeds the standard limiting value posed by international guidelines except for the leadless pacemaker, which is in compliance with the prescribed limits. However, the temperature increase never exceeds the localized temperature rise limit of 2 degrees C. Compliance with the recommended limits of SAR in the worst-case exposure scenario is likely to limit the transferred power.