Numerical evaluation of the voltage induced on pacemakers and implantable defibrillators by wireless power transfer systems for automotive

Wireless power transfer (WPT) in the automotive industry is an emerging technology that has the potential to interfere with other electronic devices, posing consequent risks that must be carefully evaluated. This is particularly crucial for cardiac implantable electronic devices (CIEDs), as malfunctioning can pose serious hazards to patient safety. Being an emerging technology, WPT electromagnetic emissions have not been explicitly addressed in the current CIEDs regulations. A voluntary standard on WPT recommend limiting the dispersed magnetic field to 15 μT. Predicting the behavior of a CIEDs when in proximity to a WPT system is not straightforward. In this paper, we first discuss the regulatory framework that defines the minimum requirements in terms of electromagnetic compatibility that CIEDs must satisfy. We then explore the emission limits allowed for WPT systems to guarantee interoperability and safety. Subsequently, we present the results of a numerical study that reproduces the magnetic field generated by a commercial WPT system for automotive applications (85 kHz). We calculate the voltage induced at the input stage of a pacemaker or implantable cardioverter-defibrillator implant, considering worst-case implant configurations and realistic positioning in relation to the WPT source. The results of the numerical study reveal that the magnetic field inside the patient's body in four realistic exposure scenarios is far below the limits provided by the ICNIRP guidelines for public exposure to electromagnetic fields. Furthermore, the resulting induced voltage is well below the immunity test levels provided by the technical standards that define the electromagnetic compatibility requirements for CIEDs.