Wireless charging in electric vehicles. EMI/EMC risk mitigation in pacemakers by active coils

An innovative shielding configuration of active coils is proposed to mitigate the magnetic field around an electric vehicle (EV) with a wireless power transfer (WPT) system during battery charging. The active coil is designed to reduce the risk for patients with pacemakers or similar devices produced by the time varying magnetic field generated by the 85 kHz WPT coil currents. A numerical analysis of the magnetic field levels is carried out solving the magneto-quasi-static (MQS) equations by a FEM-based commercial tool. The calculated field which exceeds the limits of electromagnetic compatibility (EMC) and electromagnetic field (EMF) safety standards for human exposure is mitigated by active coils. The magnetic field levels in the environment and the induced peak-to-peak voltage in the pacing lead is predicted in presence and in absence of active shielding.