Simulation of Inductive Power Transfer Systems Exposing a Human Body With Two-Step Scaled-Frequency FDTD Methods

For the simulation of the human exposure to magnetoquasi-static fields of inductive power transfer (IPT) systems two domain decomposition methods - the coupled scaled-frequency finite-difference time-domain (SF-FDTD) method and the co-simulation SF-FDTD method - are presented in this paper. Using both Huygens' principle and the SF-FDTD method, a two-step approach is developed resulting in two different simulation schemes, the coupled SF-FDTD method and the co-simulation SF-FDTD method, respectively. These two-step schemes are able to replace high-dimensional monolithic exposure simulation models by problems of smaller size with less computer memory demand. An exposure scenario, including an IPT system, a car, and a high-resolution human body voxel model, is modeled and simulated using both methods. A full-scale monolithic SF-FDTD simulation is used as reference and its results - i.e., the body-internal electric field strengths - are compared with the results of the presented two-step methods. The maximum of the body-internal electric field strength (voxel average) is determined and compared to basic restrictions given by the international commission on nonionizing radiation protection.