Evaluation of Electromagnetic Fields in Human Body Exposed to Wireless Inductive Charging System

This paper presents an evaluation of the EMFs in the human body exposed to the wireless inductive charging system of electric vehicles such that the compliance of this charging system with respect to human EM exposure limits can be examined. A magnetic resonance imaging-derived and high-resolution model of the human body is used. An exposure assessment of a representative wireless inductive charging system, under a limited set of operating conditions, is provided to estimate the induced EMFs. The numerical analysis is performed with the finite element method. Numerical modeling of the system next to a standing human model shows that the EM exposure limits can be absolutely satisfied even when the transmitter coil is very close to the body. Furthermore, the worst configuration for the exposure evaluation of the wireless charging system is taken into consideration. This paper provides a useful guideline for the industry to develop inductive charging systems following the safety standards of radiation protection.

I. Introduction

With the expansion of current research interests and anticipated further increases in the use of wireless charging systems by inductive power transfer (IPT) for electric vehicles, it is important to dedicate research efforts to interactions between the wireless charging systems and the human body [1], [2]. This research paper is mainly motivated by two factors. One is to evaluate the induced EMFs in the human body at the frequency of the wireless charging system, i.e., magnetic flux density, electric field, and current density, to evaluate the potential health effects as well as examine the compliance with standards defined by International Commission on Non-Ionizing Radiation Protection (ICNIRP) [3]. The other factor is to investigate the influence of the input current of the wireless charging system on the radiation levels and provide the valid data for determining the extent of design freedom of IPT systems.