Int. J. Environ. Res. Public Health 2017, 14(2), 157; doi:10.3390/ijerph14020157
Human Exposure to Electromagnetic Fields from Parallel Wireless Power Transfer Systems
School of Electrical Engineering, Southeast University, No. 2 Sipailou, Nanjing 210096, China
*
Authors to whom correspondence should be addressed.
Academic Editor: Martin Röösli
Received: 23 December 2016 / Revised: 19 January 2017 / Accepted: 28 January 2017 / Published: 8 February 2017
(This article belongs to the Section Environmental Health)
Abstract
The scenario of multiple wireless power transfer (WPT) systems working closely, synchronously or asynchronously with phase difference often occurs in power supply for household appliances and electric vehicles in parking lots. Magnetic field leakage from the WPT systems is also varied due to unpredictable asynchronous working conditions. In this study, the magnetic field leakage from parallel WPT systems working with phase difference is predicted, and the induced electric field and specific absorption rate (SAR) in a human body standing in the vicinity are also evaluated. Computational results are compared with the restrictions prescribed in the regulations established to limit human exposure to time-varying electromagnetic fields (EMFs). The results show that the middle region between the two WPT coils is safer for the two WPT systems working in-phase, and the peripheral regions are safer around the WPT systems working anti-phase. Thin metallic plates larger than the WPT coils can shield the magnetic field leakage well, while smaller ones may worsen the situation. The orientation of the human body will influence the maximum magnitude of induced electric field and its distribution within the human body. The induced electric field centralizes in the trunk, groin, and genitals with only one exception: when the human body is standing right at the middle of the two WPT coils working in-phase, the induced electric field focuses on lower limbs. The SAR value in the lungs always seems to be greater than in other organs, while the value in the liver is minimal. Human exposure to EMFs meets the guidelines of the International Committee on Non-Ionizing Radiation Protection (ICNIRP), specifically reference levels with respect to magnetic field and basic restrictions on induced electric fields and SAR, as the charging power is lower than 3.1 kW and 55.5 kW, respectively. These results are positive with respect to the safe applications of parallel WPT systems working simultaneously. View Full-TextKeywords:
wireless power transfer (WPT); human tissues; induced electric field; specific absorption rate (SAR)
▼
Figures
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. (CC BY 4.0).
Share & Cite This Article
MDPI and ACS Style
Wen, F.; Huang, X. Human Exposure to Electromagnetic Fields from Parallel Wireless Power Transfer Systems. Int. J. Environ. Res. Public Health 2017, 14, 157.
Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.
Related Articles
Article Metrics
Comments
[Return to top]
Int. J. Environ. Res. Public Health
EISSN 1660-4601
Published by MDPI AG, Basel, Switzerland
RSS
E-Mail Table of Contents Alert