Electromagnetic Field Exposure Assessment and Mitigation Strategies for Wireless Power Transfer Systems: A Review and Future Perspectives

TL;DR

This review analyzes electromagnetic exposure assessment methods for wireless power transfer systems, highlighting safety standards, recent computational techniques, and challenges in harmonizing guidelines for safe deployment.

Contribution

It provides a comprehensive comparison of WPT modalities, recent developments in dosimetry, and discusses challenges in standardization and safety assessment.

Findings

Significant variability in allowable transfer power based on assessment methods.

Recent advances in computational dosimetry improve exposure evaluation.

Identified gaps in harmonized guidelines for intermediate frequencies.

Abstract

Wireless power transfer (WPT) technologies are increasingly being applied in fields ranging from consumer electronics and electric vehicles to space-based energy systems and medical implants. While WPT offers contactless power delivery, it introduces electromagnetic field (EMF) emissions, necessitating careful assessment to address safety and public health concerns. Exposure guidelines developed by ICNIRP and IEEE define frequency-dependent limits based on internal quantities, such as electric field strength and specific absorption rate, intended to prevent tissue nerve stimulation < 100 kHz and heating > 100 kHz, respectively. Complementing these guidelines, assessment standards including the International Electrotechnical Commission (IEC)/IEEE 63184 and IEC Technical Report 63377, provide practical procedures for evaluating the EMF exposure in WPT systems. This review offers a comparative overview of major WPT modalities, with a focus on recent developments in computational dosimetry and standardized assessment techniques for the complex, non-uniform fields typical of WPT environments. It also discusses electromagnetic interference with medical devices and exposure scenarios involving partial body proximity and various postures. A notable observation across modalities is the considerable variability, often spanning an order of magnitude, in the allowable transfer power, depending on the field distribution and assessment approach. Remaining challenges include the lack of harmonized guidance for intermediate frequencies and localized exposure, underscoring the importance of further coordination in international standardization efforts. Addressing these issues is essential for the safe and widespread deployment of WPT technologies.