Reducing Magnetic Fields Exposure of Electric and Hybrid Cars – An Innovative Solution and an Evaluation According to Different Exposure Target Levels

Dr. Amnon Duvdevany, Mr. Shaul Shulman, Mr. Oded Einat
Dr. Amnon Duvdevany Consulting, Israel. E-mail: [email protected], SafeFields Technologies Inc., Israel

Abstract

An increasing spread of electric and hybrid cars raises concerns regarding human exposure to Low Frequency (LF) magnetic fields. An innovative solution has been developed by SafeFields Technologies Inc. for reducing the LF magnetic fields, based upon delivering antiphase magnetic fields. Evaluation of exposure reduction by the solution, according to car’s magnetic fields measurements performed using a dynamometer, will be presented and discussed. Exposure analysis according to EC/ ICNIRP recommendations and according to precautionary principle-based target levels regarding electrical grid chronic exposure reduction, will be discussed as well.

Introduction

According to EU data, electric cars (BEV, HEV, PHEV) new registrations crossed the 50% share at October 2023. The usage of electric and hybrid cars raises many concerns regarding human exposure to Low Frequency (LF) magnetic fields, originated mainly by high currents generated by the power unit and delivered through the vehicle, and its potential health effects to the passengers. The LF magnetic fields public concerns are mainly related to those that arise regarding the exposures to electrical grid, and to IARC (International Agency for Research on Cancer) classification of the fields as “possibly carcinogenic to humans”.

The WHO recommends application of reasonable precautionary measures to further reduce human exposure to these fields, particularly to new facilities and equipment. Several countries have adopted the precautionary principle according to measures suggested by the WHO, by adopting low target exposure levels (lower than ICNIRP or IEEE levels), or by administrative steps. An innovative solution has been developed by SafeFields Technologies Inc. for reducing the electric and hybrid cars LF magnetic fields, by using an active cancellation method, implemented by coils located at dedicated positions, “tailored” to each car according to its magnetic fields’ behavior, for real-time measurements and delivering of dedicated magnetic fields. The solution has been successfully implemented at several electric and hybrid cars types.

The method and the results of evaluating the exposure reduction for electric and hybrid cars, by implementing the solution, will be demonstrated. We will also discuss evaluating the exposures (before and after implementing a solution) according to EC/ ICNIRP guidelines as well as to target levels regarding chronic electrical grid exposure reduction according to precautionary principle, adopted by several countries.

AIM

The aim of the study was to examine the magnetic fields exposure of hybrid cars passengers, in cars where the solution was installed, and to evaluate exposures and their reduction by the solution according to EC/ ICNIRP guidelines and chronic exposure target levels.

Methods

• 2 Plug-In Hybrid cars where the solution was implemented, were examined, using a dynamometer.
• Magnetic fields were examined inside the cars at different car modes (idle, 15 km/h, 40 km/h, 90 km/h, acceleration/ deceleration) and at different locations (at each seat, legs, feet and head & torso, and steering wheel). Prior to car fields measurements, background measurements were carried out without a car at the dynamometer area, and tires demagnetization was performed.
• A measurement procedure, related to IEC 62764-1 2022, was implemented. Car seats were examined, while dividing passengers body areas to different test volumes, and searching for the maximum value at each volume at each car’s mode. Maximum values were measured for each car’s mode/ volume, before and after activating the dedicated solution.
• Test volumes were scanned using Narda STS EHP50F probe (1 Hz – 400 kHz) and a dedicated analysis software.
• Measurements were performed using spectral modes, to analyze time-averaged exposures and spectral weighted exposures according to ICNIRP 1998 (EU recommendations 1999/519/EC) and ICNIRP 2010, for general public.
• That is to locate and analyze the maximum exposures per volume tested and car’s mode:
  1. Exposures according to the ICNIRP’s 1998 & 2010 reference levels.
  2. Time-averaged exposures, according to different countries target levels for electrical grid exposure.

Results & Discussion

Our results indicate reducing the maximum magnetic fields exposure by the solution to about 15% of the prior levels for average levels and for ICNIRP 1998 weighted levels, and to about 10% for ICNIRP 2010 weighted levels. Maximum values were located at rear right seat for both cars, and are detailed at the tables, for car A and for car B. Example of spectral behavior (system analysis output) is demonstrated as well, regrading to 1998 ICNIRP limitations for GP (total values are represented, for a solution off/on).

CAR A

Values are magnetic flux density at the car’s maximum exposure point, mG or %ICNIRP

CAR B

Values are magnetic flux density at the car’s maximum exposure point, mG or %ICNIRP

Some of the measurements indicate exposures acceding ICNIRP 1998 for GP before implementing the solution, and meeting both 1998 and 2010 guidelines when implemented. Exposure levels are well below (about 1% and less) ICNIRP 2010 for GP. The averaged values are mostly 10 mG and less. Hence, when considering exposure time, they can meet restrictive LF recommendations of several countries to reduce LF exposure levels according to precautionary principle.

Conclusions

A reduction of passengers’ exposure levels in electrified cars was achieved by implementing a dedicated solution using active cancellation method. Reduction was demonstrated both for values evaluated according to ICNIRP’s reference levels and for time-averaged values, comparable to chronic exposure recommendations. Reducing exposure in cars helps to meet international standards and guidelines as well as precautionary principle advised by WHO and implemented by several countries, and to reduce risk and public concern regarding excessive exposures in electric and hybrid cars.

References: Assessment of low frequency magnetic fields in electrified vehicles, EC, JRC Science for policy report, Trentadue, G., Zanni, M., Martini, G.; 2020. | ICNIRP guidelines for limiting exposure to time-varying electric, magnetic and electromagnetic fields (up to 300 GHz), Health physics 74 (4):494-522; 1998. | ICNIRP guidelines for limiting exposure to time‐varying electric and magnetic fields (1Hz – 100 kHz), Health physics 99(6):818‐836; 2010. | IEC 62764-1, Measurement procedures of magnetic field levels generated by electronic and electrical equipment in the automotive environment with respect to human exposure – Part 1: Low-frequency magnetic fields, Edition 1.0; 2022.

This the text version of the technical report on cars radiation, presenting a new solution to reduce magnetic field exposure in electric and hybrid vehicles across target levels. To download the report, click here.