ELECTRIC AND MAGNETIC FIELDS <100 KHZ IN ELECTRIC AND GASOLINE-POWERED VEHICLES

Electromagnetic exposure levels of electric vehicle drive motors to cochlear implanted passenger

In order to evaluate the effects of electromagnetic radiation generated by the dual-drive motors of an electric vehicle on special passengers with cochlear implanted, this study considers a cochlear implanted passenger as the research object, takes the drive motors in electric vehicle as the exposure source. A calculation model including the vehicle body, brain tissue, skull, eyes, human body, and cochlear implant is built, and the finite element method is used to calculate the induced electric field ([Formula: see text]), specific absorption rate (SAR), and temperature changes in different tissues and organs of the passenger's body. The results show that the maximum value of [Formula: see text] on the human body surface is 60.8 mV/m at the ankle. The [Formula: see text] around the cochlear implant inside the human head is also high, with a maximum value of 57.1 mV/m. The maximum SAR of the human body is [Formula: see text], which also appears near the cochlear implant. Besides, the maximum temperature rise of the human body, brain tissue, and cochlear implant is 0.10 °C, 0.28 °C, and 0.0076 °C, respectively. Calculation shows that the [Formula: see text] and SAR of the human body and different tissues are much lower than the safety limit specified in the guidelines of the International Commission on Non-Ionizing Radiation Protection (ICNIRP), and the temperature rise does not reach the thermal damage threshold in the guidelines. The electric field around the electrode tip and the surface of the cochlear implant, the temperature rise of the cochlear implant also meet the requirements of the ICNIRP and the International Organization for Standardization's 14708-7 medical device standard. The results could enrich the study on the electromagnetic environment of electric vehicles and provide references for the design and improvement of cochlear implants and electromagnetic exposure protection for vehicles.

Electromagnetic exposure level of pure electric vehicle inverter to human body in different seating positions

The market share of pure electric vehicle (PEV) as a green transportation steadily increases as the global demand for renewable energy sources and environmentally friendly mobility continues to increase. However, during PEV operation, the inverter system, as the key power conversion device, generates strong electromagnetic field in the local space. Long-term exposure to such electromagnetic environments may have potential effects on human body. In this study, the electromagnetic environment model of the PEV body, human body and simplified inverter is established. The finite element software, COMSOL Multiphysics, is used to calculate and analyse the variations in the induction field in different tissues of the driver and rear passenger, caused by the electromagnetic field generated by the inverter system operating at maximum power. The electromagnetic exposure level of the driver and rear passenger is assessed. Results show significant differences in the electromagnetic exposure levels of different seating positions in the vehicles. The electromagnetic exposure level in the driver's body is higher than that of the rear passenger, but it does not exceed the exposure limits defined by the International Commission for Non-ionizing Radiation Protection. This finding effectively complements the study on evaluating the safety of the electromagnetic environment of PEV and improves public awareness.

Study on the safety assessment and protection design of human exposure to low-frequency magnetic fields in electric vehicles

As the power performance of electric vehicles continues to improve, the human body may be exposed to electromagnetic threats in the cabin. This study tested an electric vehicle to analyze the low-frequency magnetic field distribution in the cabin and to assess the safety of human low-frequency magnetic field exposure. A simulation analysis of human electromagnetic exposure was carried out to obtain the magnetic flux density, induced electric field strength and induced current density, and the test results were much lower than the limits specified in GB8702-2014 and the International Commission on Non-Ionizing Radiation Protection, and the relative error between the simulation results and the test results was <15%. This paper investigates the frequency, driving current, vehicle body material and cable layout to explore the law of human body induced electromagnetic field changing with power cable current, and provides theoretical reference for the design of human body low-frequency magnetic field protection.

Assessment of Low-Frequency Magnetic Fields Emitted by DC Fast Charging Columns

The expected imminent widespread use of electromobility in transport systems draws attention to the possible effects of human exposure to magnetic fields generated inside electric vehicles and during their recharge. The current trend is to increase the capacity of the battery inside the vehicles to extend the available driving range and to increase the power of recharging columns to reduce the time required for a full recharge. This leads to higher currents and potentially stronger magnetic fields. The Interoperability Center of the Joint Research Center started an experimental activity focused on the assessment of low‐frequency magnetic fields emitted by five fast‐charging devices available on the market in recharge and standby conditions. The aim of this study was to contribute to the development of a standard measurement procedure for the assessment of magnetic fields emitted by direct current charging columns. The spectrum and amplitudes of the magnetic field, as well as exposure indices according to guidelines for the general public and occupational exposure, were recorded by means of a magnetic field probe analyzer. The worst‐case scenario for instantaneous physical direct and indirect effects was identified. Measurements within the frequency range of 25 Hz–2 kHz revealed localized magnetic flux density peaks above 100 μT at the 50 Hz frequency in three out of five chargers, registered in close proximity during the recharge. Beyond this distance, exposure indices were recorded showing values below 50% of reference levels. Bioelectromagnetics. 2020;41:308–317 © 2020 The Authors. Bioelectromagnetics published by Wiley Periodicals, Inc.

LOW FREQUENCY MAGNETIC FIELDS INSIDE CARS

Magnetic fields were compared inside passenger seats of electric, petrol and hybrid cars. While driving about 5 km in an urban environment, values were recorded and compared between car types. The magnetic flux densities of the cars were less than 2.6 μT. The magnitudes of the magnetic fields of petrol cars and hybrid cars were about the same and slightly lower for electric cars. Based on our measurements, values were less than 3% of the guidelines given for the general population or people using pacemakers.

Long-Term Monitoring of Extremely Low Frequency Magnetic Fields in Electric Vehicles

Extremely low frequency (ELF) magnetic field (MF) exposure in electric vehicles (EVs) has raised public concern for human health. There have been many studies evaluating magnetic field values in these vehicles. However, there has been no report on the temporal variation of the magnetic field in the cabin. This is the first study on the long-term monitoring of actual MFs in EVs. In the study, we measured the magnetic flux density (B) in three shared vehicles over a period of two years. The measurements were performed at the front and rear seats during acceleration and constant-speed driving modes. We found that the B amplitudes and the spectral components could be modified by replacing the components and the hubs, while regular checks or maintenance did not influence the B values in the vehicle. This observation highlights the necessity of regularly monitoring ELF MF in EVs, especially after major repairs or accidents, to protect car users from potentially excessive ELF MF exposure. These results should be considered in updates of the measurement standards. The ELF MF effect should also be taken into consideration in relevant epidemiological studies.

Effect of Static Magnetic Field of Electric Vehicles on Driving Performance and on Neuro-Psychological Cognitive Functions

Human neuropsychological reactions and brain activities when driving electric vehicles (EVs) are considered as an issue for traffic and public safety purposes; this paper examined the effect of the static magnetic field (SMF) derived from EVs. A lane change task was adopted to evaluate the driving performance; and the driving reaction time test and the reaction time test were adopted to evaluate the variation of the neuro-psychological cognitive functions. Both the sham and the real exposure conditions were performed with a 350 μT localized SMF in this study; 17 student subjects were enrolled in this single-blind experiment. Electroencephalographs (EEGs) of the subjects were adopted and recorded during the experiment as an indicator of the brain activity for the variations of the driving performance and of the cognitive functions. Results of this study have indicated that the impact of the given SMF on both the human driving performance and the cognitive functions are not considerable; and that there is a correlation between beta sub-band of the EEGs and the human reaction time in the analysis

EVALUATING EXTREMELY LOW FREQUENCY MAGNETIC FIELDS IN THE REAR SEATS OF THE ELECTRIC VEHICLES

In the electric vehicles (EVs), children can sit on a safety seat installed in the rear seats. Owing to their smaller physical dimensions, their heads, generally, are closer to the underfloor electrical systems where the magnetic field (MF) exposure is the greatest. In this study, the magnetic flux density (B) was measured in the rear seats of 10 different EVs, for different driving sessions. We used the measurement results from different heights corresponding to the locations of the heads of an adult and an infant to calculate the induced electric field (E-field) strength using anatomical human models. The results revealed that measured B fields in the rear seats were far below the reference levels by the International Commission on Non-Ionizing Radiation Protection. Although small children may be exposed to higher MF strength, induced E-field strengths were much lower than that of adults due to their particular physical dimensions.

Review of Studies Concerning Electromagnetic Field (EMF) Exposure Assessment in Europe: Low Frequency Fields (50 Hz-100 kHz)

We aimed to review the findings of exposure assessment studies done in European countries on the exposure of the general public to low frequency electric and magnetic fields (EMFs) of various frequencies. The study shows that outdoor average extremely low frequency magnetic fields (ELF-MF) in public areas in urban environments range between 0.05 and 0.2 µT in terms of flux densities, but stronger values (of the order of a few µT) may occur directly beneath high-voltage power lines, at the walls of transformer buildings, and at the boundary fences of substations. In the indoor environment, high values have been measured close to several domestic appliances (up to the mT range), some of which are held close to the body, e.g., hair dryers, electric shavers. Common sources of exposure to intermediate frequencies (IF) include induction cookers, compact fluorescent lamps, inductive charging systems for electric cars and security or anti-theft devices. No systematic measurement surveys or personal exposimetry data for the IF range have been carried out and only a few reports on measurements of EMFs around such devices are mentioned. According to the available European exposure assessment studies, three population exposure categories were classified by the authors regarding the possible future risk analysis. This classification should be considered a crucial advancement for exposure assessment, which is a mandatory step in any future health risk assessment of EMFs exposure.