Study of magnetic fields in electric vehicles

This article presents the results of measuring the value and spectrum of magnetic field induction in the interior of a car, electric vehicle, hybrid car, and electric bicycle while driving in a real road environment. Problem. Electric vehicles combine high current levels, short distances between electrical equipment and passengers, and long exposure times. Objective. For the measurements, a structural and schematic diagram for measuring the parameters of alternating magnetic fields (frequency spectrum and inductions) of vehicles was developed based on the use of an electric and magnetic field analyzer type EHP-50 from Narda. A video camera recorded the speed of the vehicle – speedometer readings. Methodology. The data of frequency, magnetic induction level and speed were displayed on the laptop display in the form of a spectrum in the frequency range of 1...100 Hz and were saved automatically as a file during the measurements. Results. The results of the measurements showed that the average values of magnetic induction levels in electric vehicles (0.9 μT) are higher than in hybrid vehicles (0.7 μT) and vehicles with an internal combustion engine (0.4 μT). Originality. A statistical analysis of the observations was performed and histograms were plotted, which show a distribution law of inductions close to normal. The correlation coefficients between the speed and induction show that these values are statistically independent. The induction values increase when the car is accelerating or braking. The magnetic induction in the interior of the electric vehicle in the passenger seat to the right of the driver was also measured while the electric vehicle was charging from the charging station and compared to the induction in the electric vehicle while driving (0.85 µT). Magnetic induction vibration spectra have many harmonics. The average frequencies of the first harmonics of the vibration spectrum of a car are 2.6 Hz, an electric car 4.3 Hz, and a hybrid car 7.3 Hz. For comparison, measurements of induction in the subway and trolleybus were also carried out, which showed significantly lower levels of magnetic induction (about 0.1 μT at 50 Hz). When riding an electric bicycle, the induction reaches 0.5 μT at a frequency of about 1 Hz. Practical value: The measurement results have shown that the values of magnetic induction and their frequency in electric vehicles are close to the values that occur during magnetic storms affecting people with cardiovascular problems and can be used to further assess the impact of electromagnetic fields in vehicles on human health.