Analytic Calculation of Shielding Effect of Vehicular Body on Low Frequency Magnetic Fields Induced by High Voltage Cables

摘要

The electric propulsion system of modern electric vehicles may generate high magnetic fields in the low frequency range exceeding the thresholds for health protection. Mainly the currents through the three-phase cable system between the inverter and the electric motor are critical. This paper presents an analytic 2D solution for the magnetic fields from an infinite parallel cable system above an infinite plate. The solution considers the permeability, conductivity and thickness of the material. It is based on a fundamental solution of the diffusion equation and a Fourier-series development of the exciting line currents. The presented approach is fast and accurate for investigating the behavior of different cable arrangements and shielding materials. In this paper the shielding effect of vehicular bodies with different electrical properties is investigated. Several methods to reduce the resulting magnetic field are discussed.