Analytical Method to Estimate Radiated Magnetic Field Emissions in Automotive Electric Drives

Abstract

Automotive electric drives operate with high currents. The resulting magnetic field emissions face stringent requirements. High voltage components are usually shielded to reduce the emissions, so are the high voltage cables. Cables and their shields provide coupling paths for both intended operational and unintended parasitic currents which result in radiating loops. The magnetic field emissions depend on the shielding effectiveness, geometrical configuration of the cables and current distribution. This paper presents an analytical method to estimate the radiated magnetic field from an electric drive system. Resulting fields are calculated as the function of inner conductor currents only. The physical and geometrical parameters of the cable shields influence the calculations.