Investigation of Magnetic Field Immunity and Near Magnetic Field Reduction for the Inductors in High Power Density Design

This paper investigates the magnetic field immunity and near magnetic field reduction for different inductor-winding structures. A double-twisted winding structure, which includes two magnetic cores, is proposed for common mode (CM) inductors. The proposed CM inductor can achieve much lower near magnetic field emission, much better magnetic field immunity against the external magnetic field, and much bigger differential mode (DM) impedance than conventional winding structures. The proposed inductor structures are good for high power-density applications. Theoretical analysis, magnetic three-dimensional simulations and experiments were conducted to validate the developed theory and technique.