Accurate Modeling of Radiated Electromagnetic Field by a Coil With a Toroidal Ferromagnetic Core

Magnetic components are widely used in power electronics and are the main cause of electromagnetic couplings. Among them, coils with ferromagnetic cores belong to the class of components that are used the most. However the behavior in terms of radiation and coupling to the environment of these components is not widely explored. This paper defines a more accurate model for coils with toroidal ferrite cores in order to get a better understanding of the coupling they created. Then the effects of the winding layout around a toroidal core are first discussed. It is found that the winding topology is the major parameter controlling both the radiated field pattern and its magnitude. A measurement bench has then been developed to validate the hypothesis made. Finally, numerical and analytic models have been elaborated to predict radiated fields from magnetic components.