Physical Modeling of Core Losses in Ferrite E-Cores

The development of advanced power electronic converters requires an accurate calculation of core losses in magnetic devices. But the losses in the widely used ferrite cores depend on the shape of the core, especially above 10 kHz, meaning that core losses can not be estimated by simply scaling reference data with respect to the volume of the core. To include efficiently the geometry of the core into the calculation of core losses, this article presents the Combined Field and Material Model (CFM<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup>) for E- or U-cores. This method combines an analytical solution of the field in the core with a non-linear material model of ferrite, modelling all relevant loss phenomena such as hysteresis losses and non-linear resonant eddy currents. The CFM<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> enables an accurate calculation of core losses over a wide range of frequency and flux density using a reduced set of physical parameters.