Modeling Frequency-Dependent Core Loss of Ferrite Materials Using Permeance-Capacitance Analogy for System-Level Circuit Simulations

Ferrite core materials are preferred for magnetic components in power electronic converters considering their low cost and high permeability. Thanks to their negligible electrical conductivity, core loss is dominated by the frequency-independent hysteresis effect in most operating conditions. In the applications of high switching frequency under a certain modulation scheme, however, the core loss of ferrite materials do exhibit obvious frequency dependence, known as relaxation effect, which is strongly influenced by the magnetic flux's rate of change and cannot be ascribed to material conductivity. In order to incorporate the core loss including both frequency-dependent and frequency-independent effects into system-level simulation environment of power converters so that the system efficiency can be pre-evaluated during the design phase as a reference for optimization, dynamic model that is physically intuitive and easy to parameterize is desired. This paper proposes an approach to model the core loss of ferrite materials combining both frequency-dependent relaxation effect and frequency-independent hysteresis, which can be flexibly applied for various operation conditions with good accuracy.