Obtaining a frequency-dependent and distributed-effects model of magnetic components from actual measurements

The behavior of the magnetic components in high frequency switched power supplies depends significantly on the working frequency because of distributed magnetic and electrical field effects. Measurement equipment such as an impedance analyzer usually offers simple equivalent models that allow characterization of the frequency behavior of some magnetic components. However, it is useful to have a procedure to generate more sophisticated models for all magnetic components, including coupled inductors and multiwinding transformers in order to characterize the frequency behavior more accurately. This paper presents a procedure to obtain the parameters of a model of magnetic components that has both frequency dependence and distributed effects. The values of the parameters of this model are obtained from actual measurements. The model is suitable for any waveforms applied to the magnetic component and can separate the working conditions of the different windings. The main drawbacks of this procedure are that it is necessary to have the magnetic component already built and to have available a measurement apparatus such as an impedance analyzer.