Calculation of Ferrite Core Losses with Arbitrary Waveforms using the Composite Waveform Hypothesis

A method, the improved generalized composite calculation (iGCC) is proposed for computing ferrite core losses. This method, which is an extension of the well-known improved generalized Steinmetz equation (iGSE), applies the composite waveform hypothesis (CWH) to arbitrary excitations by using a time-varying local equivalent frequency that describes the rate of change of the magnetic flux density. The advantages of the proposed method include the ability to model materials in a wide frequency range, especially waveforms with extreme duty cycles. Measurements conducted with “EPCOS TDK N87” ferrite material (with triangular and trapezoidal excitations, across a range of temperatures) show a significant improvement over the state-of-the-art.