Computation of current waveform in ferrite power inductors for application in buck-type converters

In this paper we propose a model for the analysis of the current waveform in ferrite power inductors subjected to large-signal square-wave voltage, a typical regime of present-day switch-mode power supplies. This problem is characterized by the non-linear response of the inductor across a wide range of current values, up to the limit of inductor saturation. Consequently, non-linear differential equations must be adopted in the description of the circuit. In this paper, we solve the equations of the circuit through an effective iterative method, by which the current waveform is computed through successive approximations. These results are eventually verified by comparison with experiments performed on a commercial buck-type converter.