Current Control of Interleaved DC-DC Converter Considering a Current Dependent Inductance

Inductors with soft saturation cores built on compressed iron powder have higher saturation flux densities in comparison to ferrite gapped inductors, exhibiting a gradual drop of permeability for increasing magnetic field strength. This behavior yields to a gradual drop of differential inductance for increasing current, which avoids sudden core saturation and overcurrent produced in hard saturation cores as the inductance plummets when the maximum flux density is reached. However, the inductance in soft saturation cores starts dropping in the wide range of nominal current operation, increasing the complexity of the converter model and the control scheme. In this work, an interleaved dc-dc converter for supercapacitor management is modeled in continuous and discontinuous conduction mode, considering an inductor core with a linear drop in the differential inductance. A suitable current control strategy is proposed. Analysis of the model is given and simulated results that confirm the performance of the proposed control strategy are shown.