Comparison of Gapped and Gapless Designs for an Automotive DC-DC Converter Inductor
This paper is aimed at comparing two designs, one comprising gaps in its magnetic circuit, the other one without, for a power inductor operating in the medium frequency range (10 - 20 kHz) and crossed by a triangular current superimposed with a DC bias. The goal is to find the design that satisfies the target inductance value using the minimum volume of materials. Two kinds of material are considered for the magnetic core: soft amorphous alloy to be used with the gapped configuration and powder to be used with the gapless one. The designs are calculated through a process that includes an analytical preliminary calculation and a numerical optimization. In the case of soft magnetic alloy, the magnetic non-linearity of the material is neglected in the analytical model. On the contrary, non-linearity of powder material can not be neglected. It requires the use of an iterative calculation. The numerical optimization is based on 2D Finite Element Analysis associated to a Simplex-type algorithm. It completes the analytical calculation to reach an appropriate solution for which the target inductance and minimum volume are reached simultaneously.
Keywordspower inductor analytical calculation finite element analysis optimization simulation
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