Lessening gap loss concentration problems in nanocrystalline cores by alloy gap replacement

Abstract

A simple method is proposed here to improve the gap loss concentration problem of a nanocrystalline core in an LCL filter inductor for high switching frequency converters using SiC devices. This alloy-gapped inductor design aims to reach two primary goals. First, to reduce the concentrated gap loss in a nanocrystalline core. Second, decrease the maximum temperature around the gap region and lead to more even temperature distribution. A finite element (FE) power loss and thermal models, validated by experiment, have been created to evaluate the proposed design. Based on the FE model results, the eddy current loss on the surfaces, which used to have the most severe gap loss is reduced by either 70% or 40% for the two commonly used winding placements. The total eddy current loss can be reduced by 29% and 27% for those two winding placements. In addition, FEA thermal model indicates that the hotspot temperature can be significantly decreased, and the nanocrystalline core can achieve a more uniform temperature distribution by this design, which can be a potential downsize method for the nanocrystalline core inductor.