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Description
Finemet-type alloys are very promising materials for the inductive cores of chokes. The functional properties of such materials produced during the recrystallization of amorphous ribbons can be widely modified by the recrystallization parameters. Moreover, due to the small thickness of the nanocrystalline ribbon, the eddy current losses might be controlled by the changes in the effective conductivity of the core, determined by the efficiency of the contact between the layers of the ribbon ring core.
On the other hand, a very promising method of controlling the magnetodynamic parameters of the inductive cores of chokes is introducing the gaps in the magnetic circuit of the ribbon ring core [1]. Such gaps increase the core’s reluctance as well as cause a magnetic flux fringing effect connected with the spreading out of the magnetic flux lines as they pass through an air gap in a magnetic core. In addition, this effect can be controlled by the changes in the gap width. In addition, it is possible to split one single gap into a series of smaller gaps [2] for better control of the results.
However, an efficient modeling method is necessary for a better understanding and control of both the magnetic flux fringing effect and eddy current losses in one single gap into a series of smaller gaps in the magnetic circuit. This paper presents the results of the investigation on modeling the Finemet-type ribbon ring-shaped core with a double gap. Moreover, the ribbon ring-shaped core was subjected to high-pressure epoxy covering to improve its mechanical stability and increase the electrical separation among the ribbon layers.
Investigation was carried out on the base of open source software. A modeling toolchain covering NETGEN tetrahedral mesher, ELMER FEM solver, and GNU-OCTAVE control was created. The paper presents the modeling results compared to the experimental measurements and guidelines for the efficient finite elements-based modeling of the magnetization characteristics and losses in nanocrystalline ribbon ring-shaped cores with single or a series of gaps.
Acknowledgements
This work was supported by the National Centre for Research and Development under European Funds for a Modern Economy (FENG SMART). The project title: "Advanced design and production of hybrid cores for chokes in high-speed motor filters operating at higher frequencies using numerical analysis and innovative process improvement technologies", project number: FENG.01.01-IP.01-A00H/23.
References
[1] D. I. Zaikin et al., “An Air-Gap Shape Optimization for Fringing Field Eddy Current Loss Reductions in Power Magnetics,” IEEE Transactions on Power Electronics, vol. 34, no. 5. Institute of Electrical and Electronics Engineers (IEEE), pp. 4079–4086, May 2019. https://doi.org/10.1109/tpel.2018.2868289
[2] G. Calderon-Lopez et al., “Mitigation of Gap Losses in Nanocrystalline Tape-Wound Cores,” IEEE Transactions on Power Electronics, vol. 34, no. 5. Institute of Electrical and Electronics Engineers (IEEE), pp. 4656–4664, May 2019. https://doi.org/10.1109/tpel.2018.2863665
