Impact of Encapsulation on the Core Loss of Ferrites in Inductive Power Transfer

Inductive power transfer (IPT) magnetics are often “potted” with an encapsulant material to improve thermal performance. Mismatched thermal expansion of the encapsulation and magnetic core materials creates a residual mechanical stress that permanently reduces the magnetic perf...

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Main Authors: Alexander K. Bailey, Willsen Wijaya, Seho Kim, Jerry Sun, Tom Allen, Grant A. Covic
Format: Article
Language:English
Published: IEEE 2025-01-01
Series:IEEE Open Journal of Power Electronics
Subjects:
Online Access:https://ieeexplore.ieee.org/document/11060834/
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author Alexander K. Bailey
Willsen Wijaya
Seho Kim
Jerry Sun
Tom Allen
Grant A. Covic
author_facet Alexander K. Bailey
Willsen Wijaya
Seho Kim
Jerry Sun
Tom Allen
Grant A. Covic
author_sort Alexander K. Bailey
collection DOAJ
description Inductive power transfer (IPT) magnetics are often &#x201C;potted&#x201D; with an encapsulant material to improve thermal performance. Mismatched thermal expansion of the encapsulation and magnetic core materials creates a residual mechanical stress that permanently reduces the magnetic performance of the Mn&#x2013;Zn ferrite core layer. An encapsulated small-scale Double-D IPT pad designed for <inline-formula><tex-math notation="LaTeX">$\mathrm{2.5}$</tex-math></inline-formula> <inline-formula><tex-math notation="LaTeX">$\mathrm{kW}$</tex-math></inline-formula> is built and tested, and the core loss of the ferrite tiles increases by <inline-formula><tex-math notation="LaTeX">$\mathrm{121}$</tex-math></inline-formula>% after encapsulation with a polyurethane-based material. The change in the core loss of the potted IPT pad after encapsulation is predicted using finite element analysis, and the proposed method matches within <inline-formula><tex-math notation="LaTeX">$\mathrm{7.3}$</tex-math></inline-formula>% . Three methods are presented to mitigate this increase in losses and experimentally verified on ferrite toroids. These results show that the choice of encapsulation material significantly impacts the thermal, structural, and electromagnetic behavior of the IPT pad.
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publishDate 2025-01-01
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series IEEE Open Journal of Power Electronics
spelling doaj-art-6eb28cc3a7124187a5b2e2e9c4b845722025-08-20T02:40:47ZengIEEEIEEE Open Journal of Power Electronics2644-13142025-01-0161215122410.1109/OJPEL.2025.358475311060834Impact of Encapsulation on the Core Loss of Ferrites in Inductive Power TransferAlexander K. Bailey0https://orcid.org/0009-0002-6131-8648Willsen Wijaya1Seho Kim2https://orcid.org/0000-0002-8396-5902Jerry Sun3Tom Allen4Grant A. Covic5https://orcid.org/0000-0002-4480-7370Department of Electrical, Computer and Software Engineering, The University of Auckland, Auckland, New ZealandCentre for Advanced Materials Manufacturing and Design, The University of Auckland, Auckland, New ZealandDepartment of Electrical, Computer and Software Engineering, The University of Auckland, Auckland, New ZealandCentre for Advanced Materials Manufacturing and Design, The University of Auckland, Auckland, New ZealandCentre for Advanced Materials Manufacturing and Design, The University of Auckland, Auckland, New ZealandDepartment of Electrical, Computer and Software Engineering, The University of Auckland, Auckland, New ZealandInductive power transfer (IPT) magnetics are often &#x201C;potted&#x201D; with an encapsulant material to improve thermal performance. Mismatched thermal expansion of the encapsulation and magnetic core materials creates a residual mechanical stress that permanently reduces the magnetic performance of the Mn&#x2013;Zn ferrite core layer. An encapsulated small-scale Double-D IPT pad designed for <inline-formula><tex-math notation="LaTeX">$\mathrm{2.5}$</tex-math></inline-formula> <inline-formula><tex-math notation="LaTeX">$\mathrm{kW}$</tex-math></inline-formula> is built and tested, and the core loss of the ferrite tiles increases by <inline-formula><tex-math notation="LaTeX">$\mathrm{121}$</tex-math></inline-formula>% after encapsulation with a polyurethane-based material. The change in the core loss of the potted IPT pad after encapsulation is predicted using finite element analysis, and the proposed method matches within <inline-formula><tex-math notation="LaTeX">$\mathrm{7.3}$</tex-math></inline-formula>% . Three methods are presented to mitigate this increase in losses and experimentally verified on ferrite toroids. These results show that the choice of encapsulation material significantly impacts the thermal, structural, and electromagnetic behavior of the IPT pad.https://ieeexplore.ieee.org/document/11060834/Core lossinductive power transfer (IPT)loss measurementmagnetic losses
spellingShingle Alexander K. Bailey
Willsen Wijaya
Seho Kim
Jerry Sun
Tom Allen
Grant A. Covic
Impact of Encapsulation on the Core Loss of Ferrites in Inductive Power Transfer
IEEE Open Journal of Power Electronics
Core loss
inductive power transfer (IPT)
loss measurement
magnetic losses
title Impact of Encapsulation on the Core Loss of Ferrites in Inductive Power Transfer
title_full Impact of Encapsulation on the Core Loss of Ferrites in Inductive Power Transfer
title_fullStr Impact of Encapsulation on the Core Loss of Ferrites in Inductive Power Transfer
title_full_unstemmed Impact of Encapsulation on the Core Loss of Ferrites in Inductive Power Transfer
title_short Impact of Encapsulation on the Core Loss of Ferrites in Inductive Power Transfer
title_sort impact of encapsulation on the core loss of ferrites in inductive power transfer
topic Core loss
inductive power transfer (IPT)
loss measurement
magnetic losses
url https://ieeexplore.ieee.org/document/11060834/
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