Composite Disc Magnet Segmentation for Eddy Current Reduction
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Solution Overview
Problem
Switched mode power converters experience power loss due to eddy currents in magnets used in energy transfer elements, which are not effectively mitigated by existing solutions like laminated magnets.
Innovation Solution
A composite disc magnet is created by assembling multiple discs with magnetically active material, where each disc is initially unmagnetized and then magnetized after assembly, with their faces perpendicular to the expected magnetic field, and coated with an electrically insulating material to prevent conduction, reducing power loss by increasing effective resistivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a single solid magnet is used in the air gap, then the magnetic flux density is sufficient, but eddy currents are generated causing power loss
Solution Approach 1:
The magnet is divided into multiple thin disc-shaped segments stacked along the magnetic field direction. Each disc is electrically insulated from adjacent discs, which breaks the continuous conductive path and reduces eddy current loops. This segmentation maintains the overall magnetic flux density while significantly reducing power loss from eddy currents.
Solution Approach 2:
The magnet assembly uses composite construction with magnetic material discs combined with electrically insulating layers between them. This composite structure provides both the necessary magnetic properties and electrical insulation to prevent eddy current formation, resolving the contradiction between maintaining magnetic flux and reducing power loss.
2Loss of energy
If the magnet is divided into multiple laminated discs, then eddy currents are reduced, but the manufacturing complexity increases
Solution Approach 1:
The magnet is divided into multiple thin disc-shaped segments stacked along the magnetic field direction. Each disc is electrically insulated from adjacent discs, which breaks the continuous conductive path and reduces eddy current loops. This segmentation maintains the overall magnetic flux density while significantly reducing power loss from eddy currents.
Solution Approach 2:
The magnet assembly uses composite construction with magnetic material discs combined with electrically insulating layers between them. This composite structure provides both the necessary magnetic properties and electrical insulation to prevent eddy current formation, resolving the contradiction between maintaining magnetic flux and reducing power loss.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The composite disc magnet design significantly reduces power loss from eddy currents compared to traditional single-disc magnets, enhancing the efficiency of energy transfer in power converters.
Implementation Method 1
coated with an electrically insulating material to prevent conduction, reducing power loss by increasing effective resistivity
Implementation Method 2
a magnet, such as a permanent magnet, utilized with the core to provide flux density offset for the core of magnetically active material
Implementation Method 3
the magnet may be susceptible to eddy currents. The eddy current can produce an undesirable power dissipation in the magnet
Data Source
AI summary
A magnet comprising a center disc having a center disposed as a center of the magnet, a face of the center disc is substantially perpendicular to a central axis of the magnet. The magnet further comprises a first plurality of outer discs disposed around the center disc in a bundled rod construction, a face of each of the first plurality of outer discs substantially perpendicular to the central axis of the magnet, wherein the center disc and each disc of the first plurality of outer discs is electrically insulated from every other disc.