Induction Coil With T-Like Ferrite Bodies for Leakage Control
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Solution Overview
Problem
Existing induction coils face challenges in efficiently routing magnetic fields and preventing magnetic field leakage, particularly during inductive power transfer, which can lead to increased magnetic coupling and detuning of resonant frequencies.
Innovation Solution
The induction coil design incorporates ferrite bodies with a T-like configuration, featuring a wider head region and a narrower stem region, arranged to cover 30-70% of the winding body area, ensuring minimal magnetic coupling with the support plate and efficient flux routing without saturation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If ferrite bodies are arranged under the induction coil to route magnetic field lines downward, then magnetic field routing is improved, but magnetic field leakage and coupling with the support plate increase
Solution Approach 1:
The induction coil is divided into multiple independent winding sections, each with its own ferrite bodies. This segmentation allows the magnetic field to be routed in controlled paths through individual ferrite bodies, reducing unwanted coupling between adjacent coil sections and minimizing magnetic field leakage to the support plate.
Solution Approach 2:
Ferrite bodies are selectively positioned at specific locations under the induction coil windings, particularly at corners and along edges where magnetic field leakage is most problematic. This local placement optimizes magnetic field routing in critical areas without requiring complete coverage, thereby reducing harmful coupling while maintaining efficient flux paths.
2Shape
If ferrite bodies are used to prevent downward propagation of magnetic field, then magnetic field control is improved, but resonant frequency detuning occurs due to increased magnetic coupling
Solution Approach 1:
The harmful magnetic coupling effect is extracted and isolated by positioning ferrite bodies specifically at corner regions and edges of the induction coil, rather than providing continuous coverage. This selective extraction of ferrite material prevents excessive magnetic coupling that would cause resonant frequency detuning, while still maintaining sufficient magnetic field control in critical leakage areas.
Solution Approach 2:
Instead of providing complete ferrite body coverage under the entire induction coil, the invention uses partial coverage with ferrite bodies positioned only where most needed (corners and edges). This partial action is sufficient to control magnetic field leakage while avoiding the excessive magnetic coupling that would occur with full coverage, thereby maintaining resonant frequency stability.
3Productivity
If ferrite bodies cover larger area of winding body, then magnetic field routing efficiency is improved, but magnetic coupling with support plate increases
Solution Approach 1:
The ferrite body coverage is segmented into discrete bodies positioned at specific strategic locations (corners and edges) rather than providing continuous large-area coverage. This segmentation maintains efficient magnetic field routing at critical leakage points while creating gaps that reduce overall magnetic coupling with the support plate, minimizing energy 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
This design minimizes magnetic field leakage, reduces magnetic coupling with the support plate, and maintains optimal resonant frequencies for inductive power transfer, enhancing efficiency and reducing losses.
Implementation Method 1
an induction coil (26) with a plurality of ferrite bodies (30), in particular with T-like ferrite bodies (30), arranged under the induction coil (26) in order to route magnetic fields (FH, FL) generated by the induction coil (26)
Implementation Method 2
an induction coil (26) with a plurality of ferrite bodies (30)
Implementation Method 3
in order to transfer inductive power from the induction coil (26) to an electrical consumer with an opposing induction coil or receiver coil (43) positioned at a given distance from the induction coil (26)
Data Source
AI summary
An induction coil for a cooktop has a winding body in the form of a flat, spirally wound coil and at least four identical individual ferrite bodies therebelow. The ferrite bodies each have two regions, wherein a first, inner region is a stem region extending radially, and a second, outer region is a head region which adjoins the stem region and is wider in terms of angular degrees at its greatest width than the stem region at its greatest width. In terms of absolute width, it is over 50% wider than the stem region at its greatest width and projects radially beyond the winding body. The stem region widens radially in terms of absolute width from radially inside to radially outside, wherein it narrows radially in terms of angular degrees from radially inside to radially outside over a range of between 40% and 80% of the radius of the winding body or over a range of between 25% and 75% of the length of the ferrite body.