Compressed Inductor Coil with Spaced Gap Conductor

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Solution Overview

Problem

Existing inductor coils face issues with high direct current resistance (DCR) and significant AC losses, particularly at high frequencies, due to the use of flat wound copper windings and large magnetic gaps, which cause temperature rises and increased manufacturing costs.

Innovation Solution

The inductor coil design incorporates a core formed by two components with a gap, where the conductor is compressed along the central axis and spaced further from the axis at the gap location, using a non-conductive spacer to minimize eddy currents and maximize cross-sectional area, reducing DCR and AC losses.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If large magnetic gaps are used to achieve desirable maximum saturation currents, then saturation current capability is improved, but fringing fields increase causing eddy losses and temperature rises

Engineering Contradiction:
Improvesaturation currentVSAvoidfringing fields and eddy losses
Core Design Contradiction:
PowerVSObject-affected harmful factors

Solution Approach 1:

The conductor is positioned at different distances from the central axis at different locations: spaced further from the axis at the gap location to avoid fringing fields, and closer at other locations to maximize magnetic coupling and reduce DCR

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The conductor is compressed in advance at the gap location during assembly, positioning it optimally before the coil is fully assembled, ensuring it is spaced further from the axis where fringing fields are present while maintaining proper positioning elsewhere

Inventive Principle:
Principle #10Preliminary action

2Temperature

If bobbin shapes are used to avoid temperature hot spots, then thermal performance is improved, but cross sectional area for copper is reduced

Engineering Contradiction:
Improvethermal performanceVSAvoidcross sectional area for copper
Core Design Contradiction:
TemperatureVSArea of stationary object

Solution Approach 1:

The conductor positioning is optimized locally at the gap location where it is spaced further from the central axis, creating a non-uniform distribution that avoids hot spots in high-field regions while maximizing copper area in other regions

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The conductor is positioned in three-dimensional space at varying distances from the central axis along the gap, utilizing the radial dimension to avoid fringing fields while maintaining axial and circumferential positioning for optimal magnetic coupling

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 achieves lower DCR and AC losses comparable to existing coils, with AC losses only 1-3 times the DC losses, while avoiding temperature hotspots and maximizing thermal performance.

Implementation Method 1

At least one section of the first part of the length of conductor is compressed in the direction of the central axis

Methodology Applied
Scientific EffectCompression: Compression

Implementation Method 2

Larger magnetic gaps result in larger fringing fields, and any permeable material placed close to the magnetic gap will incur eddy losses

Methodology Applied
Scientific EffectEddy currents: Eddy Currents

Implementation Method 3

the large gap in the core of the coil that is required to achieve desirable maximum saturation currents

Methodology Applied
Scientific EffectMagnetic saturation: Magnetic Saturation

Data Source

PatentEP3992996B1An inductor coil
Publication Date: 2025.07.23 ETA GREEN POWER LTD
  • EP3992996B1 patent drawingFigure 1
  • EP3992996B1 patent drawingFigure 2
  • EP3992996B1 patent drawingFigure 3

AI summary

The present invention relates to an inductor coil, comprising: a first component (12); a second component (14); and a length of conductor (18); wherein, the first component is located adjacent to the second component; wherein, a core (16) is formed from the first component and the second component; wherein the core is located along a first portion of a central axis and a second portion of the central axis; wherein, along a third portion of the central axis the first component is spaced from the second component to form a gap (20, 30) in the core, wherein the third portion of the central axis is between the first portion of the central axis and the second portion of the central axis; wherein, a first part of the length of conductor is located around the first portion of the central axis, located around the second portion of the central axis, and located around the third portion of the central axis to form a plurality of turns of conductor around the core and the gap in the core; and wherein, at least one section of the first part of the length of conductor is compressed in the direction of the central axis.