Gapped Inductor Coil With Compressed Windings for Lower AC Loss
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Solution Overview
Problem
Inductor coils with flat helical wound copper or ribbon-shaped windings face high AC losses due to thick copper foils required for low DC resistance, leading to significant temperature rises and increased manufacturing costs, especially with large magnetic gaps causing fringing fields and eddy losses.
Innovation Solution
The design incorporates a compressed conductor configuration around a core with strategically placed gaps, using a non-conductive spacer to avoid fringing fields and maximize copper fill, reducing AC losses to 1-3 times DC losses while maintaining low DC resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If large magnetic gap is used to achieve desirable maximum saturation currents, then saturation current is improved, but fringing fields increase causing eddy losses and temperature rises
Solution Approach 1:
The magnetic core is designed with non-uniform cross-sectional area along its length, with the narrowest section positioned at the gap location. This local quality change concentrates the magnetic flux in the gap region, reducing fringing fields and eddy losses in surrounding materials while maintaining the required saturation current capability
Solution Approach 2:
The core cross-sectional area is varied along the length of the core, creating a tapered or stepped profile. This parameter change optimizes the magnetic flux distribution, confining fringing fields to minimal regions and reducing eddy current losses in adjacent conductive materials
2Temperature
If bobbin shapes are modified to avoid temperature hot spots, then thermal performance is improved, but cross sectional area for copper is reduced
Solution Approach 1:
The conductor cross-section is changed from flat to circular, and the winding geometry is optimized to improve heat dissipation. The circular cross-section has better thermal contact with the core and surrounding structures, improving thermal performance without requiring changes to the bobbin shape that would reduce copper area
Solution Approach 2:
By using circular cross-section conductors wound in three-dimensional space around the core, the invention achieves better thermal distribution through increased surface area contact and more uniform heat generation, eliminating the need for thermal optimization through bobbin shape modification
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 configuration achieves lower or equal DC resistance with significantly reduced AC losses and improved thermal performance by minimizing eddy currents and maximizing copper fill, thus enhancing the inductor coil's efficiency and thermal stability.
Implementation Method 1
Larger magnetic gaps result in larger fringing fields, and any permeable material placed close to the magnetic gap will incur eddy losses
Implementation Method 2
a significant disadvantage relating to AC losses within the flat wound element of the coil
Implementation Method 3
State of the inductor coils use flat helical wound copper or ribbon shaped windings for high current applications. This leads to low values of direct current resistance (DCR)
Implementation Method 4
the large gap in the core of the coil that is required to achieve desirable maximum saturation currents
Implementation Method 5
a core is formed from the first component and the second component
Data Source
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.