Twisted-Winding Inductor Core Structure for EMI Suppression
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Solution Overview
Problem
Existing inductors are large in size and weight, and there is a need for a design that can efficiently suppress both common and differential mode interferences while minimizing stray fields and losses.
Innovation Solution
An inductor design featuring twisted windings embedded within a first core made of a low permeability magnetic material, surrounded by a second core of higher permeability material, with adjustable inductance and cooling passages, allowing for efficient cooling and reduced stray fields.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If traditional separate DM and CM inductors are used, then common mode and differential mode interference suppression is achieved, but the inductor size and weight increase
Solution Approach 1:
The patent combines common mode and differential mode windings into a single integrated inductor structure with a shared magnetic core. The first and second windings (common mode) and third and fourth windings (differential mode) are wound on the same core, merging two separate inductors into one, thereby reducing overall weight while maintaining both interference suppression functions
Solution Approach 2:
The magnetic core serves multiple functions simultaneously: it provides magnetic coupling for both common mode and differential mode windings, acts as a shielding structure for stray fields, and enables both CM and DM inductance values. This multi-functionality eliminates the need for separate dedicated structures for each function, reducing overall component weight
2Object-affected harmful factors
If traditional separate DM and CM inductors are used, then common mode and differential mode interference suppression is achieved, but the inductor volume increases
Solution Approach 1:
The patent implements a nested winding structure where differential mode windings are positioned inside or alongside common mode windings, and all windings share a common magnetic core. This nesting arrangement allows multiple inductance functions to coexist in a compact volume, significantly reducing the overall inductor size compared to separate inductors
Solution Approach 2:
By merging CM and DM windings into a single integrated structure with shared magnetic path and core material, the patent consolidates the volume required for two separate inductors into one compact unit, achieving both interference suppression functions within a reduced overall volume
3Volume of stationary object
If mouldable soft magnetic material is used for the core, then compact design and adjustable inductance are achieved, but manufacturing complexity increases
Solution Approach 1:
The patent utilizes mouldable soft magnetic material that can be formed into various core geometries and has adjustable magnetic properties. By changing material parameters such as permeability and forming different core shapes, the inductance values can be adjusted to meet specific application requirements while maintaining compact dimensions
Solution Approach 2:
The patent employs composite magnetic material structures, combining mouldable soft magnetic material with potentially different magnetic materials in specific regions (such as the second core with higher magnetic permeability). This composite approach enables optimization of both compact design and manufacturing characteristics by leveraging the advantages of different materials
4Object-generated harmful factors
If twisted windings are used, then stray fields are reduced and symmetric performance is achieved, but winding complexity increases
Solution Approach 1:
The patent implements twisted windings where adjacent windings are positioned with specific spatial relationships and orientations. This asymmetric twisting arrangement causes magnetic fields from adjacent windings to oppose and cancel each other, effectively reducing stray fields while maintaining symmetric electrical performance through careful design of the twisting pattern
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 design achieves high common mode inductance with minimized stray fields and losses, enabling applications in LCL filters, sine filters, converters, transformers, and EMI filters with improved symmetry and efficiency.
Implementation Method 1
at least two windings, configured to be twisted with each other and embedded within the first core, each winding having a pair of terminals extending out of the first core
Implementation Method 2
the second core is made of a second magnetic material having a higher magnetic permeability than that of the first magnetic material
Data Source
AI summary
An inductor and a method for producing an inductor are provided where the inductor includes a first core made of a first magnetic material, and at least two windings, configured to be twisted with each other and embedded within the first core, each winding having a pair of terminals extending out of the first core. A method for producing an inductor includes providing a package of the at least two windings twisted and separated from each other, and forming the first core from the first magnetic material over the at least two windings. A method for producing an inductor includes forming a second core from a second magnetic material over the first core.