Nested Bobbin Magnetic Component Leakage Inductance

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Solution Overview

Problem

Transformers with stacked windings experience excessive leakage inductance due to incomplete coupling, leading to increased magnetic interference and loss.

Innovation Solution

A magnetic component design featuring a first core, second core, outer bobbin, inner bobbin, and windings where the second winding is stacked inside the first winding, with the inner bobbin's top and bottom portions abutting the outer bobbin's hollow tube, maintaining a fixed distance and reducing overall height, thereby minimizing leakage inductance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If windings are stacked from top to bottom in a core, then the structure is simple and easy to manufacture, but the windings cannot be fully coupled resulting in excessive leakage inductance

Engineering Contradiction:

Improvewinding structure simplicityVSAvoidleakage inductance

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent applies nesting by placing the inner bobbin with second winding inside the hollow tube portion of the outer bobbin with first winding. This nested configuration enables the windings to be closely coupled while maintaining manufacturing simplicity, effectively reducing leakage inductance from 0.22 pH to 0.08 pH as demonstrated in the patent.

Inventive Principle:

Principle #7Nested doll (Nesting)

2Reliability

If windings are fully coupled to reduce leakage inductance, then magnetic interference and loss are reduced, but the device complexity increases

Engineering Contradiction:

Improveleakage inductanceVSAvoidbobbin structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent segments the bobbin structure into an outer bobbin and an inner bobbin, each with distinct windings. This segmentation allows independent optimization of each winding while achieving full coupling, reducing leakage inductance without excessive complexity increase.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The nested bobbin structure places the inner bobbin within the outer bobbin's hollow tube portion, creating a compact yet fully coupled winding arrangement that achieves low leakage inductance while controlling overall device complexity.

Inventive Principle:

Principle #7Nested doll (Nesting)

3Reliability

If the distance between windings is reduced to improve coupling, then leakage inductance decreases, but the manufacturing precision requirements increase

Engineering Contradiction:

Improvecoupling efficiencyVSAvoidwinding distance control

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The nested configuration of inner and outer bobbins provides a structurally defined spacing between windings. The hollow tube portion of the outer bobbin and the positioning features ensure consistent winding distance without requiring extreme manufacturing precision, achieving full coupling while maintaining manufacturability.

Inventive Principle:

Principle #7Nested doll (Nesting)

4Volume of moving object

If the overall height of the magnetic component is reduced for miniaturization, then the device size decreases, but the available space for windings is reduced

Engineering Contradiction:

Improvemagnetic component sizeVSAvoidwinding arrangement complexity

Core Design Contradiction:

Volume of moving objectVSDevice complexity

Solution Approach 1:

The patent reduces the overall height by nesting the inner bobbin within the outer bobbin's hollow tube portion. This vertical stacking arrangement minimizes the height dimension while providing sufficient space for both windings, enabling miniaturization without compromising winding capacity or increasing excessive complexity.

Inventive Principle:

Principle #7Nested doll (Nesting)

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

Effectively reduces leakage inductance and magnetizing inductance, allowing for miniaturization of the magnetic component while maintaining performance, with demonstrated reductions in leakage inductance from 0.22 pH to 0.08 pH.

Implementation Method 1

A transformer is an important magnetic component used for increasing or decreasing voltage

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

the windings cannot be fully coupled, thereby resulting in a problem of excessive leakage inductance, which increases magnetic interference and loss

Methodology Applied

Scientific EffectMagnetic coupling: Magnetic Field

Data Source

PatentUS20230223187A1Magnetic component

Publication Date: 2023.07.13 CYNTEC

AI summary

A magnetic component includes a first core, a second core, an outer bobbin, a first winding, an inner bobbin and a second winding. The outer bobbin is disposed between the first core and the second core. The outer bobbin has a hollow tube portion, a first bottom portion and a first top portion. The first winding is wound around outer side of the hollow tube portion. The inner bobbin is disposed in the hollow tube portion. The inner bobbin has a second bottom portion and a second top portion. The second winding is wound around the inner bobbin. The second bottom portion is exposed to bottom side of the first bottom portion, such that the first bottom portion overlaps the second bottom portion in a height direction of the magnetic component. The second top portion and the second bottom portion abut against inner side of the hollow tube portion.