Magnetic Core Distributed Gap Flux Offset

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Solution Overview

Problem

Conventional energy transfer elements in switched mode power supplies face challenges with power loss due to eddy currents in permanent magnets and variability in flux density offset, making them impractical for mass production.

Innovation Solution

An energy transfer element comprising a U-shaped core with a gap and a bar of magnetizable material, such as Neodymium Iron Boron or Samarium Cobalt, which is magnetized to provide a flux density offset, reducing power loss and enabling cost-effective manufacturing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a permanent magnet is inserted into the air gap to provide flux density offset, then the flux density offset is provided, but eddy currents are generated causing power dissipation

Engineering Contradiction:

Improveflux density offsetVSAvoidpower dissipation

Core Design Contradiction:

Manufacturing precisionVSLoss of energy

Solution Approach 1:

The patent removes the permanent magnet from the air gap and extracts only the necessary function of providing flux density offset. Instead, it uses a combination of air gap and magnetic core material to achieve the same effect without the harmful eddy currents that occur with permanent magnets.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent converts the harmful effect of eddy currents in permanent magnets into a beneficial solution by using distributed air gaps in the magnetic core. The air gaps, which were traditionally seen as necessary but space-consuming, are now distributed throughout the core material to provide both the flux density offset and eliminate eddy current losses.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

2Manufacturing precision

If a permanent magnet is inserted into the air gap to provide flux density offset, then the flux density offset is provided, but the thickness matching is difficult resulting in unacceptable tolerances

Engineering Contradiction:

Improveflux density offsetVSAvoidmass production

Core Design Contradiction:

Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent changes the parameter of flux density offset provision from using a separate permanent magnet component to using the intrinsic properties of the magnetic core material itself. By controlling the composition and distribution of magnetic particles within the core, the flux density offset is achieved through material parameters rather than dimensional parameters, eliminating thickness matching issues.

Inventive Principle:

Principle #35Parameter changes

3Power

If a discrete air gap is used in the magnetic path, then the energy distribution is managed, but the flux density offset variability occurs

Engineering Contradiction:

Improveenergy distributionVSAvoidflux density offset consistency

Core Design Contradiction:

PowerVSManufacturing precision

Solution Approach 1:

The patent segments the discrete air gap into multiple distributed air gaps throughout the magnetic core. This segmentation allows for more uniform energy distribution while the surrounding magnetic material provides consistent flux density offset. The distributed structure reduces variability by spreading the magnetic path characteristics throughout the core rather than concentrating them at a single discrete gap location.

Inventive Principle:

Principle #1Segmentation

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 solution effectively reduces power loss and enhances the efficiency of energy transfer while allowing for cost-effective mass production by using magnetizable materials that can be easily magnetized, improving flux density offset consistency.

Implementation Method 1

When the magnetizable material is magnetized, the flux density produced by the magnetized material is offset from the initial flux density

Methodology Applied

Scientific EffectMagnetization: Magnetism

Implementation Method 2

The core provides a path for a magnetic field generated by an electric current in the coils of wire

Methodology Applied

Scientific EffectMagnetic field: Magnetic Field

Implementation Method 3

the permanent magnet may be susceptible to eddy currents. The eddy current can produce an undesirable power dissipation in the magnet

Methodology Applied

Scientific EffectEddy currents: Eddy Currents

Data Source

PatentUS20220208447A1Magnetic core with distributed gap and flux density offset

Publication Date: 2022.06.30 POWER INTEGRATIONS INC

AI summary

An energy transfer element comprises a U-shaped core of powder core, the U-shaped core having two legs and a gap in a magnetic path, a bar comprising magnetizable material positioned in the gap such that the magnetic core and magnetizable material form a rectangular toroid, and one or more power windings wrapped around the magnetic path. The magnetizable material is capable of being magnetized. When the magnetizable material is unmagnetized, the magnetizable material has an initial flux density. When the magnetizable material is magnetized, the flux density produced by the magnetized material is offset from the initial flux density. The magnetizable material is an unmagnetized magnet or a suspension medium such as epoxy with magnetized magnetizable particles and powder core. The magnetizable particles are selected from a group comprising Neodymium Iron Boron (NdFeB) based materials or Samarium Cobalt (SmCo) based material.