Composite Dust Core Composition for Low Core Loss Inductors

Solution Overview

Problem

Inductors with dust cores used in hybrid vehicles and transforming stations face challenges in achieving both low core loss and excellent direct-current superposition characteristics, as existing solutions either prioritize core loss reduction or magnetic permeability enhancement without evaluating direct-current superposition characteristics simultaneously.

Innovation Solution

A dust core composed of a crystalline magnetic material and an amorphous magnetic material, with a core alloy ratio of 83 mass percent or more, where the particle size distribution of the amorphous magnetic material is greater than or equal to that of the crystalline material, and a first particle size ratio between 0.3 and 2.6, enhancing direct-current superposition characteristics and reducing core loss.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If a dust core is made by compacting soft magnetic powder to reduce core loss, then core loss is reduced, but direct-current superposition characteristics deteriorate

Engineering Contradiction:

Improvecore lossVSAvoiddirect-current superposition characteristics

Core Design Contradiction:

Loss of energyVSReliability

Solution Approach 1:

The dust core uses a composite material consisting of carbonyl iron powder (crystalline magnetic material) mixed with Sendust powder (amorphous magnetic material). This composite structure allows the carbonyl iron powder to provide low core loss while the Sendust powder enhances direct-current superposition characteristics, resolving the contradiction between reducing core loss and maintaining reliability under direct-current bias.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The invention changes the material composition parameters by specifying a mixed powder formulation containing 5-20 weight percent Sendust powder with carbonyl iron powder. This parameter adjustment optimizes both core loss and direct-current superposition characteristics simultaneously, transforming the trade-off into a balanced performance.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If crystalline magnetic material powder is used to enhance direct-current superposition characteristics, then direct-current superposition characteristics are improved, but core loss increases

Engineering Contradiction:

Improvedirect-current superposition characteristicsVSAvoidcore loss

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The dust core uses a composite material consisting of carbonyl iron powder (crystalline magnetic material) mixed with Sendust powder (amorphous magnetic material). This composite structure allows the carbonyl iron powder to provide low core loss while the Sendust powder enhances direct-current superposition characteristics, resolving the contradiction between reducing core loss and maintaining reliability under direct-current bias.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The invention changes the material composition parameters by specifying a mixed powder formulation containing 5-20 weight percent Sendust powder with carbonyl iron powder. This parameter adjustment optimizes both core loss and direct-current superposition characteristics simultaneously, transforming the trade-off into a balanced performance.

Inventive Principle:

Principle #35Parameter changes

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 enhances direct-current superposition characteristics and reduces core loss in inductors, maintaining high magnetic permeability even under applied bias electric fields, suitable for applications in hybrid vehicles and transforming stations.

Implementation Method 1

the amorphous soft magnetic powder is regarded as material for reducing the core loss of the inductor

Methodology Applied

Scientific EffectMagnetic hysteresis: Magnetic Hysteresis

Implementation Method 2

the crystalline soft magnetic powder is regarded as material which increases the filling factor of the powder mixture to increase the magnetic permeability

Methodology Applied

Scientific EffectMagnetic permeability: Ferromagnetism

Data Source

PatentUS12103081B2Dust core, method for manufacturing dust core, inductor including dust core, and electronic/electric device including inductor

Publication Date: 2024.10.01 DELTA ELECTRONICS (JAPAN) INC

AI summary

A dust core contains a powder of a crystalline magnetic material powder and a powder of an amorphous magnetic material. The sum of the content of the crystalline magnetic material powder and the content of the amorphous magnetic material powder is 83 mass percent or more. The mass ratio of the content of the crystalline magnetic material powder to the sum of the content of the crystalline magnetic material powder and the content of the amorphous magnetic material powder is 20 mass percent or less. The median diameter D50a of the amorphous magnetic material powder is greater than or equal to the median diameter D50c of the crystalline magnetic material powder. A 10% cumulative diameter D10a in a volume-based cumulative particle size distribution of the amorphous magnetic material powder is 9.5 μm or less.