Reactor Composite Magnetic Core DC Saturation

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Solution Overview

Problem

The DC superposition characteristic of inductance in reactors using composite magnetic cores, which combine ferrite and soft magnetic metal cores, is inferior due to magnetic saturation issues at high currents, leading to decreased inductance and increased copper loss.

Innovation Solution

The reactor design incorporates flange-like members made of soft magnetic metal cores with high saturation magnetic flux density, externally connected to the periphery of the winding portion core, to improve magnetic flux flow and prevent saturation, thereby enhancing the DC superposition characteristic of inductance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If ferrite core is used to reduce high-frequency iron loss, then iron loss decreases, but saturation magnetic flux density is lower causing larger core sectional area needed

Engineering Contradiction:

Improveiron lossVSAvoidcore sectional area

Core Design Contradiction:

Loss of energyVSArea of stationary object

Solution Approach 1:

The patent combines ferrite core and soft magnetic metal core into a composite magnetic core structure. The ferrite core provides low high-frequency iron loss, while the soft magnetic metal core provides high saturation magnetic flux density, thereby achieving both low loss and compact size without requiring a large ferrite core sectional area

Inventive Principle:

Principle #5Merging (Combining)

2Quantity of substance

If soft magnetic metal core is used to increase saturation magnetic flux density, then saturation magnetic flux density increases, but high-frequency iron loss becomes greater

Engineering Contradiction:

Improvesaturation magnetic flux densityVSAvoidiron loss

Core Design Contradiction:

Quantity of substanceVSLoss of energy

Solution Approach 1:

The composite magnetic core merges the advantages of both ferrite and soft magnetic metal materials. The soft magnetic metal core maintains high saturation magnetic flux density for handling large currents, while the ferrite core suppresses high-frequency iron loss, achieving both high saturation flux density and low energy loss

Inventive Principle:

Principle #5Merging (Combining)

3Loss of energy

If composite magnetic core combining ferrite and soft magnetic metal core is used to reduce loss and size, then iron loss and size decrease, but DC superposition characteristic of inductance deteriorates

Engineering Contradiction:

Improveiron lossVSAvoidDC superposition characteristic

Core Design Contradiction:

Loss of energyVSReliability

Solution Approach 1:

The patent applies local quality by creating a specific composite structure where soft magnetic metal core is positioned at the winding portion and ferrite core is positioned at the yoke portion. This local differentiation allows the winding portion to handle DC superposition currents effectively while the yoke portion provides low loss at high frequencies

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent uses composite materials by combining ferrite and soft magnetic metal in a structured composite magnetic core. This composite structure leverages the complementary properties of both materials to simultaneously improve DC superposition characteristics and reduce high-frequency losses

Inventive Principle:

Principle #40Composite materials

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 design effectively increases the inductance under DC superposition while minimizing high-frequency losses, achieving improved efficiency and miniaturization in power supply circuits and power conditioners.

Implementation Method 1

a first magnetic core 22 and a second magnetic core 21 made of different magnetic materials, respectively serving as a magnetic core for a winding portion and a magnetic core for a yoke portion

Methodology Applied

Scientific EffectMagnetic permeability: Magnetic Field

Implementation Method 2

the ferrite core has a lower saturation magnetic flux density compared to the stacked electromagnetic steel plate or the soft magnetic metal powder core

Methodology Applied

Scientific EffectHysteresis loss: Magnetic Hysteresis

Implementation Method 3

the ferrite core is well known as a material for magnetic core with a small iron loss at a high frequency

Methodology Applied

Scientific EffectEddy current: Eddy Currents

Implementation Method 4

the saturation magnetic flux density of the ferrite core is lower than that of the soft magnetic metal core

Methodology Applied

Scientific EffectMagnetic saturation: Magnetic Saturation

Data Source

PatentUS9959968B2Reactor

Publication Date: 2018.05.01 TDK CORP

AI summary

A reactor uses a composite magnetic core which combines a ferrite core and a soft magnetic metal core. The reactor is composed of a pair of yoke portion cores composed of ferrite cores, winding portion core(s) disposed between the opposite planes of the yoke portion cores, and coil(s) wound around the winding portion core(s). Flange-like members are disposed at the end part of the winding portion core(s) in a way of being external connected with the periphery of winding portion core(s) which is composed of a soft magnetic metal core. The flange-like member is composed of a metal material with iron as the main component which can be magnetically attracted to a magnet, and a junction portion of the flange-like member and the yoke portion core is formed at one flat plane of the member which is the same plane with an end plane of the winding portion core.