Composite Magnetic Core Reactor for High Current Saturation
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Solution Overview
Problem
The DC superposition characteristic of inductance in reactors using composite magnetic cores, combining ferrite and soft magnetic metal cores, is inferior due to magnetic saturation issues, leading to decreased inductance and increased copper loss at high currents.
Innovation Solution
The reactor design includes a pair of yoke portion cores with ferrite, winding portion cores made of soft magnetic metal with a constant cross-sectional area, and tabular soft magnetic metal powder junction portion cores with a larger cross-sectional area (1.3 to 4.0 times that of the winding portion cores) to prevent magnetic saturation, along with optional gaps to adjust permeability and inductance levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a ferrite core is used to reduce iron loss at high frequency, then iron loss decreases, but saturation magnetic flux density is lower causing magnetic saturation at large currents
Solution Approach 1:
The patent combines ferrite core and soft magnetic metal core into a composite magnetic core structure. The ferrite core provides low iron loss at high frequency, while the soft magnetic metal core provides high saturation magnetic flux density, thus resolving the contradiction between reducing iron loss and maintaining reliability under large currents.
Solution Approach 2:
The patent uses composite magnetic core made of ferrite and soft magnetic metal materials. This composite structure allows the reactor to benefit from both materials: ferrite's low high-frequency loss and soft magnetic metal's high saturation flux density, simultaneously addressing both requirements.
2Loss of energy
If a composite magnetic core combining ferrite and soft magnetic metal core is used to reduce loss, then iron loss decreases, but DC superposition characteristic of inductance deteriorates
Solution Approach 1:
The patent applies different materials to different parts of the magnetic core: ferrite is used in the yoke portion where low loss is critical, while soft magnetic metal is used in the winding portion where high saturation flux density is needed. This local differentiation optimizes both iron loss reduction and DC superposition characteristic.
3Reliability
If the cross sectional area of ferrite core is increased to avoid magnetic saturation, then saturation magnetic flux density improves, but the shape becomes larger
Solution Approach 1:
By combining ferrite core and soft magnetic metal core, the patent achieves high saturation magnetic flux density without increasing overall core volume. The soft magnetic metal core contributes its high saturation flux density property, allowing the ferrite core to maintain a compact size while still avoiding magnetic saturation under large currents.
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 configuration improves the DC superposition characteristic of inductance, maintaining high inductance values even at high currents while reducing iron loss and allowing for miniaturization and adjustable inductance levels.
Implementation Method 1
the magnetic flux 23 in the soft magnetic metal core 22 is equivalent to that in the ferrite core 21
Implementation Method 2
the ferrite core has a lower saturation magnetic flux density compared to the soft magnetic metal core 22
Implementation Method 3
the magnetic flux 23 excited in the soft magnetic metal core of the winding portion
Data Source
AI summary
A reactor using a composite magnetic core in which a ferrite core and a soft magnetic metal core are combined. The reactor is composed of a pair of yoke portion magnetic portions composed of ferrite, winding portion core(s) disposed between the opposite planes of the yoke portion cores, and coil(s) winding around the winding portion core(s). The winding portion core(s) is/are formed using a soft magnetic metal core with a substantially constant cross sectional area. Junction portion cores composed of soft magnetic metal powder cores with a tabular shape are disposed at the spaces where the winding portion core(s) face(s) the yoke portion cores, and the area of the part where the junction portion core faces the yoke portion core is made to be 1.3 to 4.0 times that of the section of the winding portion core.