Multilayer Inductor Core with High Resistivity Layers
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Inductors sealed with a magnetic powder and resin mixture have low relative magnetic permeability, leading to high direct current resistance and eddy current loss, which hinders the efficiency of DC-DC converters.
Innovation Solution
An inductor design featuring a core with multilayer parts of magnetic and insulating layers stacked alternately, where the second magnetic layers with higher electrical resistivity and relative magnetic permeability are arranged adjacent to the coil, reducing eddy current loss by increasing the resistivity and permeability product.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a sealing material composed of magnetic powder and resin is used to seal the coil, then the inductor can be manufactured with simplified structure, but the relative magnetic permeability is low leading to high direct current resistance
Solution Approach 1:
The patent uses a composite structure combining a soft magnetic alloy core with high relative magnetic permeability and a resin-based sealing material. The core provides the necessary magnetic properties while the resin provides mechanical protection and electrical insulation, achieving both low DC resistance and ease of manufacture.
Solution Approach 2:
The patent applies different materials to different regions: the core region uses soft magnetic alloy for high permeability, while the sealing region uses resin for protection. This local differentiation allows each region to optimize its function without compromising the other.
2Reliability
If the number of turns of the coil is increased to obtain the desired inductance value, then the inductance value can be increased, but the direct current resistance becomes high
Solution Approach 1:
The patent changes the magnetic properties of the core by using soft magnetic alloy with high relative magnetic permeability. This parameter change allows the inductor to achieve the desired inductance value with fewer coil turns, thereby reducing the direct current resistance.
3Loss of energy
If eddy current loss is reduced to improve DC-DC converter efficiency, then the efficiency can be increased, but the inductor structure becomes more complex
Solution Approach 1:
The patent segments the magnetic core into laminated layers with insulating coatings between them. This segmentation breaks the continuous magnetic path into discrete layers, which reduces eddy current loops and consequently reduces eddy current loss while maintaining a relatively simple overall structure.
Solution Approach 2:
The patent introduces insulating coatings as intermediary layers between the magnetic layers. These intermediary layers provide electrical insulation that interrupts eddy current paths, reducing eddy current loss without significantly complicating the inductor structure.
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 effectively reduces eddy current loss at light loads while maintaining inductance value, enhancing the efficiency of DC-DC converters by minimizing copper loss and iron loss.
Implementation Method 1
eddy current loss and the like generated by a magnetic field arising from a current that flows through the coil
Implementation Method 2
second magnetic layers that have a larger electrical resistivity than the first magnetic layers
Implementation Method 3
second magnetic layers that have a larger relative magnetic permeability than the first magnetic layers
Data Source
AI summary
An inductor includes a core including a multilayer part in which magnetic layers and insulating layers are alternately stacked; a coil including a wound part having a winding axis substantially perpendicular to a stacking direction of the multilayer part; and an element body. The multilayer part includes a first multilayer part in which first magnetic layers and insulating layers are alternately stacked and second and third multilayer parts in which second magnetic layers and insulating layers are alternately stacked, the electrical resistivity and/or relative magnetic permeability of the second magnetic layers being larger than those of the first magnetic layers. The first multilayer part has first and second surfaces that are perpendicular to the stacking direction and face each other and third and fourth surfaces that are parallel to the stacking and winding axis directions. The second and third multilayer parts are arranged on the first and second surfaces.