Self-Shielded High Frequency Inductor with Distributed Gaps
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Solution Overview
Problem
Magnetic components in power electronics, particularly RF inductors, face challenges in miniaturization due to high losses and size constraints, as they deteriorate with physical size reduction, leading to inefficiencies and electromagnetic interference.
Innovation Solution
A self-shielded inductor structure is developed using distributed gap ferrite pieces and a shorted conductive layer to minimize magnetic field leakage, employing field balancing and low-permeability materials to reduce winding and proximity effect losses, thereby containing magnetic fields within the structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If physical size of magnetic component is reduced, then size is decreased, but performance deteriorates
Solution Approach 1:
The patent employs a nested structure where the conductive shield is placed within the ferrite core structure, and distributed air gaps are integrated into the core geometry. This nesting allows multiple functional elements to occupy overlapping spatial volumes, achieving high performance in a compact form factor.
Solution Approach 2:
The patent utilizes three-dimensional flux confinement within the ferrite core structure, transitioning from traditional planar inductor designs. The distributed air gaps create vertical flux paths that充分利用 the available volume, enabling high performance in a compact footprint suitable for modern power electronics applications.
2Loss of energy
If ferrite pieces are distributed with gaps to reduce proximity effect losses, then proximity effect losses are reduced, but magnetic field confinement may be compromised
Solution Approach 1:
The conductive shield acts as an intermediary element between the ferrite core and the external environment. It captures and redirects magnetic flux that would otherwise leak from the distributed air gaps, converting potential harmful radiation into useful flux that returns through the shield to the core, thereby maintaining both low losses and good confinement.
Solution Approach 2:
The patent converts the potential harm of magnetic flux leakage from distributed air gaps into a benefit by using the conductive shield to recapture this flux. The shield transforms what would be energy loss into useful magnetic flux that contributes to the inductor's operation, reducing net losses while maintaining effective field confinement.
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 achieves high quality factors, reduces system enclosure volume, and enhances efficiency by minimizing losses and fringing fields, enabling operation at higher frequencies and power levels with improved flexibility in system design.
Implementation Method 1
The outer region of ferrite provides a shunt path for flux to flow
Implementation Method 2
If a metal object is placed perpendicularly to a time-varying magnetic field, eddy currents and loss are generated in the metal
Implementation Method 3
the conductive layer acts as a transference, rejecting any additional flux from flowing outside of the structure
Data Source
AI summary
In one aspect, described is a magnetic-core inductor design approach that leverages NiZn ferrites with low loss at RF, distributed gaps and field balancing to achieve improved performance eat tens of MHz and at hundreds of watts and above. Also described is an inductor design which achieves “self-shielding” in which the magnetic field generated by the element is wholly contained within the physical volume of the structure rather than extending into space as a conventional air-core inductor would. This approach enables significant reductions of system enclosure volume and improvements in overall system efficiency.