Patterned Magnetic Core Segmentation for Eddy Current Losses
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Solution Overview
Problem
Existing laminated magnetic cores experience significant delocalized eddy current losses at high operating frequencies due to nonzero conductivity in interlayer insulation materials, which limits their effectiveness in applications such as DC-DC converters and power systems-on-chip.
Innovation Solution
The development of patterned magnetic core structures with electrically isolated sub-cores and strategically placed gaps filled with low conductivity materials, which suppress delocalized eddy current losses by minimizing current leakage between sub-cores.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional laminated magnetic cores are used, then magnetic energy storage is achieved, but delocalized eddy current losses increase at high operating frequencies due to nonzero conductivity in interlayer insulation materials
Solution Approach 1:
The magnetic core is divided into multiple electrically isolated sub-cores by introducing gaps filled with electrically insulating materials. This segmentation prevents current leakage between adjacent magnetic layers, eliminating delocalized eddy current losses while maintaining magnetic energy storage functionality at high operating frequencies
Solution Approach 2:
Electrically insulating gap materials (such as air, epoxy, potting materials, or inorganic materials) are introduced as intermediary elements between magnetic sub-cores. These intermediaries block current leakage paths that would otherwise occur through nonzero conductivity interlayer insulation materials, thereby suppressing delocalized eddy current losses
2Ease of manufacture
If interlayer insulation materials with nonzero conductivity are used, then lamination structure is achieved, but current leakage occurs through the insulation layers
Solution Approach 1:
The continuous magnetic core structure is segmented into discrete sub-cores separated by insulating gaps. This segmentation interrupts the current leakage paths that would otherwise propagate through nonzero conductivity interlayer insulation materials, eliminating the harmful effect while preserving the lamination manufacturing approach
Solution Approach 2:
The problematic nonzero conductivity interlayer insulation material is extracted and replaced with electrically insulating gap materials. This removal of the harmful element (current-conductive insulation) eliminates current leakage while maintaining the essential lamination structure through alternative insulation methods
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 approach effectively reduces delocalized eddy current losses to negligible levels compared to intralayer losses, enabling the operation of magnetic cores at higher frequencies with improved magnetic energy storage efficiency.
Implementation Method 1
The gap material comprises an electrically insulating material such as air, epoxy, potting materials, and inorganic materials (e.g., oxides and nitrides)
Implementation Method 2
By creating stacks of micron or sub-micron thick layers of thin magnetic alloy sheets ('laminations') with interlamination layers of extremely low conductivity, the eddy current losses within the volume of the laminated alloys can be suppressed even at MHz frequencies
Data Source
AI summary
In some examples, a patterned magnetic core includes a first sub-score and at least one second sub-core. The first and second sub-cores are spaced apart by a gap, optionally filled with material of sufficiently low electrical conductivity. Each of the first and second sub-scores includes a number of magnetic layers and a number of interlamination layers disposed between the magnetic layers in an alternating fashion.