Magnetic Unit Conductive Element Fringing Flux Control
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Solution Overview
Problem
Gapped magnetic units used in high frequency power conversion applications experience significant winding losses due to fringing flux, which are not effectively reduced by existing solutions like litz wire or distributed air gaps, leading to increased size and cost.
Innovation Solution
A magnetic unit with a conductive element positioned to control fringing flux and a heat sink to manage thermal issues, where the conductive element induces a cancelation flux to reduce eddy currents and copper losses, while also efficiently transferring heat.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If litz wire is used as windings instead of copper wires, then copper losses caused due to fringing flux are reduced, but physical size of the wire increases and footprint of the magnetic core increases
Solution Approach 1:
The patent divides the air gap into multiple segments by introducing magnetic gap shields between the fringing flux source and the windings. These shields segment the flux path and redirect the fringing flux away from the windings, reducing eddy current losses without requiring larger wire insulation layers
Solution Approach 2:
The patent introduces magnetic gap shields as intermediary elements positioned between the fringing flux source and the windings. These shields act as mediators that capture and redirect the fringing flux, preventing it from inducing eddy currents in the windings while maintaining a compact core footprint
2Loss of energy
If magnetic core having distributed air gaps is used, then copper losses resulting due to fringing flux are reduced, but cost of manufacture of the magnetic core increases
Solution Approach 1:
The patent segments the air gap using discrete magnetic gap shields positioned at specific locations rather than distributing gaps throughout the entire core structure. This selective segmentation achieves flux control with simpler manufacturing processes and lower costs compared to distributed air gaps
Solution Approach 2:
The patent applies magnetic gap shields only in specific locations where fringing flux most significantly affects the windings, rather than uniformly distributing gaps throughout the core. This localized approach reduces manufacturing complexity and cost while effectively targeting the problem areas
3Use of energy by moving object
If gapped magnetic unit is used instead of solid core magnetic unit, then high frequency switching signals are attenuated, but fringing flux at air gap induces eddy currents in copper wire windings causing higher thermal losses
Solution Approach 1:
The patent introduces magnetic gap shields as intermediary elements that capture and redirect fringing flux away from the windings. These shields mediate between the air gap and the windings, preventing harmful eddy current induction while preserving the high-frequency attenuation benefits of the gapped core structure
Solution Approach 2:
The patent converts the harmful fringing flux into a beneficial configuration by using magnetic gap shields to redirect it along controlled paths. The shields transform the原本 harmful scattered flux into directed flux paths that do not induce eddy currents in the windings, effectively turning a disadvantage into a manageable aspect of the design
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
The solution provides a compact and cost-effective reduction in winding losses by controlling fringing flux and enhancing thermal management, maintaining optimal temperature and reducing copper losses in magnetic units.
Implementation Method 1
The fringing flux at the air gap induces eddy currents in the copper wire windings
Implementation Method 2
The conductive element is configured to control a fringing flux generated at the gap
Implementation Method 3
the conductive element is further configured to transfer heat from at least one of the conductive element and the first winding to the heat sink
Data Source
AI summary
A magnetic unit is presented. The magnetic unit includes a magnetic core. The magnetic core includes a first limb and a second limb disposed proximate to the first limb, where a gap is formed between the first limb and the second limb. The magnetic unit further includes a first winding wound on the first limb. Moreover, the magnetic unit includes a conductive element disposed facing an outer periphery of the first winding, where the conductive element is configured to control a fringing flux generated at the gap. Further, the magnetic unit includes a heat sink operatively coupled to the conductive element, where the conductive element is further configured to transfer heat from at least one of the conductive element and the first winding to the heat sink. Moreover, a high frequency power conversion system and a method of operation of the magnetic unit is also presented.