Magnetically Biased Choke with Segmented Magnetic Circuit
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Solution Overview
Problem
Existing chokes with air gaps in magnetic circuits face issues with increased magnetic stray fields and winding losses, which affect their current-carrying capacity and efficiency.
Innovation Solution
A choke design featuring a magnetic circuit with a stack of soft magnet segments, alternating with permanent magnet segments and optional insulator segments, arranged in a series configuration to enhance current-carrying capacity and reduce losses, using materials like ferrite, rare earth compounds, and insulating components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If air gaps are introduced in the magnetic circuit to avoid saturation, then the component behavior is linearized, but magnetic stray fields extend further into the outside of the choke
Solution Approach 1:
The magnetic circuit is divided into multiple segments with alternating soft magnetic material segments and permanent magnet segments. This segmentation allows the magnetic circuit to maintain a continuous magnetic path while avoiding saturation through the permanent magnets, thereby reducing magnetic stray fields extending into the environment.
Solution Approach 2:
The invention changes the magnetic parameters by introducing permanent magnets with specific remanence values into the magnetic circuit. This alters the magnetic flux distribution, enabling the circuit to operate in a linear region without saturation while confining magnetic stray fields within the structured segments.
2Loss of energy
If multiple air gaps or gaps filled with insulators are provided in the magnetic circuit, then winding losses are reduced, but device complexity increases
Solution Approach 1:
The magnetic circuit is segmented into multiple sections with alternating soft magnetic material and permanent magnets. This segmentation structure naturally creates multiple magnetic paths and gaps, reducing winding losses while maintaining a systematic and manageable device complexity through the regular alternating pattern.
3Power
If permanent magnet material is inserted into the gap, then the possible magnetic stroke increases significantly, but the air gap or gap filled with insulating material must be arranged below the choke winding to avoid electromagnetic interactions
Solution Approach 1:
The magnetic circuit is divided into alternating segments of soft magnetic material and permanent magnets. This segmentation allows permanent magnets to be positioned within the magnetic path to increase magnetic stroke while the structured arrangement confines electromagnetic interactions within the segmented structure, preventing harmful interactions with external electronic assemblies.
Solution Approach 2:
Soft magnetic material segments act as intermediaries between permanent magnets and the external environment. These soft magnetic segments guide and confine the magnetic flux, allowing permanent magnets to provide increased magnetic stroke while preventing direct electromagnetic interactions with external electronic components.
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 design increases current-carrying capacity, reduces winding losses, and minimizes magnetic stray fields, allowing for more efficient operation while using less magnet material and minimizing copper losses.
Implementation Method 1
the permanent-magnetic material is arranged at a distance from the end faces of the magnetic circuit. By inserting the permanent-magnetic material into the gap, the actual working range of the inductance can be shifted because the possible magnetic stroke, ie the possible maximum induction, increases significantly by providing a permanent-magnetic material in the gap
Implementation Method 2
a coil wound around part of the core material
Implementation Method 3
a magnetic circuit made of magnetically soft core material
Data Source
Figure 1
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AI summary
The invention concerns a magnetically biased choke (1) comprising a magnetic circuit (10) with at least one stack (20) consisting of a plurality of magnetically soft segments (22), of which at least some are disposed at a spacing from each other, and of a coil (50) which is wound about the stack (20), at least two permanent magnet segments (30) being inserted into the stack (20) and at least one magnetically soft segment (22) being disposed between the at least two permanent magnet segments (30).