HTS Magnet Field Shaping Elements Reduce Radial Stress

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Solution Overview

Problem

Current superconductive magnet coil arrangements face limitations in achieving high magnetic field strengths due to radial field components, which reduce the current-carrying capacity of HTS conductors and increase manufacturing costs, while also causing inhomogeneities in the magnetic field.

Innovation Solution

The use of field-shaping elements made from LTS material, arranged axially above and below the solenoid-shaped HTS coil, reduces the radial field component and field angle, thereby increasing the critical current of the HTS tape and allowing for a more uniform distribution of current-carrying capacity, enabling stronger magnets or the use of cheaper conductor materials.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If HTS strip conductors are used in solenoid-shaped coil sections, then higher magnetic field strengths can be achieved, but the radial field component at the edge areas reduces the current-carrying capacity of the HTS conductor

Engineering Contradiction:
Improvemagnetic field strengthVSAvoidcurrent-carrying capacity of HTS conductor
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

A field-shaping device comprising field-shaping elements is introduced as an intermediary component between the HTS coil sections. This device modifies the magnetic field distribution in the edge areas, reducing the radial field component angle to below 10 degrees, thereby protecting the HTS conductors from excessive radial field stress while maintaining high magnetic field strength in the central region

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The field-shaping elements are strategically positioned only in the edge areas of the HTS coil sections where radial field components are problematic. The device creates locally optimized field conditions without affecting the overall magnet design or the central field region, allowing different parts of the system to have different field characteristics

Inventive Principle:
Principle #3Local quality

2Reliability

If the HTS conductor is routed along a complex shaped path to minimize field angle, then current-carrying capacity is optimized, but the routing becomes space-consuming and complex

Engineering Contradiction:
Improvecurrent-carrying capacity of HTS conductorVSAvoidconductor routing complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The field-shaping device acts as a mediator that modifies the magnetic field environment rather than requiring complex adaptation of the conductor routing. This allows the HTS conductors to follow simpler, more standard routing paths while still achieving optimal current-carrying capacity through field modification

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

Instead of adapting the conductor path to the field conditions (complex routing), the approach is inverted by modifying the field conditions to suit standard conductor routing. The field-shaping elements create favorable field angles along conventional conductor paths, eliminating the need for complex routing geometries

Inventive Principle:
Principle #13The other way round (Inversion)

3Stability of the object's composition

If radial field components are present in the HTS section, then shielding currents form causing field inhomogeneities, but removing them requires complex correction coils

Engineering Contradiction:
Improvemagnetic field homogeneityVSAvoidcorrection coil structure
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The field-shaping elements serve as intermediary components that proactively control radial field components before they can generate significant shielding currents. By maintaining field angles below 10 degrees at the HTS conductor location, the device prevents shielding current formation and associated field inhomogeneities without requiring complex correction coil systems

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The field-shaping elements are positioned upstream in the magnetic field path to preemptively reduce radial field components before they reach the HTS conductors. This preliminary field shaping prevents the formation of problematic shielding currents and field inhomogeneities rather than attempting to correct them afterward

Inventive Principle:
Principle #10Preliminary action

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 enhances the current-carrying capacity of HTS conductors, reduces manufacturing costs, and improves magnetic field homogeneity by minimizing shielding currents, allowing for higher magnetic field generation with reduced superconductor quality and quantity.

Implementation Method 1

The field-shaping elements are designed in such a way that they change the field angle of the magnetic field generated by the magnet coil arrangement with respect to the axial direction in the region of the HTS coil section (1) by at least 1.5°

Methodology Applied
Scientific EffectMagnetic field: Magnetic Field

Implementation Method 2

at least one solenoid-shaped HTS coil section (1), which is wound with an HTS (=high-temperature superconductor) strip conductor

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 3

a superconductive magnet coil arrangement constructed along an axial direction, having at least one solenoid-shaped coil section wound with an HTS (=high-temperature superconductor) strip conductor

Methodology Applied
Scientific EffectSuperconductivity: Superconductivity

Data Source

PatentEP3252783B1Magnet assembly with field shaping element for reducing the radial field components in the region of a hts section
Publication Date: 2019.11.27 BRUKER BIOSPIN GMBH
  • EP3252783B1 patent drawingFigure 1a~1b
  • EP3252783B1 patent drawingFigure 2a~2b
  • EP3252783B1 patent drawingFigure 3a~3b

AI summary

A superconducting magnetic coil arrangement built along an axial direction, comprising at least one solenoid-shaped coil section (1a, 1b, 1c) wound with an HTS tape conductor, and a field-shaping device comprising at least two field-shaping elements (2a, 2b, 2c), is characterized in that at least one field-shaping element is arranged adjacent to each of the two axial ends of the HTS coil section, wherein the field-shaping elements are designed such that they reduce the field angle of the magnetic field generated by the magnetic coil arrangement with respect to the axial direction in the region of the HTS coil section by at least 1.5°.With this magnetic coil arrangement according to the invention and a method for its design using simple, generally available technical means, the limitations of known arrangements of this type, which typically occur at the axial ends of the coil, can be significantly mitigated or completely avoided, whereby the magnetic field strength that can be generated with the coil is considerably increased and the magnetic coil arrangement can be designed to be particularly compact.