Superconductor Magnet Field Homogeneity via Secondary Current Control
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Solution Overview
Problem
Existing superconductor magnets face challenges in maintaining stable and homogeneous magnetic fields due to variations in critical current and magnetic field alignment, which can lead to thermal runaway and require additional shim coils for correction.
Innovation Solution
A system and method using a primary electric current source connected across a series of field coils and a secondary electric current source in parallel with a subset of these coils to supply additional DC or AC current, allowing for fine-tuning and stabilization of the magnetic field by adjusting the current distribution and heating the superconductor material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single primary electric current source is used to supply current to all field coils, then the system structure is simple, but the magnetic field homogeneity and stability deteriorate due to variations in critical current and magnetic field alignment
Solution Approach 1:
The patent divides the field coil system into multiple groups, with each group supplied by a separate current source. This segmentation allows independent control of current in different coil groups, enabling precise adjustment of magnetic field contributions from each group to achieve homogeneous overall magnetic field despite variations in critical current and alignment
Solution Approach 2:
The patent applies different current values to different coil groups based on their local characteristics (critical current, magnetic field alignment). Each current source is independently adjusted to optimize the magnetic field contribution of its associated coil group, creating local optimization that results in global magnetic field homogeneity
2Manufacturing precision
If additional shim coils are added to correct magnetic field variations, then the magnetic field homogeneity improves, but the device complexity and number of components increases
Solution Approach 1:
The patent makes the primary field coils serve dual functions: generating the main magnetic field and providing fine-tuning capability through independent current control. This eliminates the need for separate shim coils, as the field coils themselves perform both gross field generation and fine field adjustment
Solution Approach 2:
The patent combines the functions of main field generation and field correction into a single integrated system. The multiple current sources connected to different coil groups replace the traditional separate shim coil system, merging correction functionality into the existing field coil structure
3Power
If the current through field coils is increased to generate stronger magnetic field, then the magnetic field strength improves, but thermal runaway risk increases due to variations in critical current
Solution Approach 1:
The patent implements dynamic current control where each current source can be independently adjusted based on real-time conditions. This allows the system to optimize current distribution to maximize magnetic field strength while maintaining current below critical thresholds in all coils, preventing thermal runaway
Solution Approach 2:
The patent employs feedback control mechanisms to monitor and adjust current distribution among coil groups. By detecting variations in critical current and magnetic field alignment, the system dynamically adjusts current values to maintain safe operating margins while achieving maximum magnetic field strength
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 system enables precise control of magnetic field homogeneity and stability, reducing the need for shim coils and minimizing screening currents, thereby enhancing the magnet's performance and stability.
Implementation Method 1
supplying a DC electric current to the field coils to generate a magnetic field
Implementation Method 2
heating the superconductor material
Data Source
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AI summary
A superconductor magnet system comprising a superconductor magnet comprising a plurality of field coils connected in series, each field coil having a plurality of turns comprising superconductor material. The system also comprises a primary electric current source connected across the plurality of the field coils for supplying a DC electric current to the field coils to generate a magnetic field. The system further comprises a secondary electric current source connected in parallel with the primary electric current source across a subset of the field coils for supplying an additional DC electric current to the or each field coil in the subset to modify or correct the magnetic field.