Floating Cable Current Trap for MRI Common-Mode Blocking
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Solution Overview
Problem
Magnetic resonance imaging (MRI) systems face issues with transmitter-driven common mode currents causing field distortions and unpredictable heating in coil-interfacing cables, which conventional baluns attempt to mitigate but often require complex soldering processes that can degrade the cables.
Innovation Solution
A floating current trap is introduced, comprising a nonconductive spiral core with a coiled wire and tuning capacitors forming a resonant circuit, allowing mechanical engagement with cables without soldering, enabling the trap to be positioned anywhere along the cables and reducing cable degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional grounded baluns are coupled to coil-interfacing cables to block induced currents, then common mode currents are mitigated, but the soldering process exposes conductors to high temperatures leading to degradation
Solution Approach 1:
The patent replaces the thermal soldering process with a mechanical compression connection system. The current trap assembly uses a compression mechanism to establish electrical contact with the cable conductors without applying heat, thereby eliminating thermal degradation of the cable insulation and conductors while maintaining effective common mode current blocking.
2Reliability
If grounded baluns are soldered to coil-interfacing cables, then common mode currents are blocked, but the process becomes complex and time-consuming
Solution Approach 1:
The patent substitutes the complex soldering process with a simple mechanical compression connection. The current trap assembly is designed to be mechanically attached to the cable through compression forces, eliminating the need for soldering equipment, skilled soldering operations, and associated quality control steps, thereby significantly simplifying the manufacturing and installation process.
3Reliability
If conventional baluns require soldering to cables, then current blocking is achieved, but the trap cannot be easily repositioned along the cables
Solution Approach 1:
The patent implements a dynamic, reconfigurable connection system where the current trap assembly can be easily moved to different positions along the cable. The mechanical compression connection allows the trap to be detached and repositioned without damage to the cable or the trap itself, enabling flexible placement optimization for different application scenarios while maintaining effective current blocking at each position.
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 floating current trap effectively blocks transmission-induced currents, reducing field distortions and heating while allowing for easy reconfiguration and placement, thus improving MRI system performance and extending cable lifespan.
Implementation Method 1
one or more tuning capacitors physically attached to the flat core and electrically connected to the coiled wire to form a resonant circuit with the coiled wire
Implementation Method 2
The coil-interfacing cables may be subjected to electro-magnetic fields and as a result, transmitter-driven common mode currents may adversely affect coil tuning
Data Source
AI summary
Various methods and systems are provided for a current trap. In one example, the current trap has a flat core made of a nonconductive material, a coiled wire having a plurality of turns winding around the flat spiral core, and one or more tuning capacitors physically attached to the flat core and electrically connected to the coiled wire to form a resonant circuit with the coiled wire.