Permanent Current Switch Layout for MRI Quench Redundancy
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Solution Overview
Problem
Existing permanent current switch apparatuses for superconducting magnets in MRI systems face challenges in maintaining the superconducting state and reliable operation due to quench events and heater disconnections, which can lead to reduced reliability and failure to maintain the permanent current mode.
Innovation Solution
A permanent current switch apparatus is designed with multiple parallel structures of thermal permanent current switches connected in parallel and series configurations, allowing for redundancy in case of quench events and ensuring continued operation by redistributing current through intact switches. Additionally, heaters are connected in parallel to maintain consistent heating and prevent temperature differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If thermal permanent current switches are connected in series to control current flow through the superconducting coil, then the device can switch between conducting and interrupting current, but the reliability is reduced because a quench event in one switch interrupts the entire current flow
Solution Approach 1:
The switch apparatus is divided into multiple parallel structures, each containing thermal permanent current switches. This segmentation allows the system to maintain current flow through alternative paths if one structure experiences a quench event, thereby improving reliability without requiring a completely different switching mechanism
Solution Approach 2:
The parallel structure configuration provides a pre-established backup path for current flow. When a quench event occurs in one thermal permanent current switch, the system automatically redirects current through the parallel structure, cushioning against the failure and maintaining operation without requiring real-time detection or active intervention
2Reliability
If heaters are connected in series to provide uniform heating to thermal permanent current switches, then the heating control is simplified, but the reliability is reduced because a heater disconnection causes temperature differences and potential quench events
Solution Approach 1:
The heater system is segmented into multiple parallel-connected heaters, each associated with specific thermal permanent current switches. This segmentation ensures that if one heater disconnects, others continue to provide necessary heating, maintaining reliability without requiring a single complex centralized heating control system
Solution Approach 2:
Each heater is locally connected to provide heating to specific thermal permanent current switches in parallel structures. This local quality approach allows independent heating control for different parts of the system, ensuring that heating failures in one location do not affect other locations, thereby improving reliability
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 proposed solution enhances the reliability of the static magnetic field magnet by maintaining the superconducting state even if one or two thermal permanent current switches experience quench events, and allows for continued excitation and demagnetization of the superconducting coil despite heater disconnections.
Implementation Method 1
the thermal permanent current switches are capable of switching between conducting and interrupting an electric current flowing through the superconducting wire
Implementation Method 2
thermal permanent current switches connected in parallel, the thermal permanent current switches being capable of switching between conducting and interrupting an electric current
Data Source
AI summary
A permanent current switch apparatus according to an embodiment is a permanent current switch apparatus electrically connected to a superconducting coil via a superconducting wire, the permanent current switch apparatus including a plurality of parallel structures with thermal permanent current switches connected in parallel, the thermal permanent current switches being capable of switching between conducting and interrupting an electric current flowing through the superconducting wire. The parallel structures are connected in series.