Ferrous-Shielded AC/DC Power Adapter for High Magnetic Fields
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Solution Overview
Problem
Traditional AC/DC power adapters used in high external magnetic fields, such as MRI facilities, face issues with electromagnetic component saturation, overheating, and safety hazards due to magnetic attraction, limiting their ability to operate reliably and safely in close proximity to magnets.
Innovation Solution
The use of ferrous bands to shield electromagnetic components and a thermal control system that disables non-essential loads when temperature thresholds are exceeded, minimizing magnetic and thermal stresses and allowing the power adapter to operate closer to high magnetic fields while enhancing portability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the power adapter is positioned close to the magnet to improve portability, then the ability to operate near magnetic fields is improved, but the electromagnetic transformer and inductors can saturate from the high external magnetic field causing power loss, overheating, or damage
Solution Approach 1:
A ferrous shielding member is introduced as an intermediary between the external magnetic field and the electromagnetic components. The shielding member contains the external magnetic field, preventing it from reaching the transformer and inductors, thus allowing the power adapter to operate reliably close to magnets while maintaining portability
2Ease of operation
If the power adapter is positioned close to the magnet to improve portability, then the ability to operate near magnetic fields is improved, but the power adapter can create a safety hazard by becoming a projectile due to magnetic attraction
Solution Approach 1:
The ferrous shielding member acts as a mediator that attracts and contains the external magnetic field lines within itself. This prevents the magnetic field from directly attracting the power adapter housing, reducing the projectile hazard while allowing close operation near magnets
3Productivity
If electromagnetic components are used to convert power, then power conversion efficiency is improved, but the components can saturate from high external magnetic fields causing overheating
Solution Approach 1:
The ferrous shielding member serves as a protective intermediary that contains external magnetic field lines, preventing them from saturating the electromagnetic components. This allows the transformer and inductors to operate efficiently without overheating, even when positioned close to high magnetic fields
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 solution effectively minimizes magnetic immunity issues, enables reliable operation near strong magnetic fields, improves portability, and ensures safe and efficient power delivery by reducing thermal and magnetic stresses on the power adapter.
Implementation Method 1
one or more ferrous bands which encircle the electromagnetic components and which are configured to shield the electromagnetic components from the high external magnetic fields
Implementation Method 2
The ferrous bands 16, in addition to providing shielding, conduct heat away from the power converter system 12 for heat dissipation
Data Source
Figure 1~2A
Figure 2B~3
Figure 4
AI summary
A power supply (10) and corresponding method (200) supply power in high external magnetic fields. A power converter system (12) converts input power to output power using one or more electromagnetic components (18). One or more ferrous bands (16) encircle the electromagnetic components (18) and shield the electromagnetic components (18) from the high external magnetic fields.