Compact High-Voltage Feedthrough Structure for Flashover Suppression
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Solution Overview
Problem
Existing high-voltage vacuum systems face challenges with surface flashover and high dark current due to electron emission and secondary electron reemission, which are critical issues in compact fusion reactors and other low-pressure systems.
Innovation Solution
The development of compact feedthroughs using dielectric materials with specific structural features and magnetic fields to reduce electron emission and secondary electron reemission, ensuring operation at voltages up to ±600 kVDC with minimal stable dark current and negligible surface flashover, even at ultra-high vacuum pressures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional high voltage feedthroughs are used in vacuum systems, then voltage transmission is achieved, but surface flashover and high dark current occur due to electron emission and secondary electron reemission
Solution Approach 1:
A dielectric member is introduced as an intermediary component between the high voltage electrode and the vacuum chamber wall. This dielectric member includes a field emission suppression structure that acts as a mediator to prevent electron emission from the triple junction point, thereby eliminating surface flashover and dark current while maintaining voltage transmission functionality
Solution Approach 2:
The field emission suppression structure creates localized geometric features (protrusions or recesses) at the critical triple junction point where the dielectric, electrode, and vacuum chamber meet. This local structural modification changes the electric field distribution specifically at the problematic location without affecting the overall feedthrough structure, thereby suppressing field emission locally while maintaining global electrical functionality
2Productivity
If compact fusion reactors are developed, then lower power demands and shorter lead times are achieved, but high voltage transmission in compact space with minimal dark current is required
Solution Approach 1:
The feedthrough structure is segmented into distinct functional zones: a field emission suppression structure with specific geometric features, a dielectric member with controlled thickness, and an electrode portion. This segmentation allows each component to be optimized independently for its specific function while maintaining overall compactness, enabling the system to meet both space constraints and electrical performance requirements
3Reliability
If dielectric breakdown is prevented in compact bushings, then reliable high voltage operation is achieved, but electron emission and secondary electron reemission still occur
Solution Approach 1:
The field emission suppression structure is designed and positioned in advance at the triple junction point to prevent field emission before it can initiate surface flashover or generate dark current. By addressing the root cause (field emission at the triple junction) preliminarily, the system prevents the chain reaction that would lead to dielectric breakdown, thereby simultaneously achieving both prevention of electron emission and maintenance of dielectric integrity
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 electron emission and secondary electron reemission, maintaining reliable operation without surface flashover and reducing power demand by minimizing dark current, making it suitable for compact fusion reactors and other high-voltage, low-pressure environments.
Implementation Method 1
magnetic fields to reduce electron emission and secondary electron reemission
Implementation Method 2
compact feedthroughs using dielectric materials with specific structural features
Data Source
AI summary
Systems, components, and methods for feeding high voltage into a vacuum chamber are provided. An exemplary feedthrough includes a dielectric flange defining a first side, a second side, and an aperture extending from the first side to the second side and a conductor disposed through the aperture and forming a contact with the dielectric flange on the first side.