Miniature Current Sensor for High Vacuum Environments
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Solution Overview
Problem
Existing current measuring methods, such as Rogowski coils, face challenges in high vacuum applications due to air entrainment issues and packaging limitations, and are not suitable for hard-to-reach locations, requiring a more cost-effective and smaller sensor solution that can maintain high accuracy and vacuum integrity.
Innovation Solution
A miniature current sensor with a conductive housing and a toroidal current sensing loop, integrated into a small package, using readily available fabrication techniques, which provides a vacuum seal and isolated current path, allowing for high-speed current measurements in constrained spaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional Rogowski coils are used for current measurement, then current measurement capability is achieved, but the sensor cannot be used in high vacuum applications due to air entrainment and virtual leaks
Solution Approach 1:
The patent extracts the sensing function from the traditional Rogowski coil structure by using a conductive housing that serves dual purposes: as the vacuum seal barrier and as the current sensing element. This eliminates the need for separate coils and insulation materials that trap air, thereby resolving the vacuum integrity issue while maintaining current measurement capability.
Solution Approach 2:
The conductive housing performs multiple functions simultaneously: it provides the vacuum seal, serves as the current-carrying conductor, and acts as the sensing element for measuring current pulses. This multi-functionality eliminates the need for additional components that would compromise vacuum integrity, enabling use in both vacuum and non-vacuum environments.
2Reliability
If Rogowski coils are designed for high vacuum applications, then vacuum integrity is maintained, but the sensors are large and cannot accommodate hard-to-reach mounting locations
Solution Approach 1:
The patent merges the vacuum seal housing with the current sensing elements into a single integrated structure. The conductive housing itself becomes the sensing element, eliminating the need for separate coils and reducing the overall sensor volume to fit in constrained spaces while maintaining vacuum integrity.
Solution Approach 2:
The sensing loop is nested within the conductive housing structure, with the housing serving as both the vacuum barrier and the sensing conductor. This nested integration minimizes the external dimensions of the sensor while maintaining both vacuum seal and sensing functionality.
3Volume of moving object
If miniature Rogowski coils are manufactured with femtosecond laser micromachining, then small size is achieved, but manufacturing cost increases and fabrication complexity increases
Solution Approach 1:
The patent replaces expensive femtosecond laser micromachining with conventional, cost-effective fabrication methods for creating the conductive housing and sensing loop. By using standard manufacturing techniques, the sensor achieves miniature size without the high costs associated with advanced micromachining processes.
Solution Approach 2:
The conductive housing is designed to serve as both the structural vacuum seal and the sensing element, eliminating the need for separate, precisely-machined coil components. This self-service design allows the housing itself to provide the sensing function, simplifying fabrication and reducing costs.
4Volume of moving object
If sensor size is minimized for high-power applications, then SWAP is reduced, but packaging challenges increase and vacuum integration becomes more difficult
Solution Approach 1:
The patent extracts the vacuum sealing function from separate packaging components and integrates it directly into the conductive housing structure. This eliminates the need for additional vacuum flanges, seals, and mounting hardware, simplifying packaging while maintaining miniaturization.
Solution Approach 2:
The conductive housing performs multiple functions including vacuum sealing, current conduction, and sensing, eliminating the need for separate packaging components. This multi-functionality reduces packaging complexity while maintaining small sensor volume suitable for high-power applications.
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 sensor effectively measures rapid current pulses in hard-to-reach and vacuum environments with high accuracy, maintaining a vacuum seal and providing a cost-effective solution for high-speed applications, as demonstrated by its ability to reproduce current signals with single-digit nanosecond rise times and low leak rates.
Implementation Method 1
Known sensors operate principally by wrapping a coil partially or fully around the conductor and sampling the magnetic field developed when a current pulse flows down the conductor
Implementation Method 2
A miniature current sensor with a conductive housing and a toroidal current sensing loop, integrated into a small package, using readily available fabrication techniques, which provides a vacuum seal and isolated current path
Data Source
AI summary
A method and apparatus for sending current. A flow of current can be passed through a portion of the sensor, such that the sensor forms part of the current flow circuit. The sensor can be especially useful in high vacuum environments and/or in areas where a small sensor is desired. In one embodiment, the current sensor can form part of a ground circuit and a leg of the sensor can comprise a leg of the drive circuit. A current sensing loop of the sensor can at least partially encircle a portion of the sensor itself such that the current sensing loop senses current flowing through the sensor.