Current Sensor Coil with Dielectric Spacer for Accuracy
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Solution Overview
Problem
Existing current sensor devices in utility meters, such as transformer and Rogowski coils, face accuracy issues due to external magnetic fields and temperature cycles, leading to increased manufacturing costs and time from repeated calibration processes.
Innovation Solution
A sensor device with a coil in contact with a dielectric material, formed in a toroid around an aperture, is used to sense current, where the housing includes spacers and a rotational positioner to prevent coil movement, ensuring consistent accuracy and reducing capacitance coupling, thereby eliminating the need for multiple calibrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If transformer sensor devices with magnetic cores are used, then current sensing capability is provided, but the device becomes bulky and expensive while being vulnerable to external magnetic fields reducing accuracy
Solution Approach 1:
The patent removes the magnetic core from the sensor device, extracting the problematic component that causes vulnerability to external magnetic fields. The coil is positioned to sense current through the conductor without requiring a magnetic core, thereby eliminating the harmful sensitivity to external magnetic field interference while maintaining current sensing capability.
Solution Approach 2:
The patent introduces a dielectric material as an intermediary between the coil and the conductor. This dielectric material reduces capacitance coupling between the coil and conductor, which improves measurement precision by minimizing interference effects while allowing the coil to maintain its sensing function without direct contact.
2Volume of moving object
If Rogowski coils are used, then device size is reduced, but accuracy is limited during low current and high current conditions requiring multiple calibration processes
Solution Approach 1:
The dielectric material serves as an intermediary that optimizes the electrical characteristics between the coil and conductor. By reducing capacitance coupling, it enables the Rogowski coil to maintain high accuracy across the full current range (including low and high current conditions) without requiring multiple calibration processes, thus resolving the accuracy limitation.
Solution Approach 2:
The patent modifies the electrical parameters of the sensor system by introducing the dielectric material with specific permittivity characteristics. This parameter change reduces the capacitance between coil and conductor, thereby improving the linearity and accuracy of the sensor response across varying current conditions without increasing device size.
3Manufacturing precision
If repeated calibration processes are performed, then manufacturing accuracy is improved, but manufacturing time and costs increase
Solution Approach 1:
The dielectric material is positioned between the coil and conductor during the initial manufacturing process, establishing the optimal electrical configuration before the sensor is put into service. This preliminary arrangement ensures that the capacitance coupling is minimized from the start, allowing the sensor to achieve high accuracy without requiring subsequent calibration processes, thereby maintaining manufacturing efficiency.
4Device complexity
If coil movement is not prevented, then device simplicity is maintained, but accuracy consistency over time deteriorates
Solution Approach 1:
The patent combines the housing structure with integral retaining features that prevent coil movement. The housing is designed with built-in retention mechanisms that secure the coil in its optimal position relative to the conductor, merging the structural support and positioning functions into a single integrated component. This maintains accuracy consistency over time without significantly increasing device complexity.
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 provides high accuracy (±0.2%) with reduced calibration requirements, maintaining accuracy over time and across varying currents and voltages, while simplifying manufacturing and reducing costs.
Implementation Method 1
a coil (204) in contact with a dielectric material (208) positioned about the coil (204) and at least partially within the aperture (210) to detect current flowing through the conductor (114)
Implementation Method 2
The coil and the dielectric material are formed in a toroid around an aperture such that the conductor can be placed through the aperture. The dielectric material in combination with the coil improves the accuracy of the sensor device
Data Source
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AI summary
A sensor device (112) for use in detecting current in a conductor (114) is provided. The sensor includes a non-magnetic substrate defining an aperture (210) structured to receive a conductor (114) therein, a coil comprising a plurality of turns wound about at least a portion of the substrate, and a housing (312) for enclosing the substrate and coil. The housing (312) includes a dielectric material (208) having a dielectric constant and positioned adjacent to the coil (204) and at least partially within the aperture (210) such that the dielectric material (208) is disposed between the coil and the conductor (114) when the conductor (114) is received through the aperture (210) and at least one spacer (316) coupled to the aperture (210) to facilitate maintaining a position of the coil relative to the conductor (114), wherein each of the spacers (316) is positioned offset from the dielectric material (208) such that each of the spacers (316) does not radially extend between the coil and the conductor (114).