Rogowski Coil Current Sensor with Dielectric Capacitance Reduction
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Solution Overview
Problem
Existing current sensor devices in utility meters, such as transformer and Rogowski coils, are either bulky and expensive or provide limited accuracy, especially during low and high current conditions, requiring multiple calibration processes that increase manufacturing time and cost.
Innovation Solution
A sensor device with a coil and dielectric material positioned between the coil and conductor, reducing capacitance and improving accuracy across a range of currents and voltages, allowing for single calibration coefficients and simplified manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If transformer sensor devices are used, then sensing accuracy is improved, but device size and cost increase
Solution Approach 1:
The patent changes the physical parameters of the sensing system by using a Rogowski coil with specific geometric parameters (radius, number of turns) and positioning it at an optimized distance from the conductor. This allows achieving accurate current sensing without the bulky transformer structure, directly resolving the contradiction between sensing accuracy and device size.
2Volume of moving object
If Rogowski coils are used, then device size is reduced, but sensing accuracy deteriorates during low and high current conditions
Solution Approach 1:
The patent introduces a dielectric material as an intermediary between the Rogowski coil and the conductor. This dielectric material with specific permittivity values (2.2-10.0) acts as a mediator that modifies the electric field distribution, thereby improving the coil's sensing accuracy across different current conditions while maintaining the compact device structure.
Solution Approach 2:
The patent optimizes multiple parameters including the dielectric material's permittivity, the coil's geometric parameters (radius R1, turn density), and the coil-conductor distance. These parameter optimizations enable the Rogowski coil to maintain high sensing accuracy across low and high current conditions without increasing device size.
3Measurement precision
If multiple calibration processes are applied, then sensing accuracy is improved, but manufacturing time and cost increase
Solution Approach 1:
The patent performs preliminary optimization during the design and manufacturing phase by selecting specific dielectric materials with known permittivity values and configuring the coil geometry and positioning in advance. This preliminary action ensures consistent sensing performance across different current conditions, eliminating the need for multiple post-manufacturing calibration processes and thereby reducing manufacturing time.
4Measurement precision
If dielectric material is positioned between coil and conductor, then capacitance is reduced and accuracy is improved, but device complexity increases
Solution Approach 1:
The patent merges the dielectric material with the existing sensor housing or mounting structure, combining multiple functions (electrical insulation, capacitance reduction, mechanical support) into a single integrated component. This merging approach improves sensing accuracy by reducing capacitance while avoiding significant increases in 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 sensor device achieves improved accuracy and reduced calibration requirements, lowering manufacturing costs and time while maintaining consistency across different operating voltages and currents, and enhanced immunity to electromagnetic interference.
Implementation Method 1
A sensor device with a coil and dielectric material positioned between the coil and conductor, reducing capacitance and improving accuracy
Implementation Method 2
sensing current through a conductor
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
Sensor devices and related methods disclosed. One example sensor device (12) includes a non-magnetic substrate (102) defining an aperture (110) structured to receive a conductor therein, a coil (104) including a plurality of coil turns wound about at least a portion of the substrate, a first shield between the substrate and the plurality of coil turns, a second shield disposed proximate to the plurality of coil turns, opposite the first shield, such that the plurality of coil turns is disposed between the first shield and the second shield, and a filter element (136, 138, 144) coupled to at least one of the first and second shields.