AC Current Sensor Cut-Out Geometry for Frequency-Independent Accuracy
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing current sensors struggle to accurately measure AC currents with high frequency components, particularly those with frequencies ranging from 100 Hz to 2000 Hz, due to the skin effect, which causes variations in the magnetic field measurement, making it challenging to achieve precise measurements without complex spectral analysis.
Innovation Solution
A current sensor arrangement and method that positions a sensor device relative to an electrical conductor with specific cut-outs, utilizing a magnetic field gradient or difference measurement at a predefined location where the magnetic field variation is independent of frequency, allowing for accurate AC current determination with a constant factor, independent of frequency, within a predefined tolerance margin.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If magnetic field measurement is used to measure AC current, then galvanic separation and compact size are achieved, but measurement accuracy deteriorates due to skin effect at high frequencies
Solution Approach 1:
The patent applies local quality by creating a specific geometric configuration of the electrical conductor with cut-outs that generates a localized magnetic field gradient. By positioning the sensor at a specific location relative to the conductor geometry, the measurement is taken from a region where the skin effect influence is minimized, thereby maintaining measurement accuracy while preserving galvanic separation.
Solution Approach 2:
The patent changes the physical parameters of the measurement system by using a magnetic field gradient instead of a standard magnetic field measurement. The gradient measurement approach, combined with specific conductor geometry (cut-outs) and sensor positioning, transforms the measurement parameters to achieve frequency independence in the 100 Hz to 2 kHz range.
2Ease of operation
If standard magnetic field measurement is used, then measurement simplicity is maintained, but measurement accuracy deteriorates for high frequency AC currents
Solution Approach 1:
The patent changes the measurement parameter from standard magnetic field magnitude to magnetic field gradient. This parameter transformation enables accurate measurement of high frequency AC currents while maintaining relative measurement simplicity through a dedicated sensor configuration and processing algorithm.
3Device complexity
If conventional sensor positioning is used, then device complexity is minimized, but measurement accuracy deteriorates due to frequency-dependent magnetic field variations
Solution Approach 1:
The patent implements local quality by defining a specific sensor position relative to the conductor geometry where the magnetic field gradient is measured. This localized measurement approach creates a frequency-independent measurement zone, achieving accurate AC current measurement without requiring complex multi-point sensing arrangements.
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
Enables accurate measurement of AC currents with frequencies from 100 Hz to 2000 Hz with an absolute accuracy of up to +/- 5%, without the need for complex spectral analysis, by leveraging a 'sweet zone' where the magnetic field gradient is proportional to the current amplitude, ensuring high precision and simplicity in measurement.
Implementation Method 1
each sensor element configured for measuring a magnetic field component oriented in the first direction
Implementation Method 2
the sensor device is configured for determining a magnetic field difference or a magnetic field gradient along the first direction based on the measured magnetic field components
Implementation Method 3
determining said AC current based on the magnetic field gradient or magnetic field difference
Data Source
AI summary
A current sensor arrangement for measuring an AC electrical current, comprising: an electrical conductor having three transverse rectangular cut-outs; a sensor device comprising two sensor elements spaced apart along a first direction for measuring two magnetic field components oriented in said first direction, and configured for determining a magnetic field difference or magnetic field gradient, and for determining the AC current based on said difference or gradient. The sensor device is positioned at a particular location relative to the second cut-out, such that the magnetic field difference or gradient is substantially proportional to the AC current for frequencies from 100 Hz to 2 kHz. A current sensor system. A method of measuring an AC current with improved accuracy.