Multi-Core Current Sensor for Wideband Accuracy
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Solution Overview
Problem
Current sensors face challenges in maintaining measurement accuracy across a wide frequency band, particularly when the frequency of the current is high, due to variations in magnetic permeability of the magnetic core materials, leading to inconsistent readings regardless of the measuring object's position.
Innovation Solution
A current sensor design featuring a magnetic core configuration with multiple magnetic cores (first, second, and third cores) arranged in parallel, where each core has varying magnetic permeability optimized for specific frequency bands, ensuring accurate current measurement across a wide frequency range by selecting the core with the highest permeability for each frequency band.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a single magnetic core material is used in the current sensor, then the structure is simple and easy to manufacture, but the measurement accuracy deteriorates at high frequencies due to magnetic permeability variations
Solution Approach 1:
The magnetic core is segmented into multiple magnetic cores (first magnetic core, second magnetic core, third magnetic core) with different materials, each optimized for specific frequency bands. This segmentation allows the sensor to maintain high measurement accuracy across a wide frequency range by selecting the appropriate core material for the operating frequency, while still using a unified core structure that simplifies manufacturing compared to complex multi-component designs.
2Measurement precision
If permalloy case is used in the current sensor, then the accuracy for measuring current is high at low frequencies, but the accuracy deteriorates at high frequencies
Solution Approach 1:
The current sensor achieves universality by incorporating multiple magnetic cores with different permeability characteristics, enabling it to function accurately across multiple frequency bands. The first magnetic core (permalloy) provides high accuracy at low frequencies, the second magnetic core handles mid-frequency measurements, and the third magnetic core optimizes high-frequency performance, making the sensor universally applicable across a wide frequency spectrum.
Solution Approach 2:
The sensor utilizes parameter changes in magnetic permeability by selecting different magnetic core materials with distinct permeability characteristics optimized for specific frequency ranges. This parameter-based approach allows the sensor to maintain optimal measurement accuracy across varying frequency conditions by effectively changing the magnetic core material parameter based on the operating frequency.
3Measurement precision
If multiple magnetic cores with different permeabilities are used, then the measurement accuracy improves across wide frequency bands, but the device complexity increases
Solution Approach 1:
Multiple magnetic cores with different permeability characteristics are merged into a single integrated magnetic core structure that surrounds the conductor. This combining approach allows the sensor to achieve wide-frequency accuracy by utilizing all magnetic cores simultaneously, while the unified structure simplifies the overall device configuration and reduces complexity compared to separate discrete magnetic core assemblies.
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
This configuration enhances measurement accuracy by using the appropriate core for each frequency band, maintaining consistent readings regardless of the measuring object's position within the magnetic core, thereby improving the sensor's performance across a wide frequency range.
Implementation Method 1
the first magnetic core has a magnetic permeability that is higher than that of the second magnetic core in a first frequency band, and the first magnetic core has a magnetic permeability that is lower than that of the second magnetic core in a second frequency band
Implementation Method 2
a fluxgate sensor element having an annular shape
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
A current sensor 100 for detecting a magnitude of a current flowing through a measuring object 9 has a magnetic core 1 having a first magnetic core 10 and a second magnetic core 20 that is arranged magnetically in parallel to the first magnetic core 10, wherein the first magnetic core 10 has a magnetic permeability that is higher than that of the second magnetic core 20 in a first frequency band, and the first magnetic core 10 has a magnetic permeability that is lower than that of the second magnetic core 20 in a second frequency band, the second frequency band being higher than the first frequency band, and the current sensor 100 detects the magnitude of the current in a frequency band that is constituted by combining the first frequency band and the second frequency band.