Current Sensor Magnetic Core Slit Gap Saturation Prevention
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Solution Overview
Problem
Current sensors face reduced detection accuracy due to changes in magnetic flux density caused by external factors, particularly magnetic saturation at the contact points between the magnetic core and shield members, especially in high-frequency AC circuits.
Innovation Solution
Incorporating a magnetic core member with a slit-shaped gap portion and a magnetic shield member separated by clearances to prevent magnetic saturation, using a Hall IC as the magnetic sensor, and a positioning and holding mechanism to maintain the relative positions of the core and shield members, ensuring they do not contact each other.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the magnetic core member and magnetic shield member are placed in close proximity to improve sensor compactness, then the device size is reduced, but magnetic saturation occurs at contact points reducing detection accuracy
Solution Approach 1:
The magnetic core member includes a slit-shaped gap portion that divides the magnetic path, preventing magnetic flux concentration at contact points. This segmentation of the magnetic circuit eliminates magnetic saturation while allowing the sensor to maintain compact dimensions.
Solution Approach 2:
The slit-shaped gap portion acts as an intermediary element between the magnetic core and shield member, controlling magnetic flux distribution and preventing direct magnetic saturation at contact interfaces while maintaining structural integrity.
2Measurement precision
If clearances are introduced between the magnetic core and shield members to prevent magnetic saturation, then detection accuracy is improved, but the device volume increases
Solution Approach 1:
Rather than introducing large clearances, the magnetic core is segmented with a slit-shaped gap that prevents magnetic saturation with minimal space requirement, achieving accuracy improvement without significant volume increase.
3Reliability
If the magnetic core member is designed with a slit-shaped gap portion to control magnetic flux, then magnetic saturation is prevented, but manufacturing complexity increases
Solution Approach 1:
The slit-shaped gap is formed by dividing the magnetic core along its length, creating separate magnetic path segments. This segmentation can be achieved through standard manufacturing processes such as molding or machining, balancing reliability improvement with manufacturing feasibility.
Solution Approach 2:
The slit-shaped gap portion serves multiple functions simultaneously: it prevents magnetic saturation, controls magnetic flux distribution, and can be integrated into the magnetic core manufacturing process, reducing the need for additional components or complex assembly steps.
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 the detection accuracy of current sensors by reducing magnetic flux density variations caused by external factors and preventing magnetic saturation, thereby improving the linearity and reliability of current measurement, especially in AC circuits.
Implementation Method 1
a magnetic core member configured to generate a magnetic flux corresponding to a current flowing through the conductive member
Implementation Method 2
a magnetic sensor configured to output a signal corresponding to magnetic flux density in the gap portion
Implementation Method 3
a magnetic shield member configured to block magnetism between inside and outside of the shield main body by the shield main body
Data Source
AI summary
A current sensor includes: a magnetic core member including a core main body obtained by forming a slit-shaped gap portion along a tube axis direction in a tube that surrounds a conductive member, which is an object to be energized, on an inner side with a clearance, the magnetic core member being configured to generate a magnetic flux corresponding to a current flowing through the conductive member; a magnetic sensor configured to output a signal corresponding to magnetic flux density in the gap portion; and a magnetic shield member including a shield main body that surrounds the core main body from an outer side of the core main body with a clearance, the magnetic shield member being configured to block magnetism between inside and outside of the shield main body by the shield main body.