Current Sensor Magnetic Core with Recessed Probes
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Solution Overview
Problem
Current compensation current sensors face challenges when measuring high electrical currents due to limitations in magnetic module design, leading to measurement errors and non-linearity, particularly with rectangular primary conductors, as they require larger core sizes and asymmetrical magnetic modulation, causing leakage flux and partial saturation.
Innovation Solution
A current sensor arrangement with a magnetic core having a closed ring structure and at least two recesses for magnetic field probes, featuring L-shaped legs with windings shorter than half the leg length, and small air gaps to minimize leakage flux and accommodate both rectangular and round primary conductor cross-sections, using multiple probes to reduce saturation and error.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the magnetic module is optimized for a specific primary conductor cross-section (e.g., rectangular), then the measurement accuracy for that geometry is improved, but the adaptability to other conductor geometries (e.g., round) deteriorates
Solution Approach 1:
The magnetic core is designed with a circular cross-section and circular inner opening, allowing it to accommodate both rectangular and round primary conductors. The circular geometry provides universal compatibility with different conductor shapes, eliminating the need for separate optimized designs for each geometry while maintaining measurement accuracy across various conductor types.
2Measurement precision
If the core cross-section is increased to accommodate larger primary conductors, then the measurement range is improved, but the device dimensions and complexity increase
Solution Approach 1:
The patent changes the core geometry from rectangular to circular cross-section, which optimizes the magnetic flux distribution and reduces leakage flux. This parameter change allows for a more efficient use of the core material, achieving the required measurement range for high currents without proportionally increasing the core dimensions and complexity.
3Measurement precision
If windings are extended along the entire length of L-shaped legs, then the magnetic field compensation is improved, but the winding effort and manufacturing complexity increase
Solution Approach 1:
Instead of extending windings along the entire length of the L-shaped legs, the patent applies windings only to specific segments of the legs. This partial action approach provides sufficient magnetic field compensation for accurate measurement while significantly reducing the winding effort and manufacturing complexity compared to full-length windings.
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 design enhances measurement linearity and accuracy for high currents by minimizing air gap width and using multiple probes to balance magnetic flux, allowing for smaller core cross-sections and accommodating various conductor geometries without significant measurement errors.
Implementation Method 1
at least two magnetic field probes (22, 23) for measuring magnetic fields
Implementation Method 2
sensor types based on the Hall effect
Implementation Method 3
a magnetic field generated by a compensation current of known strength
Implementation Method 4
the magnetic field generated by the primary current is compensated to zero by a magnetic field generated by a compensation current
Implementation Method 5
soft magnetic elements (e.g. magnetic core) are used, which are a minimum component of a magnetic module
Data Source
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AI summary
Current sensor arrangement with a primary conductor for conducting a current to be measured, at least two magnetic field probes for measuring magnetic fields and a magnetic core which has a closed ring structure of arbitrary shape surrounding the primary conductor and at least two recesses each receiving one of the magnetic field probes.