Polygonal Magnetic Core for Current Sensor Conductor Guide
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Solution Overview
Problem
Current current sensors face challenges when measuring high electrical currents due to limitations in accommodating both round and rectangular primary conductor cross-sections, leading to measurement errors and increased non-linearity, particularly with asymmetrical magnetic modulation and partial saturation of the magnetic module.
Innovation Solution
A current sensor arrangement featuring a magnetic core with a closed, triangular or polygonal ring structure and multiple magnetic field probes, allowing for both round and rectangular primary conductor guides with overlapping openings to minimize air gaps and reduce leakage flux, thereby improving measurement accuracy and linearity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the magnetic module has a rectangular inner opening to accommodate a strip-shaped conductor, then the geometry can be optimized for rectangular primary conductors, but only two sides of the core can be provided with windings, which limits the possible measuring range and increases the non-linearity of the current sensor
Solution Approach 1:
The magnetic core is designed with a polygonal ring structure that can accommodate both round and rectangular primary conductors through a single inner opening. The polygonal shape allows the core to be optimized for rectangular conductors while still accepting round conductors, providing universal compatibility without requiring separate core designs for different conductor types.
Solution Approach 2:
The magnetic core is divided into multiple segments or sides in the polygonal ring structure, allowing windings to be provided on multiple sides rather than just two sides. This segmentation enables better distribution of the magnetic field and improves measurement linearity while maintaining compatibility with both round and rectangular conductors.
2Ease of manufacture
If a circular toroidal core with round inner opening is used, then the winding effort is reduced and the core can be evenly wound, but the winding effort and thus the overall price increase considerably, and measurements on a primary conductor with a rectangular cross-section can only be carried out with a reduced cross-sectional area
Solution Approach 1:
The polygonal ring structure serves as a universal core design that can accommodate both round and rectangular primary conductors. The inner opening is shaped to optimize for rectangular conductors while still accepting round conductors, eliminating the need for separate core designs and reducing overall manufacturing complexity.
Solution Approach 2:
The core is designed with an asymmetric polygonal cross-section rather than a symmetric circular cross-section. This asymmetric design allows the core to be optimized for rectangular conductors while still providing sufficient space for round conductors, achieving versatility without requiring a fully symmetric toroidal design.
3Area of stationary object
If the geometry of the inner opening is selected to minimize the free space between the magnetic module and the primary conductor, then the overall dimensions of the magnetic module can be kept as small as possible, but the primary conductor position is not fixed and asymmetrical magnetic modulation of the core occurs
Solution Approach 1:
The polygonal inner opening is designed with specific geometric features that preliminarily position and constrain the primary conductor in a predetermined location. This preliminary positioning action ensures that the conductor is correctly aligned before measurement, preventing asymmetrical magnetic modulation while maintaining compact module dimensions.
Solution Approach 2:
The polygonal ring structure provides localized geometric features at specific positions within the inner opening that serve to constrain and position the primary conductor. These local geometric constraints ensure proper conductor placement without requiring the entire magnetic module to be larger, maintaining compact dimensions while improving measurement accuracy.
4Measurement precision
If high core cross sections are used to counteract high magnetic fields in the magnetic core, then measurement errors from leakage flux can be reduced, but the overall dimensions of the magnetic module increase
Solution Approach 1:
The magnetic core is segmented into multiple sides in the polygonal ring structure, allowing the magnetic flux to be distributed across multiple paths rather than requiring a single large cross-section. This segmentation enables better flux distribution and reduces leakage flux effects without requiring excessively large core cross-sections, maintaining compact module dimensions.
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 solution enables accurate measurement of high currents with reduced measurement errors and non-linearity, allowing for the use of both round and rectangular primary conductors without the need for excessively large magnetic cores, while minimizing the effective gap width and leakage flux.
Implementation Method 1
the magnetic field generated by a current to be measured (primary current) flowing through a so-called primary conductor is evaluated
Implementation Method 2
In order to focus or direct the magnetic field, soft magnetic elements (e.g. magnetic core) are used
Implementation Method 3
in which the magnetic field generated by the primary current is compensated to zero by a magnetic field generated by a compensation current of known strength
Data Source
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AI summary
The invention relates to a 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, triangular or polygonal ring structure enclosing the primary conductor, wherein the magnetic field probes are arranged on the magnetic core or in recesses in the magnetic core.