Current Measurement Device with Offset Detection Coils
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Solution Overview
Problem
Current measurement devices face challenges in achieving high accuracy due to complex configurations and varying external magnetic field influences, leading to low current detection accuracy.
Innovation Solution
A current measurement device with a pair of detection coils arranged on a base with the conductor between them, spaced by an insulating distance, connected in series and opposite polarity, simplifying the configuration and improving accuracy by effectively offsetting external magnetic fields.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If one detection coil is disposed on the surface of the conductor via an insulating sheet and the other detection coil is disposed separately from the conductor, then the device configuration becomes complex, but the external magnetic field can be partially offset
Solution Approach 1:
The patent applies asymmetry by disposing both detection coils on the same surface of the conductor rather than one on the surface and one separately. This asymmetric arrangement simplifies the device configuration while maintaining measurement accuracy through proper spatial positioning and insulating distance control
Solution Approach 2:
The patent merges the two detection coils onto the same surface of the conductor, both spaced by insulating sheets. This combining approach reduces device complexity by eliminating the need for separate coil mounting structures while still achieving external magnetic field offset through their series connection in opposite polarity
2Device complexity
If the detection coils are disposed on the front surface and back surface of the conductor via insulating sheets, then the configuration is simplified, but the external magnetic field influence on the two coils differs, resulting in low current detection accuracy
Solution Approach 1:
The patent applies local quality by positioning both detection coils on the front surface of the conductor rather than distributing them on front and back surfaces. This localized arrangement ensures both coils experience identical external magnetic field conditions, enabling accurate differential measurement while simplifying the overall configuration
Solution Approach 2:
The patent creates equipotential conditions for both detection coils by placing them in the same spatial environment on the conductor surface. This ensures equal exposure to external magnetic fields, allowing the differential measurement approach to effectively cancel out external interference while maintaining configuration simplicity
3Ease of manufacture
If the conductor is fixed to a terminal block, then the detection coil on the back surface is hidden between the conductor and terminal block, but the external magnetic field influence on the two coils differs, resulting in low current detection accuracy
Solution Approach 1:
The patent resolves the spatial conflict by changing the dimensional arrangement from front-back surface distribution to side-by-side positioning on the same surface. This dimensional reconfiguration ensures both coils remain accessible and experience equal external magnetic field influence, maintaining measurement accuracy while allowing straightforward conductor fixation to the terminal block
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 arrangement simplifies the device configuration and enhances current measurement accuracy by ensuring consistent external magnetic field influence on the detection coils, allowing for precise calculation of alternating currents.
Implementation Method 1
two detection coils for outputting an inductive voltage signal in accordance with the magnetic field
Data Source
Figure 1
Figure 2A
Figure 2B
AI summary
This current measurement device (10) includes a conductor (110), a first terminal block (100), a pair of detection coils (120a, 120b) and a current calculator (300). A magnetic field, proportional to the magnitude of a to-be-measured current that is conducted, is generated around the conductor (110). The first terminal block (100) has a placement surface (F) on which the conductor (110) is disposed. The pair of detection coils (120a, 120b) has the configuration, connected in series and in opposite polarity with respect to each other, and disposed on the placement surface (F) of the first terminal block (100) such that the conductor (110) is between the pair of detection coils (120a, 120b), and each coil is spaced from the conductor (110) by an insulating distance. The detection coils (120a, 120b) output an inductive voltage signal produced by the magnetic field generated by the conductor (110) and an external magnetic field which is magnetic noise. A current calculator (300) calculates the value of the to-be-measured current on the basis of the inductive voltage signals from the pair of detection coils (120a, 120b).