Differential Coil Layout for Current Sensing in Non-Uniform Fields
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Solution Overview
Problem
Current sensing devices with coil elements face challenges in accurately measuring current due to interference from non-uniform magnetic and electric fields, which existing configurations are insufficient to address effectively.
Innovation Solution
A current sensing device comprising N coil elements arranged in an annular or polygonal configuration with specific electrical connections between wire winding layers, forming balanced and differential coil pairs to reduce interference and enhance measurement accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If coil elements are arranged in conventional configurations (successive arrangement with return conductor or intercalated forward-backward paths), then some immunity to uniform magnetic and electric fields is achieved, but strong immunity against non-uniform magnetic and electric fields is not sufficient
Solution Approach 1:
The coil element is divided into multiple wire winding layers (innermost layer, intermediate layers, and outermost layer) that are electrically connected in series. This segmentation allows each layer to contribute to the measurement signal while the series connection enhances the overall output voltage and immunity to external fields.
Solution Approach 2:
Multiple wire winding layers are electrically connected in series to combine their individual signals. The outermost wire winding layer of one coil element connects to the innermost wire winding layer of the same coil element through electrical links, merging the contribution of all layers into a single measurement signal that provides strong immunity against non-uniform fields.
2Measurement precision
If multiple wire winding layers are electrically connected in series within each coil element, then measurement accuracy and immunity to interferences are significantly improved, but device complexity increases
Solution Approach 1:
Multiple wire winding layers are nested concentrically around the winding body, with each layer wrapped around the previous one. This nested structure naturally organizes the complex multi-layer configuration in a compact and systematic manner, making the connections manageable while achieving enhanced measurement accuracy and interference immunity.
Solution Approach 2:
The wire winding layers are arranged in the radial dimension (innermost to outermost layers), transforming the complex three-dimensional connection problem into a more manageable radial structure. This dimensional organization allows systematic electrical connections between layers while maintaining a compact coil element design.
3Object-affected harmful factors
If N coil elements are arranged in annular or polygonal configuration with specific electrical connections, then strong immunity against non-uniform fields is achieved, but manufacturing complexity increases
Solution Approach 1:
The electrical connections are established locally between adjacent wire winding layers within each coil element (outermost layer to innermost layer through electrical links). This local connection approach simplifies manufacturing compared to long-distance connections, as each connection is made between nearby layers rather than requiring complex routing across the entire device.
Solution Approach 2:
The patent specifies that N is an even number greater than or equal to 4, and defines specific connection patterns based on the position numbers of coil elements. These parameter constraints standardize the manufacturing process, making it easier to reproduce the complex annular or polygonal configuration with consistent electrical connections across all coil elements.
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 provides strong immunity against magnetic and electric interferences, ensuring high measurement accuracy even in harsh environments by eliminating asymmetries and interference loops, while maintaining low manufacturing costs.
Implementation Method 1
current sensing devices comprising one or more coil elements... provide a measurement voltage of the device, which is indicative of the current in the conductor
Implementation Method 2
the measurement is also influenced by external magnetic and electric fields and by parasitic couplings... provides strong immunity against magnetic and electric interferences
Data Source
Figure 1A
Figure 1B
Figure 2A
AI summary
The present invention relates to a current sensing device comprising N coil elements (L1, L2, L3, L4, L5, ... LN:L6), wherein N is an even number greater than or equal to 4. The N coil elements are arranged in an annular or polygonal configuration. Each coil element is located at a position number i in the annular or polygonal configuration, wherein i = 1 to N, wherein the coil element (L1) at position number i=1 is located adjacent to the coil element (LN:L6) at position i=N, and wherein the coil element located at position number i=x is located adjacent to the coil element located at position i=x-1 and the coil element located at position number i=x is located adjacent to the coil element located at position i=x+1, wherein 1 < x < N. Each coil element comprises a plurality of wire winding layers comprising an innermost wire winding layer (L11, L21, L31, L41, L51, L61) and an outermost wire winding layer (L14, L24, L34, L44, L54, L64), and wherein the wire winding layers are electrically connected to each other. An outermost wire winding layer (L14) of the coil element (L1) at position number i=1 is connected to a terminal via an electrical link (100). An outermost wire winding layer (L34, L54) of the coil element (L3, L5) located at position number i=y is connected to an innermost wire winding layer (L11, L31) of the coil element (L1, L3) located at position number i=y-2 via an electrical link, wherein y is an odd number greater than or equal to 3. An outermost wire winding layer (L24) of the coil element (L2) at position number i=2 is connected to a terminal via an electrical link (200, 201). An outermost wire winding layer (L44, L64) of the coil element (L4, L6) located at position number i=z is connected to an innermost wire winding layer (L21, L41) of the coil element (L2, L4) located at position number i=z-2 via an electrical link, wherein z is an even number greater than or equal to 4. An innermost wire winding layer (L61) of the coil element (LN:L6) located at position number i=N is connected to an innermost wire winding layer (L51) of the coil element (LN-1:L5) located at position number i=N-1 via an electrical link (105, 106, 206, 300).