Annular Core Coil Layout for Position-Stable Current Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing current detection apparatuses experience variations in measured current values due to shifts in the position of the conductor relative to the magnetic core, especially with high-frequency currents, and require complex wiring to equalize feedback coil loads.
Innovation Solution
A current detection apparatus with an annular magnetic core featuring parallel-connected first and second coil groups, where coils at opposing positions have equal inductor characteristics, allowing for simple wiring and reduced variation in measured current values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If feedback coils are evenly arranged over the entire circumferential direction of the magnetic core, then measurement precision is improved by averaging out magnetic flux variations, but device complexity increases due to the need to equalize loads on opposing coils
Solution Approach 1:
The feedback coils are divided into multiple groups (first coil group and second coil group) with each group containing multiple coils. This segmentation allows independent control and equalization of loads within each group, reducing the overall wiring complexity while maintaining measurement precision through the distributed arrangement of coils around the magnetic core.
Solution Approach 2:
The patent changes the electrical connection parameters by connecting coil groups in parallel rather than series, and by adjusting the number of coils in each group. This parameter change simplifies the wiring structure and reduces the complexity of equalizing loads while maintaining the ability to average out magnetic flux variations for precise current measurement.
2Measurement precision
If feedback coils are evenly arranged over the entire circumferential direction, then measurement precision is improved, but manufacturing precision requirements increase due to the need for equal inductor characteristics on opposing coils
Solution Approach 1:
By segmenting the feedback coils into multiple groups with multiple coils each, the patent reduces the manufacturing precision requirements for individual coils. Instead of requiring all coils to have identical characteristics, only the coils within each group need to be matched, which is easier to achieve in manufacturing while still providing sufficient averaging effect for precise measurement.
Solution Approach 2:
The patent applies local quality by allowing different coil groups to have different numbers of coils and different inductor characteristics, as long as the overall distribution provides sufficient averaging. This local differentiation in coil characteristics reduces manufacturing precision requirements while maintaining measurement precision through the distributed arrangement.
3Adaptability or versatility
If the conductor position shifts from the center of the magnetic core, then adaptability is improved for handling position variations, but measurement precision deteriorates due to varying current values being detected
Solution Approach 1:
The feedback coils are segmented into multiple groups distributed around the magnetic core, creating multiple sensing points. This segmentation provides adaptability to conductor position shifts by having coils at different locations detect magnetic flux at different positions, while the combined signal maintains measurement precision through the distributed averaging effect.
Solution Approach 2:
The patent transitions from a single-point feedback mechanism to a distributed multi-point feedback system by arranging coil groups around the circumferential direction. This dimensional change from one location to multiple locations provides both adaptability to position variations and maintains measurement precision through the spatial distribution of sensing points.
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 apparatus effectively reduces current value variations and simplifies wiring by using parallel-connected coils with equal inductor characteristics, even when the conductor position shifts, and minimizes residual magnetic flux without increasing core size.
Implementation Method 1
when a current flows in the conductor to be measured, a magnetic flux is generated in the magnetic core
Implementation Method 2
a current flows in the feedback coil to cancel this magnetic flux
Data Source
AI summary
A current detection apparatus (10) according to the present disclosure includes an annular magnetic core (13), a first coil group (14) including a plurality of first coils (La) connected in series, a second coil group (15) including a plurality of second coils (Lb) connected in series, and a detector (12). The first coil group (14) and the second coil group (15) are connected in parallel between a first node (21) and a second node (22), a count of the plurality of first coils (La) and a count of the plurality of second coils (Lb) are identical, and a first coil (La), among the plurality of first coils (La), in ith place from the first node (21) and a second coil (Lb), among the plurality of second coils (Lb), in ith place from the first node (21) are arranged at opposing positions, where i is an integer.