Current Sensor Magnetic Shield Core Saturation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current sensors face challenges in measuring large currents due to magnetic saturation, leading to non-linear measurements and reduced responsiveness, as existing solutions either increase core size or exacerbate magnetic field noise.
Innovation Solution
A current sensor design featuring a magnetic shield core with a gap portion and parallel shield portions to minimize magnetic saturation and external noise, allowing for high-speed responsiveness without size increase, and a manufacturing method that adjusts the shield dimensions based on magnetic flux density and external field attenuation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the width of the core portion is increased to reduce magnetic flux density, then magnetic saturation is suppressed, but the size of the magnetic shield core increases
Solution Approach 1:
The magnetic shield core is segmented into a core portion and separate shield portions. The core portion has a fixed width, while the shield portions extend outward to provide additional magnetic shielding. This segmentation allows suppressing magnetic saturation without increasing the core portion size, as the shield portions compensate for any flux that might escape.
Solution Approach 2:
Instead of increasing the width of the core portion in one dimension, the invention extends shield portions in another dimension (outward from the core). This dimensional change allows the system to provide additional magnetic shielding without increasing the core portion's cross-sectional area, thus avoiding the trade-off between saturation suppression and core size.
2Reliability
If the gap portion is widened to reduce magnetic flux density, then magnetic saturation is suppressed, but magnetic field noise from outside has greater influence
Solution Approach 1:
The magnetic shield core is divided into a core portion and separate shield portions. The shield portions act as additional magnetic shielding elements that extend outward, blocking external magnetic field noise while allowing the gap portion to maintain an appropriate width for flux density control. This segmentation isolates the functions of flux management and noise blocking.
Solution Approach 2:
The shield portions serve as intermediary elements between the core portion and the external environment. They mediate the magnetic field by providing additional shielding that blocks external noise while allowing the core portion to maintain its magnetic flux characteristics. The shield portions act as a buffer that protects the detection element from external interference.
3Measurement precision
If a U-shaped magnetic shield core is used to concentrate current on both sides, then magnetic flux detection is improved, but phase difference increases and responsiveness deteriorates
Solution Approach 1:
The magnetic shield core is segmented into a core portion and separate shield portions. This segmentation allows the current to be concentrated on both sides of the bus bar for improved flux detection, while the shield portions are positioned to minimize phase difference. The segmentation enables independent optimization of detection precision and responsiveness.
Solution Approach 2:
Different portions of the magnetic shield core have different functions: the core portion concentrates magnetic flux for detection, while the shield portions block external noise and minimize phase difference. This local differentiation of function allows the system to achieve both improved detection precision and maintained responsiveness.
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 design achieves high-speed responsiveness and reduced magnetic field noise while maintaining core size and cost-effectiveness, with adjustable measurement ranges and improved resistance to external magnetic fields.
Implementation Method 1
a magnetic detection element configured to detect magnetism produced from a current path
Implementation Method 2
a current sensor which is provided with a magnetic detection element such as a hall element
Implementation Method 3
a magnetic shield core, which includes a core portion arranged so as to extend around the current path
Implementation Method 4
a so-called magnetically saturated state occurs at the core portion
Data Source
AI summary
A current sensor includes a magnetic detection element configured to detect magnetism produced from a current path and a magnetic shield core. The magnetic shield core includes a core portion arranged so as to extend around the current path such that the current path is positioned therein, a gap portion formed by cutting a part of the core portion and in which the magnetic detection element is arranged, and at least a pair of shield portions extending from the core portion toward the outside opposite to the inside of the core portion where the current path is arranged, so as to correspond to the magnetic detection element.