Current Sensor with Bent Conductor for Magnetoresistance Sensitivity

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Solution Overview

Problem

Current sensors with U-shaped configurations face reduced sensitivity due to magnetic fields induced by currents flowing through bent paths, affecting the magnetoresistance effect elements' sensitivity.

Innovation Solution

A current sensor design featuring a conductor with specific imaginary planes and bent portions, where the magnetoresistance effect elements are positioned on a parallel plane to minimize the magnetic field's impact on sensitivity, and the current path is optimized to ensure the magnetic field is perpendicular to the sensitivity direction, reducing interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the conductor is bent into a U shape to create a compact current sensor design, then the device complexity is reduced and compactness is improved, but the magnetic field induced by the current flowing through the bent path affects the sensitivity of the magnetoresistance effect elements

Engineering Contradiction:
Improvedevice compactnessVSAvoidmeasurement sensitivity
Core Design Contradiction:
Volume of moving objectVSMeasurement precision

Solution Approach 1:

The patent introduces imaginary flat planes and imaginary straight lines to define the spatial relationship between the conductor and magnetoresistance effect elements. By positioning elements on a first imaginary flat plane parallel to imaginary straight lines, and ensuring the magnetic field direction is perpendicular to this plane, the design achieves compact U-shaped configuration while maintaining measurement sensitivity through precise three-dimensional spatial arrangement.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Measurement precision

If the magnetoresistance effect elements are positioned close to the current path to improve detection capability, then the measurement sensitivity is improved, but the magnetic field from the current directly affects the elements and reduces sensitivity

Engineering Contradiction:
Improvedetection capabilityVSAvoidmagnetic field interference
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent introduces imaginary flat planes and imaginary straight lines as intermediary geometric constructs to mediate the spatial relationship between the current-carrying conductor and the magnetoresistance effect elements. These imaginary planes serve as reference frameworks that allow the elements to be positioned close to the current path for high detection capability while maintaining a controlled perpendicular orientation that prevents direct magnetic field interference.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Measurement precision

If bending processing is applied to the bottom part of the U-shaped portion to reduce sensitivity effect, then the manufacturing precision is improved, but the device complexity increases

Engineering Contradiction:
Improvesensitivity stabilityVSAvoidprocessing complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent employs asymmetric positioning of the magnetoresistance effect elements relative to the U-shaped conductor. The elements are positioned on a first imaginary flat plane that is parallel to imaginary straight lines, creating an asymmetric but precisely controlled spatial arrangement. This asymmetric positioning allows sensitivity stability without requiring complex bending processing of the conductor itself.

Inventive Principle:
Principle #4Asymmetry

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 configuration effectively reduces the impact of the magnetic field on measurement sensitivity, improves processing accuracy, and allows for a more compact design by centering the current distribution around the imaginary flat plane, thereby minimizing sensitivity reduction.

Implementation Method 1

a current sensor that measures a current by using a magneto-electric resistance effect element, such as a giant magnetoresistance (GMR) element or an anisotropic magnetoresistance (AMR) element

Methodology Applied
Scientific EffectMagneto-electric resistance effect: Magnetoresistance

Implementation Method 2

If a magnetic field is applied from outside in the influence-on-sensitivity direction, the sensitivity changes because application of a magnetic field is equivalent to a change in the bias magnetic field

Methodology Applied
Scientific EffectBias magnetic field effect: Magnetic Field

Data Source

PatentEP3581946B1Current sensor
Publication Date: 2022.09.28 ALPS ALPINE CO LTD
  • EP3581946B1 patent drawingFigure 1
  • EP3581946B1 patent drawingFigure 2
  • EP3581946B1 patent drawingFigure 3

AI summary

A conductor 10, through which a current to be measured Is flows, includes a first conductor portion 11A, a second conductor portion 12, a bent portion 14A, and a third conductor portion 13A. The first conductor portion 11A is separated from a first imaginary flat plane P11 on which a magnetoresistance effect element is disposed, and the current to be measured Is flows parallel to a first imaginary straight line L11A through the first conductor portion 11A. The second conductor portion 12 intersects the first imaginary flat plane P11, and the current to be measured Is flows parallel to a second imaginary straight line L12 through the second conductor portion 12. The bent portion 14A is disposed along a current path between the second conductor portion 12 and the first conductor portion 11A and is bent in the Y2 direction parallel to the first imaginary straight line L11A from the X2 direction parallel to the second imaginary straight line L12. The third conductor portion 13A is disposed along a current path between the bent portion 14A and the first conductor portion 11A. The direction of the magnetic field due to the current to be measured Is flowing through the second conductor portion 12 is perpendicular to the first imaginary flat plane P11.