Current Sensor Asymmetric Transducer Positioning

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Current current sensors with two sensor chips disposed in a magnetism-collecting core's gap experience output differences due to slight deviations in magnetoelectric transducer positions from the core's center, leading to inconsistent magnetic field exposure and reduced accuracy in anomaly detection when the core's end face area is minimized.

Innovation Solution

The sensor chips are positioned in a point or axially symmetric manner relative to the gap center, ensuring each magnetoelectric transducer is equidistant from the center, thereby maintaining uniform magnetic field exposure and minimizing output differences, even when transducers deviate from their intended positions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If two sensor chips are disposed at corresponding bilaterally symmetric positions across the end face center, then the sensor chips are exposed in a uniform magnetic field when the end face area is sufficiently large, but when the end face area is reduced to minimize sensor size, a slight difference in distance between each magnetoelectric transducer and the end face center causes a difference in magnetic field applied, thereby causing output difference between the two sensor chips

Engineering Contradiction:
Improvesensor sizeVSAvoidoutput consistency between sensor chips
Core Design Contradiction:
Volume of moving objectVSMeasurement precision

Solution Approach 1:

The patent applies asymmetry by intentionally designing the sensor chips to be disposed in a point symmetric manner rather than bilaterally symmetric manner. This means the magnetoelectric transducers are positioned at specific asymmetric locations within each sensor chip such that when viewed from the normal direction, the transducers in the two sensor chips are at different distances from the end face center, yet this asymmetric arrangement ensures both transducers are equidistant from the gap center, thereby maintaining uniform magnetic field exposure and eliminating output differences despite the reduced end face area.

Inventive Principle:
Principle #4Asymmetry

2Volume of moving object

If the end face area of the magnetism-collecting core is reduced to minimize sensor size, then the sensor becomes more compact, but the uniform range of the magnetic field in the gap decreases, causing output difference between the two magnetoelectric transducers

Engineering Contradiction:
Improvesensor sizeVSAvoiduniform magnetic field range
Core Design Contradiction:
Volume of moving objectVSArea of stationary object

Solution Approach 1:

The patent applies local quality by optimizing the specific positioning of magnetoelectric transducers within the sensor chips rather than relying on the overall uniformity of the magnetic field across the entire end face. By carefully selecting the local positions of the transducers (at points that are equidistant from the gap center), the patent ensures that each transducer experiences the same magnetic field strength even when the overall magnetic field uniformity is compromised by reduced end face area.

Inventive Principle:
Principle #3Local quality

3Ease of manufacture

If the magnetoelectric transducer is positioned at the center of the sensor chip, then the positioning is simple, but manufacturing deviations cause the transducer to deviate from the center, resulting in different distances from the end face center and causing output differences

Engineering Contradiction:
Improvetransducer positioningVSAvoidoutput consistency
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent applies preliminary action by pre-calculating and pre-positioning the magnetoelectric transducers at specific locations within the sensor chips that are point symmetric with respect to the gap center. This preliminary positioning is designed to compensate for potential manufacturing deviations. By establishing this point symmetric arrangement in advance, the patent ensures that even if manufacturing variations occur, the transducers will maintain equidistance from the gap center and produce consistent outputs.

Inventive Principle:
Principle #10Preliminary action

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 reduces output differences between sensor chips, allowing for a lower threshold for anomaly detection and improved accuracy in current measurement, especially in smaller sensor designs.

Implementation Method 1

The magnetism-collecting core collects a magnetic flux caused by a current flowing through the conductor

Methodology Applied
Scientific EffectMagnetic flux collection: Magnetic Field

Implementation Method 2

The magnetoelectric transducer measures a magnetic flux passing through the gap of the magnetism-collecting core

Methodology Applied
Scientific EffectMagnetoelectric transduction: Electromagnetic Induction

Data Source

PatentEP3315978B1Current sensor
Publication Date: 2022.06.15 DENSO CORP
  • EP3315978B1 patent drawingFigure 1
  • EP3315978B1 patent drawingFigure 2A~2B
  • EP3315978B1 patent drawingFigure 3A~3B

AI summary

Two sensor chips (32a, 32b) house respective magnetoelectric transducers (52a, 52b). The two sensor chips (32a, 32b) are disposed in the gap. The two sensor chips (32a, 32b) are disposed such that a magnetic induction direction of each of the two sensor chips (32a, 32b) is the same as a normal direction of end faces (351, 352) of the magnetism-collecting core, the end faces (351, 352) facing the gap, and the two sensor chips (32a, 32b) are disposed in an axially symmetric manner to a straight line (CL) passing through a center of the gap.