Current Sensor Yoke Gap Orientation for Adjacent Path Interference

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Solution Overview

Problem

Current sensors face challenges in accurately detecting currents due to magnetic fields generated by adjacent current paths, which interfere with the measurement of the intended current paths, leading to reduced detection accuracy.

Innovation Solution

The design includes a current sensor configuration with a first magnetic sensor and yoke arrangement that minimizes the detection of magnetic fields from adjacent current paths by positioning the sensors and yokes in a way that the induced magnetic fields from these paths become perpendicular to the sensitivity direction, using a gap in the yoke and arranging the adjacent current path in a plane that causes the magnetic lines of flux to cross at a right angle, thereby reducing interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple bus bars are arranged adjacent to each other with magnetic sensors positioned near them, then current detection can be performed for multiple current paths, but magnetic fields from adjacent current paths interfere with the measurement accuracy

Engineering Contradiction:
Improvecapability to detect current in multiple current pathsVSAvoidaccuracy of current detection
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The magnetic sensor is positioned within a yoke structure that provides localized magnetic field guidance. The yoke's magnetic path is designed to concentrate and guide the magnetic field from the specific current path of interest to the sensor, while the geometric configuration (with the adjacent current path lying in a plane where its magnetic field is perpendicular to the sensor's sensitivity direction) creates directional selectivity. This allows the sensor to selectively detect the magnetic field from the target current path while rejecting interference from adjacent current paths.

Inventive Principle:
Principle #3Local quality

2Measurement precision

If magnetic sensors are placed close to current paths to improve detection sensitivity, then detection capability is enhanced, but interference from adjacent current paths increases

Engineering Contradiction:
Improvedetection sensitivity of magnetic sensorVSAvoidmagnetic field interference from adjacent current paths
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The invention utilizes the geometric relationship between adjacent current paths to convert the harmful magnetic field interference into a beneficial directional filtering mechanism. By positioning the adjacent current path such that its magnetic field is perpendicular to the sensor's sensitivity direction, the interference is naturally rejected. The yoke structure further enhances this effect by providing a defined magnetic path that guides the target magnetic field to the sensor while the perpendicular arrangement ensures adjacent fields do not couple into the sensor, effectively transforming the potential harm into a selective detection advantage.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

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 enhances the accuracy of current detection by minimizing the impact of adjacent current paths' magnetic fields on the measurement, allowing for more precise detection of the intended current.

Implementation Method 1

a first magnetic sensor detecting a magnetic field due to the current flowing through the current path

Methodology Applied
Scientific EffectMagnetic field generation: Magnetic Field

Implementation Method 2

a first yoke having a sectional shape partially surrounding a periphery of the current path

Methodology Applied
Scientific EffectMagnetic flux guidance: Magnetic Field

Data Source

PatentEP3264049B1Current sensor
Publication Date: 2018.12.12 ALPS ALPINE CO LTD
  • EP3264049B1 patent drawingFigure 1
  • EP3264049B1 patent drawingFigure 2
  • EP3264049B1 patent drawingFigure 3

AI summary

A current sensor (100) includes: a current path (102) through which a current flows in a first direction; an adjacent current path (152) arranged in such a manner as to be adjacent to the current path; a first magnetic sensor (104) detecting a magnetic field due to the current flowing through the current path; and a first yoke (103) having a sectional shape partially surrounding a periphery of the current path in a first virtual plane (171) perpendicular to the first direction. The first yoke includes a gap delimited by two end surfaces parallel to each other. Two end edges (116-1, 116-2) spaced furthest apart from the current path at the two end surfaces, are located in a common second virtual plane (172) perpendicular to the two end surfaces. The first magnetic sensor is arranged in the gap and has a sensitivity direction parallel to the second virtual plane, and the adjacent current path is arranged in the second virtual plane.