Current Sensor with Orthogonal Paths for Magnetic Interference Cancellation

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Solution Overview

Problem

Current sensors face challenges in maintaining measurement accuracy and dynamic range due to the interference from external magnetic fields and neighboring current paths, which reduces their effectiveness in detecting currents flowing through measurement-subject current paths.

Innovation Solution

The design includes a current sensor configuration with first and second current paths arranged orthogonally to each other, where magnetoelectric conversion elements are positioned between the paths to minimize the impact of external and neighboring magnetic fields by applying these fields in opposite directions, allowing for differential measurement and cancellation of interference, thereby maintaining dynamic range and enhancing measurement accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If magnetoelectric conversion elements are arranged to measure magnetic fields from both measurement-subject current and neighboring current paths, then measurement accuracy for the measurement-subject current can be maintained by canceling neighboring current effects, but the dynamic range decreases due to the added magnetic field strength from neighboring currents

Engineering Contradiction:

Improvemeasurement accuracyVSAvoiddynamic range

Core Design Contradiction:

Measurement precisionVSQuantity of substance

Solution Approach 1:

The invention extracts only the magnetic field component from the measurement-subject current path by using a specific sensor arrangement where magnetoelectric conversion elements detect magnetic fields primarily from the measurement-subject current while minimizing sensitivity to neighboring current paths through geometric positioning and directional alignment

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The invention applies local quality by making the magnetoelectric conversion elements have different sensitive directions - specifically, the elements are arranged so that their sensitive axes are oriented to maximize detection of the measurement-subject current's magnetic field while minimizing detection of neighboring current paths' magnetic fields through directional selectivity

Inventive Principle:

Principle #3Local quality

2Measurement precision

If the sensor is positioned to detect magnetic fields from measurement-subject current, then current measurement can be performed, but external magnetic fields such as geomagnetism and neighboring current path magnetic fields interfere with measurement accuracy

Engineering Contradiction:

Improvecurrent measurement accuracyVSAvoidexternal magnetic field interference

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The invention uses asymmetric arrangement of magnetoelectric conversion elements with different sensitive directions relative to the measurement-subject current path and neighboring current paths. This asymmetric configuration creates differential sensitivity where the measurement-subject current affects both elements similarly while external fields and neighboring currents affect them differently, enabling cancellation of harmful factors through differential measurement

Inventive Principle:

Principle #4Asymmetry

Solution Approach 2:

The invention converts the harmful effect of external magnetic fields and neighboring current interference into a beneficial cancellation mechanism. By arranging magnetoelectric conversion elements to have different sensitive directions, the interference fields are detected differently by each element, allowing the system to subtract and cancel these harmful factors while preserving the measurement of the desired current

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 effectively reduces the impact of external magnetic fields and neighboring current path effects, preventing a decrease in dynamic range and improving measurement accuracy by ensuring that only the induced magnetic field from the measurement-subject current is detected, while minimizing the influence of external and neighboring fields.

Implementation Method 1

first and second magnetoelectric conversion elements arranged with the first current path interposed therebetween

Methodology Applied

Scientific EffectMagnetoelectric conversion: Electromagnetic Induction

Data Source

PatentUS9435829B2Current sensor

Publication Date: 2016.09.06 ALPS ALPINE CO LTD

AI summary

A current sensor includes first and second current paths each including a first conductive portion and second and third conductive portions extending in the X direction from both ends of the first conductive portion, and being neighboring and apart in the Y direction; and first and second magnetoelectric conversion elements arranged with the first conductive portion of the first current path interposed therebetween, and having sensitive axes along the Y direction. The second and third conductive portions of each of the first and second current paths are apart in the Z direction. The second conductive portion of the second current path is arranged in the Y direction with respect to the first and second magnetoelectric conversion elements. Perpendicular lines from the center line of the second conductive portion of the second current path to the first and second magnetoelectric conversion elements have the same direction and equivalent lengths.