Current Sensing Assembly with Magnetic Sensors in Notched Conductor

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Solution Overview

Problem

Current sensing assemblies in electrical switching apparatus face challenges with accuracy and size due to the use of resistive shunts and complex magnetic sensor configurations, which result in undesirable voltage drops, heating, and susceptibility to external magnetic fields.

Innovation Solution

A current sensing assembly featuring a conductor with notches or curled portions and strategically placed magnetic sensors to concentrate the current and magnetic field, allowing for improved accuracy and reduced size, while also canceling external magnetic fields through sensor alignment and configuration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If resistive shunts are used to sense current, then current measurement is achieved, but voltage drop and heating occur which are undesirable

Engineering Contradiction:

Improvecurrent measurement accuracyVSAvoidvoltage drop and heating

Core Design Contradiction:

Measurement precisionVSObject-generated harmful factors

Solution Approach 1:

The patent replaces the resistive shunt (electrical measurement method) with magnetic sensors that detect the magnetic field generated by current flow. This substitution eliminates the need for direct electrical contact and resistive elements, thereby avoiding voltage drop and heating while maintaining current measurement capability through non-contact magnetic field detection

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If complex configurations of magnetic sensors with large flux concentrators are used, then high accuracy and wide current range are achieved, but the assembly becomes large and expensive

Engineering Contradiction:

Improvecurrent measurement accuracy and rangeVSAvoidsensor configuration complexity and size

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent divides the current sensing function into multiple discrete magnetic sensors positioned at specific locations around the conductor. Each sensor measures the magnetic field at its location, and the individual measurements are processed to determine the total current. This segmentation allows for simpler individual sensor designs while achieving accurate measurements through combined data from multiple sensors

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent combines the measurements from multiple magnetic sensors to achieve accurate current measurement. By merging the data from sensors positioned at different locations and orientations, the system achieves wide current range and high accuracy without requiring complex individual sensor designs or large flux concentrators

Inventive Principle:

Principle #5Merging (Combining)

3Measurement precision

If magnetic sensors are used without compensation, then current measurement is achieved, but external magnetic fields cause inaccurate results

Engineering Contradiction:

Improvecurrent measurement capabilityVSAvoidsusceptibility to external magnetic fields

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent implements preliminary compensation for external magnetic field interference by positioning sensors to detect both the current-generated magnetic field and the external field components. The system预先 (in advance) accounts for external field effects through sensor placement geometry and signal processing algorithms that subtract or compensate for the external field contribution, thereby isolating the current measurement from interference

Inventive Principle:

Principle #9Preliminary anti-action

Solution Approach 2:

The patent uses multiple sensors to provide feedback information about the magnetic field environment. By comparing measurements from sensors at different positions and orientations, the system can identify and compensate for external magnetic field interference, adjusting the current measurement to account for detected interference patterns

Inventive Principle:

Principle #23Feedback

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 solution enhances the accuracy and compactness of current sensing assemblies, reducing the impact of external fields and heat generation, and enabling wider current range measurements with smaller, more integrated designs.

Implementation Method 1

magnetic sensors have also been used to measure current in circuit breakers

Methodology Applied

Scientific EffectMagnetic field: Magnetic Field

Implementation Method 2

magnetic sensors disposed in or between the notches

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentUS10191089B2Current sensing assembly employing magnetic sensors

Publication Date: 2019.01.29 EATON INTELLIGENT POWER LTD

AI summary

A current sensing assembly includes a conductor having a first side, a second side opposite the first side, a third side, and a fourth side opposite the third side. The first side has a first notch formed therein and the second side has a second notch formed therein opposite the first notch. The current sensing assembly also includes a sensor assembly including a first magnetic sensor disposed in the first notch or proximate to the third side of the conductor between the first and second notches, and a second magnetic sensor disposed in the second notch or proximate to the fourth side of the conductor between the first and second notches.