Fuse Voltage Current Sensing Without Separate Shunt Resistors

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Solution Overview

Problem

Conventional current sensors in electrical power systems are costly and bulky, making them impractical for widespread adoption, especially in residential applications, where they can account for a significant portion of the total product cost.

Innovation Solution

A compensation circuit is used to indirectly calculate current by measuring the voltage across a fuse element with non-linear resistance, eliminating the need for a separate resistive shunt and utilizing algorithms to determine the fuse resistance and current based on thermal equilibrium characteristics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional current sensors (resistive shunts, CTs, hall-effect sensors) are used for current sensing, then accurate current measurement is achieved, but the cost and physical size of the system increases significantly

Engineering Contradiction:
Improvecurrent measurement accuracyVSAvoidsystem cost and size
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The fuse element itself is utilized to perform the current sensing function by measuring its voltage drop, eliminating the need for separate current sensing components. The fuse serves dual purposes: protection and measurement, thereby reducing overall system complexity and cost while maintaining measurement capability

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The fuse element is made multi-functional by using it both for its traditional protection role and for current sensing. By measuring the voltage across the fuse and using algorithms to determine current based on the fuse's thermal equilibrium characteristics, one component performs multiple functions, reducing the need for additional specialized components

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Ease of operation

If conventional current sensors are deployed in residential electrical systems, then current monitoring capability is provided, but the cost accounts for a significant portion of total product cost

Engineering Contradiction:
Improvecurrent monitoring capabilityVSAvoidproduct cost
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The invention leverages the fuse element, which is inherently a low-cost, disposable component in residential electrical systems, to provide current monitoring. Since fuses are already present in these systems for protection, utilizing them for sensing adds functionality without requiring expensive, permanent sensing infrastructure

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The existing fuse infrastructure is made to serve an additional function (current sensing) without requiring separate dedicated sensing components, thereby providing monitoring capability at minimal additional cost

Inventive Principle:
Principle #25Self-service

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 approach reduces costs and physical space requirements while providing accurate current sensing, enabling advanced monitoring and oversight of electrical power systems with a compact and cost-effective solution.

Implementation Method 1

a conductor having a non-linear resistance when connected to an electrical power system

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 2

a processor receiving a voltage sensed across the conductor and operable to iteratively calculate a current flowing through the conductor based on at least a first detected state of the sensed voltage and a thermal equilibrium characterization of the conductor

Methodology Applied
Scientific EffectThermal equilibrium:

Data Source

PatentEP4375676B1Electric fuse current sensing systems and monitoring methods
Publication Date: 2026.03.25 EATON INTELLIGENT POWER LTD
  • EP4375676B1 patent drawingFigure 1~2
  • EP4375676B1 patent drawingFigure 3~4
  • EP4375676B1 patent drawingFigure 5A~5C

AI summary

Electrical current sensing and monitoring methods include connecting sensing a voltage across a conductor having a non-linear resistance such as a fuse element. The current flowing in the conductor is calculated based on at least a first detected state of the sensed voltage and a thermal equilibrium characterization of the conductor.