Integrated Current Transducer with Fuse-Protected Conductor Bar

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Solution Overview

Problem

Existing electrical current transducers are not compact, economical, lightweight, accurate, easy to implement, and robust enough for efficient current measurement, particularly in applications requiring miniaturization and reduced weight.

Innovation Solution

A compact electrical current transducer design featuring a magnetic core with an air-gap housing a Hall effect sensor or similar magnetic field detector, integrated with a primary conductor bar having a fuse portion and an insulating housing, allowing for a reduced magnetic core size and enhanced safety through an insulating safety cover, and facilitating crimp or bolt connections for automotive battery applications.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If a conventional transducer design with separate primary conductor and magnetic core is used, then the transducer is robust and stable, but the transducer size is large and weight is high

Engineering Contradiction:

Improvetransducer sizeVSAvoidrobustness and stability

Core Design Contradiction:

Volume of moving objectVSReliability

Solution Approach 1:

The patent combines the primary conductor bar and magnetic core into a single integrated structure where the magnetic core is positioned within indents of the conductor bar. This merging eliminates the need for separate mounting structures and reduces overall transducer size while maintaining structural integrity through the integrated design.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The magnetic core is nested within indents formed in the primary conductor bar, creating a compact configuration where the core is housed within the conductor structure itself. This nesting approach reduces the overall volume while keeping both components structurally sound and functionally effective.

Inventive Principle:

Principle #7Nested doll (Nesting)

2Volume of moving object

If the magnetic core size is reduced for miniaturization, then the transducer becomes more compact, but the manufacturing precision and assembly difficulty increase

Engineering Contradiction:

Improvemagnetic core sizeVSAvoidassembly precision

Core Design Contradiction:

Volume of moving objectVSManufacturing precision

Solution Approach 1:

The indents for housing the magnetic core are pre-formed directly in the primary conductor bar during its fabrication process. This preliminary action ensures precise positioning and fit of the magnetic core before final assembly, eliminating the need for separate precision machining or adjustment steps that would increase assembly difficulty.

Inventive Principle:

Principle #10Preliminary action

3Ease of manufacture

If integration of primary conductor and magnetic core is implemented, then manufacturing cost is reduced and compactness is improved, but the complexity of the conductor bar structure increases

Engineering Contradiction:

Improvemanufacturing costVSAvoidconductor bar structure

Core Design Contradiction:

Ease of manufactureVSDevice complexity

Solution Approach 1:

The primary conductor bar is segmented into functional zones including connection terminal ends, a core passage section with indents for the magnetic core, and a fuse portion. This segmentation allows each zone to be optimized for its specific function while being manufactured as a single integrated piece, reducing overall manufacturing complexity compared to assembling multiple separate components.

Inventive Principle:

Principle #1Segmentation

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 provides a lightweight, accurate, and robust current transducer that is economical to produce and use, offering improved performance and safety by allowing compact size and efficient current measurement while preventing short circuits and accommodating high current levels.

Implementation Method 1

a magnetic field detector, such as a Hall effect sensor in the form of an ASIC

Methodology Applied

Scientific EffectHall effect: Hall Effect

Data Source

PatentEP3093672B1Current transducer with integrated primary conductor bar

Publication Date: 2020.08.12 LEM INT SA

Figure 1a~1b
Figure 2a~2b

AI summary

Electrical current transducer including a primary conductor bar (4) for carrying the current to be measured, a magnetic core (6) comprising a magnetic circuit gap (22), a magnetic field sensor (8) comprising a magnetic field detector positioned in the magnetic circuit gap, and an insulating housing (10) surrounding the magnetic core and magnetic field sensor. The primary conductor bar comprises connection terminal ends (12a, 12b) extending outside of the housing configured for connection to an external primary conductor. The primary conductor bar comprises a core passage section (16) comprising a fuse portion (20) configured for interruption of the primary conductor if a predefined electrical current is exceeded. The core passage section has a reduced width (W1) in comparison to the connection terminal ends (12a, 12b) extending outside of the housing thereby providing indents (17a, 17b) within which at least a portion of the magnetic core is positioned such that a central passage (18) of the magnetic core has a width (W3) less than the width (W2) of the primary conductor connection ends (12a, 12b).