Current Sensor Conductor Segmentation for Overcurrent Failure Detection
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Solution Overview
Problem
Current sensors face challenges in detecting failures within the package due to overheating caused by overcurrents, which can lead to sensor damage, and existing solutions like pyrotechnic disconnects are inadequate for external detection.
Innovation Solution
A current sensor design with a conductor configuration that includes terminal portions with smaller cross-sectional areas than the turn portion, encapsulated in a package with a magnetic sensor positioned on or near the conductor, allowing for external detection of failures by concentrating current and heat at these areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the cross sectional area of the conductor inside the package is reduced to increase current density and detection sensitivity, then the detection sensitivity is improved, but the conductor overheats causing sensor failure
Solution Approach 1:
The conductor is divided into multiple sections with different cross-sectional areas: a first conductor section with smaller area for high current density and magnetic field concentration, and a second conductor section with larger area for heat dissipation. This segmentation allows simultaneous achievement of detection sensitivity and reliability.
Solution Approach 2:
Different sections of the conductor are given different local properties: the first section has smaller cross-sectional area optimized for magnetic field generation, while the second section has larger cross-sectional area optimized for thermal management. This local quality differentiation resolves the contradiction between sensitivity and reliability.
2Reliability
If pyrotechnic disconnect is used to prevent sensor damage from overcurrent, then sensor protection is improved, but detection of failure inside the package remains difficult
Solution Approach 1:
The magnetic sensor is extracted from the package and positioned on the external surface, allowing it to detect magnetic fields generated by the conductor both inside and outside the package. This enables failure detection in previously inaccessible internal regions.
Solution Approach 2:
The magnetic field serves as an intermediary that carries information about current flow and potential failures from the internal conductor to the external sensor, enabling indirect detection of internal conditions without physical access to the package interior.
3Reliability
If the conductor cross sectional area is increased to prevent overheating, then reliability is improved, but detection sensitivity decreases
Solution Approach 1:
The conductor is segmented into first and second sections with different cross-sectional areas, allowing the first section to provide high current density for sensitivity while the second section provides thermal management for reliability.
Solution Approach 2:
The solution moves from a uniform one-dimensional conductor to a multi-dimensional structure with varying cross-sectional areas along its length, enabling simultaneous optimization of electrical and thermal properties in different spatial regions.
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
Enables effective detection of failures from outside the package, preventing thermal destruction and enhancing sensitivity in measuring current amounts, even during overcurrent conditions.
Implementation Method 1
the magnetoelectric conversion element is used to detect a strength of a magnetic field that is generated by the current to be measured flowing through the conductor and convert it into an electrical signal
Implementation Method 2
at least one of a cross sectional area of a connection portion between the first terminal portion and the first body portion, or a cross sectional area of a connection portion between the second terminal portion and the second body portion, is smaller than a cross sectional area of the turn portion
Data Source
AI summary
There is provided a current sensor including: a conductor having a first terminal portion for inputting a current and a second terminal portion for outputting the current which are arranged on one side in a first axial direction, the second terminal portion being separated from the first terminal portion in a second axial direction intersecting the first axial direction, a turn portion which is arranged on another side in the first axial direction, a first body portion which connects one end of the turn portion and the first terminal portion, and a second body portion which is separated from the first body portion in the second axial direction, to connect another end of the turn portion and the second terminal portion; a magnetic sensor which is arranged on the conductor or near the conductor; and a package.