Current Sensor with Annular Conductor Gap for Magnetic Field Density
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Solution Overview
Problem
Conventional current measuring devices face inefficiencies due to the skin effect, where the magnetic field generated by current flowing intensively at the end portions of a flat conductor fails to pass through the magnetic sensor effectively, limiting the density of the magnetic field transmitted through the magneto electric conversion unit.
Innovation Solution
A current sensor design featuring a conductive member with an annular shape and a magneto electric converter positioned to face the gap between the end surfaces, allowing the magnetic field generated by the surface current to pass through, thereby increasing the magnetic field density measured by the magneto electric converter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a magnetic sensor is disposed to face a flat conductor to measure current, then the current measurement can be performed, but the magnetic field density transmitted through the sensor is reduced due to the skin effect causing current to concentrate at the end portions
Solution Approach 1:
Instead of having the magnetic sensor face the flat surface of the conductor where magnetic field density is low, the invention inverts the arrangement by having the sensor face the gap between end portions of the conductor. This inversion allows the sensor to capture the concentrated magnetic field generated by skin effect current at the edges, thereby improving both measurement accuracy and magnetic field density.
Solution Approach 2:
The invention transitions from a two-dimensional flat surface arrangement to a three-dimensional configuration where the conductor has protruding end portions creating a gap. The magnetic sensor is positioned to face this gap in the third dimension, allowing it to capture the magnetic field that concentrates at the edges due to skin effect, thus improving measurement effectiveness.
2Measurement precision
If the magneto electric converter is positioned to face the gap between end surfaces of the conductive member, then the magnetic field density increases, but the device structure becomes more complex
Solution Approach 1:
The conductive member is segmented into a body portion and separate protruding end portions. This segmentation creates the gap structure necessary for the magnetic sensor to detect the concentrated magnetic field, while allowing each segment to be independently positioned and shaped to optimize both measurement accuracy and structural simplicity.
Solution Approach 2:
The protruding end portions serve multiple functions: they create the gap for magnetic field concentration, they define the measurement region, and they can be integrated with existing conductor designs. This multi-functionality reduces the need for additional separate components, thereby limiting the increase in device complexity.
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 increases the density of the magnetic field transmitted through the magneto electric converter, enhancing the accuracy and efficiency of current measurement, particularly for alternating currents, and reducing phase shift and noise, leading to improved torque control and motor stability.
Implementation Method 1
a magneto electric converter which is arranged to be opposed to and spaced apart from the conductive member in the intersecting direction
Implementation Method 2
a magneto electric converter facing and spaced apart from the conductive member in an intersecting direction intersecting the predetermined direction
Implementation Method 3
in consideration of a variation of a current density due to a skin effect
Data Source
AI summary
The current sensor has a conductive member through which a current to be measured flows in a predetermined direction, and a magneto electric converter facing and spaced apart from the conductive member in an intersecting direction intersecting the predetermined direction. An opposing portion of the conductive member facing the magneto electric converter has an annular shape in which two tip surfaces face each other via a gap around the predetermined direction. The magneto electric converter is opposed to the hollow portion, arranged in the opposing portion having an annular shape, in the intersecting direction via the gap.