Coreless Current Sensor with Recessed Conductor Geometry
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Solution Overview
Problem
Conventional current sensors face challenges in miniaturization due to the use of magnetic cores and require larger shields to prevent magnetic saturation, while also failing to effectively account for the influence of neighboring current paths.
Innovation Solution
A current sensor configuration without a magnetic core, utilizing at least two conductors and two magnetoelectric conversion units with detection surfaces facing the same direction, and recessed portions to detect orthogonal components of magnetic flux, allowing for miniaturization and precise current measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a core made of magnetic material is arranged to surround a conductor, then magnetic flux density can be effectively detected, but the size of the current sensor increases and miniaturization becomes difficult
Solution Approach 1:
The patent removes the magnetic core from the sensor structure, extracting the problematic component that caused size increase. The detection element directly detects magnetic flux density without requiring a surrounding magnetic core, enabling miniaturization while maintaining detection capability
Solution Approach 2:
The patent introduces a magnetic flux concentration structure as an intermediary between the conductor and detection element. This structure concentrates magnetic flux without requiring a full magnetic core, achieving effective detection in a compact form factor
2Object-affected harmful factors
If first magnetism shield and second magnetism shield are disposed to sandwich the bus bar and magnetism detection element, then leakage magnetic field influence is reduced, but the device size increases and miniaturization is limited
Solution Approach 1:
The patent removes the first and second magnetism shields from the structure, extracting the components that increased device size. Alternative shielding approaches are implemented that do not require sandwiching the detection element between shields
Solution Approach 2:
The patent converts the harmful leakage magnetic field into a beneficial effect by strategically positioning detection elements to detect both the target magnetic field and the leakage field, then using signal processing to extract accurate current information
3Reliability
If the first magnetism shield and second magnetism shield are arranged further apart from the bus bar, then magnetic saturation is prevented, but the device size increases
Solution Approach 1:
The patent removes the magnetism shields entirely, eliminating the need to position them at specific distances to prevent magnetic saturation. The detection element directly measures magnetic flux density without being protected by shields
Solution Approach 2:
The patent changes the operating parameters of the detection element to handle high magnetic flux density environments without saturation. The detection element is selected or designed to operate reliably in the presence of strong magnetic fields from the bus bar
4Volume of moving object
If magnetism detection element is arranged to face the bus bar without shields, then device size is reduced, but influence from neighboring current paths increases
Solution Approach 1:
The patent positions detection elements to detect both the target magnetic field from the bus bar and the interfering magnetic field from neighboring current paths. Signal processing techniques are then used to separate and extract the target current information from the combined signal
Solution Approach 2:
The patent introduces magnetic flux concentration structures as intermediaries that preferentially guide magnetic flux from the target bus bar to the detection elements, while being less effective at guiding flux from neighboring current paths, thus reducing interference
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 enables a compact current sensor that effectively measures current flowing through conductors without the need for magnetic cores or shields, minimizing size and interference from adjacent conductors, while maintaining high precision in detecting magnetic flux density.
Implementation Method 1
detecting magnetic flux density of magnetic flux input to the detection surfaces
Implementation Method 2
magnetoelectric conversion units... each of which outputs a signal according to a difference in the magnetic flux density
Data Source
AI summary
A current sensor includes at least two conductors and at least two magnetoelectric conversion units each having at least two magnetism detection elements for detecting magnetic flux density of magnetic flux input to detection surfaces facing the same direction, and outputting a signal according to a difference in magnetic flux density between orthogonal components orthogonal to the detection surface of magnetic flux input to the detection surface of the magnetism detection elements. Each conductor includes an extending portion extending along a second-direction orthogonal to a first-direction being an adjacent direction of two adjacent conductors, and a recessed portion including orthogonal portions extending along a third-direction orthogonal to the first- and second-directions and recessed in the third-direction from the extending portion. Each magnetoelectric conversion unit is disposed with the detection surface facing the orthogonal portion of the recessed portion.