Multi-Bus-Bar Current Sensor Layout for Magnetic Interference Suppression
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Solution Overview
Problem
Existing multi-channel current sensors suffer from measurement errors due to the adverse effect of magnetism from adjacent bus bars on the detection target, which is not adequately addressed in prior designs.
Innovation Solution
The current sensor is structured with bus bars and magnetic sensing units arranged in a specific orthogonal configuration, where the sensing units are offset from the centers of the bus bars to minimize the impact of magnetic fields from adjacent conductors, and includes a shield to block external interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If magnetic sensing units are placed directly facing the bus bars, then the detection sensitivity is improved, but measurement error increases due to magnetic interference from adjacent bus bars
Solution Approach 1:
The magnetic sensing units are positioned asymmetrically relative to the bus bars. Specifically, the sensing units are offset from the central axis of the bus bars in the second direction, creating an asymmetric arrangement that reduces magnetic interference from adjacent bus bars while maintaining adequate detection sensitivity.
Solution Approach 2:
The invention introduces positional offset in the second direction (orthogonal to both the bus bar length direction and the facing direction) as an additional spatial dimension. This dimensional adjustment allows the sensing units to avoid the harmful magnetic fields from adjacent bus bars while still detecting the magnetic field from the target bus bar effectively.
2Object-affected harmful factors
If the distance between adjacent bus bars is increased, then electromagnetic induction between bus bars is reduced, but the device complexity and space requirement increase
Solution Approach 1:
Instead of uniformly increasing the distance between all adjacent bus bars, the invention applies local quality adjustment by offsetting only the magnetic sensing units from the central axis in the second direction. This localized positional adjustment reduces electromagnetic interference without requiring increased overall spacing between bus bars, thereby maintaining compact device structure.
3Object-affected harmful factors
If magnetic sensing units are offset from the center of bus bars, then interference from adjacent bus bars is reduced, but the detection sensitivity may decrease
Solution Approach 1:
The magnetic sensing units are offset partially from the center in the second direction, not completely removed from the optimal detection position. This partial offset action is sufficient to reduce interference from adjacent bus bars while maintaining adequate proximity to the target bus bar for effective magnetic field detection, thus balancing both requirements.
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 enhances detection precision by suppressing errors from adjacent bus bars, allowing for accurate measurement of currents with improved sensitivity, especially at high frequencies.
Implementation Method 1
a magnetic sensing unit that senses a magnetic field generated due to a flow of a current under measurement in one of the plurality of bus bars
Implementation Method 2
includes a shield to block external interference
Data Source
AI summary
A current sensor has a first bus bar, a second bus bar, and a third bus bar, which are formed in a plate shape, and also has a first magnetic sensing unit, a second magnetic sensing unit, and a third magnetic sensing unit placed so as to respectively face the first bus bar, second bus bar, and third bus bar. Each bus bar has a narrow-width portion with the relevant magnetic sensing unit placed so as to face it, and also has two wide-width portions. The second magnetic sensing unit, which senses a magnetic field generated from the second bus bar, and the third magnetic sensing unit, which senses a magnetic field generated from the third bus bar, are offset from their relevant narrow-width portions toward opposite sides in the Y-axis direction, when viewed along the Z-axis direction.