Magnetic Sensor Terminal Layout for Noise Reduction
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Solution Overview
Problem
The configuration of magnetoelectric transducers in current sensors can be affected by noise generated from the current path during ON-OFF switching of voltage, influencing the detection results.
Innovation Solution
A current detecting apparatus with a magnetic sensor and terminals that do not overlap the bus bar, allowing the signal and supply terminals to be distant from the bus bar, and using two plate-like magnetic shields to sandwich the bus bar and sensor, reducing noise interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the magnetoelectric transducer is disposed in the current path, then the current detection function is achieved, but noise generated from the current path during ON-OFF switching enters through terminals to affect detection results
Solution Approach 1:
The patent extracts the harmful function (noise entry path) by separating the signal terminals and supply terminals from the current path area. The terminals are extended from portions of the main body not overlapping the bus bar, effectively removing the noise coupling path while preserving the magnetic field detection function through the overlapping main body portion.
Solution Approach 2:
The patent resolves the contradiction by transitioning from a one-dimensional arrangement (terminals along the current path) to a two-dimensional spatial arrangement. The main body overlaps the bus bar in the vertical dimension for magnetic field detection, while terminals extend horizontally from non-overlapping portions, creating spatial separation in different dimensions to eliminate noise coupling.
2Measurement precision
If magnetic shields are added to reduce noise influence, then detection accuracy improves, but device complexity increases
Solution Approach 1:
The patent introduces magnetic shields as intermediary elements between the bus bar and the magnetoelectric transducer. These shields act as mediators that redirect or contain magnetic field lines, preventing extraneous magnetic fields from reaching the sensor while allowing the measurement function to proceed through the controlled magnetic path.
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 reduces the influence of noise on the detection results and allows for flexible bus bar design without size restrictions, while also minimizing extraneous magnetic field effects.
Implementation Method 1
a magnetoelectric transducer that detects a magnetic field generated when a current flows through the current path
Implementation Method 2
two plate-like magnetic shields having a same shape and same size disposed away from each other so as to sandwich the bus bar and the magnetic sensor
Data Source
Figure 1(a)~1(b)
Figure 2(a)~2(b)
Figure 3(a)~3(b)
AI summary
A magnetic sensor of the present invention is configured such that, even if noise is generated from a bus bar at ON-OFF switching of a voltage for controlling the current to be measured flowing through the bus bar, the influence of the noise on the result of measurement made by the magnetic sensor can be reduced. The magnetic sensor includes a main body having two opposing sides, the main body being capable of measuring a value of a current to be measured flowing through a bus bar by detecting a magnetic field induced by the current to be measured, wherein a signal terminal for outputting a detection signal and a supply terminal for supplying electrical power to the main body extend only from one of the two sides of the main body.