Current Sensor Frequency Dependency Reduction via Slit Conductive Plates
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Solution Overview
Problem
Conventional current sensors exhibit high frequency dependency due to changes in magnetic flux density at the detection position, affecting accuracy in current detection.
Innovation Solution
A current sensor design featuring a bus bar with a magnetic detection element, first and second shielding plates, and conductive plates made of nonmagnetic material, where the magnetic detection element is positioned closer to the first conductive plate than the bus bar's center, with a slit in the first conductive plate at the overlapping position, and the conductive plates are thinner than the depth of penetration at maximum frequency, reducing frequency dependency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a magnetic detection element is used to detect magnetic field intensity generated by electric current, then current can be calculated based on magnetic field intensity, but current detection accuracy decreases due to frequency dependency caused by changes in magnetic flux density at detection position
Solution Approach 1:
The patent introduces first and second conductive plates with slits that segment the magnetic flux path. The slits in these plates divide and guide the magnetic flux from the bus bar to the magnetic detection element, creating a more stable magnetic flux density distribution that reduces frequency dependency and improves current detection accuracy across different frequencies.
Solution Approach 2:
The first and second conductive plates act as intermediary elements between the bus bar and the magnetic detection element. These plates mediate the magnetic flux transmission, ensuring stable magnetic flux density at the detection position regardless of frequency changes, thereby improving measurement precision while reducing frequency dependency.
2Measurement precision
If conductive plates are added to reduce frequency dependency, then current detection accuracy improves, but device complexity increases
Solution Approach 1:
The patent optimizes parameters such as the distance between the bus bar and magnetic detection element, the dimensions and positioning of conductive plates, and the slit configurations. By carefully adjusting these parameters, the patent achieves reduced frequency dependency and improved accuracy without excessive structural complexity.
Solution Approach 2:
The first conductive plate is positioned closer to the bus bar than the second conductive plate, creating an asymmetric structure. This asymmetric arrangement optimizes the magnetic flux path to the magnetic detection element, effectively reducing frequency dependency while maintaining reasonable structural 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
The design significantly reduces frequency dependency in current detection while maintaining high sensitivity and accuracy, even with large currents, by minimizing skin effect and eddy currents, and effectively shields magnetic fields.
Implementation Method 1
a magnetic detection element that detects a magnetic field intensity generated by the current flowing in the bus bar
Implementation Method 2
minimizing skin effect and eddy currents
Implementation Method 3
minimizing skin effect and eddy currents
Implementation Method 4
first and second shielding plates arranged so as to sandwich the bus bar between the first and second shielding plates
Data Source
AI summary
A current sensor includes, a bus bar through which a current flows, a magnetic detection element detecting a magnetic field intensity generated by the current, first and second shielding plates arranged so as to sandwich the bus bar between the first and second shielding plates, a first conductive plate made of a conductive nonmagnetic material, arranged between the bus bar and the first shielding plate, and a second conductive plate made of the conductive nonmagnetic material, arranged between the bus bar and the second shielding plate, wherein the magnetic detection element is arranged at a first conductive plate-side. A distance between the first conductive plate and the bus bar is longer than a distance between the second conductive plate and the bus bar. The first conductive plate includes a slit formed in the first conductive plate at an overlapping position, and the slit pierces the first conductive plate.