Magnetic Current Sensor Layout for Fast di/dt Noise Rejection
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Solution Overview
Problem
Current sensing technologies face challenges in accurately measuring fast-varying electrical currents due to induced voltages from magnetic flux, leading to measurement errors and system malfunctions, and require additional magnetic shields that increase device footprint.
Innovation Solution
A magnetic field sensor configuration with sensing elements separated in directions perpendicular to the current, combined with magnetic concentrators, reduces the need for large shields by compensating external magnetic fields and improving signal-to-noise ratio through redundant signal processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If magnetic shields are introduced to reduce magnetic noise influence, then measurement precision is improved, but device footprint increases
Solution Approach 1:
The patent extracts and eliminates the magnetic shield component entirely, replacing it with a computational approach using multiple sensing elements that measure magnetic field components through mathematical operations to achieve noise rejection without physical shielding structures
Solution Approach 2:
The patent replaces the mechanical magnetic shield system with a computational field processing system using multiple sensors and mathematical algorithms to achieve the same noise rejection function without physical barriers
2Measurement precision
If traditional single sensing element configuration is used, then device complexity is reduced, but measurement precision deteriorates due to induced voltages from high di/dt currents
Solution Approach 1:
The patent segments the single sensing element into multiple sensing elements arranged in specific spatial configurations, where each element measures different magnetic field components that are then processed through mathematical operations to eliminate induced voltage errors
Solution Approach 2:
The patent transitions from a single-point measurement to a multi-dimensional measurement approach by distributing sensing elements in space and using mathematical operations to synthesize accurate current measurements that are immune to high di/dt induced voltages
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 sensor achieves accurate current sensing with enhanced immunity to electromagnetic noise and reduced parasitic coupling, allowing compact implementation and high-frequency current detection.
Implementation Method 1
A magnetic field sensor for sensing a current through a conductor comprising a hole through the conductor in which the sensor is placed
Implementation Method 2
A magnetic field sensor configuration with sensing elements separated in directions perpendicular to the current, combined with magnetic concentrators
Data Source
Figure 1~2
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Figure 6~8
AI summary
A magnetic field sensor is provided for sensing a current flowing in a first direction divided in at least two conductor portions separated in a second direction perpendicular to the first direction. It includes at least a first sensing element and second sensing element and at least one integrated magnetic concentrator for sensing the magnetic field at respectively first and second positions in a region between the two conductor portions. The sensing elements are adapted in combination with the concentrator to sense the field with a highest sensitivity in a sensing direction perpendicular to the first direction, wherein the two positions are separated by a predetermined distance in a spacing direction perpendicular to the sensing direction.