Dual-Sided Differential Magnetic Sensor for Stray Field Immunity
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Solution Overview
Problem
Conventional magnetic field sensors suffer from low accuracy and lack of interference immunity against magnetic stray fields, making them less effective in applications such as detecting wheel position or speed.
Innovation Solution
A sensor device comprising a magnet with two differential magnetic field sensors mounted on opposite surfaces, providing a top-read configuration that is galvanically isolated and less susceptible to magnetic stray fields, thereby enhancing measurement accuracy and immunity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional magnetic field sensors are used, then the device complexity is low, but the measurement precision is poor and interference immunity is weak
Solution Approach 1:
The sensor device is segmented into two separate differential magnetic field sensors mounted on opposite surfaces of the magnet. This segmentation allows each sensor to independently measure magnetic field components, improving measurement precision through differential measurement while maintaining manageable device complexity through modular architecture
Solution Approach 2:
The patent transitions from a single-sided sensor configuration to a dual-sided configuration by mounting sensors on opposite surfaces of the magnet. This dimensional change enables differential measurement of magnetic field components, significantly improving measurement accuracy and interference immunity without substantially increasing device complexity
2Object-affected harmful factors
If conventional magnetic field sensors are used, then the device structure is simple, but the immunity to magnetic stray fields is insufficient
Solution Approach 1:
By segmenting the measurement function into two separate differential sensors positioned on opposite surfaces, the system can differential measurement to cancel out common-mode magnetic stray fields, thereby improving interference immunity while keeping the added complexity minimal
Solution Approach 2:
The patent converts the presence of magnetic stray fields from a harmful factor into a beneficial measurement mechanism. By using differential measurement between two sensors, the common-mode stray fields are rejected, transforming the challenge of magnetic interference into an opportunity for enhanced measurement accuracy
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 proposed solution achieves high measurement accuracy and insensitivity to magnetic stray fields, making it suitable for various applications including automotive systems, while also being cost-effective.
Implementation Method 1
a first differential magnetic field sensor mounted on a first surface of the magnet, and a second differential magnetic field sensor mounted on a second surface of the magnet
Data Source
AI summary
A sensor device contains a magnet, a first differential magnetic field sensor mounted on a first surface of the magnet, and a second differential magnetic field sensor mounted on a second surface of the magnet, the second surface being situated opposite the first surface.