Stray-Field-Immune Magnetic Sensor Arrangement
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Solution Overview
Problem
Magnetic sensor systems are vulnerable to external magnetic disturbance fields, which can corrupt measurement accuracy in determining linear or angular positions and torque, especially in compact electrical systems like hybrid engine systems and electric vehicles.
Innovation Solution
A magnetic field sensor arrangement with a specific configuration of magnetic flux concentrators and sensors that form an air gap, allowing the signal magnetic flux and disturbance fields to be measured in distinct directions, enabling the subtraction of disturbance influence for accurate signal detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a magnetic field sensor arrangement is used to determine magnetic flux or torque, then measurement capability is provided, but measurement precision deteriorates due to external magnetic disturbance fields
Solution Approach 1:
The magnetic field sensor arrangement segments the measurement process by using multiple sensors oriented in different directions. Each sensor measures a specific component of the magnetic field, allowing the system to separate the signal magnetic flux from disturbance fields through directional measurement components
Solution Approach 2:
The patent applies local quality by configuring sensors with specific directional sensitivities at different locations within the air gap. Each sensor is optimally oriented to detect particular field components, creating localized measurement capabilities that collectively enable disturbance rejection while maintaining signal detection accuracy
2Measurement precision
If magnetic flux concentrators are added to guide magnetic flux, then measurement capability is improved, but device complexity increases
Solution Approach 1:
The magnetic flux concentrators serve multiple functions: they guide the signal magnetic flux from the magnet across the air gap, define the geometric boundaries of the air gap, and influence the distribution of both signal and disturbance fields. This multi-functionality reduces the need for additional separate components, thereby limiting the increase in device complexity
Solution Approach 2:
The patent introduces spatial dimensionality through the three-dimensional arrangement of flux concentrators with specific geometric shapes. The concentrators extend in multiple directions to guide flux paths in different planes, enabling comprehensive field control without requiring an excessive number of discrete components
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 solution provides highly accurate and insensitive measurements to external magnetic disturbance fields, ensuring precise determination of magnetic flux and torque even in the presence of such interference, using simple arithmetic processes suitable for microprocessors without requiring complex signal processing.
Implementation Method 1
the first and second magnetic flux concentrator are configured for guiding a signal magnetic flux generated by the signal magnetic field source to and across the air gap substantially in the first direction
Data Source
AI summary
A magnetic field sensor arrangement for determining a signal magnetic flux in a manner which is substantially strayfield immune, comprises: a signal magnetic field source; a first and second magnetic flux concentrator forming an air gap between exterior faces of the magnetic flux concentrators; the flux concentrators being configured for guiding a signal magnetic flux to and across the air gap in a gap direction; a magnetic field sensor arranged inside the air gap, and configured for measuring a first and second signal in the gap direction and perpendicular to the gap direction; and for reducing or eliminating an magnetic disturbance field based on the first and second signal. An angle sensor arrangement. A torque sensor. A method of measuring a signal flux, an angle, a torque in a substantially strayfield immune manner.