Magnetic Angle Sensor Disturbance Resistance via Segmentation
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Solution Overview
Problem
Magnetic angle sensors are highly sensitive to magnetic disturbances, leading to significant errors in determining the rotational position of a shaft, particularly in harsh environments like hybrid or electric vehicles where external magnetic fields from current-carrying wires can interfere with the accuracy of magnetic angle measurements.
Innovation Solution
A magnetic angle sensor arrangement that includes a shaft with a magnetic field source and multiple magnetic angle sensors positioned at different distances along the rotation axis, combining their signals to calculate a robust and disturbance-resistant combined rotation angle, using diametric magnetic fields and compensating for external disturbances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single magnetic field sensor is used to detect rotational position, then the device complexity is low, but the measurement precision deteriorates due to high sensitivity to magnetic disturbances
Solution Approach 1:
The patent divides the sensing function into multiple independent magnetic field sensors (at least two sensors) positioned at different locations relative to the magnetic field source. Each sensor provides an independent measurement that is then combined through signal processing to achieve disturbance-resistant angle determination, thereby resolving the contradiction between simple device structure and high measurement precision.
Solution Approach 2:
The patent introduces a signal processing unit as an intermediary that receives signals from multiple magnetic field sensors and combines them to calculate the rotational angle. This intermediary processing stage eliminates the direct sensitivity to magnetic disturbances by using the combined information from multiple sensors, achieving high precision without excessive device complexity.
2Reliability
If multiple magnetic angle sensors are used to improve measurement precision, then the reliability improves, but the device complexity increases
Solution Approach 1:
The patent segments the sensing system into multiple independent sensors positioned at different locations, each contributing to the overall measurement. This segmentation provides redundancy and disturbance resistance (improved reliability) while keeping each individual sensor simple, thereby managing overall device complexity.
Solution Approach 2:
The patent makes the signal processing unit multi-functional by having it perform both the combination of sensor signals and the calculation of rotational angle. This universal processing approach improves reliability through combined measurements while avoiding the need for separate dedicated circuits for each function, thus controlling device complexity.
3Measurement precision
If sensors are positioned closer to the magnetic field source to improve signal strength, then the measurement precision improves, but the sensitivity to magnetic disturbances worsens
Solution Approach 1:
The patent positions multiple sensors at different distances and/or angular positions relative to the magnetic field source. This spatial segmentation allows the system to detect the magnetic field with good signal strength while the combined processing of multiple sensors compensates for and reduces the impact of magnetic disturbances, resolving the contradiction between signal strength and disturbance sensitivity.
Solution Approach 2:
The patent implements a feedback mechanism through signal processing that combines measurements from multiple sensors. The processing unit continuously adjusts the angle calculation based on the combined sensor inputs, providing feedback that compensates for magnetic disturbances and maintains measurement precision even when sensors are positioned for optimal signal strength.
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 accurate and reliable rotation angle measurements that are less affected by external magnetic disturbances, enhancing the robustness and reliability of the sensor system, especially in environments with significant magnetic interference.
Implementation Method 1
a first diametric magnetic field from a magnetic field source applied to the first magnetic angle sensor
Implementation Method 2
The first magnetic angle sensor is configured to determine a first signal that represents a first angle based on a first diametric magnetic field applied to the first magnetic angle sensor
Data Source
AI summary
A magnetic angle sensor device and a method for operating such device is provided. The magnetic angle sensor device includes a shaft rotatable around a rotation axis; a magnetic field source coupled to the shaft; a first magnetic angle sensor configured to generate a first signal that represents a first angle based on a first diametric magnetic field from the magnetic field source applied to the first magnetic angle sensor; a second magnetic angle sensor configured to generate a second signal that represents a second angle based on a second diametric magnetic field from the magnetic field source applied to the second magnetic angle sensor; and a combining circuit configured to determine a combined rotation angle based on the first signal and on the second signal.