Differential Magnetic Angle Sensor Robustness
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Magnetic angle sensors used in vehicles are highly sensitive to magnetic disturbances, leading to inaccurate measurements due to external magnetic fields generated by current-rails, which is particularly problematic in hybrid and electric vehicles with numerous wires carrying high currents near the sensor systems.
Innovation Solution
A magnetic angle sensor arrangement that utilizes a differential magnetic field produced by a plurality of diametric magnetic fields, with multiple angle sensors placed at different distances from the magnet, generating signals that are combined to determine a robust and accurate rotation angle, effectively mitigating the impact of external disturbance fields.
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 sensitivity to magnetic disturbances
Solution Approach 1:
The patent divides the sensing system into multiple segments: a first magnetic field sensor and a second magnetic field sensor are used instead of a single sensor. Each sensor measures the magnetic field at different positions, and their signals are combined through evaluation circuitry to calculate the rotational angle. This segmentation allows the system to differentiate between the target magnetic field and disturbance fields, thereby improving measurement precision while maintaining manageable device complexity.
Solution Approach 2:
The patent introduces an intermediary evaluation unit that processes the signals from multiple sensors. This intermediary component combines the magnetic field measurements from the first and second sensors, applies mathematical operations (such as arctan calculations), and outputs the corrected rotational angle. The intermediary effectively filters out disturbance field effects while preserving the target field information, resolving the contradiction between simple device structure and accurate measurement.
2Measurement precision
If multiple sensors are used to improve measurement accuracy, then the measurement precision improves, but the device complexity increases
Solution Approach 1:
The patent merges the functionality of multiple sensors with signal processing operations into an integrated evaluation unit. The first and second magnetic field sensors are combined with the evaluation circuitry that processes their outputs, creating a unified system that calculates rotational angle from the combined sensor data. This merging approach improves measurement precision through multi-sensor input while containing device complexity by integrating the processing function into a single evaluation module.
3Use of energy by moving object
If sensors are placed closer to the magnet to increase field strength, then the signal strength increases, but the sensitivity to external magnetic disturbances worsens
Solution Approach 1:
The patent applies local quality by positioning the first and second magnetic field sensors at different locations relative to the magnet and disturbance sources. The first sensor is placed at a position where it detects both the target magnetic field and disturbance field, while the second sensor is positioned to detect a different combination of these fields. This differential local positioning allows the evaluation unit to distinguish and separate the target field signal from disturbance field signals, thereby maintaining strong signal detection while reducing sensitivity to external disturbances.
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 a robust and accurate determination of rotational position or movement of a shaft, significantly reducing errors caused by external magnetic disturbances, enhancing the reliability of magnetic angle measurements in harsh environments like those found in hybrid and electric vehicles.
Implementation Method 1
a magnetic arrangement coupled to the shaft, where the magnetic arrangement produces a differential magnetic field comprising a plurality of diametric magnetic fields
Implementation Method 2
a first magnetic angle sensor provided in the differential magnetic field and configured to generate a first signal that represents a first angle based on a first diametric magnetic field of the differential 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 arrangement coupled to the shaft, where the magnetic arrangement produces a differential magnetic field comprising a plurality of diametric magnetic fields; a first magnetic angle sensor provided in the differential magnetic field and configured to generate a first signal that represents a first angle based on a first diametric magnetic field of the differential magnetic field; a second magnetic angle sensor provided in the differential magnetic field and configured to generate a second signal that represents a second angle based on a second diametric magnetic field of the differential magnetic field; and a combining circuit configured to determine a combined rotation angle based on the first signal and on the second signal.