Angle Sensor With Symmetric Magnet And Asymmetric Sensors
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Solution Overview
Problem
Existing magnet-based angle sensors for capturing the angular position of rotatable components are limited by restricted usable angular ranges and are susceptible to magnetic disturbance/interference fields, particularly in electrified vehicle systems, which can falsify measurements.
Innovation Solution
A sensor arrangement featuring a magnet and a sensor assembly with magnetically sensitive elements arranged symmetrically relative to the axis of rotation, using two-dimensional magnetically sensitive sensor elements to capture magnetic fields parallel to the sensor plane, and an evaluation unit to process signals and compensate for magnetic disturbances, ensuring accurate angular position measurement over 360°.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a segmented multi-pole-pair magnet is used for angle measurement, then magnetic disturbance fields can be compensated, but the usable angular measuring range is restricted to less than 360°
Solution Approach 1:
The magnet is divided into multiple pole pairs arranged segmentally around the rotor, with each pole pair contributing to the magnetic field pattern. This segmentation enables the magnetic field to wrap around the full 360° while maintaining the disturbance compensation capability through the alternating pole structure.
Solution Approach 2:
The patent transitions from a limited angular range measurement to full 360° measurement by utilizing the radial dimension of the rotor. The magnet poles are arranged circumferentially around the entire rotor perimeter, allowing the magnetic field to be sensed continuously across all angular positions rather than being confined to a segmented arc.
2Ease of manufacture
If sensors measuring magnetic field components parallel to the sensor plane are used, then two-dimensional magnetically sensitive sensor elements can be employed, but magnetic disturbance fields from power lines and electromagnets cannot be suppressed
Solution Approach 1:
The patent employs an asymmetric arrangement of sensor elements relative to the magnet poles. The sensors are positioned at specific angular offsets from the pole centers, creating an asymmetric measurement geometry that enables discrimination between the symmetric rotor magnetic field and asymmetric disturbance fields through differential measurement techniques.
Solution Approach 2:
The evaluation unit processes signals from multiple sensors and uses feedback algorithms to distinguish the rotating magnetic field pattern from stationary or linear disturbance fields. By analyzing the temporal and spatial characteristics of the magnetic field variations, the system can suppress disturbance components while maintaining sensitivity to the rotor position signal.
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 enables reliable and interference-field-insensitive measurement of the angular position over a full 360° range, enhancing measurement accuracy and robustness against magnetic disturbances, particularly beneficial in electrified vehicle systems.
Implementation Method 1
a magnet (10), which is configured to produce a magnetic field (20)
Implementation Method 2
a first magnetically sensitive element (32) arranged at a predetermined distance from the axis of rotation (100), a second magnetically sensitive element (33) arranged opposite to the first magnetically sensitive element (32) relative to the axis of rotation (100), the second magnetically sensitive element (33) being arranged at the predetermined distance from the axis of rotation (100)
Data Source
AI summary
An arrangement for detecting the angular position of a rotatable component includes: a magnet, configured to generate a magnetic field, and a sensor assembly, configured to detect the magnetic field, and to supply therefrom an angle signal corresponding to the angular position of the component. The sensor assembly has a first sensor group, including a first magnetically sensitive element, a second magnetically sensitive element, and a third magnetically sensitive element, a second sensor group, having a fourth magnetically sensitive element, a fifth magnetically sensitive element, and a sixth magnetically sensitive element, and an evaluation unit, which is connected to each of the magnetically sensitive elements of the first sensor group and the magnetically sensitive elements of the second sensor group and supplies the angle signal corresponding to the angular position of the component.