Hall Sensor Angular Position Determination
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional sensor arrangements for determining the angular position of a rotor relative to a stator are prone to errors due to external magnetic fields, and are limited in design, requiring precise placement on the rotor's end face and restricted to 'on-axis' configurations, making them inflexible and susceptible to interference.
Innovation Solution
A sensor arrangement with two pairs of sensor elements spaced apart by an angle of rotation, where each pair has sensor elements on the same radial side of the axis of rotation, allowing for differential value calculation to eliminate external magnetic field interference, enabling precise angular position determination regardless of sensor placement relative to the rotor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If sensor elements are arranged on the end face of the rotor in conventional sensor arrangements, then the angular position can be determined, but the arrangement is limited to 'on-axis' configurations and is susceptible to external magnetic field interference
Solution Approach 1:
The patent transitions from conventional end-face mounting to radial mounting of the sensor on the rotor. The sensor is positioned at a radial distance from the axis of rotation, allowing the magnetic field to act axially on the sensor elements. This dimensional change enables flexible placement on various rotor designs while maintaining measurement capability and eliminating external magnetic field interference through proper geometric arrangement.
2Measurement precision
If conventional sensor arrangements are used, then angular position can be determined, but external magnetic fields cause measurement errors
Solution Approach 1:
The patent employs an asymmetric geometric arrangement where the sensor is positioned radially offset from the rotor axis at a specific distance. This asymmetric positioning creates a unique magnetic field geometry where the field lines are substantially perpendicular to the sensor elements. This asymmetric configuration eliminates sensitivity to external magnetic fields while maintaining accurate angular position determination through the periodic variation of the magnetic field strength.
3Adaptability or versatility
If the sensor is arranged radially far away from the axis of rotation, then flexibility is improved, but the magnetic field strength may be insufficient for accurate measurement
Solution Approach 1:
The patent optimizes the radial distance parameter between the sensor and the rotor axis to achieve the desired balance. By carefully selecting this geometric parameter, the design ensures that the magnetic field strength at the sensor location is sufficient for accurate measurement while maintaining the flexibility of radial mounting. The periodic variation of the magnetic field strength with rotor rotation provides the necessary signal for angular position determination.
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
This solution allows for precise and flexible determination of the angular position of a rotor relative to a stator, enabling the sensor arrangement to be used on various designs, including 'off-axis' configurations, while minimizing the influence of external magnetic fields and reducing manufacturing costs.
Implementation Method 1
the magnet generates a magnetic field on the sensor that varies depending on the angle around the axis of rotation
Implementation Method 2
Each sensor element is designed to determine the field component of the magnetic field provided by the magnet along the axis of rotation
Data Source
Figure 1a~1b
Figure 1c~1d
Figure 2a~2b
AI summary
The invention relates to a sensor assembly (1) for determining an angular position of a rotor (4) in relation to a stator (5), the sensor assembly (1) comprising two components, namely a magnet (2) and a sensor (3), wherein the components (2, 3) are arranged in such a way that the components can be rotated in relation to each other about an axis of rotation (A), wherein the sensor (3) comprises a first and a second sensor pair (31, 32), which each have a first and a second sensor element (311, 312, 321, 322). A straight line (313, 323) is associated with each sensor pair (31, 32), along which straight line the two sensor elements (311, 312, 321, 322) lie and which straight line intersects with the axis of rotation (A), wherein the first sensor element (311, 321) has a smaller distance from the surface of rotation (A) than the second sensor element (312, 323), wherein the straight line (313) associated with the first sensor pair (31) is spaced apart from the straight line (323) associated with the second sensor pair (32) by a rotational angle about the axis of rotation (A).