Magnetic Angle Sensing System with Hall Plate Interpolation
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Solution Overview
Problem
Conventional magnetic angle sensors face challenges in accurately determining the rotational position of a shaft when the sensor chip is shifted off the rotation axis or under the influence of external magnetic disturbances, leading to failure in detecting locations where the magnetic field component vanishes.
Innovation Solution
A magnetic angle sensing system utilizing multiple Hall plates arranged in a plane, where the output signals from these plates are used to interpolate points where the magnetic field component Bz=0, allowing for the determination of the rotation angle based on the angle between a pointer and a reference direction, even when the sensor chip is offset or under magnetic interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional magnetic angle sensors are used to detect rotational position, then the system can determine shaft position, but the detection fails when the sensor chip is shifted off the rotation axis or under external magnetic disturbances
Solution Approach 1:
The sensor chip is divided into multiple Hall sensing elements (at least two, preferably three or four) arranged in specific patterns. Each element detects magnetic field components independently, and their combined outputs enable robust angle calculation that tolerates chip misalignment and external interference through mathematical processing of multiple signals.
Solution Approach 2:
The system continuously processes outputs from multiple Hall elements to calculate rotational angle with compensation for offset errors and external magnetic fields. The processor uses feedback from all sensing elements to determine the actual rotational position while compensating for disturbances, ensuring reliable detection even when chip position varies.
2Adaptability or versatility
If the sensor chip is shifted off the rotation axis, then installation flexibility increases, but the ability to accurately detect zero-points of the magnetic field is lost
Solution Approach 1:
The system transitions from relying on precise spatial positioning in the physical plane to using mathematical relationships in a computational dimension. By processing outputs from multiple Hall elements arranged in specific geometric patterns (lines or triangles), the system calculates rotational angle through mathematical operations that are invariant to chip position, enabling accurate measurement regardless of whether the chip is on or off the rotation axis.
Solution Approach 2:
The system changes the detection parameter from direct magnetic field zero-point location to a calculated rotational angle derived from multiple Hall element outputs. This parameter transformation allows the system to maintain measurement accuracy under varying chip positions by using mathematical relationships rather than fixed spatial references.
3Reliability
If multiple Hall plates are arranged in a plane not on a single straight line through the rotation axis, then robustness against misalignment is improved, but the device complexity increases
Solution Approach 1:
Multiple Hall sensing elements are merged into a single integrated sensor chip, with their outputs combined through mathematical processing to achieve misalignment robustness. The chip integrates several simple Hall elements in specific geometric arrangements (collinear or triangular), and the processor combines their signals to calculate rotational angle with compensation for offset errors, achieving high reliability without complex individual component structures.
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 system effectively determines the rotational position of the shaft by interpolating zero-points of the magnetic field, providing robustness against chip misalignment and external magnetic disturbances, ensuring accurate angle detection.
Implementation Method 1
A first embodiment relates to a magnetic angle sensing system for detecting a rotation angle of a magnetic field source... at least two magnetic field sensing elements... are configured to provide output signals that are functions of the same magnetic field component
Data Source
AI summary
A magnetic angle sensing system for detecting a rotation angle of a magnetic field source arranged rotatably around a rotation axis, the magnetic angle sensing system including at least two magnetic field sensing elements that are located in/on a plane, are not arranged on a single straight line through the rotation axis, and are configured to provide output signals that are functions of the same magnetic field component which is in parallel to the rotation axis. The system also including a processor that is arranged to determine the rotation angle from an angle between a pointer and a reference direction, wherein the pointer is determined based on the output signals of the at least two magnetic field sensing elements.