Inductive Sensor System for Absolute Angular Position Detection
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Solution Overview
Problem
Existing rotational property sensors for rotating elements, such as camshafts, face limitations in continuous position detection, resolution, and sensitivity to magnetic interference, with complex structures that complicate installation and removal, and lack true power-on functionality.
Innovation Solution
A sensor system comprising an inductive position sensor with a coil arrangement and a phase encoder, including a magnetic field generator and sensor element, which detects inductive coupling and phase signals to determine angular position and speed, enabling absolute angle detection up to 360° and true power-on functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a sensor wheel with teeth and Hall sensor is used to determine camshaft position, then the phase position can be determined, but continuous position measurement is not possible and absolute angle measurement within 360° range is not possible
Solution Approach 1:
The patent combines multiple sensor types (inductive sensor with coil arrangement and magnetic field sensor with Hall element) into a single integrated sensor system. This merging allows the system to simultaneously provide continuous position measurement and absolute angle determination within 360° range, resolving the limitation of the sensor wheel approach while maintaining manageable complexity through functional integration.
Solution Approach 2:
The inductive sensor system is designed to perform multiple functions: determining absolute angular position, measuring rotational speed, and providing continuous position measurement throughout the 360° range. This multi-functionality replaces the need for separate sensor systems, achieving comprehensive position measurement capability while streamlining the overall device architecture.
2Volume of moving object
If a small diameter encoder wheel is used, then the sensor can be compact, but the resolution is limited by minimal gap sizes that must be maintained
Solution Approach 1:
The patent replaces the mechanical encoder wheel system with an inductive sensor system that uses magnetic field coupling between coils. This substitution eliminates the need for physical gaps and mechanical contact, allowing for higher angular position resolution without being constrained by minimal gap requirements. The system achieves fine resolution through the spatial distribution and winding density of the coils rather than mechanical features.
3Measurement precision
If a Hall sensor with sensor wheel is used, then the phase position can be determined, but absolute position determination is only possible in dynamic scenario when the encoder wheel is rotating
Solution Approach 1:
The inductive sensor system is designed to determine absolute angular position independently of rotational motion. The coil arrangement and magnetic field configuration allow the system to establish position reference at power-on state without requiring the camshaft to be rotating. This preliminary positioning capability ensures accurate position determination is available from the moment the engine starts, eliminating the dynamic scenario requirement.
4Measurement precision
If a Hall sensor system is used, then rotational position can be detected, but the system exhibits high sensitivity to magnetic interference
Solution Approach 1:
The patent introduces an inductive sensing mechanism as an intermediary between the magnetic field source and the measurement system. The coil arrangement detects changes in magnetic flux through inductive coupling, which provides inherent immunity to external magnetic interference. This intermediary approach maintains accurate rotational position detection while filtering out harmful magnetic effects that would directly affect a Hall sensor.
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 sensor system provides enhanced accuracy, simplified installation, and robustness against magnetic interference, enabling real-time angular position availability and meeting functional safety requirements with improved resolution and reduced complexity.
Implementation Method 1
The excitation coil is energized by an excitation source and generates a magnetic flux. The receiver coil generates a received signal through inductive coupling between the excitation coil and the receiver coil.
Implementation Method 2
The phase generator comprises at least one magnetic field generator and at least one magnetic sensor element
Implementation Method 3
The phase generator comprises at least one magnetic field generator and at least one magnetic sensor element
Data Source
Figure 1~3
Figure 4~6
AI summary
The invention relates to a sensor system (110) for determining at least one rotation property of an element rotating about at least one rotation axis (120). The sensor system (110) has at least one transmitter wheel (116) which can be connected to the retaining element, and the transmitter wheel (116) has a transmitter wheel profile (118). The sensor system (110) additionally has at least one inductive position sensor (122), wherein the inductive position sensor (122) has at least one coil assembly (112) comprising at least one excitation coil (124) and at least one receiving coil (126). The sensor system (110) additionally has at least one phase transmitter (128), said phase transmitter (128) having at least one magnetic field generator (130) and at least one magnetic sensor element (132).