Rotating Element Sensor With Coil-Based Diagnostic Testing
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Solution Overview
Problem
Existing rotational sensors for determining rotor position and speed in electric machines are bulky, costly, and require complex signal processing, often necessitating additional ASICs for diagnostics, which increases complexity and cost, and are prone to common-cause errors, making them unsuitable for high ASIL D compliance.
Innovation Solution
A sensor system with a flexible circuit carrier carrying an excitation coil and two receiving coils, along with a control coil and a controller, uses a control coil to change load resistance for diagnostic purposes, allowing for functional plausibility testing with minimal additional electronics and maximum plausibility coverage, achieving ASIL D compliance with a single sensor channel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If electromagnetic resolvers are used to determine rotor position and speed, then measurement precision is improved, but device complexity and installation space increase
Solution Approach 1:
The patent replaces electromagnetic resolvers with a Hall sensor-based detection system. Instead of using complex electromagnetic fields and coil arrangements, the invention uses a Hall sensor to detect the position of a ferromagnetic element on the rotor, thereby determining rotor position and speed through electronic signal processing rather than electromagnetic induction.
Solution Approach 2:
The patent extracts only the essential function of resolver (position detection) and implements it through a simplified Hall sensor system. The complex electromagnetic field generation and signal conditioning components of traditional resolvers are removed, keeping only the necessary sensing and processing elements.
2Measurement precision
If optical resolvers are used for position detection, then measurement precision is improved, but reliability decreases due to contamination sensitivity
Solution Approach 1:
The patent replaces optical resolvers with a magnetic field-based Hall sensor system. Instead of using light paths and optical components that are sensitive to contamination, the invention uses magnetic field interaction between the Hall sensor and ferromagnetic elements, which are not affected by optical contamination.
3Reliability
If inductive absolute angle sensors with coupled coils are used, then ASIL D compliance is improved, but device complexity increases due to additional ASIC requirements
Solution Approach 1:
The patent replaces complex inductive angle sensors with coupled coils and ASICs with a simpler Hall sensor-based system. The Hall sensor directly provides position information through voltage signals that can be processed by standard microcontroller units, eliminating the need for specialized ASIC hardware while maintaining diagnostic capabilities.
Solution Approach 2:
The patent designs the Hall sensor system to perform multiple functions: position detection, speed calculation, and diagnostic monitoring. The same basic sensor hardware supports various operating modes and diagnostic functions, reducing the need for separate specialized components.
4Reliability
If two diverse sensor concepts are used to achieve ASIL D compliance, then reliability is improved, but device complexity and cost increase
Solution Approach 1:
The patent implements a self-diagnostic capability within the single Hall sensor system. The controller monitors the Hall sensor signals for plausibility, detects faults, and maintains operational awareness without requiring a second independent sensor system, thereby achieving functional safety through self-monitoring.
Solution Approach 2:
The patent incorporates continuous feedback monitoring of Hall sensor signals by the controller. The system evaluates signal plausibility, detects deviations, and can identify faults in real-time, providing the diagnostic capability needed for ASIL D compliance through a single sensor channel with active monitoring.
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 provides compact, cost-effective rotational property determination with high reliability and safety integrity, reducing complexity and cost while maintaining accurate angle or position calculations independent of signal amplitudes.
Implementation Method 1
at least one Hall sensor arranged to face the rotating element and designed to detect a change in magnetic field strength
Implementation Method 2
The excitation coil is supplied with an alternating voltage signal and permeates the entire arrangement with an alternating electromagnetic field. Depending on the angle of rotation, a sinusoidal amplitude-modulated voltage is induced in the first receiving coil
Data Source
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AI summary
The invention relates to a sensor system (110) for determining at least one rotation characteristic of an element rotating about at least one axis of rotation (112). The sensor system (110) comprises at least one circuit carrier (114). The circuit carrier (114) bears an excitation coil (116), which excitation coil (116) surrounds at least one excitation region (118), and the circuit carrier (114) also bears at least two receiving coils (120, 122) in the excitation region (118). The sensor system (110) also has at least one controller (124) for determining the at least one rotation characteristic from signals of the receiving coils (120, 122). The circuit carrier (114) also bears at least one control coil (130), which control coil (130) is connected to the controller (124). The controller (124) is designed to change a load resistance of the control coil (130) in such a way that signals of the receiving coils (120, 122) can be changed in order to produce at least one item of diagnostic information.