Magnetic Field Sensor Calibration via Spinning-Current
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Solution Overview
Problem
Existing Hall sensor systems for detecting spatial components of a magnetic field require multiple sensors, leading to calibration challenges and increased effort, as they cannot measure the magnetic field at a single point, resulting in corruption and limited precision due to offset voltages from device tolerances and asymmetries.
Innovation Solution
A magnetic field sensor arrangement with symmetrical sensor elements that can be calibrated during operation using a single excitation line, allowing simultaneous measurement and calibration, and employing the spinning-current method to compensate for offset voltages, enabling precise measurement of spatial components at a reference point.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple Hall sensor elements are used to detect spatial components of a magnetic field, then the ability to measure magnetic field components is improved, but the calibration effort and device complexity increase
Solution Approach 1:
The patent combines multiple Hall sensor elements (first, second, and third sensor elements) into a single integrated sensor arrangement that detects all three spatial components (Bx, By, Bz) simultaneously. This merging approach allows the system to measure the complete magnetic field vector at a single point without requiring separate calibration procedures for each sensor element, thereby reducing overall calibration effort while maintaining measurement precision.
Solution Approach 2:
The sensor arrangement is designed with symmetrical sensor elements that can detect all three spatial components using a unified structure. The excitation line serves multiple functions: it provides operating current for measurement operations and simultaneously generates calibration field components for calibrating all sensor elements. This multi-functionality eliminates the need for separate calibration hardware and procedures, reducing device complexity while maintaining comprehensive measurement capability.
2Measurement precision
If multiple Hall sensor elements are used to detect spatial components, then measurement capability is improved, but measurement precision deteriorates due to offset voltages from device tolerances and asymmetries
Solution Approach 1:
The patent employs symmetrical sensor elements arranged in a specific configuration where the first, second, and third sensor elements are positioned to detect different spatial components. The symmetrical arrangement, combined with the spinning current method, creates a system where offset voltages from device tolerances and asymmetries cancel each other out through mathematical processing of the sensor signals, thereby improving measurement precision despite the presence of tolerances.
Solution Approach 2:
The patent implements a feedback mechanism through the spinning current method, where the sensor elements are excited with currents that are alternately reversed. This creates a feedback loop where the measured signals are processed to compensate for offset voltages. The calibration field components generated by the excitation line provide a reference that feeds back into the measurement system, allowing continuous compensation for tolerances and asymmetries during operation.
3Measurement precision
If traditional calibration methods are used, then calibration accuracy is improved, but additional hardware and time effort are required
Solution Approach 1:
The excitation line is designed to serve dual purposes: it provides the operating current necessary for the Hall sensor elements to function during measurement operations, and simultaneously generates the calibration field components required for calibrating the sensor elements. This multi-functionality eliminates the need for separate calibration hardware, reducing device complexity while maintaining calibration accuracy. The same excitation line used for measurement also performs calibration, saving additional hardware and time effort.
Solution Approach 2:
The patent enables continuous calibration during measurement operations through the spinning current method. The excitation line continuously generates both measurement signals and calibration field components without interruption. This allows calibration to occur simultaneously with measurement, eliminating the need for separate calibration steps and reducing total time effort. The useful action of measuring and calibrating continues without pause, improving efficiency while maintaining accuracy.
4Reliability
If Hall sensor elements are used for contactless detection, then reliability is improved, but calibration and measurement operation become more complex
Solution Approach 1:
The sensor arrangement performs self-calibration using its own excitation line and sensor elements. The calibration field components are generated by the excitation line itself, and the sensor elements measure these fields to determine calibration parameters. This self-service approach eliminates the need for external calibration equipment, reducing device complexity while maintaining the reliability benefits of contactless Hall sensor detection. The system calibrates itself during normal operation without requiring additional external hardware.
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 simple and uncomplicated calibration and testing of magnetic field sensors, reducing additional hardware and time effort, and enabling continuous monitoring and adjustment in security-critical applications like the automobile industry and medical technology, with improved measurement precision and reduced offset voltages.
Implementation Method 1
an excitation line arranged such with respect to the first, second, and third sensor element arrangements that when impressing a predetermined current into the excitation line, a first predetermined calibration field component BKz with respect to the first spatial axis x in the first sensor element arrangement is generated
Implementation Method 2
Hall sensor elements based on the Hall-Effect are frequently used in the art, for contactless touchless signal generators for wearless detection of the position of switches or actuators
Implementation Method 3
employing the spinning-current method to compensate for offset voltages, enabling precise measurement of spatial components at a reference point
Data Source
AI summary
A magnetic field sensor for detecting first, second, and third spatial components of a magnetic field at a reference point includes a first sensor element arrangement for detecting the first magnetic field component having a first measurement field component and a first calibration field component with respect to a first spatial axis at a reference point, a second sensor element arrangement for detecting the second magnetic field component having a second measurement field component and a second calibration field component with respect to a second spatial axis y at the reference point and a third sensor element arrangement for detecting the third magnetic field component having a third measurement field component and a third calibration field component with respect to a third spatial axis x at the reference point. An excitation line is arranged such with respect to the three sensor element arrangements that when impressing a predetermined current into the excitation line respective predetermined calibration field components with respect to the spatial axes in the sensor element arrangements are generated.