Angle Position Sensor Phase Error Compensation
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Solution Overview
Problem
Existing measurement apparatuses for determining angle position signals are prone to errors due to external magnetic interference fields, which can lead to incorrect calculations of the angle position, especially in safety-critical applications like automotive technology.
Innovation Solution
The measurement apparatus incorporates a sensor apparatus with at least three magnetic field sensors arranged to detect phase-shifted magnetic field measurement signals. A transformation device converts these signals into orthogonal phase-shifted transformation signals, and an evaluation device calculates the angle position using the arctangent function. Additionally, a comparator and phase position comparison element are used to detect phase errors and ensure accurate angle position calculation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If three magnetic field sensors are used to generate phase-shifted signals, then angle position measurement is enabled, but external magnetic interference fields cause measurement errors
Solution Approach 1:
The patent uses a comparator to generate a reference signal by comparing one of the magnetic field sensor signals with a threshold value. This reference signal is then fed back to the transformation device to correct the transformation process, enabling compensation of interference effects and improving measurement accuracy under adverse magnetic conditions
Solution Approach 2:
The patent combines multiple signal processing approaches (transformation of three phase-shifted signals, comparator-based reference signal generation, and arctangent calculation) into a composite measurement system. This composite approach allows the system to maintain high measurement precision even in the presence of external magnetic interference fields
2Ease of operation
If transformation device converts three magnetic field signals into two orthogonal transformation signals, then angle position calculation is simplified, but phase position errors may occur due to interference
Solution Approach 1:
The comparator generates a reference signal that is fed back to monitor and correct phase position errors in the transformation signals. This feedback mechanism ensures that the simplified arctangent calculation remains reliable even when interference affects the transformation process
Solution Approach 2:
The system dynamically adjusts the transformation process by incorporating the comparator reference signal, which changes based on the detected magnetic field conditions. This allows the system to maintain accurate phase position information despite variations in external interference
3Measurement precision
If more than three magnetic field sensors are used, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The transformation device is designed to process any number of phase-shifted magnetic field sensor signals through a universal transformation process. This multi-functional approach allows the system to achieve high measurement precision with more than three sensors without proportionally increasing the complexity of the signal processing architecture
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 enhances the precision of angle position measurements by compensating for external magnetic interference and allows for zero-point calibration, thereby improving the reliability and accuracy of the angle position signal in the presence of interference.
Implementation Method 1
The sensor apparatus has a number of at least three magnetic field sensors that are arranged to be offset from one another, with reference to the axis of rotation, in terms of the angle of rotation, to generate magnetic field measurement signals that are phase-shifted relative to one another
Data Source
AI summary
A measurement apparatus has a magnet apparatus and a sensor apparatus, which can be rotated relative to one another about an axis of rotation. To generate magnetic field measurement signals, the sensor apparatus has a number of at least three magnetic field sensors, which are arranged offset from one another by an angle of rotation, each having an output to output a magnetic field measurement signal. The outputs are connected to a first signal path, in which a transformation device for transforming the magnetic field measurement signal into a plurality of phase-shifted transformation signals is arranged, which plurality is less than the number of the magnetic field sensors. Output connectors for the transformation signals are connected to an evaluation device for generating the angle position signal. A comparator is arranged in a further signal path and is connected to the measurement signal output of a magnetic field sensor, for comparing the magnetic field measurement signal of one of the magnetic field sensors with a comparator threshold value signal. For detecting a phase error, the evaluation device has a phase position comparison element, which has a first phase position comparison element input connected to an output connector of the transformation device, and a second phase position comparison element input connected to the comparator output.