Magnetic Field Sensor Angle Correction via Lookup Tables
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Solution Overview
Problem
Magnetic field sensors face challenges in providing high angular accuracy and speed, particularly due to temperature-dependent sinusoidal errors and varying magnetic field strengths, which affect the accuracy of angle sensing in rotating applications.
Innovation Solution
The implementation of a magnetic field sensor system that utilizes temperature-dependent sinusoidal error correction coefficients, interpolation modules, and correction versus rate and current spin sequence modules to adjust angle error values, thereby improving the accuracy and speed of angle sensing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If temperature-dependent sinusoidal error correction is applied, then angular accuracy is improved, but device complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing correction coefficients in a lookup table during the manufacturing process. These coefficients compensate for temperature-dependent sinusoidal errors without requiring complex real-time calculations during operation. The correction module simply retrieves pre-computed values based on measured temperature and magnetic field strength, resolving the contradiction between improved angular accuracy and reduced device complexity.
2Measurement precision
If multiple correction coefficients are used for temperature and magnetic field variations, then measurement precision is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent applies parameter changes by introducing temperature and magnetic field strength as additional parameters for error correction. Instead of relying solely on geometric precision, the system dynamically adjusts correction coefficients based on measured environmental parameters. This shifts the burden from manufacturing precision to parameter-based compensation, allowing standard manufacturing tolerances while achieving high measurement precision through adaptive correction.
3Measurement precision
If real-time error correction is performed, then angular accuracy is improved, but processing time increases
Solution Approach 1:
The patent resolves the time-accuracy tradeoff by performing error correction calculations in advance during manufacturing. Correction coefficients for various temperature and magnetic field conditions are pre-computed and stored in lookup tables. During real-time operation, the system only needs to measure current conditions, retrieve corresponding pre-computed coefficients, and apply simple corrections, eliminating complex real-time calculations while maintaining high angular accuracy.
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 approach significantly reduces angular errors by compensating for temperature and magnetic field variations, enhancing the precision and speed of angle sensing in dynamic environments.
Implementation Method 1
A vertical Hall element tends to be responsive to magnetic field parallel to a surface of a substrate on which the vertical Hall element is formed
Data Source
Figure 1~1A
Figure 2
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AI summary
A magnetic field sensor can use a variety of different current spinning phase sequences, and/or can provide an angle error value to correct errors of the magnetic field sensor. An associated method is described.