Magnetic Field Sensor Angle Correction via Temperature Feedback

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Solution Overview

Problem

Magnetic field sensors face challenges in achieving high angular accuracy due to inherent angular errors in their output signals, which can vary with temperature and magnetic field strength, affecting their precision in applications requiring precise angle measurements.

Innovation Solution

A magnetic field sensor system comprising multiple magnetic field sensing elements, an angle processing circuit, a temperature sensor, an angle error correction module, and a combining module that generates corrected angle values by using stored correction coefficients and sine values to reduce angular errors, thereby improving the accuracy of angle measurements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If magnetic field sensing elements are used to detect angle, then angle measurement capability is provided, but angular errors occur in the output signal

Engineering Contradiction:
Improveangle measurement accuracyVSAvoidangular error in output signal
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent implements feedback by using the measured magnetic field strength and temperature to dynamically calculate correction values that are applied to the raw angle measurement. The correction module continuously adjusts the output based on feedback from sensors monitoring field strength and temperature, thereby compensating for angular errors in real-time

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent applies parameter changes by utilizing variations in magnetic field strength and temperature as correction parameters. These parameters are measured and used to compute correction values that adjust the angle output, transforming the raw measurement into a compensated measurement that accounts for environmental variations

Inventive Principle:
Principle #35Parameter changes

2Productivity

If temperature variations occur, then sensor operation continues, but angular accuracy deteriorates

Engineering Contradiction:
Improvecontinuous operation capabilityVSAvoidangular accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

A temperature sensor provides continuous feedback on the thermal state of the system. This temperature information is fed to the correction module, which uses it to calculate temperature-dependent correction values that compensate for thermal effects on the angle measurement, maintaining accuracy during continuous operation

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent uses temperature as a dynamic correction parameter. By measuring temperature variations and applying them as correction factors to the angle measurement, the system maintains measurement precision despite continuous operation under varying thermal conditions

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If magnetic field strength varies, then sensing range is extended, but angular error increases

Engineering Contradiction:
Improvesensing rangeVSAvoidangular error
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

A magnetic field strength sensor provides feedback on the amplitude of the magnetic field. This information is used by the correction module to calculate field-strength-dependent correction values, enabling the system to maintain angular precision across a wide sensing range by adapting to varying field strengths

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent employs magnetic field strength as a dynamic correction parameter. By measuring the field strength and using it to compute correction factors, the system compensates for angular errors that arise when operating at different field amplitudes, thereby extending the usable sensing range without sacrificing precision

Inventive Principle:
Principle #35Parameter changes

4Measurement precision

If correction module is added, then angular accuracy is improved, but device complexity increases

Engineering Contradiction:
Improvecorrected angle value accuracyVSAvoidsensor system structure
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The correction module acts as an intermediary between the raw angle measurement and the final corrected output. It receives inputs from the angle sensor, temperature sensor, and magnetic field strength sensor, processes this information through correction algorithms, and produces the corrected angle output, thereby isolating the complexity of compensation from the core sensing function

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The correction module serves multiple functions: it processes temperature compensation, magnetic field strength compensation, and angle correction in a single integrated unit. This multi-functionality reduces overall system complexity by consolidating multiple compensation tasks into one modular component

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 significantly reduces angular errors in magnetic field sensor outputs, providing more accurate angle measurements that are less affected by temperature and magnetic field strength variations, enhancing the precision of applications such as angle sensing in rotating objects.

Implementation Method 1

Planar Hall elements and vertical Hall elements are known types of magnetic field sensing elements

Methodology Applied
Scientific EffectHall effect: Hall Effect

Data Source

PatentEP3019882B1Magnetic field sensor and related techniques that provide an angle correction module
Publication Date: 2017.04.26 ALLEGRO MICROSYSTEMS LLC
  • EP3019882B1 patent drawingFigure 1~1A
  • EP3019882B1 patent drawingFigure 2
  • EP3019882B1 patent drawingFigure 3

AI summary

A magnetic field sensor provides an angle error value to correct errors of the magnetic field sensor. The angle error value is a function of temperature and magnetic field strength and is used to correct a measured magnetic field angle. Associated methods are also described.