Pressure Sensor Dynamic Offset Compensation Circuit

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Solution Overview

Problem

Pressure sensors in combustion systems face challenges in accurately compensating for offset drift caused by thermal and mechanical stress, particularly in cyclic environments where rapid changes occur, leading to variability in ambient temperature and mechanical stress.

Innovation Solution

The method involves identifying a target value for the sensor output, calculating the difference between the measured and target values, determining the number of steps needed to adjust the output, and implementing dynamic offset compensation (DOC) using a circuit that adjusts the output voltage in small, adaptive steps to maintain a stable baseline, even in the presence of temperature and mechanical fluctuations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional offset compensation methods are used, then the sensor output can be corrected for temperature variations, but the compensation is insufficient for rapid cyclic changes in temperature and mechanical stress

Engineering Contradiction:
Improveoffset compensation accuracyVSAvoidresponse speed to cyclic changes
Core Design Contradiction:
Measurement precisionVSSpeed

Solution Approach 1:

The patent implements dynamic offset compensation by continuously adjusting the offset value based on real-time detection of cyclic patterns in sensor output. The system adapts the compensation parameters dynamically rather than using fixed compensation values, allowing the offset correction to track rapid changes in temperature and mechanical stress conditions.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system employs feedback mechanisms by detecting cyclic patterns in the sensor output and using this information to adjust the offset compensation. The controller continuously monitors the sensor signal, identifies cyclic variations, and modifies the compensation accordingly, creating a closed-loop system that responds to changing conditions.

Inventive Principle:
Principle #23Feedback

2Adaptability or versatility

If the sensor operates in harsh cyclic environments, then the sensor can withstand temperature and mechanical stress variations, but the offset drift increases leading to measurement errors

Engineering Contradiction:
Improveenvironmental toleranceVSAvoidoffset stability
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent converts the harmful effect of cyclic offset drift into a detectable pattern. By identifying the cyclic nature of the offset variations, the system uses this predictable behavior to its advantage, applying corrective actions that specifically target the cyclic component of the drift while maintaining operation in harsh environments.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

3Measurement precision

If real-time correction is implemented, then measurement accuracy is maintained, but the system complexity increases

Engineering Contradiction:
Improvereal-time measurement accuracyVSAvoidcorrection system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The system performs self-diagnosis and self-correction by automatically detecting cyclic patterns in its own output and adjusting the offset compensation without external intervention. The controller monitors the sensor signal and autonomously implements the correction, reducing the need for additional complex external compensation systems.

Inventive Principle:
Principle #25Self-service

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 enables real-time correction of pressure sensor data, ensuring accurate and reliable measurements by actively compensating for offset drift, thereby maintaining a consistent output level despite environmental changes, and can be applied to various cyclic sensing applications beyond pressure sensors.

Implementation Method 1

at least one piezoresistive element configured for sensing pressure and outputting voltage

Methodology Applied
Scientific EffectPiezoresistive effect: Piezoresistive Effect

Data Source

PatentEP3002574B1Sensor with method to correct offset drift in cyclic signals.
Publication Date: 2019.05.08 SENSATA TECHNOLOGIES INC
  • EP3002574B1 patent drawingFigure 1~2
  • EP3002574B1 patent drawingFigure 3~5
  • EP3002574B1 patent drawingFigure 6~7

AI summary

A method for correcting offset drift in a sensor used in cyclic sensing is provided. The method includes: identifying a target value for a parameter of a signal between sensing cycles of the sensor; ascertaining a difference between a measured value for the signal and the target value; ascertaining a duration between the sensing cycles; using the difference and the duration, calculating a number of steps to attain the target value from the measured value; and adjusting the measured value by the number of steps to substantially agree with the target value. A pressure sensor is disclosed.