Eddy Current Position Measurement in Harsh Environments: A Temperature Compensation and Calibration Approach

Gabriel Gruber*, Bernhard Schweighofer, Matthias Berger, Thomas Leitner, Gerald Kloesch, Hannes Wegleiter

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

Eddy current displacement sensors (ECDSs) are widely used for the noncontact position measurement of small displacements (lift-offs). Challenges arise with larger displacements as the sensitivity of the ECDSs decreases. This leads to a more pronounced impact of temperature variations on the inductance and, consequently, an increased position error. Design solutions often rely on multiple coils, suitable coil carrier materials, and compensation measures to address the challenges. This study presents a single-coil ECDS for large displacement ranges in environments with high temperatures and temperature variations. The analysis is based on a sensor model derived from an equivalent circuit model (ECM). We propose design measures for both the sensing coil and the target, focusing on material selection to handle the impact of temperature variations. A key part of improving performance under varying temperatures includes model-based temperature compensation for the inductance of the sensing coil. We introduce a method to calibrate the sensor for large displacements, using a modified coupling coefficient based on field simulation data. Our analysis shows that this single-coil ECDS design maintains a position error of less than 0.2% full-scale for a temperature variation of 100 K for the sensing coil and 110 K for the target.

Original languageEnglish
Article number1483
JournalSensors
Volume24
Issue number5
DOIs
Publication statusPublished - Mar 2024

Keywords

  • eddy current displacement sensor
  • harsh environment
  • high temperature variations
  • large displacements
  • position measurement
  • sensor design
  • vaporization effects

ASJC Scopus subject areas

  • Analytical Chemistry
  • Information Systems
  • Atomic and Molecular Physics, and Optics
  • Biochemistry
  • Instrumentation
  • Electrical and Electronic Engineering

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