Simple Technique for Linear-Range Extension of Linear Variable Differential Transformer

Petchmaneelumka, Wandee; Koodtalang, Wittaya; Riewruja, Vanchai

doi:10.1109/jsen.2019.2902879

Cited by 24 publications

(30 citation statements)

References 15 publications

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“…Differential transformers are already used in various sensing applications. One prominent example is the linear variable differential transformer, usually consisting of a movable magnetic soft iron or ferrite core inside a configuration of three coaxial coils [8][9][10][11]. These coils are arranged symmetrically to each other.…”

Section: Introductionmentioning

confidence: 99%

How Geometry Affects Sensitivity of a Differential Transformer for Contactless Characterization of Liquids

Berger

Zygmanowski

Zimmermann

2021

Sensors

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The electrical and dielectric properties of liquids can be used for sensing. Specific applications, e.g., the continuous in-line monitoring of blood conductivity as a measure of the sodium concentration during dialysis treatment, require contactless measuring methods to avoid any contamination of the medium. The differential transformer is one promising approach for such applications, since its principle is based on a contactless, magnetically induced conductivity measurement. The objective of this work is to investigate the impact of the geometric parameters of the sample or medium under test on the sensitivity and the noise of the differential transformer to derive design rules for an optimized setup. By fundamental investigations, an equation for the field penetration depth of a differential transformer is derived. Furthermore, it is found that increasing height and radius of the medium is accompanied by an enhancement in sensitivity and precision.

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Section: Introductionmentioning

confidence: 99%

How Geometry Affects Sensitivity of a Differential Transformer for Contactless Characterization of Liquids

Berger

Zygmanowski

Zimmermann

2021

Sensors

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“…Multi frequency electromagnetic method and compensation technique on phase signature could be also used to compensate the decentralization of coils and material effects in the position sensor [31]- [32] in addition to using ratiometric function [11]. Extension of linear range of the LVDT position sensors usin g techniques, for example, techniques based on t h e fract io nal order LVDT, LVDT inverse transfer characteristic and functional link artificial neural network allows sensor performance improvement for industrial applications [12], [14] and [33].…”

Section: Discussionmentioning

confidence: 99%

A Position Sensor With Novel Configuration of Linear Variable Differential Transformer

2021

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Th is paper presents a position sensor ba s ed o n a novel configuration of linear variable differential transform er. Design and optimization of the position sensor a re pre sent ed using finite element method. The sensor has short air core coi ls and long magnetic armatures. The arrangement direction of the re ctangular excitation coil and two antiserially connected re ctangular pick up coils is perpendicular to the motion direction of the position sensor. The coils are located be t ween two parallel silicon steel laminations a s t he a rm a t ures. Th e position sensor is optimized wi th compromise between minimization of nonlinearity error and maximum s e nsit ivi t y. The main advantage of the proposed position sensor is the small ratio of coils dimensions to the working range. The position sensor is operated for the measurements and calculations at excit at io n fre quencies, 500 Hz and 1000 Hz and 2000 Hz. The maximum nonlinearity error is less than 1.5% for theoretical analysis a nd i t i s le ss than 2% for the measurement results in ±90 mm position range.

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“…The linear range of LVDT can be significantly extended by digital techniques. Extension from 4 to 30 mm stroke was reported in [17] while linearity error was only 0.07%. A transformer position sensor was also used to measure Sensors 2020, 20, 65 5 of 15 the position of the piston in a pneumatic cylinder.…”

Section: Linear Inductance and Transformer Sensorsmentioning

confidence: 96%

Inductive Position and Speed Sensors

Ripka

Blažek

Mirzaei

et al. 2019

Sensors

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Magnetic position and speed sensors are rugged and durable. While DC magnetic sensors use permanent magnets as a field source and usually have only mm or cm range, inductive sensors use electromagnetic induction and they may work up to a distance of 20 m. Eddy current inductive sensors equipped with magnetoresistive sensors instead of inductive coils can operate at low frequencies, allowing detection through a conductive wall. In this paper, we make an overview of existing systems and we present new results in eddy current velocity and position measurements. We also present several types of inductive position sensors developed in our laboratories for industrial applications in pneumatic and hydraulic cylinders, underground drilling, large mining machines, and for detecting ferromagnetic objects on conveyors. While the most precise inductive position sensors have a resolution of 10 nm and linearity of 0.2%, precision requirements on the industrial sensors which we develop are less demanding, but they should have large working distance and large resistance to environmental conditions and interference.Sensors 2020, 20, 65 2 of 15 Eddy Current Inductive SensorsAn advantage of eddy current position and speed sensors is that they do not require a ferromagnetic target: Any conducting material can be used.Author Contributions: Conceptualization, P.R. and J.B.; design, calculations, and measurements: M.M., P.L., M.Š., and K.D.; writing-original draft preparation, P.R. and J.B.; writing-review and editing, all authors.

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Simple Technique for Linear-Range Extension of Linear Variable Differential Transformer

Cited by 24 publications

References 15 publications

How Geometry Affects Sensitivity of a Differential Transformer for Contactless Characterization of Liquids

How Geometry Affects Sensitivity of a Differential Transformer for Contactless Characterization of Liquids

A Position Sensor With Novel Configuration of Linear Variable Differential Transformer

Inductive Position and Speed Sensors

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