scholarly journals Two-Probe Setup with Improved Calibration for Online Impedance Measurement of Electrical Assets

2021 ◽  
Author(s):  
Hui Lin Chou
Keyword(s):  
Impedance Measurement ◽  
Calibration Procedure ◽  
Inductive Coupling ◽  
Physical Contact ◽  
Calibration Model ◽  
Electrical System ◽  
Frequency Range ◽  
Frequency Dependent ◽  
Coupling Technique ◽  
Electrical Device

<p>The online impedance serves as one of the most crucial specification to evaluate the health status and efficiency of an electrical device or system. The inductive coupling technique is a preferred approach to measure the online impedance due to the ease of implementation of the circuit which has zero physical contact to the live electrical system. The existing inductive coupling method deployed to measure the online impedance of an electrical device under test (DUT) adopts two probes in total: an injecting inductive probe (IIP) and a receiving inductive probe (RIP). An open/short/load (OSL) calibration procedure is implemented to eradicate the ramifications of the probe-to-probe coupling, however, based on the assumption that the calibration criterions (shorted, open and 50Ω) are approximated to their theoretical values in a specified frequency range. Hence, any measurement with frequency outside the specified range (i.e. larger than 1 MHz) will not be accurate due to the frequency-dependent residual inductances and capacitances of the calibration model. To overcome the aforesaid limitation, this paper introduces an improved calibration procedure which is applicable for a wider frequency range which takes the frequency-dependent characteristics into consideration. With the two-probe measurement setup (TPMS), the adopted improved calibration procedure is introduced to eradicate the ramifications of the probe-to-probe coupling with the intention to refine the accuracy of the extracted online impedance.<a></a></p><p></p>

scholarly journals Two-Probe Setup with Improved Calibration for Online Impedance Measurement of Electrical Assets

2021 ◽  
Author(s):  
Hui Lin Chou
Keyword(s):  
Impedance Measurement ◽  
Calibration Procedure ◽  
Inductive Coupling ◽  
Physical Contact ◽  
Calibration Model ◽  
Electrical System ◽  
Frequency Range ◽  
Frequency Dependent ◽  
Coupling Technique ◽  
Electrical Device

<p>The online impedance serves as one of the most crucial specification to evaluate the health status and efficiency of an electrical device or system. The inductive coupling technique is a preferred approach to measure the online impedance due to the ease of implementation of the circuit which has zero physical contact to the live electrical system. The existing inductive coupling method deployed to measure the online impedance of an electrical device under test (DUT) adopts two probes in total: an injecting inductive probe (IIP) and a receiving inductive probe (RIP). An open/short/load (OSL) calibration procedure is implemented to eradicate the ramifications of the probe-to-probe coupling, however, based on the assumption that the calibration criterions (shorted, open and 50Ω) are approximated to their theoretical values in a specified frequency range. Hence, any measurement with frequency outside the specified range (i.e. larger than 1 MHz) will not be accurate due to the frequency-dependent residual inductances and capacitances of the calibration model. To overcome the aforesaid limitation, this paper introduces an improved calibration procedure which is applicable for a wider frequency range which takes the frequency-dependent characteristics into consideration. With the two-probe measurement setup (TPMS), the adopted improved calibration procedure is introduced to eradicate the ramifications of the probe-to-probe coupling with the intention to refine the accuracy of the extracted online impedance.<a></a></p><p></p>

Frequency dependent resistance calculation of multiple conductors

2017 ◽  
Vol 36 (5) ◽  
pp. 1396-1410
Author(s):  
Tomislav Župan ◽  
Bojan Trkulja
Keyword(s):  
Design Methodology ◽  
Numerical Approach ◽  
Effective Resistance ◽  
Proximity Effects ◽  
The Finite Element Method ◽  
Frequency Range ◽  
Frequency Dependent ◽  
Content Type ◽  
Electromagnetic Devices ◽  
Practical Implications

Purpose The purpose of this paper is to present a method for calculating frequency-dependent resistance when multiple current-carrying conductors are present. Design/methodology/approach Analytical and numerical formulations are presented. Both skin- and proximity-effects are considered in the numerical approach, whereas only skin-effect can be taken into account in analytical equations. The calculation is done using a self-developed integral equation-based field solver. The results are benchmarked using professional software based on the finite element method (FEM). Findings Results from the numerical approach are in agreement with FEM-based software throughout the whole frequency range. Analytical formulations yield unsatisfactory results in higher frequency range. When multiple conductors are mutually relatively close, the proximity-effect has an impact on effective resistance and has to be taken into account. Research limitations/implications The methodology is presented using axially symmetrical conductors. However, the same procedure can be developed for straight conductors as well. Practical implications Presented fast and stable procedure can be used in most electromagnetic devices when frequency-dependent resistance needs to be precisely determined. Originality/value The value of the presented numerical methodology lies in its ability to take both skin- and proximity-effects into account. As conductors are densely packed in most electromagnetic devices, both effects influence the effective resistance. The method can be easily implemented using a self-developed solver and yields satisfactory results.

scholarly journals A Blind Calibration Model for I/Q Imbalances of Wideband Zero-IF Receivers

Electronics ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 1868
Author(s):  
Xiaoye Peng ◽  
Zhiyu Wang ◽  
Jiongjiong Mo ◽  
Chenge Wang ◽  
Jiarui Liu ◽  
...  
Keyword(s):  
Frequency Domain ◽  
Finite Impulse Response ◽  
Low Cost ◽  
Classification Rule ◽  
Statistical Characteristics ◽  
High Signal ◽  
Calibration Model ◽  
Frequency Dependent ◽  
Frequency Independent ◽  
Blind Calibration

Frequency-dependent I/Q imbalance and frequency-independent I/Q imbalance are the major impairments in wideband zero-IF receivers, and they both cannot be ignored. In this paper, a blind calibration model is designed for compensating these I/Q imbalances. In order to accurately estimate the imbalance parameters with low cost, a classification rule is proposed according to the frequency-domain statistical characteristics of the received signal. The calibration points in the frequency-domain are divided into two groups. Then, the amplitude imbalance and the frequency-dependent phase imbalance are derived from the group of signal points and, separately, the frequency-independent phase imbalance is calculated from the group of noise points. In the derivation of the frequency-dependent phase imbalance, a general fitting model suitable for all signal points is proposed, which does not require special calculations for either DC point or fs/2 point. Then, a finite impulse response (FIR) real-valued filter is designed to correct the impairments of received signal. The performances of the proposed calibration model are evaluated through both simulations and experiments. The simulation results show the image rejection ratio (IRR) improvement to around 35–45 dBc at high signal-to-noise ratio (SNR). Based on the mismatched data of the ADRV9009 evaluation board, the experimental results exhibit the IRR improvement of both multi-tone and wideband signals to about 30 dBc.

Modeling of respiratory system impedances in dogs

1987 ◽  
Vol 62 (2) ◽  
pp. 414-420 ◽  
Author(s):  
A. C. Jackson ◽  
K. R. Lutchen
Keyword(s):  
Respiratory System ◽  
Element Model ◽  
Parameter Estimates ◽  
Frequency Range ◽  
Nonlinear Regression Analysis ◽  
Entire Frequency Range ◽  
Frequency Dependent ◽  
Impedance Data ◽  
Parameter Values ◽  
Gas Compressibility

Mechanical impedances between 4 and 64 Hz of the respiratory system in dogs have been reported (A.C. Jackson et al. J. Appl. Physiol. 57: 34–39, 1984) previously by this laboratory. It was observed that resistance (the real part of impedance) decreased slightly with frequency between 4 and 22 Hz then increased considerably with frequency above 22 Hz. In the current study, these impedance data were analyzed using nonlinear regression analysis incorporating several different lumped linear element models. The five-element model of Eyles and Pimmel (IEEE Trans. Biomed. Eng. 28: 313–317, 1981) could only fit data where resistance decreased with frequency. However, when the model was applied to these data the returned parameter estimates were not physiologically realistic. Over the entire frequency range, a significantly improved fit was obtained with the six-element model of DuBois et al. (J. Appl. Physiol. 8: 587–594, 1956), since it could follow the predominate frequency-dependent characteristic that was the increase in resistance. The resulting parameter estimates suggested that the shunt compliance represents alveolar gas compressibility, the central branch represents airways, and the peripheral branch represents lung and chest wall tissues. This six-element model could not fit, with the same set of parameter values, both the frequency-dependent decrease in Rrs and the frequency-dependent increase in resistance. A nine-element model recently proposed by Peslin et al. (J. Appl. Physiol. 39: 523–534, 1975) was capable of fitting both the frequency-dependent decrease and the frequency-dependent increase in resistance. However, the data only between 4 and 64 Hz was not sufficient to consistently determine unique values for all nine parameters.

Part Authentication Using Indirect Electromechanical Impedance Measurements

2020 ◽  
Author(s):  
Mohammad I. Albakri ◽  
Pablo A. Tarazaga
Keyword(s):  
Numerical Solutions ◽  
Numerical Models ◽  
Impedance Measurement ◽  
Piezoelectric Transducers ◽  
Frequency Range ◽  
Impedance Measurements ◽  
Manufacturing Defects ◽  
Electromechanical Impedance ◽  
Non Destructive Evaluation ◽  
Non Destructive

Abstract Motivated by its success as a structural health monitoring solution, electromechanical impedance measurements have been utilized as a means for non-destructive evaluation of conventionally and additively manufactured parts. In this process, piezoelectric transducers are either directly embedded in the part under test or bonded to its surface. While this approach has proven to be capable of detecting manufacturing anomalies, instrumentation requirements of the parts under test have hindered its wide adoption. To address this limitation, indirect electromechanical impedance measurement, through instrumented fixtures or testbeds, has recently been investigated for part authentication and non-destructive evaluation applications. In this work, electromechanical impedance signatures obtained with piezoelectric transducers indirectly attached to the part under test, via an instrumented fixture, are numerically investigated. This aims to better understand the coupling between the instrumented fixture and the part under test and its effects ON sensitivity to manufacturing defects. For this purpose, numerical models are developed for the instrumented fixture, the part under test, and the fixture/part assembly. The frequency-domain spectral element method is used to obtain numerical solutions and simulate the electromechanical impedance signatures over the frequency range of 10–50 kHz. Criteria for selecting the frequency range that is most sensitive to defects in the part under test are proposed and evaluated using standard damage metric definitions. It was found that optimal frequency ranges can be preselected based on the fixture design and its dynamic response.

scholarly journals Relationship between moisture content and electrical impedance of carrot slices during drying

2015 ◽  
Vol 29 (1) ◽  
pp. 61-66 ◽  
Author(s):  
Ákos Kertész ◽  
Zuzana Hlaváčová ◽  
Eszter Vozáry ◽  
Lenka Staroňová
Keyword(s):  
Moisture Content ◽  
Electrical Impedance ◽  
Fruits And Vegetables ◽  
Physiological State ◽  
Impedance Measurement ◽  
Biological Tissues ◽  
Impedance Spectra ◽  
Frequency Range ◽  
Impedance Parameters ◽  
Precision Balance

Abstract Electrical properties of food materials can give information about the inner structure and physiological state of biological tissues. Generally, the process of drying of fruits and vegetables is followed by weight loss. The aim of this study was to measure the impedance spectra of carrot slices during drying and to correlate impedance parameters to moisture content in different drying periods. Cylindrical slices were cut out from the carrot root along the axis. The slices were dried in a Venticell 111 air oven at 50°C. The weight of the slices was measured with a Denver SI-603 electronic analytical and precision balance. The weighing of the samples was performed every 30 min at the beginning of drying and every 60 min after the process. The moisture content of the samples was calculated on wet basis. The magnitude and phase angle of electrical impedance of the slices were measured with HP 4284A and 4285A precision LCR meters in the frequency range from 30 Hz to 1 MHz and from 75 kHz to 30 MHz, respectively, at voltage 1 V. The impedance measurement was performed after weighting. The change in the magnitude of impedance during drying showed a good correlation with the change in the moisture content.

Analysis of Process Interactions in Dynamic System Using Frequency Dependent RGA

2011 ◽  
Vol 403-408 ◽  
pp. 895-899
Author(s):  
Amit Jain ◽  
B.V. Babu
Keyword(s):  
Transfer Function ◽  
Process Model ◽  
Transfer Function Model ◽  
Control Loop ◽  
Frequency Range ◽  
Function Model ◽  
Frequency Dependent ◽  
Relative Gain ◽  
Relative Gain Array ◽  
Correct Pairing

A frequency dependent approach to defining a dynamic relative gain array (DRGA) is discussed. The approach assumes the availability of a dynamic transfer function based process model for control loop pairing analysis. Two examples are considered: one in which the traditional RGA (based on steady-state gain matrix) gives the correct pairing recommendation and the other in which the traditional RGA suggests wrong pairings particularly in the frequency range of interest. The calculations pertaining to analysis of control loop pairing is performed using MATLAB (version 7.0.1). An inaccurate indication of the amount of interaction present is discussed. The first example uses 2x2 transfer function model [1] and the second one uses 3x3 transfer function model [2].

scholarly journals Planar Offset Short Applicable to the Calibration of a Free-Space Material Measurement System in W-Band

2021 ◽  
Vol 21 (1) ◽  
pp. 51-59
Author(s):  
Jin-Seob Kang ◽  
Jeong-Hwan Kim
Keyword(s):  
Electrical Properties ◽  
Measurement System ◽  
Free Space ◽  
Physical Contact ◽  
Frequency Range ◽  
Electromagnetic Devices ◽  
W Band ◽  
Measurement Results ◽  
Properties Of Materials ◽  
Space Material

The electrical properties of materials and their dependence on frequency and temperature are indispensable in designing electromagnetic devices and systems in various areas of engineering and science for both basic and applied researches. A free-space transmission/reflection method measuring the free-space scattering parameters of a material under test (MUT) located at the middle of transmit/receive antennas in a free space is suitable for non-destructively testing the MUT without prior machining or physical contact in high-frequency range. This paper describes a planar offset short applicable to the calibration of a quasi-optic based free-space material measurement system in the millimeter-wave frequency range. The measurement results of the dimensional and electrical properties for the three fabricated planar offset shorts with the phase difference of 120° between the reflection coefficients of the planar shorts in the W-band (75–110 GHz) are presented.

scholarly journals DEFECTED GROUND COPLANAR MULTI-BAND-PASS MICROSTRIP FILTER

2021 ◽  
Vol 9 (1) ◽  
pp. 64-68
Author(s):  
Reena Pant, Rakesh Kumar Maurya, Pradyot Kala
Keyword(s):  
Ground Plane ◽  
Inductive Coupling ◽  
Defected Ground Structure ◽  
Ground Structure ◽  
Microstrip Filter ◽  
Coupling Technique ◽  
Filter Performance ◽  
Band Pass ◽  
5 Ghz ◽  
Good Agreement

This paper presents a combination of an inductive coupling technique and coplanar ground plane microstrip filter. Here, inductive coupling technique is used to overcome the unwanted radiation loss generated by the gap between the co-planar ground plane and the transmission line which improves filter characteristics. A defected ground structure (DGS) is integrated with the proposed filter to achieve a tri-bandpass characteristic (1.85, 3.53, and 5 GHz) without hampering the filter performance. The experimental results of the proposed filter are found in good agreement with simulated results.

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