Applied Sciences

Research

14 pages, 771 KiB

Open AccessArticle

Nonlinear Analysis and Solution for an Overhead Line Magnetic Energy Harvester with an Active Rectifier

by Alexander Abramovitz, Moshe Shvartsas and Alon Kuperman

Appl. Sci. 2024, 14(23), 11178; https://doi.org/10.3390/app142311178 (registering DOI) - 29 Nov 2024

Recently, there has been a significant focus on developing various energy harvesting technologies to power remote electronic sensors, data loggers, and communication devices for smart grid systems. Among these technologies, magnetic energy harvesting stands out as one straightforward method to extract substantial power [...] Read more.

Recently, there has been a significant focus on developing various energy harvesting technologies to power remote electronic sensors, data loggers, and communication devices for smart grid systems. Among these technologies, magnetic energy harvesting stands out as one straightforward method to extract substantial power from current-carrying overhead lines. Due to the relatively small size of the harvester, the high currents in the distribution system quickly saturate its magnetic core. Consequently, the magnetic harvester operates in a highly nonlinear manner. The nonlinear nature of the downstream AC to DC converters further complicates the process, making precise analytical modeling a challenging task. In this paper, a clamped type overhead line magnetic energy harvester with a controlled active rectifier generating significant DC output power is investigated. A piecewise nonlinear analytical model of the magnetic harvester is derived and reported. The modeling approach is based on the application of the Froelich equation. The chosen approximation method allowed for a complete piecewise nonlinear analytical treatise of the harvester’s behavior. The main findings of this study include a closed-form solution that accounts for both the core and rectifiers’ nonlinearities and provides an accurate quantitative prediction of the harvester’s key parameters such as the transfer window width, optimal pulse location, average DC output current, and average output power. To facilitate the study, a nonlinear model of the core was developed in simulation software, based on parameters extracted from core experimental data. Furthermore, theoretical predictions were verified through comparison with a computer simulation and experimental results of a laboratory prototype harvester. Good agreement between the theoretical, simulation, and experimental results was found. Full article

(This article belongs to the Special Issue Trends and Prospects in Applied Electromagnetics)

23 pages, 14830 KiB

Open AccessArticle

Electromagnetic Interference Shielding Analysis of Hybrid Buckypaper-Reinforced Polymer Matrix Composites: A Quantum Tunneling-Informed Equivalent Circuit Approach

by Kartik Tripathi, Mohamed H. Hamza, Madeline A. Morales, Todd C. Henry, Asha Hall and Aditi Chattopadhyay

Appl. Sci. 2024, 14(19), 8960; https://doi.org/10.3390/app14198960 - 4 Oct 2024

Viewed by 993

Abstract

A novel modeling approach is developed for investigating the effectiveness of buckypaper (BP), a porous membrane made of a highly cross-linked network of carbon nanotubes, in improving the electromagnetic interference (EMI) shielding properties of carbon fiber-reinforced polymer (CFRP) composites. The methodology uses quantum [...] Read more.

A novel modeling approach is developed for investigating the effectiveness of buckypaper (BP), a porous membrane made of a highly cross-linked network of carbon nanotubes, in improving the electromagnetic interference (EMI) shielding properties of carbon fiber-reinforced polymer (CFRP) composites. The methodology uses quantum tunneling-based equivalent electrical circuits and Monte Carlo simulations to predict the frequency-dependent electrical conductivity and EMI shielding effectiveness (SE) of the hybrid BP/CFRP composites. The study examines a signal frequency range of 50 MHz to 12 GHz that includes the very high and X-band. The results show that at a frequency of 12 GHz, the transverse conductivity increases to approximately 12.67 S/m, while the longitudinal conductivity decreases to about 3300 S/m from an initial value of 40,000 S/m. These results are then integrated into the ANSYS High-Frequency Structure Simulator to predict SE by simulating the propagation of electromagnetic waves through a semi-infinite composite shield element. The numerical simulations illustrate that incorporating BP significantly improves the SE of CFRP composites beyond 2 GHz owing to its high conductivity in that frequency range. For instance, at 12 GHz signal frequency, adding a single BP interleaf enhances the SE of a [90, 0] laminate by up to ~64%. Full article

(This article belongs to the Special Issue Trends and Prospects in Applied Electromagnetics)

► Show Figures

Figure 1

19 pages, 2721 KiB

Open AccessArticle

Observations about Propagation, Attenuation, and Radiation of EMI from HVDC Converter Stations

by John B. Schneider and Robert G. Olsen

Appl. Sci. 2024, 14(15), 6740; https://doi.org/10.3390/app14156740 - 1 Aug 2024

Viewed by 1338

Abstract

The electromagnetic interference (EMI) generated by switching operations within high-voltage DC (HVDC) converter stations is an issue that has been addressed by CIGRE, and methods to manage EMI should be considered in the design phase using electromagnetic modeling techniques. It is shown that [...] Read more.

The electromagnetic interference (EMI) generated by switching operations within high-voltage DC (HVDC) converter stations is an issue that has been addressed by CIGRE, and methods to manage EMI should be considered in the design phase using electromagnetic modeling techniques. It is shown that the methods of the moments-based techniques that have been used in many previous studies may not be sufficient. Here, a finite-difference time-domain method is used to study the properties of single switching events using a realistic model of an HVDC converter station with a special emphasis on determining the impact of the valve hall on shielding EMI. It is shown that the valve hall does not confine high-frequency electromagnetic fields to the valve hall; rather, it delays them from exiting through bushings in the wall and spreads them out in time. Further, it is shown that incorporating electromagnetic absorbing material into the valve hall’s design can significantly reduce EMI outside the converter station. Full article

(This article belongs to the Special Issue Trends and Prospects in Applied Electromagnetics)

► Show Figures

Figure 1

Figure 1
Computational domain showing (a) a projection onto the <math display="inline"><semantics> <mrow> <mi>x</mi> <mi>y</mi> </mrow> </semantics></math> plane, (b) projection onto the <math display="inline"><semantics> <mrow> <mi>x</mi> <mi>z</mi> </mrow> </semantics></math> plane, and (c) an oblique perspective view. The red lines represent conductors, the shaded box corresponds to the valve hall, and the green-shaded plane on which the hall sits is a perfectly conducting ground plane. Full article ">Figure 2
The log magnitude of the electric field measured inside and outside the valve hall when (a) 2 m segments of the conductors that nominally pass through the valve hall walls are removed and when (b) the conductors that pass through the walls are intact. Full article ">Figure 3
The log magnitude of the spectral content of the <math display="inline"><semantics> <msub> <mi>E</mi> <mi>z</mi> </msub> </semantics></math> component of the field, measured at two points when (a) the observation points are inside and outside the valve hall. The reference curve shows the Fourier transform of the source function. (b) Fields at the observations points normalized by the source function. (c) The valve hall has been removed, with no other changes to the simulation. Full article ">Figure 4
The log magnitude of the normalized spectrum of the current measured at two points along the top-most line from the valve hall to the DC hall. (a) The hall is present. (b) The hall has been removed. Full article ">Figure 5
The electric field magnitude measured approximately 200 m from the converter station. (a) Field observed when the valve hall is and is not present. (b) Fields observed when there is and is not a lossy dielectric slab placed in the valve hall. Full article ">Figure 6
The normalized spectrum of the <math display="inline"><semantics> <msub> <mi>H</mi> <mi>x</mi> </msub> </semantics></math> field (in dB), measured approximately 200 m from the valve hall. The results are shown for an intact valve hall, when no valve hall is present, and when the valve hall is intact but contains a lossy dielectric slab. Full article ">

15 pages, 4820 KiB

Open AccessArticle

An S–K Band 6-Bit Digital Step Attenuator with Ultra Low Insertion Loss and RMS Amplitude Error in 0.25 μm GaAs p-HEMT Technology

by Quanzhen Liang, Kuisong Wang, Xiao Wang, Yuepeng Yan and Xiaoxin Liang

Appl. Sci. 2024, 14(9), 3887; https://doi.org/10.3390/app14093887 - 1 May 2024

Cited by 1 | Viewed by 3092

Abstract

This paper presents an ultra-wideband, low insertion loss, and high accuracy 6-bit digital step attenuator (DSA). To improve the accuracy of amplitude and phase shift of the attenuator, two innovative compensation structures are proposed in this paper: a series inductive compensation structure (SICS) [...] Read more.

This paper presents an ultra-wideband, low insertion loss, and high accuracy 6-bit digital step attenuator (DSA). To improve the accuracy of amplitude and phase shift of the attenuator, two innovative compensation structures are proposed in this paper: a series inductive compensation structure (SICS) designed to compensate for high frequency attenuation values and a small bit compensation structure (SBCS) intended for large attenuation bits. Additionally, we propose insertion loss reduction techniques (ILRTs) to reduce insertion loss. The fabricated 6-bit DSA core area is only 0.51 mm², and it exhibits an attenuation range of 31.5 dB in 0.5 dB steps. Measurements reveal that the root-mean-square (RMS) attenuation and phase errors for the 64 attenuation states are within 0.18 dB and 7°, respectively. The insertion loss is better than 2.54 dB; the return loss is better than −17 dB; and the input 1 dB compression point (IP1 dB) is 29 dBm at IF 12 GHz. To the best of our knowledge, this chip presents the highest attenuation accuracy, the lowest insertion loss, the best IP1dB, and a good matching performance in the range of 2–22 GHz using the 0.25 μm GaAs p-HEMT process. Full article

(This article belongs to the Special Issue Trends and Prospects in Applied Electromagnetics)

► Show Figures

Figure 1

19 pages, 4632 KiB

Open AccessArticle

Compliance Assessment of the Spatial Averaging Method for Magnetic Field Leakage from a Wireless Power Transfer System in Electric Vehicles

by Masanori Okada, Keishi Miwa, Sachiko Kodera and Akimasa Hirata

Appl. Sci. 2024, 14(7), 2672; https://doi.org/10.3390/app14072672 - 22 Mar 2024

Cited by 1 | Viewed by 1087

Abstract

Wireless power transfer (WPT) via magnetic resonance offers efficient electrical power transfer, making it an increasingly attractive option for charging electric vehicles (EVs) without conventional plugs. However, EV charging requires a transfer power in order of kW or higher, resulting in a higher-leaked [...] Read more.

Wireless power transfer (WPT) via magnetic resonance offers efficient electrical power transfer, making it an increasingly attractive option for charging electric vehicles (EVs) without conventional plugs. However, EV charging requires a transfer power in order of kW or higher, resulting in a higher-leaked magnetic field than conventional wireless systems. The leaked magnetic field is nonuniform, and the assessment in terms of the limit prescribed in the guideline is highly conservative because it assumes that a person standing in free space is exposed to a uniform field. In such cases, an assessment should be performed using the limits of the internal electric field, as it is more relevant to the adverse health effects, whereas its evaluation is time-consuming. To mitigate this over-conservativeness, international product standards introduce a spatial averaging method for nonuniform exposure assessment. In this study, we investigate assessment methods, especially for measurement points of nonuniform magnetic field strength leaked from the WPT system. Various spatial averaging methods are correlated with the internal electric field derived from electromagnetic field analysis using an anatomically based human body model. Our computational results confirm a good correlation between the spatially averaged magnetic and internal electric fields. Additionally, these methods provide an appropriate compliance assessment with the exposure guidelines. This study advances our understanding of the suitability of spatial averaging methods for nonuniform exposure and contributes to the smooth assessment in WPT systems. Full article

(This article belongs to the Special Issue Trends and Prospects in Applied Electromagnetics)

► Show Figures

Figure 1

10 pages, 890 KiB

Open AccessCommunication

A Filtering Switch Made by an Improved Coupled Microstrip Line

by Xiangsuo Fan, Xiaokang Chen, Wenhao Xu, Lingping Feng, Ling Yu and Haohao Yuan

Appl. Sci. 2023, 13(13), 7886; https://doi.org/10.3390/app13137886 - 5 Jul 2023

Viewed by 1192

Abstract

In this paper, we propose a new filtering switch with excellent working performance made using an optimized coupled microstrip line. Upon analyzing the RF (radio frequency) front-end’s system structure, the switching device was simplified to a diode, which was connected to the microstrip [...] Read more.

In this paper, we propose a new filtering switch with excellent working performance made using an optimized coupled microstrip line. Upon analyzing the RF (radio frequency) front-end’s system structure, the switching device was simplified to a diode, which was connected to the microstrip circuit we designed to become a filter switch with both filtering and shutdown functions. First, we obtained an equivalent schematic of this filtering switch based on the relevant microstrip line theory. This switch consists of two coupled microstrip circuits, parallel-coupled feed lines and coupled-line stub-load resonators (CLSs), and a PIN diode. Second, the operating principle is described by the switching of the operating states, with ideal shutdown performance in the off state and considerable selectivity and excellent out-of-band rejection performance in the filtered state. Finally, a prototype filtering switch with a center frequency of 0.8 GHz was designed and tested. After subsequent optimization and improvement, the simulation and test performance results were noticeably consistent, consequently verifying the performance requirements of this filtering switch in two operating states in the center frequency band. Full article

(This article belongs to the Special Issue Trends and Prospects in Applied Electromagnetics)

► Show Figures

Figure 1

17 pages, 6645 KiB

Open AccessArticle

Design of a Novel Ultra-Wideband Common-Mode Filter Using a Magnified Coupled Defected Ground Structure

by Ding-Bing Lin, Mei-Hui Wang, Aloysius Adya Pramudita and Tjahjo Adiprabowo

Appl. Sci. 2023, 13(13), 7404; https://doi.org/10.3390/app13137404 - 22 Jun 2023

Cited by 2 | Viewed by 1543

Abstract

An ultra-wideband common-mode (CM) filter for a gigahertz (GHz) data rate signal is proposed in this paper. The proposed filter was designed only on the printed circuit board (PCB) ground plane; no additional components wererequired. We took advantage of producing second-order transmission zero [...] Read more.

An ultra-wideband common-mode (CM) filter for a gigahertz (GHz) data rate signal is proposed in this paper. The proposed filter was designed only on the printed circuit board (PCB) ground plane; no additional components wererequired. We took advantage of producing second-order transmission zero by an asymmetrical magnified coupled DGS to extend the suppression bandwidth. Full-wave simulations and equivalent circuit models of the DGS resonator were established to predict the suppression performance. The measured differential-mode insertion loss (S_dd21) from direct current (DC) to 12.35 GHz was obtained within the −3 dB definitionin the frequency domain. The CM noise was suppressed by more than10 dB in the frequency range from 2.9 GHz to 16.2 GHz. The fractional bandwidth (FBW) reached 139.3%. The proposed filter blocked 62.3% of the CM noise magnitude in the time domain measurement. In addition, the eye diagram measurement proved that good transmission quality was maintained. The proposed filter can be widely implemented to reduce electromagnetic interference (EMI) in radio frequency (RF) andWi-Fi (wireless fidelitystandard) 5 and 6E wireless communication applications. Full article

(This article belongs to the Special Issue Trends and Prospects in Applied Electromagnetics)

► Show Figures

Figure 1

21 pages, 12662 KiB

Open AccessArticle

Design of N-Way Wilkinson Power Dividers with New Input/Output Arrangements for Power-Halving Operations

by Ceyhun Karpuz, Mehmet Cakir, Ali Kursad Gorur and Adnan Gorur

Appl. Sci. 2023, 13(11), 6852; https://doi.org/10.3390/app13116852 - 5 Jun 2023

Cited by 1 | Viewed by 3225

Abstract

In this paper, new single/double-layer N-way Wilkinson power dividers (WPDs) were designed by using slow-wave structures such as narrow-slit-loaded and meandered transmission lines. For size reduction, the slit-loaded and meandered lines were used instead of the quarter-wavelength transmission lines of a conventional WPD. [...] Read more.

In this paper, new single/double-layer N-way Wilkinson power dividers (WPDs) were designed by using slow-wave structures such as narrow-slit-loaded and meandered transmission lines. For size reduction, the slit-loaded and meandered lines were used instead of the quarter-wavelength transmission lines of a conventional WPD. Based on the proposed approaches, two-, four-, and eight-way power dividers were designed, simulated, and fabricated. The fabricated 2-, 4-, and 8-way circuits were measured at the center frequencies of 2.03, 1.77, and 1.73 GHz, which are in excellent agreement with the predicted ones. The meandered transmission lines were also used to design WPD types with novel input/output port arrangements. For this purpose, two three-way WPDs were located on both sides of the same board to have different power-splitting ratios at different inputs and outputs in order to provide alternative solutions for antenna arrays. Furthermore, a five-way dual-layer WPD was introduced by locating the meandered transmission lines into two layers. The most important advantage of the proposed 3- and 5-way WPDs is that they allowed the input power at the next output port to be halved, in the order of P/2, P/4, P/8, P/16, and P/16. All the designed power-halving WPDs were simulated, fabricated, and successfully tested. Full article

(This article belongs to the Special Issue Trends and Prospects in Applied Electromagnetics)

► Show Figures

Figure 1

14 pages, 3994 KiB

Open AccessArticle

Discrete Wavelet Transform—Based Metal Material Analysis Model by Constant Phase Angle Pulse Eddy Current Method

by Yong Xie, Yating Yu and Liangting Li

Appl. Sci. 2023, 13(5), 3207; https://doi.org/10.3390/app13053207 - 2 Mar 2023

Cited by 1 | Viewed by 1406

Abstract

Traditional eddy current technology identifies metal information with information of single frequency of limited frequency spectrum. To solve existing problems, this paper proposes a discrete wavelet transform-based metal material analysis model by using a constant phase angle pulse eddy current (CPA-PEC) sensor which [...] Read more.

Traditional eddy current technology identifies metal information with information of single frequency of limited frequency spectrum. To solve existing problems, this paper proposes a discrete wavelet transform-based metal material analysis model by using a constant phase angle pulse eddy current (CPA-PEC) sensor which collects and depicts metal feature information from multiple dimensions; then, the quantification calculation model of metal material by CPA-PEC feature is presented; finally, an experimental platform is built to collect the CPA-PEC features of various metal samples and verify recognition accuracy of the proposed metal material analysis model. In the investigation, 1000 eddy current signals from four standard metals (Cu, Fe, Al, St) and three types of metallic irons (Fe-K162, Fe-K163, Fe-K240) are measured and the features are identified by discrete wavelet transform. The feature correlation and significance are determined by regression analysis. Finally, the calculation model of feature evaluation index is present. The experimental analysis indicates that the stability of the quantitative evaluation index of eddy current features reaches 97.1%, the comprehensive accuracy error is less than 0.32% and the average measurement speed is about 50 ms for 1000 random sampling tests on standard metals. Full article

(This article belongs to the Special Issue Trends and Prospects in Applied Electromagnetics)

► Show Figures

Figure 1

Journal Menu

Journal Browser

Trends and Prospects in Applied Electromagnetics

Share This Special Issue

Special Issue Editors

Special Issue Information

Keywords

Benefits of Publishing in a Special Issue

Published Papers (9 papers)

Research

Further Information

Guidelines

MDPI Initiatives

Follow MDPI