Compact Transmission Research Articles

Investigation of Bragg gratings in planar hybrid metal–insulator–metal plasmonic waveguide using graded profile

The design of integrated components using hybrid plasmonics is attracting a widespread interest in the recent years. This work proposes a consistent approach to design Bragg gratings employing the concept of graded profile in a planar hybrid metal–insulator–metal plasmonic waveguide. A comparative study of various width modulations such as triangular, parabolic and rectangular profiles is presented. The most striking observation is that Bragg gratings with parabolic profile offer best performance in terms of compact track length (3.48 μm), wide stopband (168 nm) and good transmission characteristics with fewer side lobes. Additionally, a nanocavity analysis is performed by introducing a defect length of 140 nm in the Bragg grating structure with parabolic profile. A peak transmission of 89% is observed at the resonance wavelength of 1550 nm.

Conceptual Study on lighter and more compact transmission cable systems for Hybrid Aircrafts

More electrically driven aircrafts with electric propulsion systems are supposed to require 1-40 MW. In order to realize such heavily electrical aircrafts the development of lighter and more compact transmission cable systems is indispensable. We compared metal cables and superconducting cables, and found that DC superconducting cables are lighter and more compact than metal cables at voltages as high as ±6 kV.

Development of Compact Overhead Power Transmission Line Tower using 8-legged Configuration

Development of Compact Overhead Power Transmission Line Tower using 8-legged Configuration

Discharge voltage prediction of UHV AC transmission line–tower air gaps by a machine learning model

Full-scale discharge tests of transmission line–tower air gaps are costly and time-consuming, and they cannot exhaustively simulate all the gap configurations in practical engineering. In this paper, a machine learning model established by support vector machine is introduced to predict the switching impulse discharge voltages of the ultra-high-voltage (UHV) AC transmission line–tower air gaps. The three-dimensional finite element models of a UHV cup-type tower and a UHV compact transmission line were established for electric field calculation, and some features were extracted from the hypothetic discharge channel and the shortest path between the bundled conductor and the tower. These features under a given voltage were normalised and input to the SVM model, while the output is two binary values, respectively, representing gap withstanding or breakdown. Trained by experimental data of one type of the UHV transmission line–tower gaps, the SVM model is able to predict the discharge voltages of another gap type. The mean absolute percentage errors of the two engineering gap types, under different gap distances, are 8.31 and 4.86%, respectively, which are acceptable for engineering applications. The results provide a possible way to obtain the discharge voltages of complicated engineering gaps by mathematical calculations.

Synthesis method for compact dual-clutch transmission with four DOFs gear mechanism

The design of dual-clutch transmission with multi-degrees-of-freedom (DOFs) is a good solution to increase in number of gears and a wider range of gear ratio in the limited space and weight. This article proposes a novel synthesis method for scheme design of the dual-clutch transmission with four degrees-of-freedoms gear mechanism. First, the shift sequences considering the path of power flow and shift logics are analyzed based on the degrees-of-freedom model, abstracted from the degrees-of-freedom of the schemes. Second, the schemes of gear-pair and shaft, defined as the scheme that ignores the arrangement of synchronizers, are derived from the basic configurations, defined as the schemes of gear-pair and shaft that contains only one of each type of the variable connections, and the numbers of each type of the variable connections. Finally, multi-parameter, including synchronizers arrangement and gear ratios, is optimally designed for the results of synthesis. The seven-speed dual-clutch transmission schemes with four degrees-of-freedom and two shaft systems are taken as an example to explain this synthesis method. In addition, this article helps to obtain a deeper understanding of the systematic design of other fixed gear transmission schemes, such as automated mechanical transmission, automated mechanical transmissions with electric torque supporting, and even some novel multi-input transmissions.

Structural integrity analysis of transmission structure in flapping-wing micro aerial vehicle via 3D printing

3D printing makes the small and compact transmission system of flapping-wing micro aerial vehicle (FMAV) available for in-house designs and tests. However, the high flapping frequency requiring stringent strength integrity and fatigue longevity for the structure itself always serves as the major responsible reason for the structural failure of FMAV. In this paper, experiment as well as numerical computation efforts were acted in concert to gain an insightful understanding of the failure mechanism for the transmission structure of FMAV. Firstly, a FMAV structure was fabricated by 3D printing using Ultraviolet(UV) Cureable Resin. The isotropic constitutive behavior of the resin was evaluated and confirmed. Further, numerical computation model describing the mechanical behavior of FMAV structure was established and verified by experiments. Secondly, together with the computational structural model and constitutive model, the dynamic response of the transmission structure subject to high frequency flipping motion was described. Both simulation and experiments share the same failure mode and configuration and the dominate factor for the failure was found out to be the excessive bending deformation. Finally, design parametric study along with different boundary conditions aiming at the future ground testing were conducted to uncover the governing influences over the transmission structure integrity. Results may shed lights on the structural integrity design of FMAV and pave a new road for future advanced FMAV design, manufacturing and testing. • A finite element modeling methodology for transmission system of FMAV was presented. • The dominate factor for the failure of the transmission structure was uncovered. • Impacts of different boundary conditions on the structural strength were discussed. • Improvement design of the main components were carried out.

An Approach to Develop a Compact Transmission Line Tower with Special 8-Legged Configuration

For transmission of electricity from power generation plant to substations, many types of structures are being used. The main function of these structures is to support the power conductors and earth-wire. 4-legged steel lattice tower is one of these structures, which is widely used for this purpose. The main drawback of a 4-legged lattice tower is its larger base width, which occupy very large area. Nowadays, in many countries, adequate land is not available to consider such large land occupying towers. In these situations, using monopoles became common practice. But the monopoles are much costlier than the 4-legged lattice towers. To avoid the use of monopoles and to reduce the base width at the same time, in the present work, an approach has been adopted to use a special lattice type structure with eight legs. A 220 kV multi-circuit suspension tower with 0°–2° deviation has been considered for present study. The detail explanations, like, tower geometry, load calculations, analysis and design of the proposed structure has been covered in the paper. It has been observed that land requirement can be considerably minimized by use of the proposed 8-legged tower. The cost of the 8-legged tower is slightly more than a 4-legged tower but much lesser than that of monopoles as the total weight of steel required is very less as compared to monopole. The results obtained from the study of the proposed tower have been compared with 4-legged tower and monopole. This paper discusses the feasibility of using the transmission line tower with 8-legs. The paper also discusses a comparative study of cost, right of way, height and base width of 4-legged tower, monopole and proposed 8-legged tower.

Elaborate Method for Analyzing Shielding Lightning Performance of 500 kV Tension Tower in Compact Transmission Line

Elaborate Method for Analyzing Shielding Lightning Performance of 500 kV Tension Tower in Compact Transmission Line

Optimal Selection and Arrangement of Cables for Compact Overhead Transmission Lines of 138/230 kV

The use of compact overhead transmission lines are promising alternatives for high voltage transmission in urban areas. The cost of right of way acquisition for new projects is prohibitive in some cases. So, the use of existent right of way as a corridor of large amount of energy is interesting in the environment point of view and is very economic. This paper presents a new methodology developed for optimizing the project of compact overhead transmission lines with multiple circuits. This methodology comprises the selection of both bare wire conductors and earth-wires, its spatial arrangement, the topology of the tower for circuits under voltages of 138kV and 230kV. In this work, two independent electrical power for each voltage level are considered. The problem is formulated as a constrained many objective optimization, which is solved using evolutionary optimization techniques. To aid the decision maker in the choice of the non-dominated solution at the end of the optimization process, a decision making procedure is proposed. The result point out to structures with narrow right of way and high efficiency when compared to conventional transmission line.

A GEAR-SHIFTING MECHANISM WITH A ROTARY CONFIGURATION FOR APPLICATIONS IN A 16-SPEED BICYCLE TRANSMISSION HUB

A multi-speed bicycle transmission hub includes a geared speed-changing mechanism for providing different speed ratios and a gear-shifting mechanism for controlling the gear stage. This paper focuses on the embodiment design of a mechanical gear-shifting mechanism with a rotary configuration used in a 16-speed transmission hub for bicycles. A 16-link, five-degrees of freedom (DOF) split-power epicyclic gear mechanism, which consists of a gear differential and four sets of parallel-connected basic planetary gear trains, is introduced. Based on the clutching sequence table, a systematic design process is developed to come up with the embodiment design of the gear-shifting mechanism. A feasible and compact 16-speed rear transmission hub for bicycles is presented.

Design of a compact 18-speed epicyclic transmission for a personal mobility vehicle

This paper describes the design and shifting dynamics of a novel and small-sized transmission which composed of three epicyclic gear modules and a hub shaft in conjunction with several clutches. The proposed epicyclic gear train can be used in a personal mobility vehicle such as an electric utility vehicle and small car, etc. And it is distinguished from others for its small size, light weight, high efficiency, and wide speed range up to 18 gear steps. In this paper, its dynamic behavior is dealt with in order to ensure the automatic and robust shifts according to the shift commands, focused on the shift mechanism design. First the overall structure and operating principles of the transmission are described in detail. Based on the CAD data of whole components, a detailed multibody dynamic model is built using ADAMS software which can analyze the dynamic behavior of a mechanical system. Then numerical simulations are performed during the shift and whole operating period. From the simulation and experiment results, the overall performance and operating principles of the 18 speed epicyclic transmission are discussed and the design of shift device is optimized to ensure the robust shift finally.

Design of a novel high performance Schottky barrier based compact transmission gate

In this work, we propose and simulate a novel single transistor based transmission gate. The proposed device is a double gate Schottky device employing a stack of platinum silicide and erbium silicide materials to realize metal source and drain regions. The novelty of the proposed device lies in its ability to realize both n and p type modes simultaneously, which is normally being realized by a parallel combination of NMOS and PMOS transistors in a conventional transmission gate. The proposed device is compact, has reduced number of regions, junctions and interconnects in comparison to the conventional transmission gate. A two dimensional (2D) calibrated simulation study has shown a reduction of 10.42% in average delay and 18.7% in the total power dissipation in the proposed transmission gate in comparison to the conventional Schottky barrier MOSFETs based transmission gate. Furthermore, it has been observed that such a transmission gate action cannot be realised by folding the conventional NMOS and PMOS transistors.

Reducing Gear Size for Compact Transmission Design Using Computer Modeling

Abstract Modeling shows that achieving required gear performance in a reduced gear size is possible by changing the steel grade and heat treatment parameters during the design stage. This article describes work in which virtual computer models using DANTE software are applied to help achieve gear size reduction by including steel grade hardenability and heat treatment parameters in the design process.

28nm FPGA based Power Optimized UART Design using HSTL I/O Standards

UART abbreviated as Universal Asynchronous Receiver Transmitter is one of the essential element of communication system. It is being mostly used when there is a short-distance, between computer and peripherals. Whenever there is low-cost data exchange or the speed required for transmission is not high, UART’s are also being used there. For the achievement of compact, stable and reliable data transmission, the implementation of UART with VHDL language can be integrated into FPGA. The Total power and Junction temperature of UART have been analyzed in the following paper when it is operating on different I/O standards of HSTL (HIGH SPEED TRANSCEIVER LOGIC) logic family and different range of frequencies from 1 GHz to 46 GHz. Analysis have also been done for two different 28nm FPGA’s which helps to compare the total power reduction at two different FPGA technology so that the best suited FPGA for UART design consuming the least could be discovered. After analysis, it has been concluded that 91.96% of the total power can be saved in the case Kintex-7 and 91.98% of total power can be preserved in case of Artix-7 by operating the design at a frequency of 1 GHz. On the other hand the Junction temperature has been reduced to 11.84% in case of Kintex-7 and it has been reduced to 15.28% in case of Artix-7.

Closed‐form impedance model for annular through‐silicon via pairs in three‐dimensional integration

Annular through-silicon via (TSV) is one of the promising solutions for vertical interconnects in three-dimensional integration, which diminishes mismatch effects of the coefficients of thermal expansion between two different materials and saves cost, as compared with other TSV structures. In this study, an analytical impedance model is proposed. Closed-form formulas for calculations of the per-unit-height resistances and inductances are derived by calculating the electromagnetic field quantities in the cylindrically multilayered media, via solving the longitudinal current densities in the conducting layers. Combining with the conventional admittance model, a compact transmission line model is obtained, which can be used to model the electrical properties of annular TSVs. These formulas appropriately capture the real current distribution because of skin effects in metal conductors as well as the eddy current loss in semiconductor regions. The results from these analytical formulas have comparable accuracy as those obtained by the full-wave solver in a wideband frequency range, yet much higher computational efficiency than existing modelling methods.

Spatio-temporal resolution studies on a highly compact ultrafast electron diffractometer

Time-resolved diffraction with femtosecond electron pulses has become a promising technique to directly provide insights into photo induced primary dynamics at the atomic level in molecules and solids. Ultrashort pulse duration as well as extensive spatial coherence are desired, however, space charge effects complicate the bunching of multiple electrons in a single pulse. We experimentally investigate the interplay between spatial and temporal aspects of resolution limits in ultrafast electron diffraction (UED) on our highly compact transmission electron diffractometer. To that end, the initial source size and charge density of electron bunches are systematically manipulated and the resulting bunch properties at the sample position are fully characterized in terms of lateral coherence, temporal width and diffracted intensity. We obtain a so far not reported measured overall temporal resolution of 130 fs (full width at half maximum) corresponding to 60 fs (root mean square) and transversal coherence lengths up to 20 nm. Instrumental impacts on the effective signal yield in diffraction and electron pulse brightness are discussed as well. The performance of our compact UED setup at selected electron pulse conditions is finally demonstrated in a time-resolved study of lattice heating in multilayer graphene after optical excitation.

フレキシブル薄フィルム上2層構造カットワイヤーによるテラヘルツ波用大口径1/4波長板の設計と評価

The polarization control of a terahertz wave can provide fruitful technology for communication, imaging, and exploration of novel phenomena in terahertz frequencies. However, it is not so easy to realize a high-performance wave plate with a large aperture, flexibility, and thinness at low cost and by easy fabrication. We design and fabricate a terahertz quarter-wave plate on a cyclo-olefin polymer film with a copper layer by etching. Measurements by terahertz time-domain spectroscopy confirm a transmission power with 82% and an ellipticity with -1.0 at 0.43 THz. The quarter-wave plate would lead to compact transmission devices and many progressive applications.

基于面电荷密度法的高压输电线路电场计算

为了研究高压输电线路周围的电场分布，本文提出了基于面电荷密度的计算方法。该方法将每个子导线的表面进行剖分，以各个节点的面电荷密度作为变量，并利用线性插值来表示弧段的电荷密度，然后根据电磁场理论建立线形方程组来求解各个节点的面电荷密度。最后，本文用500 kV紧凑型输电线路的算例来说明该方法的优点。 In order to study the electric field around high voltage overhead transmission line, surface charges method is given in this paper. The surface of every splitting conductor is divided into many arc segments; surface charges density of every node acts as the variable and linear interpolation is used to express the charges density of every arc segment. Then, linear equations have been set up according to the electromagnetic theory, and the surface charge density of every splitting conductor can be calculated. An example of 500 kV compact transmission line is presented to illustrate the advantage and the precision of the new given method.

A compact transmission line with dual‐band filter characteristics using a CRLH metamaterial

ABSTRACTIn this article, a size‐reduced dual band‐pass transmission line (TL) with a composite right/left handed (CRLH) shunt‐stub is presented. It uses a T‐shaped quarter‐wavelength TL, which shows dual band‐pass characteristics, when the electrical length is +nλ/4 or −nλ/4, where n is odd integer. These wavelengths can be achieved at arbitrary frequencies by the CRLH‐TL with the property of a nonlinear β versus ω. The phase delay at the two operating frequencies can be adjusted by designing the series TL part, identical to the case of a conventional TL. The performance of this TL is demonstrated in both simulations and measurements, which show good agreement, exhibiting insertion losses of 0.32 and 0.98 dB at the two operating frequencies, respectively. Also, the phase response difference was determined to be 180° at these frequencies. The size of the proposed TL is 16 × 19 mm2. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:2150–2153, 2014

Structural optimization of grading rings on composite insulators on 500‐kV compact transmission lines

AbstractSerious corona discharges occur on some grading rings of 500‐kV compact transmission lines in China owing to defects in the structural design. The noise of the corona is heard clearly even 50 m away from the tower. In order to solve this problem, we have optimized the structure of the grading rings to suppress the corona. In this study, the grading rings that had serious corona discharges were identified and observed with an ultraviolet imager (UVI), and the electric field (E‐field) distributions of the grading rings were calculated by means of the three‐dimensional finite element method. Based on an analysis of the areas on the grading ring where excessive high E‐field magnitudes were observed, we optimized the structures of the grading rings to improve the field distributions on their surfaces. Based on the optimization suggestions, new grading rings were manufactured to replace the old ones. UVI observations showed that the new grading rings could effectively prevent the occurrence of corona discharge. © 2014 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.