bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparison Study on Experimental and Computational Structural Analysis for Kevlar Composite by Polyester resin.
Authors: Nagaraj Goud B. , Aravind P. , Jawahar Lal B. , Sanskruti K. , Pavan Ch.
Published: October 2024

The finite element method was used to analyze Kevlar composite material under the most extreme conditions. The goal of the comparison study between experimental and computational studies of the tensile and flexural behavior of Kevlar woven fabric laminated composite was tested experientially under UTM. As a result, this work aims to approach the modelling of Kevlar composite material by focusing on material properties and failure criteria. The computational results agree well with the experimental results from the literature. The research is conducted utilizing the ANSYS (ACP) program and the finite element technique (FET). ANSYS (ACP) Software was used to model the fiber geometry and generate meshes and approaches to incorporate damage initiation and evolution. The experimental results of woven Kevlar fiber combined with polyester resin were obtained for six layers of the laminate by ASTM Standards, as well as mechanical properties of the woven Kevlar fiber. The CATIA V5 software is used to create the composites design model, and the modal responses are obtained via a simulation model that takes into account the individual layer effects of each Sample test specimen via the ANSYS static-structural module.
Dynamic mechanical analysis, flammability and quasi-static test on Kevlar/basalt-epoxy hybrid composite laminates
Authors: Parekh Ruval P , Rakesh Ballina , Uttrani Chakrala , Eekshit  , Haginilaathan Subramaniam , Jensin Joshua J , Ganesh M , Seralathan S
Published: October 2024

The composites made of Kevlar and basalt are studied individually. The experimental investigations aims to study the hybrid composites made from both materials. The present study examines the thermal as well as mechanical properties of the composites by conducting tests such as dynamic mechanical analysis (DMA), flammability (UL-94) and quasi-static tests on Kevlar, basalt, and Kevlar/basalt hybrid composites. The composite laminates are fabricated by hand-layup method and the results are compared to evaluate the thermal and mechanical properties. DMA test showed that Kevlar has a higher storage modulus, while basalt has a higher loss modulus. Quasi-static test showed basalt has the higher energy absorption capacity followed by the hybrid Kevlar/basalt composite. The hybrid Kevlar/basalt composite showed these values at par with pure Kevlar laminate. The flammability UL-94 test demonstrated that hybrid composite exhibited better flame retardancy properties. Based on the results, it is found that Kevlar/basalt hybrid composite is a better material for the applications of balanced mechanical properties with flame retardancy when compared to Kevlar or basalt individually.
Experimental Studies on properties of Blended High Strength Concrete with the impact of SCMs
Authors: Kumar Gongalla Nitish , Satyanarayana G V V , Vivek Kumar C
Published: October 2024

A major increase in the number of construction activities is taking place daily, with a particular emphasis being placed on the construction of high-rise structures. High-strength concrete (HSC) provides a variety of advantages over standard concrete in the construction sector. These advantages include the fact that it is more durable and has a longer lifetime than conventional concrete. Certain cementitious materials, such as mineral admixtures, are used in the production of high-strength concrete (HSC) to partially replace ordinary Portland cement (OPC). This experimental investigation focused on the features of M70-grade HSC, which is produced by using Silica Fume (SF), Metakaolin (MK), and Alccofine 1203 (ALC) as the principal components in the manufacturing process. While MK and SF are used at replacement levels ranging from 5% to 15%, ALC is utilized at a weight ratio of 5% to OPC. Tests were conducted on the properties of the concrete after it had hardened intending to examine its strength and durability. Based on the findings of the tests, it was determined that the combination of 5% Alccofine, 10% MK, and SF dose, in addition to the OPC.
Flexural and Shear Strength Analysis of Kevlar/Carbon-Epoxy Composites using Finite Element Modelling
Authors: Mohammed Mohaideen M , Sriya Bandi , Anusha Kolakani , Nagaraju Veeraboina
Published: October 2024

The current study aims to investigate the mechanical behavior of Kevlar/carbon-epoxy composites, specifically their response to various mechanical stresses. These materials are intended for use as aircraft wing skins, making it crucial to understand their performance under different conditions. Several tests were conducted, including Inter delamination, Double Shear and Flexural, to assess the material’s ability to withstand these stresses. The hybrid composites have been set volume fraction ratio as 0.5. The obtained results were analyzed using NASTRAN analysis software. It was found that Kevlar/carbon composites exhibit high shear strength under ambient conditions, but the presence of notches significantly affects this property. Additionally, the flexural strength and resistance to compression failure were observed to vary accordingly.
Optimization of Impact Strength in GFRP Composites Reinforced with MWCNT Using RSM and Mother Optimization Algorithm
Authors: Rajeswari Ch. , Punna Eshwaraiah
Published: October 2024

Present study delves into the optimization of fabrication parameters for glass fibre reinforced polymer (GFRP) composites augmented with multi-walled carbon nanotubes (MWCNTs) using the hand layup method. The primary objective is to enhance the impact strength of the composite material, which is crucial for its performance in demanding structural applications. To achieve this, the response surface methodology (RSM) is employed as a statistical tool to design the experiments and to understand the interactions between the various fabrication parameters on responses by analysis of variance. The optimization process is further refined through the application of the Mother Optimization Algorithm (MOA), a novel approach that systematically searches for the optimal combination of parameters to achieve the desired material properties. This research provides insights into the effects of MWCNT incorporation on GFRP composites and proposes a methodical approach to optimize the fabrication process. The outcomes of this investigation are expected to contribute significantly to the field of composite materials, offering a robust framework for developing high-performance MWCNT with GFRP composites with improved impact resistance for industrial applications.
Performance evaluation of composite plastic modified pavement blocks with Geogrid Reinforcement
Authors: Asha R.M. , Sivaramakrishnan S. , Rajesh J. , Kolappan K. , Ponshanmugakumar A.
Published: October 2024

According to estimates made on March 31, 2018, India’s roads will be 6,603,293 kilometres long, which is 4,103,096 miles. The Indian road network is now the second biggest in the world, after the US road network. The roads in question, on the other hand, don’t have the desired effects because their CBR number is too low. In India, most of the roads are in bad shape. The most common problems are potholes, ruts, cracks, and areas of sinking and settlement, which happen more often during the rainy season. First and foremost, these are the effects of the subgrade being in an area that is heavily waterlogged, which means that the subgrade is not strong enough to support it. That being said, the CBR value of the subgrade dirt is usually between 2 and 5 percent. In the CBR method of pavement design (IRC:37-2012), as the CBR value of the subgrade soil goes down, the total thickness of the pavement goes up by a factor of ten. This is what takes place when the subgrade soil’s CBR value goes down. In turn, this means that the total cost of the construction job goes up. Since this is the case, many different efforts have been made to use the geo-grid material to improve the subgrade’s ability to hold weight. The soil samples are looked at before they are used for CBR testing in the lab and in a simulated area. You can run these tests with or without the geo-grid layer, and you can also change where the geo-grid layer is placed inside the block. When geo-grid is used, the CBR value of the subgrade goes up. This makes the sidewalk thinner by up to forty percent. The prices will go down because the study’s results will lower the general cost of the project and the cost of keeping the road in good shape. This will help bring down the project’s total cost. For our assignment, we are going to talk in great detail about the method and how it can be used successfully.
Gate Dielectric Engineering on 2D FETs for Continued Scaling
Authors: Kumar Aruru Sai , Bharath Srinivasulu V. , Nishnath Rao K , Keerthi Kondeti , Kethapelly Shivani , Abhinav Ragidimilli Sai
Published: October 2024

In the last few years, a significant interest has been shown in 2D field effect transistors (2D FETs) as an appropriate candidate for advanced electronics devices. This study presents a comprehensive performance analysis of 2D FETs with channels consisting of MOS2, MOSe2 and MoTe2 using various dielectric materials, focusing on their application in low-power electronic devices. Materials such as molybdenum disulfide (MOS2), molybdenum Di selenide (MoSe2), molybdenum ditelluride (MoTe2) belong to the transition metal dichalcogenide (TMD) family, which are known for their fascinating electronic properties. This study addresses the performance evaluation of 2D field effect transistors (FETs) while emphasizing low power consumption. The research examines three critical design parameters - channel lengths, channel materials and dielectrics and examines their influence on FET performance. The miniaturization of transistor technology, critical to compact and power-efficient devices, is analyzed, highlighting the effects of shorter channels on static power, subthreshold swing, and on-off current ratio. In addition, the study examines the role of channel materials and contrasts traditional silicon with new two-dimensional materials such as graphene. Insights are provided into optimizing nanosheet FETs for power-efficient electronic applications and mastering the delicate balance between advantages and limitations in design decisions.
Development and characterization of carbon fiber reinforcement in Aluminium metal matrix composites
Authors: Menachery Nice , Thomas Lijo P. , Thomas Shijo , Deepanraj B.
Published: October 2024

Carbon fibers (CF) possess exceptional mechanical properties and the highest degree of chemical stability. However, carbon reinforcement in metal matrix composites is extremely scarce due to production difficulties, particularly in obtaining a uniform distribution. Carbon fiber reinforced composites are typically made using high temperature processing processes. However, the fibers must be coated with Ni or Cu in order to achieve effective particle dispersion; otherwise, there is a larger likelihood of intermetallic compound formation, which reduces the chances for enhanced properties. In this work, the metallurgical, mechanical, and tribological characteristics of the carbon fiber reinforcement in AA 7050 are examined. Uncoated carbon fibers are reinforced into the Aluminium matrix using a low temperature processing technique known as powder metallurgy. The AA 7050 matrix reinforced with carbon fibers at various weight percentages between 0 and 1.5. The samples undergone mechanical and metallurgical testing in accordance with ASTM guidelines. The findings indicate that the 0.25 weight percent carbon fiber reinforcement in the matrix increased the material’s hardness by 30% over the monolithic alloy, making it an excellent alternative for structural applications.
Nanofluids: Bridging nanotechnology and fluid dynamics for enhanced thermal performance
Authors: Reddy G. S. , Sumalatha V.
Published: October 2024

The manuscript explores the latest developments in nanofluids, investigating their synthesis, characterization, and diverse applications across various fields. Nanofluids, colloidal suspensions of nanometre-sized particles in a base fluid, exhibit enhanced thermal and physical properties. This article reviews multiple synthesis methods, such as mechanical milling and chemical reduction, emphasizing the importance of stability and dispersion. Characterization techniques, including dynamic light scattering and thermal conductivity measurement, provide insights into key properties. Applications span mechanical engineering, aerospace, nuclear energy, and healthcare, showcasing nanofluids’ versatility. The comprehensive understanding presented here lays the groundwork for leveraging nanofluids in optimizing heat transfer and efficiency in various industries.
Comparisons of reported and predicted tensile properties of natural fiber reinforced HDPE composites
Authors: Gupta Hariome Sharan , Palsule Sanjay
Published: October 2024

Natural fiber offers eco-friendly nature, biodegradability, renewability, easy availability, and low cost; compared with synthetic fibers. Natural fibers reinforced polymer composites provide several applications because their good physical, mechanical and thermal properties and the composites also support agro-based economy. Natural fibers reinforced High-Density Polyethylene (HDPE) composites provide good tensile properties and many applications. This study predicts tensile properties of a few natural fibers / HDPE composites by various equations and compares them with their reported tensile properties.
Analysis and Fabrication of Aluminium Composite with SiC and Graphite Using Stir Casting Method (MMC).
Authors: Sura Sreekanth , Nagaraj Goud B , Gowtham Reddy A. , Veeraprathap E. , Jaikanth T. , Yashwanth U.
Published: October 2024

Composites, as we all know, are used to reduce weight while boosting strength, stiffness, and other material properties as required by the application. Material science and engineering have sparked a lot of curiosity in the contemporary era. There has been a huge impact since the invention of composite materials. As a result of its high strength and durability. Low weight is the winning combination that propels composite materials towards the future. new frontiers Composites are commonly used to substitute natural materials like wood. Steel, iron, and other metals are distinguished by their surface properties. Metal Matrix was discovered in the literatures. Traditional materials are being phased out of the aerospace and automotive industries, while composites are being seriously studied. Because of their mechanical properties, Aluminum alloy MMCs are becoming increasingly used in a wide range of industrial applications. Using the stir casting method, the main theme of this project is to produce and fabricate composite materials based on aluminium alloy (A1-2024) reinforced with 15% volume fraction of silicon carbide Particulates (SiC) and 5% volume fraction of graphite particulates, taking into account the aforementioned factors and the following. As a result, the major purpose is to show that traditional metals may be used instead of composites in aircraft and vehicle applications. As a result, the project involves Metal Matrix Composite MMC testing and analysis, in which the produced composite is put to the test to assess its strength, hardness, and other physical attributes. Additionally, cracking and composite behaviour were investigated using Ansys Software. Finally, the final findings are compared to traditional material quality, demonstrating that composites are the best alternative.
Geometric synthesis in the profile of the involute tooth for improving the performance of bending in the material of the spur gear
Authors: Joshi Amol Vikas , Jaju Santosh
Published: October 2024

Transferring power from one rotational axis to another in numbers of axes requires portable equipment such as gear. In operation, involuted teeth were reported as bending and pitting failures. Bending fatigue causes gear tooth cracks at the root, and pitting causes more wear. This bending failure was reduced with the help of material selection, geometric modifications like changes in profile shape, transmission error, module, tip relief, pressure angles, and the application of forces. A normal force acting on a gear tooth gets resolved into three components, like tangential, radial, and axial. When it comes to enhancing bending strength, the geometric forms of profiles have a significant impact. A variety of tools and techniques, including hobbing, shaping, grinding, etc., are available at the fingertips for altering gearing tooth. Changing the borders of gear tooth profiles with hobbing tools is becoming more popular among the authors as a means for altering gear tooth. There are four distinct geometric profiles that may be used to change gear geometries and enhance bending strength by reducing stress on the tooth. These profiles include trochoidal, circular, bezier, and cubic spines, and they are implemented using a hob cutter. It is noteworthy to note that these designs boost strength by integrating the shape of number of teeth on the spur gear. This study compares the number of teeth on the gear’s pinion with other geometric characteristics, including pressure angle, module, etc., in order to discover the optimal way for modifying the involute tooth of the gear in order to increase the bending resistance effectively of the spur gear. For the purpose of boosting the strength of gear material, a number of research endeavours have utilized circular profiles; nonetheless, this profile is older than the Bezier curve profile. Here, Bezier curves with a three-and five-point profile give better results than other profiles with significant reductions in bending stress for the same quantity of tooth on the gear.
A Comparative Analysis of Single and Multi-objective Process Parameter Optimization of Dissimilar Metal Friction Welds
Authors: Pratyusha M , Venkata Ramana P , Prasanthi G
Published: October 2024

In the present work welding of pure aluminium and pure copper is carried out employing friction welding process. The selected process parameters in the investigation are spindle speed, friction force, upset force and burn off. The evaluated responses are tensile strength and total shrinkage. Single and multi-objective optimization is carried out to understand the significance of process parameters. Design of experiments and ANOVA analysis is carried out in single objective optimization and Taguchi based Grey relational analysis is carried out for multi objective optimization. Regression equations are generated in either cases to interpret the relation between selected process parameters and responses. Comparison of optimized process parameters of tensile strength and total shrinkage for single objective optimization and multi objective optimization is carried out and presented to showcase the process parameter importance in obtaining the required response.
Design of Bio inspired wing using additive manufacturing
Authors: Sukumar D , Gupta Rahul , Thakur Vishali , Prasad G
Published: October 2024

Humpback whales have a morphological feature on the front edge of their flippers that allows them to be extremely manoeuvrable. Tubercle design, which is inspired by nature, has been used in wing-like structures such as wind turbines and marine propellers. The research attempts to create a bio-inspired alteration to the existing wing that will lower the aeroplane’s drag. The experiment is carried out at different Angle of attack ranging from α = 0° to α = 20°. The goal of the research is to reduce friction drag, which results in a significant reduction in fuel expenditures and environmental effects. The initial technique involved designing a suitable context enclosure and 3D printing normal and bio wings, which depicted the experimental results of a standard wing. The experiment for a conventional NACA 23012 aeroplane wing was carried out using the subsonic wind tunnel with Velocity 70 m/s. Thus, comparing the computational results to the experimental data revealed bio-inspired wing forms that are more efficient than ordinary wings and can be used in the future aviation sector.
The creation and assessment of an electrical all-terrain vehicle and its effects on efficiency
Authors: Vasamsetti Subrahmanyam , Kunda Aruna , Roy Manoj Kumar , Raghavendrarao M.V. , Phani Babu Vemuri Venkata
Published: October 2024

The suspension system consists of tires, tire air, springs, shock absorbers, and connections that facilitate the relative movement among the axles and the automobile. Although ride quality and road holding/handling are mutually exclusive, suspension components nevertheless need to provide both. Adjusting suspensions requires striking the ideal balance. Maintaining maximum contact between the road wheel and the road surface is crucial for the suspension. The vehicle’s suspension greatly affects its handling; since the vehicle must operate on all types of terrain and retain ideal steering geometry, an adaptable system of suspension should be employed. The EATV’s suspension elements will be designed in Solid works, and the resulting model will be examined utilizing Ansys software for optimizing design variables while taking into account how they may affect the efficiency of other automobile parts through simulator testing.
A high precision comparator design for 12-bit SAR ADC
Authors: Fu Yikun , Li Haisong , Jiang Yihu
Published: October 2024

A comparator circuit applied to a 12-bit successive approximation analog-to-digital converter (SAR ADC) is proposed in this paper. The circuit is designed based on 0.18 μm CMOS technology, consisting of an open-loop comparator, a regenerative comparator, and buffer circuits. The open-loop comparator adopts a differential input structure and incorporates cross-coupled pairs to enhance gain, introducing reset and clamping techniques to improve speed. The regenerative comparator employs a positive feedback structure to enhance response speed. Additionally, a novel biasing circuit using external components for fine-tuning is designed to address performance degradation caused by process variations in bias current, thereby improving the stability of the comparator circuit, which can serve as an analog IP core for SAR ADC design. Simulation verification is conducted by using a Cadence Spectre simulator with a working voltage of 3.3 V and a sampling frequency of 3.2 MHz. Simulation results indicate that the comparator achieves a resolution of 0.4 mV, with an accuracy of 12 bits and a dynamic power consumption of 1.8 mW. The proposed circuit has been successfully applied in 12-bit SAR ADC.
Optimization of AC contactor closing phase angle based on entropy weight method and efficacy coefficient method
Authors: Zhang Junhui , Liu Shuxin , Liu Yang , Xing Chaojian , Xu Jing
Published: October 2024

Aiming at the problem that the optimal closing phase angle cannot be determined in the optimal closing control of AC contactor, this paper combines the finite element model of AC contactor with experimental data to determine the optimal range through the influence of different closing phase angles on the core closing speed, closing time and bounce time indexes, and then uses the entropy weight method to determine the weight of each index. The comprehensive evaluation function is constructed with the method of power function, and the optimal closing phase angle is obtained. Finally, the experiment shows that selecting the best closing phase angle can greatly reduce the closing impact energy and the number and time of contact bounce, and the closing performance can be greatly optimized.
Three-level control for open winding permanent magnet synchronous motors
Authors: Liu Yu , Li Wei , Jia Yunlong , Luo Mingyang , Zhang Shuai
Published: October 2024

Based on the structure and characteristics of open winding motors, this article uses voltage space vector pulse width modulation (SVPWM) technology to study the driving system of open winding motors from aspects of principle analysis, mathematical modeling, fault-tolerant control (FTC), and simulation.
Analysis and prediction of vibration characteristics of electromagnetic relays
Authors: Guo Guoqing , Zhao Xinghai , Li Qingshi , Ke Zhanghongda , Yao Wang
Published: October 2024

During the operation of rolling stock, wheel-rail vibrations, coupled with the excitation of the bogie’s nodding motion, will induce vertical vibrations in the vehicle body as well as its equipment. Electromagnetic relays are critical onboard signaling devices that require robust vibration resistance. In this regard, this research employs a specific model of relays to construct a dynamic model of the relay system, thus analyzing diverse primary factors influencing the vibration characteristics of the system based on the theory of vibration mechanics. Subsequently, this research conducts the modal simulation analysis of the relay system based on Hertz’s contact theory to validate the theoretical model. The results reveal that the vibration characteristics of the relay system are associated with local contact stiffness. Specifically, increasing the contact stiffness or pressure between the armature and the limit frame improves the vertical natural vibration frequency of the system. Hence, the vibration resistance of the relay system can be predicted through the control of the pressure between the armature and the limit frame, which is validated through simulation and experiments featuring random vibrations. In short, the proposed method is applicable for rapid prediction of vibration resistance during the production of vehicle relays, ensuring the consistency of product quality and fulfilling the requirements of various application scenarios of rolling stock.
An intermediate frequency variable gain amplifier with 1.5 dB gain flatness and optimized layout in the 45-nm SOI technique
Authors: Chuanyuan E , Li Xiaoran , Liu Zicheng
Published: October 2024

A high-performance intermediate frequency variable gain amplifier (IF-VGA) in a superheterodyne receiver is presented. This IF-AMP has a cascade structure of a two-stage cascode amplifier with inductance-capacitance (LC) load and a one-stage common-source amplifier. The circuit is implemented in GlobalFoundries 45-nm SOI technology. It has a maximum gain of 17.1 dB, a gain tuning range of 18.7 dB, a gain flatness of 1.5 dB across a 3-4 GHz frequency range, and a 7.1 dB stopband rejection for the out-of-band 700 MHz frequency component. An optimized layout of digitally controlled resistor and capacitor arrays is proposed to minimize parasitic capacitance.
Research on self-calibration model of weighing sensors based on fusing ELM and GWO
Authors: Yin Yuwei , He Chuchao , Zhao Xiangmo
Published: October 2024

Piezoresistive weighing sensors have shown great potential in industrial production. The accuracy and stability of weighing sensors may be affected by factors such as temperature changes, creep effects caused by long-term loading, nonlinearity, and hysteresis during use. Therefore, compensation calibration is necessary to ensure the accuracy and reliability of measurement results. This article combines the optimized GWO algorithm with the ELM algorithm to obtain the best calibration results. After compensation, the sensitivity coefficient of the weighing sensor decreased from around 1.2% F.S to around 0.06% F.S.
Study of permanent magnet synchronous motor control based on sliding mode observer
Authors: Jiang Mengxing , Li Linsheng
Published: October 2024

Permanent magnet synchronous motors have been widely used in modern life production. In order to realize the high precision control of permanent magnet synchronous motor, the traditional control method is to use an encoder and so on to obtain real-time speed and rotor position, but this method is difficult to maintain in the later stage. This article uses a sliding film observer instead of an encoder to obtain speed and rotor position. This paper adopts the saturation function instead of the traditional switching function, so as to reduce the vibration phenomenon of the traditional sliding mode observer, and at the same time, adopts the phase-locked loop instead of the traditional inverse tangent function and phase compensation. The simulation experimental results show that the improved sliding mode observer can suppress the vibration problem.
A Design of high-low voltage compatible fully differential operational amplifier
Authors: Zhou Fanchao , Zhou Cheng , Li Yanling
Published: October 2024

This paper presents a high-low voltage compatible wide-range fully differential operational amplifier designed using the DB HiTek 0.18 μm BCD process. The operational amplifier accurately tracks differential voltage changes within the input voltage range of 3~48 V. By employing common-mode voltage feedback, the amplifier achieves high-precision tracking of the differential voltage with a tracking voltage error accuracy of less than 1%. The designed fully differential operational amplifier finds applications in bidirectional Buck-boost converters, where it can be utilized for monitoring and controlling input/output current magnitude, preventing input power overload, and stabilizing dual-terminal voltages.
Design of an electronic device for detection of exhaled gas concentration
Authors: Fan Chuanxiu , Liu Xue , Yu Zhichao , Du Changsong , Jia Shengde , Liu Qing , Yan Pengbo
Published: October 2024

To enable preliminary diagnosis of various diseases in the human body, detecting the concentrations of targeted components in exhaled gases is an effective way without invasive diagnosis. An exhaled gas concentration detection device is proposed in this paper. Firstly, this device employs a high-accuracy analog front end (AFE) for transmitting the concentrations of targeted components to an electronic voltage signal. The core circuit of AFE is a high-precision and low-current constant current source. Secondly, a heating circuit with controllable temperature is also designed to provide an appropriate operating temperature for different types of gas sensor materials. Thirdly, the system applies a microcontroller to directly read multiple-channel gas concentrations and independently control multiple heating circuits. The performance of the device has been validated through simulations.
Research on power regulation of virtual synchronous generators in microgrid
Authors: Hu Liang , Zhan Weiqiang , Yao Xiaoshan , Xiong Zhihao , Yang Mingbo
Published: October 2024

This article proposes a virtual synchronous generator (VSG) control strategy with power regulation for island microgrids. A model is built in Matlab/Simulink, and the influence of key parameters on the inertia and damping of the VSG is analyzed through simulation experiments. It has been verified that virtual synchronous generators can adjust the power output in real time, thereby regulating the output of clean energy, reducing the fuel consumption of diesel generators, and achieving maximum economic benefits.
Limit calculation of LED luminous efficiency
Authors: Zhou Shuwei , Liu Baolin
Published: October 2024

LED is widely used due to its many advantages. As the fourth generation lighting source, it has always been limited by its luminous efficiency. How to improve the luminous efficiency of LED is one of the current research hotspots. The paper aims to conduct a limited analysis of the luminous efficiency of LED and provide theoretical support for LED luminescence research. Firstly, theoretical analysis and derivation were conducted on the luminous efficiency of LED, and it was found that the main factor determining its luminous efficiency is the light extraction efficiency of LED. Then, the optical path of internal photons during LED emission was analyzed, and the calculation formula for the limit value of traditional rectangular LED luminous efficiency was derived. Based on the formula, it was found that GaN LED has the highest luminous efficiency limit among the most common LEDs, but it is only 27.3%. Finally, two methods to break through the limit of LED luminous efficiency were proposed in theory, and simulation verification was carried out using TracePro software. By selecting a semiconductor material with a refractive index of 2.2 to make the luminous layer of LED, the luminous efficiency limit of LED can be increased to 30%. The improvement of the LED luminous efficiency limit can also be achieved by changing the light path of photons in the LED. In this paper, two different LED shapes from traditional rectangular shapes were simulated, and their luminous efficiency limit values were greatly improved, reaching a maximum of 40.7%. The limit calculation theory in the paper can provide theoretical support for most current research on LED luminous efficiency.
A transformer winding mechanical fault diagnosis method based on ST-SVD and DBO-SVM models
Authors: Han Jing , Zhu Yichao , Zhang Ruizhi , Li Zichao , Cai Xiaopeng
Published: October 2024

To explore the large amount of state information contained in transformer vibration signals, a transformer winding looseness fault diagnosis method based on S-transform singular value decomposition (ST-SVD) and dung beetle optimized support vector machine (DBO-SVM) model is proposed. Firstly, based on the transformer fault simulation experimental platform, vibration signals of transformer windings under different states are collected. Secondly, the vibration signal of the transformer is S-transformed to obtain its time-frequency matrix. Then, the amplitude matrix corresponding to the time-frequency matrix is calculated for SVD, and the eigenvectors are defined. Finally, the Dung Beetle Optimization Algorithm is used to optimize the SVM model parameters and input feature vectors to complete fault diagnosis. The experimental results show that the proposed method has a higher accuracy in fault identification than traditional method models and is suitable for diagnosing mechanical faults in transformer windings.
A study of the effects of arc damage from aviation faults
Authors: Liao Maoqiao , Zhang Tiechun , Si Xiaoliang
Published: October 2024

In this paper, according to the terminal vibration test method in SAE-AS5692, a ground fault arc test platform was designed to simulate aircraft vibration-induced ground fault arcs in wiring harnesses and fuel lines, and tandem ground fault arc damage tests were carried out under different conditions and parameters, to study the effects of different power supply types and vibration frequencies on arc damage. The results show that: 1) compared with the arc generated by DC 28 V and AC 115 V, the arc generated by DC 28 V is more damaging to the fuel pipeline, and the pipeline vaporization is more serious; 2) as the vibration frequency is increased from 15 Hz to 60 Hz, the duration of the arc is prolonged, and the arc energy is increased, resulting in a positive correlation between the arc damage and the vibration frequency.
Virtual impedance control of double-fed induction generator for damping enhancement in hvdc collection system
Authors: Tian Sijia , Wang Kun , Tian Yanjun
Published: October 2024

Wind power has become the focus of new energy generation by its abundant resources and clean and environmentally friendly features. However, as the proportion of wind power connected to the grid rises, there is a risk of causing sub-synchronous oscillation. For the problem of sub-synchronous oscillation, an additional damping control strategy taking into account the rotor side converter of the wind turbine was proposed. This paper establishes the wind power grid connection model, including wind turbine, MMC, and transmission line, and analyzes the generation mechanism of sub-synchronous oscillation using the impedance modeling method. The simulation test was carried out by MATLAB/Simulink. The results show that the control strategy can suppress the oscillation faster, improve the power quality better, and verify the correctness of the method.
A pulse-width-modulation-based approach to eliminate inrush currents of switch-mode power supply
Authors: Xue Bingxin , Zhang Jian , Zhang Pin , Liu Yawen , He Zhejia , Liao Congwei , Qiu Leilei , Huang Shengxiang , Deng Lianwen
Published: October 2024

A PWM method was suggested to eliminate inrush currents in SMPS circuits by digitally controlling the voltage rise rate of the input capacitor. Once the capacitor voltage is fully charged, a bypass switch maintains high conversion efficiency. This PWM-SMPS, tested considering PVT variations, reduces inrush currents by 6× compared to conventional methods with passive components, thus enhancing environmental suitability for SMPS applications.
Bi-level optimization scheduling of electric vehicle-distribution network considering demand response and carbon quota
Authors: Chai Xiaoliang , Zhang Yuanbo , Du Dongyang , Sun Yue
Published: October 2024

To mitigate the adverse effects of uncoordinated charging of electric vehicles (EVs) on the distribution network (DN) stability, this paper proposes a bi-level cooperative optimization scheduling method for EVs and DNs, considering demand response (DR) and carbon quotas. Firstly, EVs are considered flexible resources, and real-time electricity prices are used to guide electric vehicle users to respond to demand, reducing net load fluctuations of DN. Secondly, a carbon quota incentive mechanism based on carbon pricing is introduced, and a dual incentive mechanism of DR and carbon quota is explored to reduce the peak valley load difference further. Then, aiming to minimize the operating cost of the upper-layer EVs and the network loss of the lower-layer DN, a dual-layer cooperative optimization scheduling model for EVs and DNs is constructed, and an improved Particle Swarm Optimization (PSO)-Simulated Annealing (SA) algorithm is used to solve the dual-layer coordination optimization problem. Finally, through case study analysis, the model proposed in this paper demonstrates a 6.32% increase in renewable energy utilization, a 23.75% reduction in carbon emissions, and a significantly reduced network loss.
Simulation study of a novel tensor CSAMT field source based on COMSOL
Authors: Yue Chenyun , Zhang Yiming , Wang Xuhong , Wang Jiaqi
Published: October 2024

At present, the controlled-source audio-frequency magnetotellurics (CSAMT) adopts the traditional tensor measurement with the problems of fragmented detection area and weak signal strength in the far area. In order to realize the 360° omnidirectional tensor measurement of CSAMT, enhance the signal-to-noise ratio of the detection in the far area, and improve the usability of CSAMT under the interference of stronger electromagnetic signals, this paper puts forward a square artifactual source, which is firstly analyzed by the vector synthesis method to realize 360° omnidirectional tensor measurement and simulation verification is carried out. Then, the finite element software COMSOL Multiphysics 6.1 is used to establish the 3D CSAMT model of the square artificial field source and the 3D CSAMT model of the traditional cross-shaped artificial field source, respectively. Through the simulation results of the two types of sources, the signal strengths of the two sources in the far-field region are compared and analyzed, and it is found that the signal strengths of the square field source are improved by about 3.6 times compared with that of the cross-shaped field source in the same position.
Characteristic analysis of space charge in crosslinked polyethylene slices under DC superimposed square wave electric field
Authors: Cheng Lin , Luo Jianyong , Chen Zongrang , Zhang Zhe , Yang Fuyuan
Published: October 2024

Space charge retention occurs in DC transmission systems during Crosslinked polyethylene (XLPE) cable operation, which causes electric field distortion and insulation failure. For promoting the operation performance of XLPE cable, this paper builds the space charge test system, tests the steady-state space charge distribution of XPLE material at high and low levels in a single period of DC superimposed square wave electric field, and explores the dynamic behavior changes of space charge at the edge time after changing the pressurization time. The reason and macroscopic behavior of the variation of space charge in materials are analyzed from the mechanical point of view. The experimental results show that when the electric field intensity reaches a certain value, the polar space charge will accumulate at the junction of the two poles and the dielectric. The variation of heteropolar space charge is contrary to the absolute value of applied voltage amplitude before and after the edge time. When the edge time increases, the variation of the peak value of space charge at the interface decreases, and the short edge time is more likely to cause microstructure damage. This paper provides direction for explaining the mechanism of electrical branch initiation of XLPE materials.
Cellular mobile station positioning algorithm based on IRS
Authors: Yan Yuqi , Deng Ping
Published: October 2024

Aiming at the problem of positioning performance degradation in complex ground environments due to the Non-Line-of-Sight (NLoS) propagation of cellular uplink signals, in this paper, a cellular mobile station (MS) positioning algorithm based on Intelligent Reflecting Surfaces (IRS) is proposed. First of all, the angle domain method is used to obtain the Angle of Arrival (AoA) information between the MS and each IRS, taking advantage of the emerging IRS technology. Then, based on the position information of each IRS and the AoA measurements, the position of MS can be estimated. In a heavy NLoS environment, when the number of IRS exceeds four, the estimated position mentioned above can be used as the initial position to make position refinement. Based on the known IRS position, base station position, and Time of Arrival measurements from MS to the base station through different paths of IRS, the distances from the MS to each IRS can be estimated. Each IRS can be considered as a Virtual Base Station (VBS) to make this position refinement, and a Time Difference of Arrival (TDoA) positioning algorithm based on iterative Least Squares Estimation (LSE) is proposed to refine the position of the MS. Simulation results show that utilizing the TDoA positioning algorithm proposed in this paper in a heavy NLoS environment, the average positioning error could be reduced to about 0.24 meters compared with only using the AoA positioning algorithm.
Research on synchronized multi-channel data acquisition technology for micro-vibration testing equipment
Authors: Zhang Jiangcheng , Li Hao , Zhang Zhaolin , Ge Lili
Published: October 2024

In response to the requirements of a satellite micro-vibration testing method, a multi-channel synchronous data acquisition system was designed based on FPGA. The system adopts a modular design philosophy, allowing flexible configuration of the number of acquisition channels by modifying program parameters and reconstructing hardware resources. Signal sampling is performed using high-precision Σ-Δ type ADCs with synchronization capabilities. The synchronization signals for each ADC and the clock signal for filters are uniformly generated by the FPGA, achieving mutual synchronization of multiple sampling channels. LVDS is chosen as the data interface to meet the bandwidth requirements. The host computer communicates with the hardware through the RS232 interface, sending control commands and retrieving LVDS-transmitted data through USB via an interface conversion circuit. The acquired data is displayed in real-time on the user interface in a graphical format. Test results indicate that the system successfully achieves the synchronous acquisition of analog voltage signals across multiple channels, making it suitable for the development of space payload equipment and ground testing devices.
Control strategy of distributed flexible distribution network based on hierarchical optimal control
Authors: Song Zihong , Zheng Youzhuo , Yang Yekui , Wang Xuexue , Guo Dao
Published: October 2024

In traditional hierarchical control strategies, droop control is employed to simulate the behavior of power system generators, modifying the distributed generation (DG) output in relation to frequency and voltage adjustments. However, this control strategy has a single control mode, with all DG operating at the same voltage level, which cannot achieve the economic mode of prioritizing renewable energy supply. Moreover, the adoption of traditional droop control leads to poor current sharing and is not conducive to system stability. This invention introduces a hierarchical optimization control strategy, building upon the traditional hierarchical control strategy. Its characteristics lie in two aspects. Firstly, the hierarchical control strategy is combined with the DC bus signaling (DBS) control strategy, using the bus voltage to reflect the operating state and switch working modes, thereby achieving the optimization control goal of prioritizing renewable energy generation. Secondly, by compensating for the bus voltage and reducing bus voltage fluctuations, the system circulating current is suppressed, and operational stability is enhanced through a PI controller that uses the deviation between the output voltage of the converter and the desired bus voltage. Finally, the effectiveness of the proposed strategy is validated through simulation by using the Matlab/Simulink platform.
The collection method of status information in TSN based on monitoring packet
Authors: Li Lei , Zhang Yong , He Guangcheng , An Gaoxiang , Qiu Shuang , Feng Hao
Published: October 2024

Time-sensitive network requires monitoring the network’s operational status in real-time and dynamically changing the network’s traffic scheduling configuration. A method that can timely obtain network operation information is needed. In this paper, a method for proxy hosts to send monitoring packets is proposed, which enables visits and the collection of status information for all switches through a single monitoring packet. Then, it returns the monitoring packet to the CNC controller for processing. To verify this method, the collection of TSN status information in a ring topology is simulated, mainly to obtain the delay of each hop node. The simulation results show that the BE flow is blocking some switches and requires adjustment and load balancing, while the delay of TT flow is relatively stable on all switches. The end-to-end latency difference between BE and TT flows is nearly 20 times. The experiment shows that under the TSN scheduling mechanism, a deterministic delay of TT flow has been achieved.
A 4.52 ppm/°C TC, 28.4 μW bandgap reference with 1.8-3.3 V supply-range
Authors: Zhao Tianting , Sun Ming , Su Haoze , Rao Guangxuan , Yu Wenxin , Hu Yi , Li Mengjiao , Wang Tao , Li Jiping
Published: October 2024

The Bandgap reference (BGR), usually referred to as a voltage source with high stability, is an indispensable basic circuit module in digital analog systems such as sensors, serdes, linear voltage regulators (LDO), and switching regulators. This paper put forward a BGR, which is based on the Brokaw structure, with a low-temperature coefficient and high precision. The BGR has the characteristics of fewer components, wide applicability, and an excellent index. At the process corner, in the range of -40-125°C, the temperature coefficient can reach 4.52 ppm/°C, while in the Monte Carlo simulation, the 3σ accuracy is 0.6%. The circuit can work under a wide input voltage of 1.8-3.3 V, which greatly reduces the influence of resistance, bipolar transistor, and op-amp input offset voltage on BGR output.