To address the issue of low transmission efficiency in dual active bridge (DAB) converters during electric vehicle charging and discharging processes, a minimum current stress optimization control strategy combining the differential extremum method with segmented control is proposed. This strategy effectively optimizes current stress and suppresses backflow power under soft-switching constraints, thereby significantly improving transmission efficiency. Firstly, taking forward power transmission as an example, the conditions for achieving zero voltage soft-switching for all switches in two operation modes under extended phase shift (EPS) control are derived, and the mechanism of backflow power generation is analyzed, elucidating how reducing current stress contributes to its suppression. Subsequently, the optimization phase-shift combinations for minimum current stress are derived using the differential extremum method, and a segmented control scheme is implemented based on the soft-switching ranges of different modes. Finally, experimental results demonstrate that when the voltage conversion ratio is greater than 1, the proposed strategy achieves soft-switching for all switches across the full power range, while effectively reducing current stress and suppressing backflow power, leading to a significant improvement in transmission efficiency. However, when the voltage conversion ratio is less than 1, while current stress is still reduced, zero voltage switching cannot be achieved for all switches.
Ta-based refractory alloys offer excellent high-temperature strength, but high W content significantly reduces room-temperature tensile ductility. Here for Ta-14W alloy with fracture strain of ∼5%, we demonstrate that a minor Hf addition significantly improves its ductility to over 30%. Firstly, Hf induces an asymmetric core structure of screw dislocation and reduces generalized stacking fault energy (GSFE), thereby promoting dislocation mobility and dislocation multiplication during plastic deformation. Secondly, Hf can strengthen grain boundaries (GBs) by preferentially segregating near GBs. Thirdly, Hf binds with O atoms to form HfO2 particles at GBs, lowering the risk of oxygen embrittlement. All these mechanisms offer insightful guide for the development of advanced Ta-W-based refractory alloys.
Materials of engineering and construction. Mechanics of materials
With the advancement of flexible electronics and low-power circuit design, wearable sensing systems have emerged as a interdisciplinary research area within electronic and computer engineering. These kind of systems can support continual identification with non-disruptive, precise sensing of the physical signs of person with pliable, various type sensor arrays. Viewed from the perspective of the systems engineering approach, this paper classifies wearable device architectures into three mutually supportive electrical paths: the analog signal chain, the digital signal chain, and the energy self-sufficiency chain. At the signal chain level, it focuses on analog front-end design for flexible electrochemical, strain sensor, high-input-impedance Transimpedance Amplification design, differential anti-interference design, analog-to-digital conversion design to ensure that the signal-to-noise ratio and low-drift performance of the microampere-level signal are very high. In the digital chain the study is on the signal processing and information transmitting using an embedded MCU unit. Adaptive filtering, dynamic gain adjustment, and event-driven communication have achieved real-time, low-power data management: The energy chain combines biofuel cell (BFC) and power management unit (PMU), it's proposing the hybrid power chain, which would be combining NFC and the energy scheduling algorithm for autonomous power. Looking at it from the system level, it is hard to say that wearable electronics' core competitiveness comes from better analog, digital, but more likely the synergy between them: This provides a solution for field-effect transistors (FETs) and self-powered smart health trackers. It establishes a scalable implementation approach suitable for both low-power signal processing and energy-autonomous circuits.
Marianna Di Pietrantonio, Giacomo Russo, E. Guerra
et al.
State-of-the-art systems used to supply superconducting magnets in nuclear fusion devices introduce significant energy losses and impact the power quality of the external electrical grid. Additionally, current leads that transition from room to cryogenic temperatures represent a major source of heat load for the cryogenic system. While these are notable drawbacks in current experiments, they could become critical obstacles for the feasibility and costeffectiveness of future fusion reactors. Flux pumps are contactless, compact systems capable of inducing currents in superconductors with minimal operational losses. Several smallscale experiments have already demonstrated the feasibility of this concept, but no engineering designs or prototypes have yet been developed specifically for fusion magnets. As part of a research initiative focused on designing various types of flux pumps tailored to fusion applications, this paper outlines the general advantages of this approach, particularly in terms of energy consumption, but also in terms of compactness, modularity, and reliability. The numerical analysis presented focuses on the design of a flux pump intended to supply the DTT toroidal field coils. However, the developed model and insights are broadly applicable to a wide range of scenarios.
Aymen Abdelmoumen, Zakaria Benzadri, Ismael Bouassida Rodriguez
et al.
The increasing adoption of system-of-systems (SoS) engineering has emerged as a crucial approach for designing architectures that manage complex, decentralized systems across various domains, including IoT-enabled infrastructure. This paper introduces a metamodel that aligns with the ISO/IEC/IEEE 42010:2022 standard for architecture description, tailored to address the unique challenges of SoS. A formal classification technique leveraging first-order predicate logic ensures precise and consistent SoS categorization. The metamodel’s applicability is demonstrated through a case study on integrated water and energy management, involving real-world implementation. To evaluate its effectiveness, the Goal-Question-Metric (GQM) methodology is applied, detailing metrics for performance, relevance, usefulness and adaptability. A comparative analysis with existing models underscores the metamodel’s strengths in addressing SoS-specific requirements. By bridging theoretical rigor with practical usability, this work advances SoS modeling and offers a standards-based solution, with IoT-enabled examples illustrating its versatility and potential.
Purpose. Selection of adequate software and development of a modeling methodology for economical multi-domain simulation of the power distribution and conversion system, taking into account the control system for modern vehicles, in particular, for a hybrid electric vehicle with a fuel cell (HEV). Methodology. The main research method is mathematical modeling; for the structural synthesis of the model of the power conversion system and comparative analysis of programs, heuristic decision-making methods based on the comparison of variant metrics were used. Findings. A method of decomposition of HEV from the point of view of the scope of application of existing programs for modeling its subsystems is proposed. Subsystems from blocks of such a structural scheme are suitable for research using single-domain modeling programs. The prospects of the computer-aided design in electronics (ECAD) programs for multi-domain HEV modeling are shown, since the central and main conversion unit is the electronic domain. Based on the selected software metrics, the choice of programs for modeling the power conversion system is justified, with the possibility of organizing model interfaces to ensure multi-domain modeling and correct export-import of models when transitioning between abstraction levels. The sequential use of selected computer-aided engineering (CAE) and ECAD programs is proposed, with the transfer of information about the model and simulation results. This is capable of providing both optimal synthesis of the Automatic Control System based on the Phase Margin criterion with the study of the stability zone according to the Solution map, and in-depth analysis of the energy performance of the power stage of the converters. To test the method, a parallel topology of the power system with a block of supercapacitors, a boost-type converter in voltage control mode and a promising Four-Switch Bidirectional Buck-Boost converter in current control mode were selected. To increase the stability of the system, it is proposed to use a Type3 controller, which combines the capabilities of a compensator and a modulator. Originality. A new approach to modeling the HEV energy subsystem is proposed, which takes into account the multi-domain nature of the system and requires its consideration, first, as an Automatic Control System at the macro level in the CAE program SmartCtrl, with a preliminary expansion of its library by synthesizing Transfer Functions in the ECAD program PSIM, and a subsequent return to the micro level for analyzing energy characteristics and parametric optimization of converters together with control systems at the level of electrical circuits in PSIM. Based on the analysis of the capabilities of the programs for modeling the components of the HEV aggregate system, a variant of the structural diagram of the model of the energy subsystem is proposed, taking into account the possibilities of adequate application of "single-domain" programs and the prospects for their use for multi-domain modeling of HEV are shown. A specific set of program metrics is determined for a reasonable choice of software when studying such systems. Practical value. The presented method of sequential modeling of the energy system in the complex of automated engineering and automated design programs SmartCtrl+PSIM from Altair Group with mutual data exchange provides a comprehensive analysis and optimization of the characteristics of this subsystem of modern vehicles.
Abstract A drastic decline in the number of students that are enrolled for Engineering is now being experienced in developed as well as developing countries. Learning is becoming boring as a generation brought up on technology is losing the ability to pay attention in traditional classes for a long stretch of time. This has led to the idea that other teaching methods do exist and can be applied in teaching/learning. This work leveraged the use of Digital Game-Based Learning (DGBL) in Engineering classrooms to develop a serious game named LogicHouse Version 1 (LogicHouse-V1 or LogicHouse for short). The game, is a web-based serious game prototype that targets selected topics in Digital Electronics course. This course is a core component of undergraduate curriculum in Electrical & Electronics Engineering, Computer Engineering, Information Technology, Communication Engineering, Computer Science and other related Science Technology Engineering and Mathematics (STEM) courses. LogicHouse involves a virtual broken house where the player has to play the various levels to fix the house and gain points along the way. This game was designed based on the Learning Mechanics-Game Mechanics (LM-GM) model and the Unified Modeling Language (UML). Furthermore, the design was implemented using Adobe Illustrator, Procreate, Unity Engine, C#, Microsoft Azure Playfab and deployed on itch.io. Preliminary evaluation results indicate that students are interested in the game and its application. Based on this, there is a prospect of improved performance in any course in which the game is implemented.
Abstract: Power electronics is an engineering field dealing with the control and conversion of electrical energy. Many institutions are using CDIO (Conceive/Design/Implement/Operate) framework for their curricular planning and outcome-based assessment which demands huge self-learning. A virtual laboratory is an online platform allowing users to conduct simulations in a digital environment to improve self-learning. In this work, a virtual laboratory which provides an interactive platform for students to learn and experiment with power electronics circuits and devices, without the need for physical equipment is developed. The laboratory consists of a web-based interface that simulates the behaviour of different power electronics circuits. Learners can select different components and parameters to build and test circuits, and observe the results in real-time. The virtual laboratory also provides access to various measurement tools to analyse the behaviour of the circuits. The virtual laboratory has been designed to provide a user-friendly and intuitive interface, with detailed instructions and feedback to support students' learning. The laboratory has been integrated into a power electronics course. Feedback is collected through surveys from a total of 75 students including open ended questions and Likert responses. The learning of two set of students with and without using virtual lab before doing physical experimentation are assessed using a descriptive test. CDIO components analysis is done with the results of Mini projects developed by the students. The results indicate that the virtual laboratory provides a valuable and engaging learning experience and improves learning. Keywords: Virtual laboratory, Online, Simulation, Experimentation, Power Electronics, Analysis, Education
This paper implements a systematic methodological approach to review the evolution of YOLO variants. Each variant is dissected by examining its internal architectural composition, providing a thorough understanding of its structural components. Subsequently, the review highlights key architectural innovations introduced in each variant, shedding light on the incremental refinements. The review includes benchmarked performance metrics, offering a quantitative measure of each variant’s capabilities. The paper further presents the performance of YOLO variants across a diverse range of domains, manifesting their real-world impact. This structured approach ensures a comprehensive examination of YOLOs journey, methodically communicating its internal advancements and benchmarked performance before delving into domain applications. It is envisioned, the incorporation of concepts such as federated learning can introduce a collaborative training paradigm, where YOLO models benefit from training across multiple edge devices, enhancing privacy, adaptability, and generalisation.
Abstract In the field of underwater target detection, the passive sonar is an important means of long‐distance target detection. The sonar detection information typically includes both surface and underwater targets, whereas it is a great challenge on effectively distinguishing between surface and underwater targets solely based on sonar information. Effective fusion of sonar and AIS (Automatic Identification System) data can leverage their complementary nature to compensate for the limitation of sonar information. However, the sonar information and AIS information are acquired based on different detection principles and systems, which are essentially multi‐source heterogeneous information with obvious spatio‐temporal misalignment in nature. Existing fusion methods normally struggle to effectively align sonar and AIS data in both time and space subject to the complexity of the problem. In this study, the Dynamic Time Warping (DTW) algorithm is applied to align sonar and AIS data in the time domain. In addition, a deep learning algorithm with multi‐head attention mechanism is proposed to achieve the spatial alignment of sonar and AIS data, where the matching between the surface targets in AIS data and the same surface targets in sonar data can also be successfully achieved. It provides a priori knowledge to enhance the underwater target detection of the passive sonar by eliminating the interference of the surface targets. Based on the attention mechanism, the abstract features extracted from the intermediate‐layer of the neural networks are found to be effective to represent the typical features of the target motion trajectories, which also demonstrates the effectiveness of the attention mechanism. The experiment results show that the proposed method can successfully achieve a MatchingSucccessRate of over 95% between the AIS targets and sonar detection targets.
This study discusses a reconfigurable testbed system that is easy to use and tests circuit and power electronic converter systems in power engineering research. Features of the reconfigurable power electronics testbed system include hardware protection against failures such as sudden overvoltages, undervoltages, and overcurrents. The testbed has six voltage and current sensors available to sense the circuit's voltage and current. The voltages and currents detected by the sensors are displayed on the sensor's voltmeters and ammeters that are attached to the sensors. The testbed has input and output voltmeters to show the measured input and output voltages of the completed circuit. The user has the flexibility to create a variety of power electronics circuits thanks to the availability of IGBT switches and passive circuit components like capacitors and inductors. By creating an external electrical connection, all topologies that call for a minimum of 1 switch, a maximum of 12 power electronics switches, constant or variable inductors, and capacitors in the specified voltage and current range may be made possible. Users can utilize the testbed's internal controller or add their own external controller to create a variety of circuits. In this paper, an example with synchronous boost and synchronous cuk converter is shown.
F. Okonkwo, T. Eleogu, Oluwafunmi Adijat Elufioye
et al.
The pursuit of sustainable energy solutions has highlighted the importance of efficient waste heat recovery in nuclear power plants, with thermoelectric materials emerging as a promising technology to enhance waste heat recovery while mitigating corrosion in critical components; this review examines the current applications of thermoelectric materials in nuclear power plants and their potential to address corrosion challenges associated with waste heat recovery systems, noting that nuclear power plants generate significant waste heat during operation which, if harnessed effectively, can improve overall energy efficiency, but the high-temperature environment and aggressive chemical conditions can lead to corrosion, compromising system components; thermoelectric materials, capable of converting temperature gradients into electrical energy, offer a dual benefit by enabling waste heat recovery and reducing thermal and chemical stress on materials to minimize corrosion, and this review explores various thermoelectric materials, such as bismuth telluride, lead telluride, and silicon-germanium alloys, assessing their performance in high-temperature environments typical of nuclear power plants, while discussing innovative thermoelectric device designs, including modules integrated with existing waste heat recovery systems to enhance thermal management and address corrosion issues, and highlighting advancements in material engineering, such as nanostructuring and compositional optimization, which have improved thermoelectric efficiency and corrosion resistance; through case studies and experimental results, this review provides insights into the effectiveness of thermoelectric materials in real-world nuclear applications, concluding that the integration of thermoelectric materials in waste heat recovery systems of nuclear power plants is a significant step toward enhancing energy efficiency while mitigating corrosion risks, with future research focusing on developing novel thermoelectric materials with superior performance characteristics and exploring their scalability in commercial nuclear applications.
Meso-and microforming is a technology to shape parts from extremely small metal billets. Parts with geometric dimensions are a few millimetres to a few micrometres. With the rapid development of the electrical-electronics industry and biomedical engineering, the technology of forming microscopic parts has been researched and applied because of its efficiency, accuracy, and high productivity. Deep drawing is an operation that turns flat sheet metal blanks into hollow, open-mouth parts. It is an essential process in sheet metal stamping. Micro deep drawing is one of the micro-shaping technologies that has been widely studied and applied in recent years. However, the bases for calculating technological and geometrical parameters in the micro-deep drawing have not yet been analyzed and evaluated in detail. Therefore, this paper has proposed a theoretical basis combined with simulation applied to the design of technology to manufacture a connector head part drawing die with a diameter of 300µm and height of 1500µm using materials SUS304 material. Numerical simulation also allows evaluation of the stamping part's internal stress state, the ability to pull the workpiece into the die, and the thickness distribution on the product wall. Experimental research has also verified that, with the determined parameters, the stamping parts meet the quality requirements. This indicates the proposed calculation methods for the tiny deep drawing operation are entirely suitable. The results of this research can be wholly applied to the production of micro-sized cylindrical cup parts using the deep drawing method.
Recently, soft and stretchable electronics integrated with various functional devices are attracting attention as they can be used for stretchable display, stretchable battery, and electronic skin (e-skin). It is essential to impart stretchability to the electrical components (e.g., electrodes and devices). However, conventional materials used in electronics have low stretchability, which hinders the development of stretchable electronics. To solve this problem, various strategies for geometrical engineering that enhance stretchability to rigid materials have been reported. In this paper, geometrical engineering such as serpentine, kirigami, and island structures are discussed, focusing on the progress of recent developments and future prospects.
The prospects for the use of glass-ceramic materials as electrical products are analyzed. The priority of the formation of a self-organized macro- and nanostructure, glass-ceramic materials under conditions of low-temperature heat treatment to ensure their high physical and chemical properties is characterized. The effect of crystallization catalysts on the formation of the structure and viscosity of magnesium aluminosilicate glasses during their heat treatment is analyzed. The composition of magnesium aluminosilicate glass is optimized by using a combined crystallization catalyst in its composition, and an optimal heat treatment mode is established. The features of structure formation in magnesium-alumino silicate glass-ceramic materials are analyzed, which consist in the sequential course of the following stages: phase separation of glass by the spinodal mechanism $(\mathbf{T}=800-850\ {{}^{\circ}}\mathbf{C})$; nucleation of crystals of µ-cordierite $(\mathbf{T}=850\ {{}^{\circ}}\mathbf{C})$ and the formation of prismatic crystals of mulite $(\mathbf{T}=1100\ {{}^{\circ}}\mathbf{C})$, which are tightly connected. The formation of the nano- and submicron structure of the developed glass-ceramic material containing 80 vol. % mulite allows obtaining high physicochemical and electrical properties, which, along with its reduced weight, makes it promising for development as substrates in the design of a hybrid integrated circuit, vacuum-tight shell and capacitor dielectrics.
Satyam Panchal, Krishna Gudlanarva, Manh-Kien Tran
et al.
In this paper, an analogous study of the velocity and temperature profiles inside microchannel cooling plates (with hydraulic diameter of 6 mm), placed on a large pouch-type LiFePO<sub>4</sub> battery, is presented using both the laboratory and simulation techniques. For this, we used reverse engineering (RE), computed tomography (CT) scanning, Detroit Engineering Products (DEP) MeshWorks 8.0 for surface meshing of the cold plate, and STAR CCM+ for steady-state simulation. The numerical study was conducted for 20 A (1C) and 40 A (2C) and different operating temperatures. For experimental work, three heat flux sensors were used and were intentionally pasted at distributed locations, out of which one was situated near the negative tab (anode) and the other was near the positive tab (cathode), because the heat production is high near electrodes and the one near the mid body. Moreover, the realizable <i>k</i>-ε turbulence model in STAR CCM+ is used for simulation of the stream in a microchannel cooling plate, and the computational fluid dynamics (CFD) simulations under constant current (CC) discharge load cases are studied. Later, the validation is conducted with the lab data to ensure sufficient cooling occurs for the required range of temperature. The outcome of this research work shows that as C-rates and ambient temperature increase, the temperature contours of the cooling plates also increase.