Hasil untuk "Applications of electric power"

J. Jeyashanthi, J. Barsana Banu, T. Deepika vinothini

Many power electronic applications utilize Cascaded H-Bridge (CHB) Multi-Level Inverters (MLIs) due to their bidirectional control capabilities. Multi-Level Inverters (MLIs) are utilized in Electric Vehicles (EVs) to minimize overall drive losses by reducing Total Harmonic Distortion. Also, MLI is preferred for solar energy generation to attain maximum power point tracking. This research work focuses on reducing drive losses and improving the transient response of induction motor drives for EV applications. For that, three different intelligent control algorithms are proposed. There are PI-PSO, PI-PSO-ANN, and PI-PSO-ANFIS controllers. This work uses the three-phase 15-level cascaded H-bridge multilevel inverter supplied by a solar energy source. Intelligent control algorithms generate pulses via pulse-width modulation, thereby reducing harmonic distortion. The drive's performance is analysed to investigate the operations of PI-PSO, PI-PSO-ANN, and PI-PSO-ANFIS controllers. The performance of this CHB-MLI-driven 4kW Induction Motor (IM) drive is verified by simulation using MATLAB/Simulink. This approach showed the successful implementation of the suggested design. The PI-PSO-ANFIS controller demonstrated better performance, with lower THD and faster dynamic response, when applied to control the IM drive with a 15-level CHB-MLI. The findings of this comparative analysis focus on features such as drive speed, load torque, and power-quality problems associated with total harmonic distortion (THD).

Hazirah Syahirah Zakria, Sou Taminato, Hiroki Eimura et al.

Next-generation energy storage, aqueous lithium–air batteries emerge as a strong candidate, particularly for electric vehicle applications, due to their inherently high energy and power characteristics and their ability to function without stringent environmental control. A key component enabling this system is the separator, which must effectively isolate the anolyte from the catholyte while ensuring stable operation and safety. In this work, an ultrathin (< 10 μm), water-blocking polymer membrane capable of conducting lithium ions was fabricated, exhibiting an ionic conductivity in the range of 2 × 10−6 to 3 × 10−6 S cm−1 at 25°C. The experimental cell consisted of a lithium metal electrode, a 4.5 M LiFSI solution in 1,2-diethoxyethane as the anolyte, the fabricated polymer separator, a 1 M LiOH–10 M LiCl catholyte, and a carbon-based air electrode. The assembled battery produced an open-circuit voltage of about 3 V, which is in good agreement with predicted thermodynamic values and with earlier studies on aqueous Li–air cells employing ceramic membranes. Depending on the separator type, the measured cell resistance at 25°C was within 300 to 1500 Ω·cm2. Under a current density of 0.5 mA·cm−2 and a capacity limit of 0.5 mAh·cm−2, the cell was capable of operating stably for more than 200 cycles at room temperature.

Frederick B. Davies, Eduardo Bañados, Sarah E. I. Bosman et al.

Here we report the spectroscopic and geometric confirmation of an extremely bright ($i=14.77$) and compact (Einstein radius of $\sim0.45''$) quadruply-lensed quasar at $z=2.22$, J1330$-$0905, which we dub Persephone's Torch. The system had been previously selected as a candidate lensed quasar based on large-area survey data; here we confirm its quasar nature and redshift using public spectrophotometry from the SPHEREx mission, a.k.a. "from the couch". Adaptive optics imaging with LBT/LUCI resolves four images in a "circular kite" configuration. The system is the brightest gravitationally-lensed quasar system ever found. While an elliptical power-law mass distribution plus external shear accurately reproduces the locations of the images and lensing galaxy, and predicts a total magnification of $\sim56$, the brightnesses of the lensed images present highly anomalous flux ratios. Together with short time delays between images ($\leq 2$ days), this makes Persephone's Torch a promising candidate for future microlensing studies. Our discovery highlights the potential of SPHEREx full-sky infrared spectrophotometry to uncover extraordinarily bright objects that have otherwise been overlooked.

Yanfei Sun, Tao Zhao, Li Gao et al.

ABSTRACT Reliable fault diagnosis of power transformers is vital for ensuring the safe and continuous operation of power systems. Although deep learning methods have shown success with single‐sensor data, their diagnostic performance remains limited due to the inability to capture complex, multimodal fault characteristics. To address this, we propose an attention‐guided semi‐supervised vibration‐acoustic fusion (AG‐SVAF) model, which combines vibration and acoustic signals to enhance diagnostic robustness under limited labelled data conditions. The model integrates time‐frequency representations derived via short‐time Fourier transform (STFT) with a multilevel attention mechanism—including channel, spatial and self‐attention—to highlight fault‐relevant features and model cross‐modal dependencies. A novel attention‐weighted consistency loss further improves the utilisation of unlabelled data during training. Validated on practical transformer datasets, AG‐SVAF achieves superior performance in terms of diagnostic accuracy and stability, particularly under challenging scenarios involving class imbalance and label scarcity. This approach provides a promising and scalable solution for intelligent condition monitoring in real‐world power system applications.

Xiong LI, Tingfang YANG, Huikang ZHOU et al.

To address the issue of decreased reliability in power transmission caused by the incapability of existing parallel protection gaps to actively extinguish arcs，a method utilizing the power-flow current flowing through coil to generate a magnetic field，and employing electromagnetic force to drive a piston to compress air and jet high-speed airflow for arc extinction is proposed. Consequently，a double-ended electromagnetic air-blast segmented arc-extinguishing device is designed. Based on the theory of magnetohydrodynamic，the theoretical model is built by using finite element simulation software，and the arc-extinction process of the device is simulated and analyzed. The results show that the arc-extinguishing airflow maximum speed is up to 330 m/s. Arc-extinguishing airflow rapidly act on the arc from the upper and lower ends，under the action of high-speed airflow，the arc gradually thinned out to break the dynamic equilibrium. The arc column temperature decreases to 2 000 K within 3 ms，and the arc channel pinch off，so as to realize the ″no arc channel″. The arc-extinguishing time is only 9% of the time before the installation of the device. The device can greatly shorten the arc-extinguishing time，and improve the reliability of the power supply system.

LAN Guoqin, LU Ye, KAN Yansheng et al.

ObjectivesWith the continuous advancement of the national “dual carbon” strategy, integrated energy services, as a new model and new form of the energy industry, are gradually becoming an important means for China to build a new energy system and create new quality productive forces in the energy field. In order to facilitate the high-quality development of China’s integrated energy service industry, the development trends and strategies of integrated energy services are studied.MethodsThrough in-depth analysis of the development status of integrated energy services at home and abroad, the structure-conduct-performance (SCP) analysis model is used to analyze the development and trend of the integrated energy service industry under the new situation.ConclusionsFrom the national level, the countermeasures and suggestions of “three synergies” for the high-quality development of the integrated energy service industry are put forward, focusing on “policy-reform-planning”. From the enterprise level, the implementation path of “four advantages” for high-quality development is put forward, focusing on “layout-model-science and innovation-brand”. These strategies aim to support the healthy and sustainable development of the integrated energy service industry, providing innovative demonstrations and value contributions to the construction of China’s new power system and the implementation of the “dual carbon” strategy.

Riku Kobayashi, Yoshihiro Kawahara, Takuya Sasatani

The powering range of wireless power transfer (WPT) systems is typically confined to areas close to the transmitter. Shape-reconfigurable two-dimensional (2-D) relay resonator arrays have been developed to extend this range, offering greater deployment flexibility. However, these arrays encounter challenges due to cross-coupling among adjacent resonators, which detune system impedance and create power dead zones. This issue often necessitates active components such as receiver position tracking, increasing system overhead. This study introduces a passive reactance compensation mechanism that counteracts detuning effects, enabling the simultaneous activation of all resonators at a fixed operating frequency, regardless of the array's shape, thus providing a consistent charging area. The key innovation involves mechanically appending reactance elements to neutralize detuning caused by inductive coupling, facilitating hassle-free resonator reconfiguration without requiring prior knowledge. Our experiments demonstrate the elimination of dead zones with multiple configurations, boosting the minimum power transfer efficiency from 3.0% to 56.8%.

Chenxin Jiang, Changhu Wang, Jingyi Jessica Li

Differential expression (DE) analysis is a key task in RNA-seq studies, aiming to identify genes with expression differences across conditions. A central challenge is balancing false discovery rate (FDR) control with statistical power. Parametric methods such as DESeq2 and edgeR achieve high power by modeling gene-level counts using negative binomial distributions and applying empirical Bayes shrinkage. However, these methods may suffer from FDR inflation when model assumptions are mildly violated, especially in large-sample settings. In contrast, non-parametric tests like Wilcoxon offer more robust FDR control but often lack power and do not support covariate adjustment. We propose Nullstrap-DE, a general add-on framework that combines the strengths of both approaches. Designed to augment tools like DESeq2 and edgeR, Nullstrap-DE calibrates FDR while preserving power, without modifying the original method's implementation. It generates synthetic null data from a model fitted under the gene-specific null (no DE), applies the same test statistic to both observed and synthetic data, and derives a threshold that satisfies the target FDR level. We show theoretically that Nullstrap-DE asymptotically controls FDR while maintaining power consistency. Simulations confirm that it achieves reliable FDR control and high power across diverse settings, where DESeq2, edgeR, or Wilcoxon often show inflated FDR or low power. Applications to real datasets show that Nullstrap-DE enhances statistical rigor and identifies biologically meaningful genes.

O.V. Bialobrzheskyi, M.Y. Oliynichenko, V.V. Vorona et al.

Мета роботи. Дослідження симетричних складових струму та напруги в елементах мікромережі з автономним синхронним генератором обмеженої потужності, який працює паралельно з мережевим трансформатором за умови несиметричного навантаження. Методи дослідження. Під час проведення дослідження використано методи візуального програмування в пакеті Simulink/Matlab, методи теорії електротехніки в частині визначення симетричних складових струмів та напруг в гілках спостереження, методи синтезу схем заміщення елементів електроенергетичних систем для симетричних складових струмів, методи обробки даних та побудови діаграм з використанням профільних програмних засобів. Отримані результати. В результаті аналізу відомих досліджень встановлено, що за умови дослідження генеруючих систем малої потужності в умовах несиметрії недостатньо уваги приділяється характеру несиметричного навантаження. З використанням відомої структури мікромережі, яка включає синхронний генератор, машинне навантаження та трансформатор зовнішньої мережі, побудовано її модель в якій шляхом введення несиметричного навантаження різного типу реалізовано серії експериментів з реєстрацією напруг та струмів прямої, зворотньої та нульової послідовностей в гілках мережі. Аналіз отриманих в ході дослідження результатів встановив, що напруга прямої послідовності у разі зміни активного навантаження не змінює свого рівня, за тих же обставин у разі активно-ємнісного та активно-індуктивного навантаження змі-на напруги має протилежний характер. У разі зростання несиметрії активно-індуктивного характеру напруга прямої послідовності знижується, а у разі активно-ємнісного збільшується. Зазначені зміни в деяких випадках перевищують 3%. Струми прямої послідовності у разі небалансу активного навантаження відрізняються незначним чином. У разі прямої послідовності струму трансформатора спостерігається безперервне його зростання, яке у випадку активно-ємнісного, та активно-індуктивного навантаження перевищує активне в середньому в 1,5 рази. Струми нульової послідовності в досліджуваній моделі, які утворені несиметричним навантаженням, повністю замикаються на трансформатор, викликаючі напруги нульової послідовності, а характер несиметричного навантаження суттєво впливає на значення цих струмів, відмічене зростання на 61%. Наукова новизна. Встановлено, що в мікромережі, яка включає синхронний гененератор, машинне навантаження, симетричне активне навантаження, співставної з генератором потужності, трансформатор зовнішньої мережі, окрім самого факту несиметрії викликаної несиметричним навантаженням суттєвий вплив на симетричні складові має і характер несиметричного навантаження (активний, активно-індуктивний чи активно-ємнісний). Практична цінність. За умови використання в мікромережах пристроїв які забезпечують підвищення якості електричної енергії, наприклад симетруючих, необхідно прийняти до уваги окрім фактору несиметрії ще й характер навантаження, яке останню викликає.

Müjdat Ersarı, Murat Gündoğdu

This study investigates the optimization of gear ratios for a 2-speed transmission, with a focus on enhancing performance and efficiency in diverse operating conditions. Specifically, the research addresses the need for two dis-tinct gears: one optimized for field use and the other for road use. The goal is to improve the versatility and functionality of the transmission system, ensuring that it meets the demands of both rugged terrains and smooth highways. To achieve this, the study employed the company’s lifetime test simulation to fine-tune the gear ratios, optimizing them for the most effective power delivery. A significant aspect of the research is the exploration of the tran-sition from a traditional combustion engine tractor, which typically requires multiple gear ratios, to an electric motor setup with only two gears. This transition is made feasible by the electric motor’s ability to deliver high torque across a broad RPM range, thereby enhancing performance while reducing the complexity of gear selection. The results of this optimization process show marked improvements in both the transmission's efficiency and its adaptability, making it highly suitable for a range of applications. This research offers valuable insights into the future of transmission design, particularly in the fields of agriculture and transportation, where there is a growing need for systems that are both efficient and versatile.

YANG Jie, SUN Zhe, SU Xinyi et al.

As the construction of new power systems, DC microgrids will become an important part of the distribution network. As AC load connecting to DC microgrids, the oscillating power will enter the DC system, which affects the power distribution of energy storage system. To solve this issue, the comprehensive principle of power distribution of distributed energy storage system was given, and a wireless power sharing method was proposed. This method takes the charge state as the “information carrier”, each energy storage unit can realize state of charge (SOC) balancing and oscillating power sharing at same time. In addition, from the perspective of equivalent output impedance, this paper gived a detailed analysis and discussion on the distribution effect of different control algorithms, which showed the proposed control algorithm could meet the requirements of the comprehensive principle. Finally, the effectiveness of the proposed distributed energy storage control strategy was validated by experiments.

WANG Ting, WANG Yinshun, GUO Lining et al.

ObjectivesHigh-field superconducting magnets have great application value in many fields. Due to the immature welding technology, the second-generation high-temperature superconducting magnets cannot achieve persistent current mode operation. A rare earth barium copper oxide (REBCO) closed-loop superconducting gourd-shaped loop stacked magnet can achieve unimpeded closed-loop operation. It has been verified that it has the functions of flux density amplification and flux accumulation, and has the potential to achieve high magnetic field output. Therefore, it is crucial to study whether this magnet can maintain stability under high current and high magnetic field conditions.MethodsA three-dimensional finite element model of this REBCO closed-loop superconducting gourd-shaped loop stacked magnet was established to analyze its electromagnetic response and stress-strain distribution under the field cold excitation method.ResultsThe electromagnetic force per unit volume of the stacked magnet decreases gradually from the inner diameter to the outer diameter of the circular loop, with higher values at both ends and lower values in the middle, it presented a “U” shaped distribution. Additionally, the areas with significant stress are located at the connecting bridge and the junction between the loop and the bridge, making these regions prone to deformation and potential quench risks.ConclusionsThe analysis of the distribution characteristics of stress and strain of the magnet has a reference significance for improving the geometric shape of the gourd-shaped double-hole closed-loop superconducting sheet and the structure of the stacked magnet, and is of great significance to the safe operation of the magnet.

D.O. Danylchenko, S.O. Fedorchuk, A.E. Potryvay et al.

Мета роботи. Метою цієї статті є вивчення ролі "Зеленої енергетики" у концепції розподіленої генерації, аналіз внеску відновлюваних джерел у стабільність енергетики. Основні завдання включають удосконалення моделей фотоелектричних панелей і вітрогенераторів для досягнення екологічної та економічної ефективності. Методи дослідження. Математичне моделювання фотоелектричних панелей та вітрогенераторів, аналіз впливу уточнюючого коефіцієнта та коефіцієнта корисної дії інвертору на електрогенерацію. Використовується порівняльний аналіз отриманих результатів з реальними даними для валідації моделей. Досліджуються аеродинамічні характеристики вітрогенератора та вплив на вихідну потужність. Розробляється оптимізована модель для прогнозування ефективності гібридних систем з використанням зелених технологій. Отримані результати. Отримані результати дослідження розкривають ключовий внесок "Зеленої енергетики" у концепцію розподіленої генерації. Методи математичного моделювання фотоелектричних панелей та вітрогенераторів, разом із застосуванням уточнюючого коефіцієнта та врахуванням ККД інвертору, дозволили покращити точність прогнозування електрогенерації. Розроблена модель враховує аеродинамічні характеристики вітрогенератора, підкреслюючи реалізовану можливість перевищення номінальної потужності відповідно до реальної характеристики. Отримані результати порівнюються з реальними даними для валідації та підтвердження ефективності систем. Наукова новизна. . Полягає в удосконаленні моделі комбінованої генерації фотоелектричних панелей та вітрогенератору, шляхом уточненого врахування роботи інвертору. Також було отримано дані по потенціалу застосування гібридної станції в обраному регіоні та доведено її переваги над застосуванням окремо СЕС та ВЕС. Практична цінність. Полягає в оптимізації прогнозування електрогенерації в гібридних системах, що визначено підвищенням точності та адаптованістю до реальних умов. Дослідження виявляє потенціал для розвитку "Зеленої енергетики" в громадах з великою площею та середньою потужністю.

Richard Soref, Francesco De Leonardis, Oussama Moutanabbir et al.

The commercially available 4000-Watt continuous-wave Erbium-doped-fiber laser, emitting at the 1567-nanometer wavelength where the atmosphere has high transmission, provides an opportunity for harvesting electric power at remote off the grid locations using a multi-module photovoltaic receiver panel. This paper proposes a 32-element monocrystalline thick-layer Germanium photovoltaic panel for efficient harvesting of a collimated 1.13-meter-diameter beam.The 0.78-meter squared PV panel is constructed from commercial Ge wafers. For incident continuous-wave laser-beam power in the 4000 to 10000 Watt range, our thermal and electrical and infrared simulations predict 660 to 1510 Watts of electrical output at panel temperatures of 350 to 423 Kelvin.

Ignasi Ventura Nadal, Jochen Stiasny, Spyros Chatzivasileiadis

Time-domain simulations are crucial for ensuring power system stability and avoiding critical scenarios that could lead to blackouts. The next-generation power systems require a significant increase in the computational cost and complexity of these simulations due to additional degrees of uncertainty, non-linearity and states. Physics-Informed Neural Networks (PINN) have been shown to accelerate single-component simulations by several orders of magnitude. However, their application to current time-domain simulation solvers has been particularly challenging since the system's dynamics depend on multiple components. Using a new training formulation, this paper introduces the first natural step to integrate PINNs into multi-component time-domain simulations. We propose PINNs as an alternative to other classical numerical methods for individual components. Once trained, these neural networks approximate component dynamics more accurately for longer time steps. Formulated as an implicit and consistent method with the transient simulation workflow, PINNs speed up simulation time by significantly increasing the time steps used. For explanation clarity, we demonstrate the training, integration, and simulation framework for several combinations of PINNs and numerical solution methods using the IEEE 9-bus system, although the method applies equally well to any power system size.

Amirhossein Sajadi, Bri-Mathias Hodge

Contemporary theories and models for electric power system stability are predicated on a widely held assumption that the mechanical inertia of the rotating mass of synchronous generators provides the sole contribution to stable and synchronized operation of this class of complex networks on subsecond timescales. Here we formulate the electromagnetic momentum of the field around the transmission lines that transports energy and present evidence from a real-world bulk power network that demonstrates its physical significance. We show the classical stability model for power networks that overlooks this property, known as the "swing equation", may become inadequate to analyze systems with high shares of inverter-based resources, commonly known as "low-inertia power systems". Subsequently, we introduce a plane wave dynamic model, consistent with the structural properties of emerging power systems with up to 100% inverter-based resources, which identifies the concept of inertia in power grids as a time-varying component. We leverage our theory to discuss a number of open questions in the electric power industry. Most notably, we postulate that the changing nature of power networks with a preponderance of variable renewable energy power plants could strengthen power network stability in the future; a vision which is irreconcilable with the conventional theories.

Richard Soref, Francesco De Leonardis, Gerard Daligou et al.

Transferring energy without transferring mass is a powerful paradigm to address the challenges faced when the access to, or the deployment of, the infrastructure for energy conversion is locally impossible or impractical. Laser beaming holds the promise of effectively implementing this paradigm. With this perspective, this work evaluates the optical-to-electrical power conversion that is created when a collimated laser beam illuminates a silicon photovoltaic solar cell that is located kilometers away from the laser. The laser is a CW high-energy Yb-doped fiber laser emitting at a center wavelength of 1075 nm with ~1 m2 of effective beam area. For 20 kW illumination of a solar panel having 0.6 m2 of area, optical simulations and thermal simulations indicate electrical output power of 3000 Watts at a panel temperature of 550 K. Our investigations show that thermo-radiative cells are rather inefficient. In contrast, an optimized approach to harvest laser energy is achieved by using a hybrid module consisting of a photovoltaic cell and a thermo-electric generator. Finally, practical considerations related to infrared power beaming are discussed and its potential applications are outlined.

Khalil Ur Rehman, Wasfi Shatanawi, Uroosa Firdous

It is well consensus among researchers affiliated with the field of thermal engineering that the thermophysical characteristics of heat transfer in fluid science own abundant applications like thermal distillation systems, heat exchangers, steam-electric power generation, electronic cooling, solar collectors, refrigeration systems and spacecraft thermal protection are to mention just a few. Considering such importance we offer a thermal case study on thermophysical aspects in a thermally magnetized non-Newtonian fluid along with a first-order chemical reaction effect. The flow field is carried with the following thermophysical effects namely, mixed convection, heat generation, viscous dissipation, thermal radiations, and temperature-dependent variable thermal conductivity. We have offered comparative analysis for temperature and Nusselt number by considering thermally radiative and non-radiative thermal flow fields. The thermal outcomes on temperature and Nusselt number are also reported for both the absence and presence of the heat generation effect. For both radiative and non-radiative Casson flow, the temperature shows an inciting nature towards Casson and variable thermal conductivity parameters. The magnitude of the Nusselt number towards Eckert, Prandt numbers, curvature, heat generation, and Casson fluid parameters is higher for the presence of thermal radiations while the opposite is the case for positive variation in the thermal conductivity parameter.

Yogesh Khatri, Arti Kashyap

Magnetic materials are used in a variety of applications, such as electric generators, speakers, hard drives, MRI machines, etc. Discovery of new magnetic materials with desirable properties is essential for advancement in these applications. In this research article, we describe the development and validation of a machine-learning model to discover new manganese-based stable magnetic materials. The machine learning model is trained on the input data from the Materials Project database to predict the magnetization and formation energy of the materials. New hypothetical structures are made using the substitution method, and the properties are predicted using the machine learning model to select the materials with desired properties. Harnessing the power of machine learning allows us to intelligently narrow down the vast pool of potential candidates. By doing so, we deftly reduce the number of materials that warrant in-depth examination using density functional theory, rendering the task more manageable and efficient. The selected materials, seemingly promising with their magnetic potential, undergo a meticulous validation process using the Vienna Ab initio Simulation Package, grounded in density functional theory. Our results underscore the paramount significance of input data in the efficacy of the machine learning model. Particularly in the realm of magnetic materials, the proper initialization of atomic magnetic spins holds the key to converging upon the true magnetic state of each material.

Octavio Guerrero, Libertad Barrón-Palos, Daniel Sudarsky

The continued interest in placing bounds on the neutron's Electric Dipole Moment (EDM) is due to the implications regarding the characteristics of the strong interaction and, in particular, its behavior under the CP symmetry. In this work, we discuss the apparent tension resulting from the discrepancy of about 13 orders of magnitude between the current bounds and the expected quantum uncertainty in the relevant quantity. We offer a resolution of the "puzzle" in terms of the notion of a weak measurement, using a version of the corresponding formalism adapted to consideration of the nEDM experiment at the Spallation Neutron Source at the Oak Ridge National Laboratory.