Owing to their high energy density and power density, supercapacitors exhibit great potential as high-performance energy sources for advanced technologies. Recently, carbon nanomaterials (especially, carbon nanotubes and graphene) have been widely investigated as effective electrodes in supercapacitors due to their high specific surface area, excellent electrical and mechanical properties. This article summarizes the recent progresses on the development of high-performance supercapacitors based on carbon nanomaterials and provides various rational concepts for materials engineering to improve the device performance for a large variety of potential applications, ranging from consumer electronics through wearable optoelectronics to hybrid electric vehicles.
Poly(vinylidene fluoride)-based dielectric materials are prospective candidates for high power density electric storage applications because of their ferroelectric nature, high dielectric breakdown strength and superior processability. However, obtaining a polar phase with relaxor-like behavior in poly(vinylidene fluoride), as required for high energy storage density, is a major challenge. To date, this has been achieved using complex and expensive synthesis of copolymers and terpolymers or via irradiation with high-energy electron-beam or γ-ray radiations. Herein, a facile process of pressing-and-folding is proposed to produce β-poly(vinylidene fluoride) (β-phase content: ~98%) with relaxor-like behavior observed in poly(vinylidene fluoride) with high molecular weight > 534 kg mol−1, without the need of any hazardous gases, solvents, electrical or chemical treatments. An ultra-high energy density (35 J cm−3) with a high efficiency (74%) is achieved in a pressed-and-folded poly(vinylidene fluoride) (670-700 kg mol−1), which is higher than that of other reported polymer-based dielectric capacitors to the best of our knowledge. Dielectric materials are candidates for electric high power density energy storage applications, but fabrication is challenging. Here the authors report a pressing-and-folding processing of a dielectric with relaxor-like behavior, leading to high energy density in a polymer-based dielectric capacitor.
Supercapacitors or ultracapacitors are considered as one of the potential candidates in the domain of energy storage devices for the forthcoming generations. These devices have earned their significance in numerous applications, viz., to power hybrid electric/electric vehicles and other power and electronic systems which require electrical energy for their operation. Supercapacitors are the most versatile devices which are most widely used for delivery of electrical energy in short time and in arenas which demand long shelf life. Therefore, the development of supercapacitors has huge market requirements, and long-term progress is needed for their successful advancement and commercialization. Meanwhile, supercapacitors are also facing challenges such as technical problems, establishing electrical parameter models, consistency testing, and establishing industrial standards. In this paper, the above challenges and the future development opportunities of supercapacitors are introduced in detail. This perspective will provide corresponding guidance and new directions for the development of supercapacitors.
Abstract To meet the growing need for energy efficiency in power electronics and electric machines, a number of new soft magnetic materials are being investigated. Among them, high silicon Fe-Si alloy has been recognized as a promising candidate for low-to-medium-frequency applications. Compared to the currently most widely used 3 wt% silicon steel, the steel containing 6.5 wt% Si possesses more favorable properties, including high electrical resistivity, good saturation magnetization, and near-zero magnetostriction. However, the high silicon content facilitates the formation of ordered phases, resulting in severe brittleness that prohibits mass production using the economical conventional processing methods. A number of new processing routes have been investigated and inspiring progress has been made. Prototypes of motors and transformers using high silicon steel have been demonstrated with improved efficiency and power density. If the processing cost and limitations of size and shape are properly addressed, high silicon steel is expected to be widely adopted by the industries. Among all the investigated processing techniques, rapid solidification appears to be the most cost-effective method for mass producing thin sheet of high silicon steel. This paper reviews the current state-of-the-art of the Fe-Si based soft magnetic materials including their history, structure, properties, processing, and applications.
Road transportation is heading towards electrification using Li-ion batteries to power electric vehicles offering eight or ten years' warrant. After that, batteries are considered inappropriate for traction services but they still have 80% of its original capacity. On the other hand, energy storage devices will have an important role in the electricity market. Being Li-ion batteries still too expensive to provide such services with economic profit, the idea to reuse affordable electric vehicle batteries for a 2nd life originated the Sunbatt project, connecting the automotive and electricity sectors. The battery reuse is, by itself, a path towards sustainability, but the cleanliness of energy storage also depends on the electricity generation power sources and the battery ageing or lifespan. This paper analyses the rest of useful life of 2nd life batteries on four different stationary applications, which are: Support to fast electric vehicle charges, self-consumption, area regulation and transmission deferral. To do so, it takes advantage of an equivalent electric battery-ageing model that simulates the battery capacity fade through its use. This model runs on Matlab and includes several ageing mechanisms, such as calendar ageing, C-rate, Depth-of-Discharge, temperature and voltage. Results show that 2nd life battery lifespan clearly depends on its use, going from about 30 years in fast electric vehicle charge support applications to around 6 years in area regulation grid services. Additionally, this study analyses the day-to-day emissions from electricity generation in Spain, and states that grid oriented energy storage applications will hardly offer environmental benefits in the nearby future. On the other hand, applications that go by the hand of renewable power sources, such as self-consumption applications, are much more appropriate.
Abstract Recently, the technology of lithium metal-based batteries has devoted substantial importance with suggesting the great potential for power sources that could promise the revolution of electric vehicle (EV) and power grid. It is expected to overcome the challenges and barriers experienced during the use of these high energy density batteries in the desired large-scale applications such as hybrid electric vehicle (HEV), plug-in hybrid electric vehicle (PHEV) and pure electric vehicle (PEV). Apart from the high energy density and enormous applications of Li-ion batteries, still there are some issues affecting the rate capability, performance, safety and cost due to dendritic growth during cycling of lithium batteries. Therefore, it is generous worthy to provide existing and timely apprises of constantly improving techniques to diminish the dendrites formation, especially for the metallic Li anode, because dendritic growth is the main problem that inhibits the commercial applications of lithium metal batteries in regular portable electronics to EV. In this review, we concisely summarize the fundamentals, existing issues, solid electrolyte interphases (SEI) on lithium metal anode, insight understanding and growth of dendritic structure and morphologies. Moreover, different prevention techniques for dendrites suppression, and some significant remarks are provided for future research and development of advanced dendrite free Li metal batteries for safe and potential use in the electric vehicles and also in high load-leveling applications.
Cyclical heat engines are a paradigm of classical thermodynamics, but are impractical for miniaturization because they rely on moving parts. A more recent concept is particle-exchange (PE) heat engines, which uses energy filtering to control a thermally driven particle flow between two heat reservoirs1,2. As they do not require moving parts and can be realized in solid-state materials, they are suitable for low-power applications and miniaturization. It was predicted that PE engines could reach the same thermodynamically ideal efficiency limits as those accessible to cyclical engines3–6, but this prediction has not been verified experimentally. Here, we demonstrate a PE heat engine based on a quantum dot (QD) embedded into a semiconductor nanowire. We directly measure the engine’s steady-state electric power output and combine it with the calculated electronic heat flow to determine the electronic efficiency η. We find that at the maximum power conditions, η is in agreement with the Curzon–Ahlborn efficiency6–9 and that the overall maximum η is in excess of 70% of the Carnot efficiency while maintaining a finite power output. Our results demonstrate that thermoelectric power conversion can, in principle, be achieved close to the thermodynamic limits, with direct relevance for future hot-carrier photovoltaics10, on-chip coolers or energy harvesters for quantum technologies.Direct thermal-to-electric energy conversion can be performed at electronic efficiencies comparable to efficiencies of traditional cyclical heat engines.
ABSTRACT An in‐depth mathematical analysis of torque and force production mechanisms is presented in this paper for the Doubly Salient Parallel Path Magnetic Motor (DS‐PPMM). This paper focuses on a comprehensive torque force analysis through analytical modelling and is verified by a detailed finite element analysis (FEA). Electromagnetic force distribution, torque ripple characteristics and the contributions of magnetic salience to overall torque production and performance of the machine are analysed. Tangential and radial components of the force vectors are computed using Maxwell's stress tensor. The results confirm the effectiveness of DS‐PPMM in offering high torque density with low torque ripple.
In an electric vehicle, energy storage systems (ESSs) are critical for sinking and sourcing power as well as ensuring operational protection. Because of their high power density, quick charging or discharging, and low internal loss, supercapacitors (SCs) are a recent addition to the types of energy storage units that can be used in an electric vehicle as an energy storage systems. They can be used in conjunction with batteries or fuel cells to create a hybrid energy storage device that maximizes the benefits of each component while minimizing the disadvantages. This paper presents a multilayer perceptrons (MLP) feedforward artificial neural network for supercapacitor state-of-charge diagnosis in vehicular applications. The proposed approach is tested using a supercapacitor Maxwel model that is subjected to complex charge and discharge current profiles as well as temperature changes. The proposed wavelet neural network and the validation results significantly improves state-of-charge estimation accuracy in different current discharge profiles.
Abstract We construct two rainbow tensor models with multi-tensors of rank-3 and present their W-representations. We give the formula of counting number of independent gauge-invariant operators in terms of Hurwitz numbers and establish a one-to-one correspondence between connected operators and colored Dessins. By means of the colored Dessins and W-representations, respectively, we derive two compact expressions of correlators for each of rainbow tensor models. Furthermore, two complex multi-matrix models from the degradations of the constructed rainbow tensor models are also discussed.
Astrophysics, Nuclear and particle physics. Atomic energy. Radioactivity
This research presents a novel, energy-efficient control strategy for brushless direct current (BLDC) motor drives, specifically designed to enhance battery usage in electric vehicle (EV) applications. The proposed approach integrates a current-blocking technique with an optimized torque hysteresis current controller to enhance both charging efficiency and torque response, which are critical parameters in EV power management. Unlike traditional motors, BLDC motors offer superior efficiency and reliability due to their brushless architecture and low mechanical wear. However, achieving optimal performance requires precise electronic control. In this work, a custom-designed BLDC motor with 40 stator slots and 48 rotor poles, powered by a 72 V supply and configured in a star connection, is analyzed. Electromagnetic modeling using Motor Solver software ensured minimal cogging torque and near-sinusoidal back electromotive force (EMF) characteristics, contributing to smoother operation. The starting torque was assessed across various rotor positions, with peak performance observed at a 90° magnet alignment. To validate the proposed control strategy, a comprehensive mathematical model of the BLDC drive was developed and simulated. The results demonstrate effective phase current regulation and improved dynamic torque behavior, confirming the suitability of the method for real-world EV integration. Overall, the proposed system supports enhanced energy utilization and contributes to the advancement of sustainable electric mobility.
Boris V. Malozyomov, Nikita V. Martyushev, Anton Y. Demin
et al.
This article presents a mathematically grounded approach to increasing the operational reliability of current collectors in electric transport systems by ensuring a constant contact force between the collector shoe and the power rail. The core objective is achieved through the development and analysis of a mechanical system incorporating spring and cam elements, which is specifically designed to provide a nearly invariant contact pressure under varying operating conditions. A set of equilibrium equations was derived to determine the stiffness ratios of the springs and the geometric conditions under which the contact force remains constant despite wear or displacement. Additionally, the paper introduces a method for synthesizing the cam profile that compensates for nonlinear spring deformation, ensuring force constancy over a wide range of movement. The analytical results were validated through parametric simulations, which assessed the influence of wear depth, rail inclination, and external vibrations on the system’s force output. These simulations, executed within a numerical framework using scientific computing tools, demonstrated that the deviation of the contact force does not exceed a few percent under typical disturbances. Experimental verification further confirmed the theoretical predictions. The study exemplifies the effective use of mathematical modeling, nonlinear mechanics, and numerical methods in the design of energy transmission components for transport applications, contributing to the development of robust and maintainable systems.
Naema M. Mansour, Abdelazeem A. Abdelsalam, Ibrahim A. Awaad
Protecting microgrids poses significant challenges owing to their diverse operational modes, multiple power infeed sources, variable fault current levels, heterogeneous control strategies, and the high penetration of intermittent renewable energy sources (RESs). These characteristics undermine the effectiveness of conventional protection schemes, particularly those based on overcurrent relays (OCRs) that are designed for systems with predictable and high fault currents. During islanded operation, a common mode in microgrids, fault currents are often reduced, making fault detection and isolation even more difficult. These limitations underscore the urgent need for intelligent, adaptive, and fast-responding fault detection and classification algorithms tailored specifically to the nature of microgrids. To address this gap, this study proposes a novel fault detection and classification approach that combines the Wavelet Scattering Transform (WST) for robust feature extraction with a Long Short-Term Memory (LSTM) network for accurate temporal pattern recognition and classification. Although WST has demonstrated remarkable performance in audio and image classification, its use in power system analysis remains largely unexplored. In this study, WST was used for the first time to process fault current signals in microgrids, resulting in significant feature matrices for training and testing. WST is especially excellent for capturing hidden properties in current waveforms, making it ideal for classification applications. The proposed methodology was validated using a Consortium for Electric Reliability Technology Solutions (CERTS) microgrid testbed. All simulations were performed in MATLAB, which served as the platform for modeling the CERTS microgrid, configuring the WST, and implementing the LSTM network. A comparative analysis with conventional techniques highlighted the superior classification accuracy and robustness of the proposed WST-LSTM framework.
Yaramala Anil Kumar, Sirimalla Mahesh, Shetapagula Raviteja
et al.
Nowadays, power electronic converters are employed in various appliances to efficiently transform voltages. This paper focuses on designing a single-switch DC-DC converter with low ripple content, high voltage gain, and minimal power losses. This type of converter finds applications in diverse areas such as solar systems, electric vehicles, and DC micro grids. In this paper, we specifically design the single-switch converter for electric vehicle applications. Given the rising costs of fuel and diesel, there is a growing shift towards economical electric vehicles. This converter incorporates active elements, diodes, a single switch, and a Li-ion battery. The results demonstrate that the battery can be efficiently charged in less time with reduced ripple content and increased gain. These outcomes were achieved through simulations using MATLAB Simulink.
Abstract The authors present a low‐loss dual‐permanent‐magnet‐excited vernier (DPMEV) machine with segmented stator design to meet the requirements of low iron loss of electric aircraft based on the field modulation theory. The stator topology features and losses of both the original and segmented DPMEV machines are comparatively investigated. Then, the armature air‐gap flux density is deduced by the magnetic motive force‐permeance model, and the influence of each harmonic on the losses are analysed. It is found that the harmonic which produces losses in the original machine reduced greatly after introducing the segmented structure. Furthermore, the electromagnetic performances of two DPMEV machines are comparatively analysed by finite element analysis. Finally, two prototypes of the original and segmented DPMEV machines are built and tested to verify the theoretical analysis.
Lucas Barroso Spejo, Tanya Thekemuriyil, Renato Amaral Minamisawa
This study evaluates the annual global energy-savings potential of various power electronics applications utilizing commercial silicon carbide (SiC) wide bandgap (WBG)-based power converters. As the first analysis to focus on real market products, our findings reveal that SiC-based converters offer significant energy-saving potential across all examined applications. Additionally, given the substantial yearly growth in installing photovoltaic (PV) systems and electric vehicle (EV) chargers, we project a considerable future energy-saving potential. This research underscores the importance of SiC technology in enhancing energy efficiency and supports its broader adoption in power electronics to achieve global energy savings.