Search Results (224)

In response to the urgent requirement for sustainable power supply for deep-sea or offshore underwater sensing equipment, this work investigates autonomous power generation aboard marine vessels. The vertical vibrations induced by wave excitation at the bottom of the vessel are utilized to drive the vibration energy harvesters on the deck for power generation. In a scenario involving automatic steering, a multiplicity of magnetoelectric harvesters mounted on the deck would move vertically in response to surface wave motion, enabling continuous conversion of wave energy into electrical power. The key feature of this study is that the ship-based self-power generation system is simple to install and safe, with the vibration energy harvesters mounted above the sea surface to avoid the unpredictable underwater sea conditions. This study presents a numerical case analysis of a three-magnet energy harvester designed to generate induced electrical power under wave conditions characterized by a speed of V = 3.0 m/s, amplitude of Z_o = 0.4 m, and wavelength of λ = 2.0 m. Prior to optimizing the ship-based energy harvester, the mathematical model of a three-magnet vibration system was validated against experimental data to ensure accuracy. Subsequently, a sensitivity study was performed to evaluate the influence of wave parameters (e.g., amplitude and wavelength) and the harvester’s geometric parameters on the electrical power output. To maximize power generation, the flower pollination algorithm—an efficient bio-inspired optimization method known for its robustness in global search—was integrated with the objective function defined as the root-mean-square electrical power. Simulation results indicate that the optimized harvester is capable of producing up to 0.1943 W. These findings highlight the potential of ship-based energy harvesters as a sustainable and reliable source of electrical power. Full article

This research paper presents Volvo SmartCell, an AC battery technology that integrates modular multilevel converters and battery cells to form a unified system for electric vehicle propulsion and power supply. The research work addresses the broader challenge of reducing driveline cost and complexity by replacing traditional components such as inverters, onboard chargers, centralized DC/DC converters, vehicle control units and many more. SmartCell uses distributed Cluster Boards comprised of H-bridges which are controlled via wireless communication to generate AC voltage, deliver redundant low voltage power, and support cell level protection mechanisms. The prototype testing demonstrates that the system can supply traction power by engaging clusters according to the required voltage depending on motor speed, achieve AC grid charging by synthesizing sinusoidal voltages without a dedicated charger, and provide autonomous DC/DC operation through cluster level voltage regulation. Simulations further indicate that multilevel voltage generation can reduce switching losses and improve electric machine efficiency compared to conventional systems. Additional benefits include active cell balancing, support for mixed cell chemistries, and high redundancy through multiple independent power branches. Challenges remain in wireless bandwidth limitations and cost optimization of Cluster Boards. Ongoing development aims to enhance communication robustness and validate safety for non-isolated grid charging. Full article

This article presents a performance assessment of an electrical power and cooling system powered by a parabolic dish collector and using refrigerants with low global warming potential. The study was conducted using energy and mass balances for each component and system. The simulation includes various parameters, such as solar radiation, the focal temperature of the solar collector, the ambient temperature, the power cycle pressure ratio, and the chiller’s evaporation temperature. The results show that the efficiency of the organic Rankine cycle with the refrigerant R1233zd(E) is similar to that of the refrigerants R123 and R245fa and is up to 11 and 50 times lower than with R290 and R744, respectively. The solar absorption chiller using the refrigerant R717 can achieve cooling with a supply temperature up to 5 °C lower than that of R718. The dynamic simulation results show that the energy efficiency of the proposed solar-powered generator–chiller is 14% higher than that of a standard solar-powered absorption chiller. Furthermore, the same solar-powered generator–chiller reduces the primary energy required by a conventional system by 60% (PESr = 0.60). The presented results may be useful for the design of sustainable generator–chillers for rural areas or for autonomous housing in tropical climates. Full article

In this work the feasibility of fully autonomous hydrogen homes designed for complete off-grid operation is presented. A detailed mathematical modeling and optimization model is developed to evaluate the technical performance and economic feasibility of hydrogen fuel cell-powered residential systems with no grid connection or fallback. The system integrates primary and standby Proton Exchange Membrane (PEM) fuel cells, multi-day hydrogen storage, advanced power conditioning, and comprehensive controls to achieve reliable year-round power supply. The analysis encompasses a complete 20-year lifecycle cost assessment. The results demonstrate that fully autonomous hydrogen homes achieve 99.85% system availability with 13.1 h of potential downtime annually, providing reliable energy independence. The levelized cost of electricity over the 20-year system lifetime is calculated at 0.4543 US$/kWh at baseline hydrogen prices of 6 US$/${\mathrm{kg}}_{{\mathrm{H}}_2}$, substantially higher than grid-connected alternatives. The analysis identifies critical sensitivity to hydrogen pricing and demonstrates that at hydrogen costs below 3 US$/${\mathrm{kg}}_{{\mathrm{H}}_2}$ (achievable with mature green hydrogen production), competitive payback periods of 12–15 years are possible in high-cost electricity regions. This study concludes that hydrogen-based autonomous homes represent a viable long-term solution for residential energy independence, particularly in remote or off-grid locations where grid connection is impractical or in regions with high electricity tariffs and developing green hydrogen production capacity. Full article

Electricity forecasting is one of the most crucial aspects in maintaining stable, reliable, and autonomous power systems. While recently developed forecasting methods based on large language models can make accurate predictions, these models are still struggling due to their computational complexity, which requires more computing power, and their reliance on carefully designed prompts. This makes them complicated and harder to use in practice. To address this, we propose a Single-Attention Large Language Model (SA-LLM) that uses a unified attention mechanism to understand relationships between main and additional variables, without the need for manually created prompts. The proposed framework has been tested on real electricity supply and demand datasets, which are obtained from major U.S. electricity markets, including PJM, MISO, NYISO, ISO New England, ERCOT, SPP, and CAISO. Experimental results demonstrate that the proposed SA-LLM method outperforms the existing counterpart methods in terms of accuracy and associated errors. More specifically, the SA-LLM has also achieved a 22.5% improvement in the mean absolute error compared with traditional LSTM-based models, while reducing memory usage by 52.1% and training time by 38.4% relative to recent LLM-based methods. Furthermore, the SA-LLM demonstrates strong zero-shot generalization, achieving an additional 18.2% improvement in the MAE on previously unseen regions. Full article

Vibration energy harvesting is a promising approach to support and supplement power, thereby extending the lifetime of low-power sensor nodes under suitable vibration conditions, i.e., in environments where sufficient ambient vibrations are available. It is not a universal autonomous power-supply solution, particularly when generalized across the Internet of Things (IoT), because the harvested power is typically limited to the µW–mW range and depends strongly on the vibration frequency content, amplitude, and operating point relative to resonance. Furthermore, many practical harvesters rely on resonant mechanisms, which are inherently narrowband, and therefore their performance can degrade significantly under detuning or broadband/variable-frequency excitations. In addition, energy-management and power-conditioning electronics (rectification, storage, and regulation) are required to convert the generated electrical energy into a stable and usable DC supply for practical loads. In this work, we develop a nonlinear state-space model of a three-phase electromagnetic vibration energy harvester with spatially displaced coils and evaluate its electrical output characteristics and DC power behavior using numerical simulations. Full article

This survey is an integrated and complete summary of the strategies and technological systems of surveying environmental hazard in marine, freshwater, and brackish environments. Contrary to the previous articles where the separate parts of the monitoring chain are investigated or certain environments/enabling technologies are considered, the given work has a cross-domain approach that unites sensing modalities, data acquisition schemes, communication schemes, operational platforms, data analytics, energy management schemes, and regulatory compliance into one consistent framework. The survey systematically examines the entire sensing-to-cloud pipeline, which includes sensor technologies, data acquisition systems, telecommunication infrastructures, and a variety of monitoring platforms such as buoy-based systems, Unmanned Surface Vehicles (USVs), Autonomous Underwater Vehicles (AUVs), and Unmanned Aerial Vehicles (UAVs). In addition, it touches on the administration and examination of mass environmental data, including cloud-based systems and AI-based methods of automated feature identification, anomaly recognition and predictive modeling. The key points of the autonomy of the system, including power supply solutions and energy-conscious management, are also mentioned, as well as the relevant regulations on the environmental monitoring nationally, at the European level, and globally. This paper presents a systematic six-step design process of aquatic environmental monitoring systems: (1) risk categorization, (2) physical data acquisition systems, (3) monitoring platforms, (4) data management & analytics, (5) energy autonomy strategies, and (6) regulatory compliance. The systematic framework offers researchers and practitioners practical guidelines to follow when designing end-to-end systems, thus completing the gaps in the historically disjointed research strands and going beyond the traditional domain- and technology-based studies. Full article

To meet the power supply requirements of autonomous underwater vehicles (AUVs) in dynamic ocean environments, this study proposes a wireless power transfer (WPT) system for AUVs, incorporating novel nanocrystalline flake ribbon cores. The proposed system utilizes the excellent magnetic field concentrating and shielding characteristics of nanocrystalline materials. The flake ribbons are fabricated by compressing dielectric materials mixed with nanocrystalline ribbons, which effectively reduces eddy-current loss. The layout arrangement of nanocrystalline materials is investigated, and a magnetic coupler employing ribbon-type nanocrystalline materials is adopted based on simulation analysis and comparison. The influence of nanocrystalline materials on the mutual inductance distribution between the transmitting and receiving coils is explored. Considering the potential positional misalignments between the transmitting and receiving coils in practical marine environments, the misalignment tolerance of the system is comprehensively analyzed and experimentally verified. An experimental prototype is established, and the results demonstrate that the proposed magnetic coupler design significantly improves the performance of the WPT system. Compared with the conventional WPT system without nanocrystalline flake ribbon cores, the proposed design effectively increases the power transfer efficiency by 2.99% and greatly stabilizes the output power by 36%. This study validates the effectiveness and practicability of using nanocrystalline flake ribbon cores in WPT systems for AUV applications. Full article

Nonlinear energy harvesting systems based on multibody structures constitute a promising solution for autonomous devices powered by ambient vibrations. This paper presents the modeling and control of a nonlinear energy harvester employing a double pendulum configuration and BLDC motors operating as generators. The primary objective of the study was to develop a control strategy that enables the maximization of harvested power while simultaneously improving the energy conversion efficiency during the charging of the battery supplying the target system. The developed model incorporates the mechanical equations of motion of the double pendulum, an electrical model of the BLDC motors, and two independently controlled buck–boost converters, each connected to one joint of the pendulum. In addition, a perturb-and-observe (P&O) maximum power point tracking (MPPT) algorithm was implemented, which utilizes a portion of the computational resources of the target system’s microcontroller and allows for dynamic adjustment of the electrical loads seen by the generators. Simulation results obtained in the Simulink environment confirm that the application of independent power converters combined with local MPPT control leads to an increase in the total harvested power and ensures more stable battery charging under conditions of variable mechanical excitation. The obtained results demonstrate the effectiveness of the proposed approach and indicate its potential applicability in self-powered systems operating in environments characterized by irregular and stochastic vibrations. Full article

For next-generation biomedical and biochemical sensor nodes, the analog front-end demands a direct interface with current-output sensors, extreme miniaturization, and nanowatt power consumption to enable energy autonomy. This work directly addresses these needs by presenting a comparative analysis of four minimalist, first-order, current-mode $\Delta \Sigma$ modulator ($\Delta \Sigma$M) architectures. Optimized for ultra-low-voltage operation (supply $\le 0.5$ V), the investigated topologies—including resistive, switched-capacitor, and current-reference-based cores—exploit passive integration and charge-domain feedback, eliminating the need for power-hungry active blocks. Detailed circuit-level simulations confirm that, with ad hoc techniques, it is possible to achieve stable first-order noise shaping in the deep near-threshold region, delivering up to 10-bit resolution while consuming less than 10 nW at a 0.5 V supply voltage achieving a signal bandwidth in the sub-10 hertz range. This study validates that robust $\Delta \Sigma$ conversion is feasible under extreme area and power constraints by leveraging architectural simplicity. The clear performance–complexity trade-offs outlined make these current-mode architectures ideal candidates for monolithic integration within miniaturized, energy-autonomous sensing systems. Full article

The development of autonomous mobile robots or automated guided vehicles is consistently challenged by energy-storage constraints, and while batteries are the standard solution for mobile robots, dynamic wireless power transfer is an alternative way to supply power without reliance on chemical energy storage. For efficient dynamic wireless power transfer, transmitting coils should be energized as required, necessitating real-time position tracking of the receiving coil. Current prevalent techniques require complex modifications to existing systems and additional position sensors, which increase total costs. This article proposes a novel receiving coil position detection method for wireless power transfer systems without using external receiving coil position detection sensors and describes the application of the sensorless coil position detection method and its advantages compared to other methods. The proposed method was implemented on an existing low-power, miniaturized test bench. The described method was successfully validated and correctly switched transmitting coils, ensuring continuous movement of an electric vehicle, therefore proving its viability as a potential new approach for sensorless receiving-coil detection. Experimental results demonstrate that the prototype achieved a maximum power transfer efficiency of 53.8% while maintaining continuous transmitting coil switching operation at vehicle speeds up to 77 cm/s. Full article

The integration of 3D printing and artificial intelligence is transforming healthcare management by driving innovations in personalized care, supply chain operations, and clinical workflows. This review offers a comprehensive overview and in-depth analysis of recent (2018–2025) applications where AI technologies enhance 3D printing within healthcare. We explore how AI-powered design and optimization facilitate the creation of patient-specific medical devices, implants, and even bioprinted tissues, while intelligent process control increases both quality and efficiency. Additionally, we examine regulatory and ethical considerations, including the evolution of frameworks for AI-enabled devices, as well as challenges in data governance, validation, and equitable access. The review takes a global perspective, presenting real-world case studies that showcase both successful implementations and ongoing challenges. We also discuss various perspectives and controversies, such as the balance between innovation and safety in autonomous AI design, and highlight areas where further research is needed. In contrast to previous narrative reviews that focus solely on clinical applications or technical aspects, this review uniquely evaluates the combined impact of AI and 3D printing on healthcare management—including cost-effectiveness, governance, decision-making processes, and point-of-care manufacturing. This work is particularly valuable for hospital administrators, clinical operations leaders, health policymakers, and biomedical innovation teams seeking to understand the broader implications of AI-enhanced 3D printing in healthcare management. Nevertheless, despite promising advancements, the field is constrained by heterogeneous evidence, a lack of standardized evaluation metrics, and insufficient long-term outcome data, which together limit the ability to fully assess the sustained impact of AI-integrated 3D printing in healthcare environments. Full article

A new approach to end-to-end power delivery for increasingly sought-after hierarchical power delivery units (PDUs) is presented, improving the power efficiency of portable systems. The benefits of the technique are demonstrated through a PDU comprising multiple DC–DC converters, such as low-dropout regulators (LDOs), and the support of heterogeneous loads. A properly tailored Q-algorithm is combined with power gating to manage the power supplied by a multi-level PDU. The effectiveness of the proposed method is evaluated via a realistic PDU for different combinations of loads. The learning-based technique yields up to 13% higher total end-to-end power efficiency in the case of similar loads by utilizing four available LDOs compared to the case of a single LDO, which supports the same span of loads. Moreover, the proposed method improves power efficiency by up to 5% in the case of heterogeneous loads when compared to other autonomous state-of-the-art power management units. Full article

Ocean current energy, owing to its predictability and stability, is regarded as an ideal power source for distributed marine observation networks and underwater intelligent equipment. However, conventional ocean current energy devices that rely on rigid turbines and electromagnetic generators generally suffer from high cut-in flow velocity, bulky size, high maintenance costs, and significant environmental disturbance, making them unsuitable for deep-sea, miniaturized, and long-duration power supply scenarios. These limitations highlight the urgent need for flexible and low-speed energy harvesters capable of autonomous, long-term operation. In recent years, nanogenerator technology has provided new opportunities for distributed and low-power ocean current energy harvesting. PENGs and TENGs can directly convert weak mechanical energy into electricity, enabling energy harvesting in small-scale and low-velocity flow fields. PENGs offer high durability and mechanical robustness, whereas TENGs exhibit superior output performance in low-speed and intermittent flows. This paper provides a comprehensive review of structural designs, material innovations, interface engineering, hybrid energy-conversion architectures, and power-management strategies for PENG- and TENG-based ocean current energy harvesters. Overall, future progress will rely on the integration of intelligent materials, multi-field coupling mechanisms, and system-level engineering strategies to achieve durable, scalable, and autonomous ocean current energy harvesting for distributed marine systems. Full article

The growing incorporation of distributed energy resources (DER) in power distribution grids, although pivotal to the energy transition, increases operational variability and amplifies the exposure to disturbances that can compromise resilience and the continuity of service during contingencies. Addressing these challenges requires both a shift toward flexible distribution architectures and the adoption of advanced power electronics interfacing systems. In this setting, this paper proposes a resilience-oriented strategy for medium-voltage (MV) distribution systems and clustered hybrid AC/DC microgrids interfaced through solid-state transformers (SSTs). When a fault occurs along an MV feeder segment, the affected microgrids naturally transition to islanded operation. However, once their local generation and storage become insufficient to sustain autonomous operation, the proposed framework reconfigures the power routing within the cluster by activating an emergency low-voltage DC (LVDC) power path that bypasses the faulted MV section. This mechanism enables controlled power sharing between microgrids during prolonged MV outages, ensuring the supply of priority loads without oversizing SSTs or reinforcing existing infrastructure. Experimental validation on a reduced-scale SST prototype demonstrates stable grid-forming and grid-following operation. The reliability of the proposed scheme is supported by both steady-state and transient experimental results, confirming accurate voltage regulation, balanced sinusoidal waveforms, and low current tracking errors. All tests were conducted at a switching frequency of 50 kHz, highlighting the robustness of the proposed architecture under dynamic operation. Full article