Browse Topic: Electrical systems

Items (16,580)
Although carbon fiber-reinforced aluminum-lined hydrogen storage vessels (Type III) exhibit outstanding specific strength and specific stiffness, the constraints imposed by their design parameters on fatigue performance and ultimate load-bearing capacity remain incompletely elucidated. We propose a fatigue life prediction method for high-pressure vessels that couples progressive damage in the fiber composite with cumulative damage in the metallic liner, aimed at forecasting the fatigue performance of Type III pressure vessels under cyclic loading. Furthermore, a finite element analysis systematically investigates the influence of key design parameters, for nominal pressure, liner diameter and liner thickness, on fatigue performance and ultimate load-bearing capacity. Results indicate that fatigue life significantly decreases with increasing nominal pressure and liner diameter, with nominal pressure exerting a more pronounced effect. Notably, altering the autoclave pressure alone cannot
Bi, ZhihaiZhang, Qian
To address the issues of battery overcharge damage caused by voltage imbalance and excessive grid-connected inrush current when high-rate charge-discharge energy storage batteries are connected to the DC side of cascaded energy storage converters, this paper proposes a three-stage pre-charging control strategy considering battery characteristics. This strategy achieves rapid charging and voltage balancing control of energy storage modules through the orderly connection of three stages: “uncontrolled rectification - sorting and voltage balancing - balancing maintenance”. In the first stage, an uncontrolled rectification method with series soft-start resistors is adopted to reduce the inrush current at power-on. In the second stage, based on the FPGA parallel full-comparison sorting algorithm, the DC-side voltage of each sub-module is quickly balanced by switching sub-modules. In the third stage, the number of fixed sub-modules to be cut off is maintained to continuously optimize the
Gu, CongWu, RuiZhou, WenCai, WenjieTian, YunxiangYang, Zhiqing
To enhance the safety and efficiency of power batteries for new energy vehicles, a high-fidelity thermal management simulation model for lithium-ion batteries was established using a multi-scale coupled approach encompassing "cell-module-pack" levels. Charge/discharge experiments within the 15–45°C temperature range and under various State of Charge (SOC) conditions were conducted to obtain cell characteristic parameters. A second-order RC equivalent circuit model was constructed and validated. A three-dimensional thermal model of the battery pack was developed using the NX and STAR-CCM+software platforms and validated through high/low-temperature humidity tests. Results indicate that simulation errors for battery pack temperature and cooling line pressure were both below 3%. The model accurately simulates thermal behavior from microscopic cell characteristics to macroscopic battery pack dynamics.
Luo, ZhaoyangSong, Lan
With the rapid growth of renewable energy sources such as photovoltaics, energy storage systems, and wind power, hybrid AC/DC microgrids (H-MGs) are gradually emerging as a key technology for achieving efficient interconnection between generation units and load demands. However, issues such as communication delays, unequal power sharing, and the restoration of voltage and frequency in hybrid microgrids have posed serious threats to the stable operation of microgrids. We also need to appropriately adjust the simulation parameters to ensure that the proposed control framework maintains sufficient flexibility under different load conditions and achieves high operating efficiency in simulation. To tackle these challenges, this paper proposes a distributed secondary control strategy grounded in coordinated consensus and combined with droop-based interlinking converters (ICs) to realize power coupling between the AC and DC subgrids. The proposed method enables precise active-power sharing
Yu, PeijieZhang, FanghaiSun, WeiYuan, WeiboPeng, Bo
In this paper, the design and process research of uniform filling linear trajectory for filament wound hydrogen storage tank with unequal polar holes are carried out. Firstly, by optimizing the slip coefficient, the winding angles of the left and right heads are smoothly and continuously transitioned to the cylindrical section. We study the necessary conditions for achieving the central angle of uniform filling, and calculate the tangent points of the trajectory line based on the continuous fraction principle. Meanwhile, the slip coefficients at the left and right ends that satisfy stable winding and uniform covering are determined. Based on the equal contour constraint conditions, we analyze the motion trajectory equation of the four-axis winding machine and convert it into the corresponding machine code for actual winding operations. Experimental results show that stable winding of fibers on the surface of the unequal-polar-hole mandrel is achieved, and uniform filling and winding
Chen, BaosenFu, JianhuiCao, XuewenYu, Libin
Aimed at the high energy consumption for battery heating of a light hybrid truck in low-temperature winter, this paper proposes an optimized battery thermal management scheme based on motor waste heat and PTC cooperation. Then it verifies its energy-saving performance based on multi-condition simulation and testing. Taking the constant-speed condition at -5°C as an example, firstly, the accuracy of the battery thermal management model is verified by comparative simulation and test. Then, based on the verified model, the battery thermal management model is simulated under typical winter conditions at 0°C and 5°C. The analysis results show that, when the battery temperature is raised from the initial state to a certain target, the energy consumption of the motor waste heat-assisted PTC heating scheme is obviously less than that of PTC heating. The energy saving rates are 33.137% at -5°C, 32.45% at 0°C, and 32.56% at 5°C, respectively. The research results have proved that the effective
Meng, ShunZhang, DongZhang, YuZhang, ChunyuYao, MingyaoQiu, LiangQian, Yejian
Currently, with the continuous development of electric vehicles, DC microgrids have attracted widespread attention due to their flexible access methods and high energy transmission efficiency. However, since the distributed secondary control of DC microgrids relies on information exchange through communication networks, false data injection (FDI) attacks on these networks may cause control algorithms to fail, leading to voltage deviations, output current imbalance, and in severe cases, system instability. This study focuses on DC microgrids based on parallel DC–DC buck converters and proposes a distributed secondary control strategy based on a sliding mode observer to address FDI attacks. By treating the system's FDI attack signals as an extended state, an extended sliding mode observer is designed to track the attack signals. Based on the observed attacks, a control algorithm is proposed that compensates the control inputs through the observer, ensuring proportional sharing of bus
Sun, WeiChen, JingYu, JinzhuYuan, WeiboPeng, BoLin, Fei
The global automotive industry is accelerating its transition toward low-carbon solutions, with hydrogen fuel cell vehicles offering core advantages of zero emissions and extended range. Their critical component is the Type III fiber-wound hydrogen storage tank, whose performance directly impacts vehicle operational safety and driving range. This technology has now achieved widespread adoption. However, two significant challenges persist in the dome region of these tanks: first, modeling accuracy is difficult to control due to dynamic variations in thickness and winding angles; second, fiber thickness buildup frequently occurs near the pole holes. These issues compromise both the design reliability and manufacturing quality of hydrogen storage tanks. Therefore, this study adopted a combined approach of theoretical analysis and numerical simulation. First, based on composite mechanics theory and calibrated with experimental data (Tensile, Compression, and Shear Tests on NOL and
Wang, JianguoZhang, QianCao, XuewenZheng, XuanxuanLi, Jiajie
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Li, ZhiyingLi, JeiZhu, AndingBai, XianxuLi, WeihanLi, Rui
The monorail crane is important in mining operations, and its operation affects both safety and efficiency. Currently, fault diagnosis for monorail cranes has several challenges, such as heterogeneous mixing of multimodal data, poor use of knowledge, low real-time requirements, and high deployment costs for large-scale models. To solve these problems, we present an agent framework using a multimodal knowledge graph and a lightweight large model. In particular, we construct a fault knowledge graph for monorail cranes, organizing professional knowledge about components, failure modes, symptoms, and maintenance. By employing retrieval-augmented generation (RAG) technology, the knowledge graph is merged with the Qwen lightweight large model (low-rank adaptation) for fine-tuning to develop a diagnostic agent with task planning, tool invocation and memory. The experimental results show that the agent framework reduces “machine hallucination” and outperforms conventional diagnostic accuracy
Zhang, YixuanXue, ShunBi, XiangWei, XingKang, RanyuJue, JieCheng, Liruiran
In China, the installed capacity of renewable energy sources such as wind and photovoltaic power has ranked first in the world for consecutive years, and new energy has become a core driver of energy structure transition. However, the strong volatility and intermittency of new energy output seriously affect the safe and stable operation of the power system, and high-efficiency energy storage technology is the key to solving this problem. Focusing on the short-term high-power charging and discharging characteristics of high-temperature superconducting magnets (SMES), this study proposes a Hybrid Energy Storage System (HESS) that combines SMES with Battery Energy Storage Systems (BESS) to enhance the short-term power support capability of electrochemical energy storage. Variational Mode Decomposition (VMD) is introduced to establish a multi-level power allocation method, which addressing issues such as mode mixing, end effects, and low decomposition efficiency that are prone to occur in
Liu, HaiyangWang, PengfeiZhou, WenLu, JingWu, YananYin, YunkuoJiang, Liping
AE-8D Wire and Cable Committee
A full lithium-ion battery (LIB) pack has hundreds to thousands of cells, coolant flow lines and channels, and channel bends to control cell temperature within its operating window and minimize cell internal resistance, aging, and fire risk. A 75 kWh LIB pack has four modules, and each has 23–25 bricks. Two challenges in battery state predictions for hot and subzero temperatures are battery temperature (Tbatt ) and coolant flow within the whole pack. In this work, a 1D 75 kWh full-pack model with its thermal management system is developed using a holistic reverse-engineering method, which can predict Tbatt at any bricks/modules and inlet/outlet coolant flow characteristics. A Tesla Model Y equipped with dual e-motors is tested on an in-house state-of-the-art chassis dynamometer. The test data at V = 60–80 km/h, 100–150 A constant discharge, and Tbatt = −10°C to 40°C are used to develop the model. The 75 kWh pack model features 4000+ cylindrical cells (96S46P, Panasonic 21700-format
Sok, RatnakKusaka, Jin
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