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Journal articles on the topic 'Voltage capacity curve'
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1
Han, Xuebing, Xuning Feng, Minggao Ouyang, Languang Lu, Jianqiu Li, Yuejiu Zheng, and Zhe Li. "A Comparative Study of Charging Voltage Curve Analysis and State of Health Estimation of Lithium-ion Batteries in Electric Vehicle." Automotive Innovation 2, no. 4 (December 2019): 263–75. http://dx.doi.org/10.1007/s42154-019-00080-2.
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AbstractLithium-ion (Li-ion) cells degrade after repeated cycling and the cell capacity fades while its resistance increases. Degradation of Li-ion cells is caused by a variety of physical and chemical mechanisms and it is strongly influenced by factors including the electrode materials used, the working conditions and the battery temperature. At present, charging voltage curve analysis methods are widely used in studies of battery characteristics and the constant current charging voltage curves can be used to analyze battery aging mechanisms and estimate a battery’s state of health (SOH) via methods such as incremental capacity (IC) analysis. In this paper, a method to fit and analyze the charging voltage curve based on a neural network is proposed and is compared to the existing point counting method and the polynomial curve fitting method. The neuron parameters of the trained neural network model are used to analyze the battery capacity relative to the phase change reactions that occur inside the batteries. This method is suitable for different types of batteries and could be used in battery management systems for online battery modeling, analysis and diagnosis.
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Wang, Wen Juan, Guang Xi Zheng, and Wei Dong Lu. "A Design of Charger with Intelligent Charging and Capacity Detection." Applied Mechanics and Materials 263-266 (December 2012): 64–68. http://dx.doi.org/10.4028/www.scientific.net/amm.263-266.64.
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This is a design of intelligent charger with battery capacity detection based on STC12C5AS2 single chip microcomputer. By connecting PC, users could set cut-off charge-discharge voltage and current directly to get monitor the no-man. It realized to judge limiting voltage and current automatically and has intelligent floating and trickle charge. The users could see voltage curve, current curve, percent of charge, capacity both charge and discharge respects. Here, we introduced partly, including simply circuit design and offered our photo both circuit and real device. We focus to detail program design of PC end in the paper. We used double buffer technique to solve flicker phenomenon. Meanwhile, when we designed and performed repeatedly, we found another good ways to save CPU and reduce volume of calculation. That is that we created another two container to save calculated data so to plot more fast when grid is in unchanged.
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Wu, Shu-Hsien, Yue Kuo, and Chi-Chou Lin. "Light Wavelength Effects on Performance of a-Si:H PIN Photodiodes." MRS Proceedings 1426 (2012): 199–204. http://dx.doi.org/10.1557/opl.2012.840.
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ABSTRACTLight effects on the performance of the a-Si:H PIN photodiode has been studied. The leakage current-voltage and capacitance-voltage curves under the red, green and blue light illuminations were measured. The apparent charge storage density in the negative voltage range was quantified from the capacitance-voltage curve; charges in the positive voltage range were estimated from the leakage current-voltage curve. A comparison of charge storage capacities of diodes with different intrinsic layer thicknesses is also presented. The diode under the long wavelength light illumination condition stored more charges than that under the short wavelength light illumination condition because the former could penetrate the intrinsic a-Si:H layer deeper than the latter could. The leakage current and charge storage capacity of the diode are determined by the generation of electron-hole pairs, the depletion of charges in the intrinsic layer, and the supply of charges from the electrodes. The number of incident photons is critical to the process.
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Kulanchikov, Yuriy O., Pavel S. Vergeles, and Eugene B. Yakimov. "Effect of low-energy electron irradiation on voltage-capacity curves of Al/SiO2/Si structure." Modern Electronic Materials 5, no. 4 (December 31, 2019): 175–79. http://dx.doi.org/10.3897/j.moem.5.4.52311.
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Charging of dielectric targets by electron irradiation is a well-known phenomenon which should be taken into account in characterization of dielectric materials and coatings with electron microscopy, in electron beam lithography, in development of dielectric coatings for spacecrafts and other fields of science and engineering. Charging kinetics is strongly affected by spatial distribution of electrons and holes formed by irradiation. At the experimental electron beam energy electron penetration depth is smaller than dielectric thickness and this allows identifying the contribution of excess carrier transport to trap formation at the SiO2/Si interface. Low-energy electron beams have been shown to substantially affect C–V curve slope, i.e., to form traps at the interface. We have studied the effect of bias applied to the test structure before and after electron beam irradiation. The experiment has shown that bias of either polarity applied to the test MOS structure before low-energy electron beam irradiation practically does not affect the C–V curves of the test structure. Positive bias applied to the metallization layer during low-energy electron beam irradiation has a strong effect on the C–V curve pattern while negative bias affects the C–V curves but slightly. Study of the stability of the changes caused by electron beam irradiation has shown that the C–V curves of the test structure restore slowly even at room temperature. Application of negative bias decelerated charge relaxation.
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Liu, Meng, Wei Yong Jiang, Yi Wei Zhang, and Yong Min. "Available Transmission Capacity Analysis for the Receiving-End Grid of UHV-DC Transmission System." Applied Mechanics and Materials 740 (March 2015): 390–96. http://dx.doi.org/10.4028/www.scientific.net/amm.740.390.
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UHV-DC transmission system presents certain adverse reactive characteristics to its receiving-end grid. Based on the approach of P-V curve and V-Q curve, this paper presents a method of voltage stability analysis for the receiving-end grid of UHV-DC transmission system, which gives its available transmission capacity (ATC), voltage limit and reactive power margin, with the consideration of the normal, N-1 and N-2 operation situations and the situation of the commutation failure. Different with traditional ATC analysis, the characteristics of UHV-DC transmission system is included here. With the real UHV-DC project of ±800kV HaZheng in China, the effectiveness and efficiency of the proposed mothed are verified.
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Oyarbide, Mikel, Mikel Arrinda, Denis Sánchez, Haritz Macicior, Paul McGahan, Erik Hoedemaekers, and Iosu Cendoya. "Capacity and Impedance Estimation by Analysing and Modeling in Real Time Incremental Capacity Curves." Energies 13, no. 18 (September 16, 2020): 4855. http://dx.doi.org/10.3390/en13184855.
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The estimation of lithium ion capacity fade and impedance rise on real application is always a challenging work due to the associated complexity. This work envisages the study of the battery charging profile indicators (CPI) to estimate battery health indicators (capacity and resistance, BHI), for high energy density lithium-ion batteries. Different incremental capacity (IC) parameters of the charging profile will be studied and compared to the battery capacity and resistance, in order to identify the data with the best correlation. In this sense, the constant voltage (CV) step duration, the magnitudes of the IC curve peaks, and the position of these peaks will be studied. Additionally, the behaviour of the IC curve will be modeled to determine if there is any correlation between the IC model parameters and the capacity and resistance. Results show that the developed IC parameter calculation and the correlation strategy are able to evaluate the SOH with less than 1% mean error for capacity and resistance estimation. The algorithm has been implemented on a real battery module and validated on a real platform, emulating heavy duty application conditions. In this preliminary validation, 1% and 3% error has been quantified for capacity and resistance estimation.
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Feng, Xuning, Caihao Weng, Xiangming He, Li Wang, Dongsheng Ren, Languang Lu, Xuebing Han, and Minggao Ouyang. "Incremental Capacity Analysis on Commercial Lithium-Ion Batteries Using Support Vector Regression: A Parametric Study." Energies 11, no. 9 (September 3, 2018): 2323. http://dx.doi.org/10.3390/en11092323.
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Incremental capacity analysis (ICA) has been used pervasively to characterize the degradation mechanisms of the lithium-ion batteries, and several online state-of-health estimation algorithms are built based on ICA. However, the stairs and the noises in the discrete sampled voltage data obstruct the calculation of the capacity differentiation over voltage (dQ/dV), therefore we need methods to fit the sampled voltage first. In this paper, the support vector regression (SVR) algorithm is used to smooth the sampled voltage curve using Gaussian kernels. A parametric study has been conducted to show how to enhance the performances of the SVR algorithm, including (1) speeding up the algorithm by downsampling; (2) avoiding overfitting and under-fitting using proper standard deviation σ in the Gaussian kernel; (3) making precise capture of the characteristic peaks. A novel method using linear approximation has been proposed to help judge the accuracy of the SVR algorithm in tracking the ICA peaks. And advanced SVR algorithms using double σ and using cost function that directly regulates the differentiation result have been proposed. The advanced SVR algorithm can make accurate curve fitting for ICA with overall error less than 1% (maximum 3%) throughout cycle lives, for four kinds of commercial lithium-ion batteries with LiFePO4 and LiNixCoyMnzO2 cathodes, making it promising to be further applied in online SOH estimation algorithms.
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Jones, C. Birk, Matthew Lave, Matthew J. Reno, Rachid Darbali-Zamora, Adam Summers, and Shamina Hossain-McKenzie. "Volt-Var Curve Reactive Power Control Requirements and Risks for Feeders with Distributed Roof-Top Photovoltaic Systems." Energies 13, no. 17 (August 19, 2020): 4303. http://dx.doi.org/10.3390/en13174303.
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The benefits and risks associated with Volt-Var Curve (VVC) control for management of voltages in electric feeders with distributed, roof-top photovoltaic (PV) can be defined using a stochastic hosting capacity analysis methodology. Although past work showed that a PV inverter’s reactive power can improve grid voltages for large PV installations, this study adds to the past research by evaluating the control method’s impact (both good and bad) when deployed throughout the feeder within small, distributed PV systems. The stochastic hosting capacity simulation effort iterated through hundreds of load and PV generation scenarios and various control types. The simulations also tested the impact of VVCs with tampered settings to understand the potential risks associated with a cyber-attack on all of the PV inverters scattered throughout a feeder. The simulation effort found that the VVC can have an insignificant role in managing the voltage when deployed in distributed roof-top PV inverters. This type of integration strategy will result in little to no harm when subjected to a successful cyber-attack that alters the VVC settings.
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Zheng, Yuejiu, Languang Lu, Xuebing Han, Jianqiu Li, and Minggao Ouyang. "LiFePO4 battery pack capacity estimation for electric vehicles based on charging cell voltage curve transformation." Journal of Power Sources 226 (March 2013): 33–41. http://dx.doi.org/10.1016/j.jpowsour.2012.10.057.
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Lee, Park, and Kim. "Incremental Capacity Curve Peak Points-Based Regression Analysis for the State-of-Health Prediction of a Retired LiNiCoAlO2 Series/Parallel Configured Battery Pack." Electronics 8, no. 10 (October 4, 2019): 1118. http://dx.doi.org/10.3390/electronics8101118.
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To recycle retired series/parallel battery packs, it is necessary to know their state-of-health (SOH) correctly. Unfortunately, voltage imbalances between the cells occur repeatedly during discharging/charging. The voltage ranges for the discharge/charge of a retired series/parallel battery pack are reduced owing to the voltage imbalances between the cells. To determine the accurate SOH of a retired series/parallel battery pack, it is necessary to calculate the total discharge capacity using fully discharging/charging tests. However, a fully discharging/charging test is impossible owing to the reduced voltage range. The SOH of a retired series/parallel battery pack with a voltage imbalance should be estimated within the reduced discharging/charging voltage range. This paper presents a regression analysis of the peak point in the incremental capacity (IC) curve from the fresh state to a 100-cycle aging state. Moreover, the SOH of the considered retired series/parallel battery pack was estimated using a regression analysis model. The error in the SOHs of the retired series/parallel battery pack and linear regression analysis model was within 1%, and hence a good accuracy is achieved.
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Gambert, R., and H. Baumgärtel. "The appearance of a “hump” in the capacity—voltage curve of nonaqueous CH3CN electrolytes at mercury." Journal of Electroanalytical Chemistry and Interfacial Electrochemistry 190, no. 1-2 (August 1985): 283–86. http://dx.doi.org/10.1016/0022-0728(85)80096-6.
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Xiao, Bin, Bing Xiao, and Luoshi Liu. "State of Health Estimation for Lithium-Ion Batteries Based on the Constant Current–Constant Voltage Charging Curve." Electronics 9, no. 8 (August 9, 2020): 1279. http://dx.doi.org/10.3390/electronics9081279.
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The state of health is an indicator of battery performance evaluation and service lifetime prediction, which is essential to ensure the reliability and safety of electric vehicles. Although a large number of capacity studies have emerged, there are few simple and effective methods suitable for engineering practice. Hence, a least square support vector regression model with polynomial kernel function is presented for battery capacity estimation. By the battery charging curve, the feature samples of battery health state are extracted. The grey relational analysis is employed for the feature selection, and the K-fold cross-validation is adopted to obtain hyper-parameters of the support vector regression estimation model. To validate this method, the support vector regression estimation model was trained and tested on the battery data sets provided by NASA Prognostics Center of Excellence. The experimental results show that the proposed method only needs some battery feature data, and can achieve high-precision capacity estimation, which indicates that the proposed method shows great efficiency and robustness.
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Chen, Yingqian, Chae-Ryong Cho, and Sergei Manzhos. "Lithium Attachment to C60 and Nitrogen- and Boron-Doped C60: A Mechanistic Study." Materials 12, no. 13 (July 3, 2019): 2136. http://dx.doi.org/10.3390/ma12132136.
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Fullerene-based materials including C60 and doped C60 have previously been proposed as anodes for lithium ion batteries. It was also shown earlier that n- and p-doping of small molecules can substantially increase voltages and specific capacities. Here, we study ab initio the attachment of multiple lithium atoms to C60, nitrogen-doped C60 (n-type), and boron doped C60 (p-type). We relate the observed attachment energies (which determine the voltage) to changes in the electronic structure induced by Li attachment and by doping. We compare results with a GGA (generalized gradient approximation) functional and a hybrid functional and show that while they agree semi-quantitatively with respect to the expected voltages, there are qualitative differences in the electronic structure. We show that, contrary to small molecules, single atom n- and p-doping will not lead to practically useful modulation of the voltage–capacity curve beyond the initial stages of lithiation.
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Gao, Jun Ying, and Jian She Tian. "Research on Photovoltaic Power Capacity Optimization in Microgrid." Applied Mechanics and Materials 291-294 (February 2013): 22–27. http://dx.doi.org/10.4028/www.scientific.net/amm.291-294.22.
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An optimization model to get the optimal capacity of photovoltaic connected to the microgrid aimed at reducing the loss and satisfying the node voltage constraints is proposed. A microgrid with n nodes and n-1 feeders is taken as an example to set a linear programming model. Taking a microgrid with 11 nodes, first sensitivity analysis method is applied to determine the best location of the photovoltaic power, and then the optimal value of the PV power capacity is calculated by the Matlab programming. Finally, the curve of the relationship between loss and the capacity of the ptotovoltaic power is plotted through Matlab, which qualitatively verifies the feasibility and practicality of the method.
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Kurzweil, Peter, and Wolfgang Scheuerpflug. "State-of-Charge Monitoring and Battery Diagnosis of Different Lithium Ion Chemistries Using Impedance Spectroscopy." Batteries 7, no. 1 (March 4, 2021): 17. http://dx.doi.org/10.3390/batteries7010017.
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For lithium iron phosphate batteries (LFP) in aerospace applications, impedance spectroscopy is applicable in the flat region of the voltage-charge curve. The frequency-dependent pseudocapacitance at 0.15 Hz is presented as useful state-of-charge (SOC) and state-of-health (SOH) indicator. For the same battery type, the prediction error of pseudocapacitance is better than 1% for a quadratic calibration curve, and less than 36% for a linear model. An approximately linear correlation between pseudocapacitance and Ah battery capacity is observed as long as overcharge and deep discharge are avoided. We verify the impedance method in comparison to the classical constant-current discharge measurements. In the case of five examined lithium-ion chemistries, the linear trend of impedance and SOC is lost if the slope of the discharge voltage curve versus SOC changes. With nickel manganese cobalt (NMC), high impedance modulus correlates with high SOC above 70%.
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Goh, Taedong, Minjun Park, Minhwan Seo, Jun Gu Kim, and Sang Woo Kim. "Capacity estimation algorithm with a second-order differential voltage curve for Li-ion batteries with NMC cathodes." Energy 135 (September 2017): 257–68. http://dx.doi.org/10.1016/j.energy.2017.06.141.
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Zhou, Di, Hongtao Yin, Wei Xie, Ping Fu, and Wenbin Lu. "Research on Online Capacity Estimation of Power Battery Based on EKF-GPR Model." Journal of Chemistry 2019 (January 23, 2019): 1–9. http://dx.doi.org/10.1155/2019/5327319.
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Capacity degrading over repeated charge/discharge cycles is a main parameter for evaluating battery performance, which is commonly used for determining the state of health. However, it is difficult to measure the available capacity because it requires the normal operation to be terminated and a long time-consuming detection process. This study presents an online available-capacity estimation method by combining extended Kalman filter (EKF) with Gaussian process regression (GPR) for the daily partial charge data of lithium-ion batteries. First, GPR is used to establish an empirical model of the time-voltage curve in the constant current charge cases. Second, by analyzing the characteristics of the charge curve, the daily piecewise partially charge data are registered with the piecewise complete charge data to update GPR model and preestimate the equivalent complete charge time. On this basis, the equivalent complete charge time is refined by EKF. Furthermore, the available capacity estimation of the battery with constant current charge processes under different aging conditions is achieved. It is verified by experiments that the estimated error can be controlled within 5% when the actual available capacity is greater than 90% of the initial capacity.
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Yu, Quanqing, Changjiang Wan, Junfu Li, Lixin E, Xin Zhang, Yonghe Huang, and Tao Liu. "An Open Circuit Voltage Model Fusion Method for State of Charge Estimation of Lithium-Ion Batteries." Energies 14, no. 7 (March 24, 2021): 1797. http://dx.doi.org/10.3390/en14071797.
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The mapping between open circuit voltage (OCV) and state of charge (SOC) is critical to the lithium-ion battery management system (BMS) for electric vehicles. In order to solve the poor accuracy in the local SOC range of most OCV models, an OCV model fusion method for SOC estimation is proposed. According to the characteristics of the experimental OCV–SOC curve, the method divides SOC interval (0, 100%) into several sub-intervals, and respectively fits the OCV curve segments in each sub-interval to obtain a corresponding number of OCV sub-models with local high precision. After that, the OCV sub-models are fused through the continuous weight function to obtain fusional OCV model. Regarding the OCV curve obtained from low-current OCV test as the criterion, the fusional OCV models of LiNiMnCoO2 (NMC) and LiFePO4 (LFP) are compared separately with the conventional OCV models. The comparison shows great fitting accuracy of the fusional OCV model. Furthermore, the adaptive cubature Kalman filter (ACKF) is utilized to estimate SOC and capacity under a dynamic stress test (DST) at different temperatures. The experimental results show that the fusional OCV model can effectively track the performance of the OCV–SOC curve model.
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Wang, Shiqi, Chun Wei, Wenwen Ding, Linmin Zou, Yongyang Gong, Yuanli Liu, Limin Zang, and Xu Xu. "High-Voltage Sulfolane Plasticized UV-Curable Gel Polymer Electrolyte." Polymers 11, no. 8 (August 4, 2019): 1306. http://dx.doi.org/10.3390/polym11081306.
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A high-voltage electrolyte can match high-voltage positive electrode material to fully exert its capacity. In this research, a sulfolane plasticized polymer electrolyte was prepared by in situ photocuring. First, the effect of the sulfolane content on the ionic conductivity of the gel polymer electrolyte was investigated. Results showed that the ionic conductivity variation trend was in good agreement with the exponential function model for curve fitting. Second, the activation energy was calculated from the results of the variable temperature conductivity tests. The activation energy was inversely proportional to the sulfolane content. For the sulfolane content of 80 wt. % in gel polymer electrolyte (GPE)-80 (19.5 kJ/mol), the activation energy was close to conventional liquid electrolyte (9.5 kJ/mol), and the conductivity and electrochemical window were 0.64 mS/cm and 5.86 V, respectively. The battery cycle performance test showed that the initial specific discharge capacities of GPE-80 and liquid electrolyte were 176.8 and 148.3 mAh/g, respectively. After 80 cycles, the discharge capacities of GPE-80 and liquid electrolyte were 115.8 and 41.1 mAh/g, and the capacity retention rates were 65.5% and 27.7%, respectively; indicating that GPE-80 has a better specific discharge capacity and cycling performance than the liquid electrolyte. SEM images indicated that GPE-80 can suppress the growth of lithium dendrites. The EDS test showed that GPE-80 can inhibit the dissolution of metal ions in the cathode material.
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He, Qin, Yabing Zha, Quan Sun, Zhengqiang Pan, and Tianyu Liu. "Capacity Fast Prediction and Residual Useful Life Estimation of Valve Regulated Lead Acid Battery." Mathematical Problems in Engineering 2017 (2017): 1–9. http://dx.doi.org/10.1155/2017/7835049.
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The usable capacity of acid lead batteries is often used as the degradation feature for online RUL (residual useful life) estimation. In engineering applications, the “standard” fully discharging method for capacity measure is quite time-consuming and harmful for the high-capacity batteries. In this paper, a data-driven framework providing capacity fast prediction and RUL estimation for high-capacity VRLA (valve regulated lead acid) batteries is presented. These batteries are used as backup power sources on the ships. The relationship between fully discharging time and partially discharging voltage curve is established for usable capacity extrapolation. Based on the predicted capacity, the particle filtering approach is utilized to obtain battery RUL distribution. A case study is conducted with the experimental data of GFM-200 battery. Results confirm that our method not only reduces the prediction time greatly but also performs quite well in prediction accuracy of battery capacity and RUL.
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Chen, Sujuan, Zhendong Zhao, and Xinyan Gu. "The Research on Characteristics of Li-NiMnCo Lithium-Ion Batteries in Electric Vehicles." Journal of Energy 2020 (June 17, 2020): 1–10. http://dx.doi.org/10.1155/2020/3721047.
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The energy density of canode materials for lithium-ion batteries has a major impact on the driving range of electric vehicles. In order to study the charge-discharge characteristics and application feasibility of Li-NiMnCo lithium-ion batteries for vehicles, a series of charge and discharge experiments were carried out with different rates of Li-NiMnCo lithium-ion batteries (the ratio of nickel, cobalt, and manganese was 5 : 2 : 3) in constant-current-constant-voltage mode. Firstly, a set of charge-discharge experiments were performed on different types of single-cell lithium-ion batteries. The results show that, under temperature conditions, the charge and discharge voltage-capacity curves of the four different types of Li-NiMnCo lithium batteries mentioned in the paper are not much different, and the charge-discharge characteristic curves are similar, indicating that different types of batteries with the same material composition have similar charge and discharge characteristics. Subsequently, a series of charge and discharge tests with different rates were conducted on such ternary lithium batteries. The characteristic curves with different charge-discharge rates indicate that this new type of ternary lithium battery has high current charge and discharge capability and is suitable for use in new energy electric vehicles. In addition, by analyzing the voltage-SOC curve under different magnification conditions, it is known that there is an approximate linear relationship between the battery voltage value and the SOC within a certain SOC range. The SOC value can be evaluated by the battery voltage, which should be controlled within a reasonable range to avoid overcharge or overdischarge of battery, thereby, causing permanent damage to the battery.
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Duan, Jun Dong, and Ying Long Hu. "Study on Optimal Mode of Distributed Generation Accessing to Distribution Network." Advanced Materials Research 614-615 (December 2012): 819–24. http://dx.doi.org/10.4028/www.scientific.net/amr.614-615.819.
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The distributed generation(DG) location, capacity and its influence to distribution network is an important research subject of smart grid. According to the typical daily load curve change rule in distribution network, selecting two operation modes of weighted largest load and weighted least load, taking the minimum of reverse flow times and network loss for the target, combined with the type of DG and operation characteristics , confirming optimal accessing points and optimal capacity of DG. Through the comparative study, the rational introduction of DG improves the voltage level of distribution network and reduces the network loss.
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Ren, Gaojian. "Study on electrochemical principle and characteristic curve of nickel hydrogen battery for mine." E3S Web of Conferences 233 (2021): 01071. http://dx.doi.org/10.1051/e3sconf/202123301071.
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As a kind of high-energy secondary battery, mining Ni MH battery is very suitable for mine backup power because of its advantages of high capacity, high power, no pollution, long cycle life, strong charging and discharging ability and high safety. This paper mainly introduces the electrochemical reaction of Ni MH battery under normal operation, overcharge and over discharge, introduces the types and components of Ni MH battery, describes the change curve of charging and discharging terminal voltage with time under different conditions, analyzes the self discharge situation of Ni MH battery under different conditions, and analyzes the cycle life and safety of Ni MH battery. The software and hardware design of battery intelligent management and SOC estimation analysis provide the basic basis.
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Yang, Hao, and Fei Tang. "Research and Establishment of UHV AC Transmission Model." Applied Mechanics and Materials 752-753 (April 2015): 1139–45. http://dx.doi.org/10.4028/www.scientific.net/amm.752-753.1139.
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There is different applicable transmission capacity and range between 1000kV and 500kV AC transmission. The traditional method is to use the continuous power flow algorithm by BPA simulation software. But this method is complicated and time-consuming. Calculation is particularly large when electricity has a variety of power demand analysis. This paper presents an algorithm based on the AC line transmission capacity, using MATLAB software programming to achieve the establishment of UHV AC transmission model and economical optimization strategy. The method can use thermal limit, voltage limit, landing stability constraints to get the AC line transmission capacity curve by considering the factor of power network strength. On the basis of this method, an UHV AC transmission model can be built combining with unit capacity annual cost algorithm, which can meet the power transmission of arbitrary transmission capacity and the optimal economic of any transmission distance, has an important reference significance and practical value for the planning and construction of electric transmission lines in China.
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Biswas, Liton Kumar, Md Habibur Rahman, and Saiful Haque. "An Intelligent Characteristics Analyzer of PV Module." Dhaka University Journal of Science 61, no. 1 (May 27, 2013): 65–70. http://dx.doi.org/10.3329/dujs.v61i1.15098.
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This paper describes construction, development and testing of a low cost PV module characteristics analyzer. A computer-based, fully automatic characteristic analyzer has been designed and developed using locally available components. The system is capable of acquiring current and voltage of PV module by varying the operating point to draw the IV curve and to analyze the module characteristics. In this system, a Pico ADC-16 has been used to convert the analog data into digital. The module current and voltage is changed by using a transistor active load. The operating point of the active load has been changed by the analog output of a DAC and the DAC is driven by a digital counter. A driver program has been developed for the system using C language. Finally, the system was assembled and the characteristics of some PV modules of different power capacity have been studied. It is found that, the system is capable of finding characteristics of PV modules up to the capacity of 75Watt. Dhaka Univ. J. Sci. 61(1): 65-70, 2013 (January) DOI: http://dx.doi.org/10.3329/dujs.v61i1.15098
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Qu, Xin Bo, Bi Hua Zhou, Ning Sheng Cao, Ya Peng Fu, and Xiao Gang Huang. "The Analysis of Transient Grounding Resistance of Portable Horizontal Grid Earth Electrodes." Applied Mechanics and Materials 347-350 (August 2013): 1753–57. http://dx.doi.org/10.4028/www.scientific.net/amm.347-350.1753.
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Based on current situation of mobile equipments earth devices, a new type of portable horizontal grid earth electrode has been designed. With the impulse ground measurement system, different number of earth electrodes responses to double exponential pulse current have been tested on cement grounds. Impulse waves of voltage and current have been gotten by experiments, and the curve of Transient Grounding Resistance (TGR) can be calculated. The analysis of discharging capacity of horizontal grid earth electrodes in time domain has great significance in the design of mobile equipments earth devices.
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Tian, Xiaochao, Jinzhi Zhu, Zhicong Wang, Hu Wang, Yuze Sun, HaiGang Wang, Sida Zhang, and Zhigang Yang. "Influence of the Power Generation Capacity of the Structural Parameters of a Piezoelectric Bimorph." Shock and Vibration 2021 (July 14, 2021): 1–7. http://dx.doi.org/10.1155/2021/8960671.
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With the popularization of integrated circuits, MEMS, and portable electronic devices, chemical batteries have many disadvantages as the main energy supply method, such as large size, high quality, and limited energy supply life, requiring regular replacement, resulting in waste of materials, environmental pollution, and other issues. From the above reasons, energy harvesting technology plays an important role in improving the efficiency and life of electronic equipment. In order to explore the influence of the bimorph piezoelectric vibrator’s structural parameters on the power generation capacity, this paper establishes a cantilever beam rectangular bimorph piezoelectric vibrator power generation model, derives the mathematical expression of the bimorph piezoelectric vibrator power generation, and determines the parameter factors that affect the power generation effect. Using MATLAB simulation analysis to obtain the influence relationship curve of system output voltage and structural parameters, the experiment tests the influence law of output voltage and thickness ratio, width-to-length ratio, and Young’s modulus ratio; the test results are consistent with the theoretical analysis, verifying the theory and the correctness of the analysis. The results show that when the thickness ratio is 0.58 and the width-to-length ratio is 1, the power generation effect of the piezoelectric vibrator is the best to reach 14.5V; the power generation capacity of the transducer is inversely proportional to Young’s modulus ratio. This research provides a new idea for the popularization of integrated circuits, MEMS, and portable electronic devices.
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Gaevskii, A., V. Bodnyak, and A. Gaevskaya. "ANALYSIS OF MONITORING DATA ON THE OPERATION OF PV-INVERTERS CONNECTED TO DISTRIBUTION NETWORK." Alternative Energy and Ecology (ISJAEE), no. 31-36 (January 6, 2019): 12–22. http://dx.doi.org/10.15518/isjaee.2018.31-36.012-022.
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The article deals with the problems of the PV plants operation in the low voltage network (LVN), namely the influence of PV generation on bus voltages and stability of network, as well as disconnecting the inverters from network in order to avoid overvoltages. The operating of PV inverter tied to LVN is considered on the framework of the reduced two-bus equivalent circuit. One bus of this circuit describes the inverter which is connected to the step-up transformer via short line and second one is the equivalent representation of LVN. The reduced two-bus circuit in contrast to the multi-bus schemes has exact solutions for power flows between PV plant and network. The analytical solutions obtained for this model allows us to determine the voltage stability region, the disconnecting conditions from the network (islanding), the dependence of the bus voltages on the levels of generation and load. On the base of this model, the monitoring data for power and output voltages of three-phase Growatt 30 kW inverter were analyzed. The inverter is tied to LVN by a relatively short line segment with known parameters which is typical for private and small industrial photovoltaic systems. The stable operation of PV plant in the network depends on the ratio of generation and consumption levels at the bus on the plant side, as well as on the capacity of the connecting line. Under analyzing of an overvoltage in the inverter bus appearing due to large solar radiation, one should take into account the limited inverter’s possibility to reduce the output power by changing the operating point on the curve “voltagepower”. The article performs the optimization calculations which determine the parameters characterizing the inverter and line capacity. The developed method for analyzing monitoring data of modern inverters can be a useful tool in solving problems of PV plant equipment diagnostics, as well as of predicting the electricity amount supplied to the network.
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Blizanac, B., Slavko Mentus, Nikola Cvjeticanin, and N. Pavlovic. "Temperature effect on graphite KS44." Journal of the Serbian Chemical Society 68, no. 2 (2003): 119–30. http://dx.doi.org/10.2298/jsc0302119b.
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Graphite Lonza KS44 in a solution 1 M LiClO4 in a propoylene carbonate ethylene carbonate (1 M:1 M) mixture was lithiated and delithiated galvanostatically at room temperature and at the elevated temperature of 55 ?C. Voltage?time profiles and complex impedance diagrams were recorded and are discussed for this particular system. It was confirmed that this type of graphite shows a relatively small current loss consumed by exfoliation, if lithiated at room temperature. However, the voltage?time curve of the first charging at 55 ?C shows a long voltage plateau at 0.7 Vvs. Li/Li+, which corresponds to 540 mAh g-1 of irreversible capacity attributed to exfoliation. The solid electrolyte layer formed at elevated temperature although less protecting in the sense of electrolyte reduction, shows a remarkably higher electrical resistance than that formed at room temperature. A comparison of the impedance diagrams of lithiated and delithiated samples allows the conclusion that mass transfer through the graphite, not that through the solid electrolyte layer, plays a dominant role in the mass transfer limitations.
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Solway, J., J. J. Fredberg, R. H. Ingram, O. F. Pedersen, and J. M. Drazen. "Interdependent regional lung emptying during forced expiration: a transistor model." Journal of Applied Physiology 62, no. 5 (May 1, 1987): 2013–25. http://dx.doi.org/10.1152/jappl.1987.62.5.2013.
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We recognized similarities between isovolume pressure-flow curves of the lung and emitter-collector voltage-current characteristics of bipolar transistors, and used this analogy to model expiratory flow limitation in a two-generation branching network with parallel nonhomogeneity. In this model, each of two bronchi empty parenchymal compliances through a common trachea, and each branch includes resistances upstream and downstream of a flow-limiting site. Properties of each airway are specified independently, allowing simulation of differences between the tracheal and bronchial generations and between the parallel bronchial paths. Simulations of four types of parallel asymmetry were performed: unilateral peripheral bronchoconstriction; unilateral central bronchoconstriction; asymmetric redistribution of parenchymal compliance; and unilateral alteration of the bronchial area-transmural pressure characteristic. Our results indicate that multiple axial choke points can exist simultaneously in a symmetric lung when large airway opening-pleural pressure gradients exist; despite severe nonhomogeneity of regional lung emptying, flow interdependence among parallel branches tends to maintain a near normal configuration of the overall maximal expiratory flow-volume (MEFV) curve throughout a large fraction of the vital capacity; and sudden changes of slope of the MEFV curve (“knees” or “bumps”) may reflect choking in one branch in a nonuniform lung, but need not be obvious even when severe heterogeneity of lung emptying exists.
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Costa, Michela, Gaia Martoriello, and Raffaele Tuccillo. "Modelling of an innovative and autonomous micro-grid based on a biomass - solar PV hybrid power system." E3S Web of Conferences 238 (2021): 02003. http://dx.doi.org/10.1051/e3sconf/202123802003.
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Micro-Combined heat and power (m-CHP) systems fuelled by renewables, such as residual biomasses, are today of great interest to produce energy in an efficient and green way. The aim of the present work is to develop a numerical model of a hybrid energy system including a biomass powered m-CHP unit based on gasification and coupled with solar photovoltaic (PV) modules and to an electrical storage device, able to provide energy to remote areas. Main advantages of the considered configuration are its ultra-low environmental impact and just its autonomous operation by local resources. The developed unsteady multiphysical model accounts for the main plant components, namely the syngas powered engine, the PV panels and the battery, as well for a dynamic use of the produced energy. Main features of the adopted schematization of the actual system rely on the proper description of syngas combustion, that takes into account the extreme difficulty of working with a non-conventional gas, and on a PID control that is considered for energy flow management to meet the electrical demand curve. The PV panel current is calculated through an ad-hoc function that reads, at any given time, actual solar irradiance data in the city of Naples, Italy, the battery voltage and the main parameters of the PV module. The battery, with a voltage of 48V and a capacity of 100kWh, is modelled as an equivalent circuit with its proper State of Charge (SoC) versus Open Circuit Voltage (OCV) curve. The voltage response to a current at a particular SoC and temperature are calculated. This dynamic modelling permits the optimal control of the whole system to meet the electrical and thermal user’s demand and also to better design any possible change in the storage or PV size to meet specific real uses of the produced energy.
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Yu, Bin, Haifeng Qiu, Liguo Weng, Kailong Huo, Shiqi Liu, and Haolu Liu. "A Health Indicator for the Online Lifetime Estimation of an Electric Vehicle Power Li-Ion Battery." World Electric Vehicle Journal 11, no. 3 (August 31, 2020): 59. http://dx.doi.org/10.3390/wevj11030059.
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With the further development of the electric vehicle (EV) industry, the reliability of prediction and health management (PHM) systems has received great attention. The original Li-ion battery life prediction technology developed by offline training data can no longer meet the needs of use under complex working conditions. The existing methods pay insufficient attention to the dispersive information of health indicators (HIs) under EV driving conditions, and can only calculate through standard configuration files. To solve the problem that it is difficult to directly measure the capacity loss in real time, this paper proposes a battery HI called excitation response level (ERL) to describe the voltage variation at different lifetimes, which could be easily calculated according to the current and voltage under the actual load curve. In addition, in order to further optimize the proposed HI, Box–Cox transformation was used to enhance the linear correlation between the initially extracted HI and the capacity. Several Li-ion batteries were discharged to the 50% state of health (SOH) through profiles with different depths of discharge (DODs) and mean states of charge (SOCs) to verify the accuracy and robustness of the proposed method. The average estimation error of the tested batteries was less than 3%, which shows a good performance for accuracy and robustness.
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Yan, Xiangwu, Chenguang Wang, Ziheng Wang, Hongbin Ma, Baixue Liang, and Xiaoxue Wei. "A United Control Strategy of Photovoltaic-Battery Energy Storage System Based on Voltage-Frequency Controlled VSG." Electronics 10, no. 17 (August 24, 2021): 2047. http://dx.doi.org/10.3390/electronics10172047.
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At present, the installed capacity of photovoltaic-battery energy storage systems (PV-BESs) is rapidly increasing. In the traditional control method, the PV-BES needs to switch the control mode between off-grid and grid-connected states. Thus, the traditional control mode reduces the reliability of the system. In addition, if the system is accidentally disconnected from the grid or the energy storage battery fails to work normally, the DC voltage of the inverter increases or decreases rapidly. To address these two problems, in this paper, a united control strategy is proposed. In the case of grid connection, based on the voltage-frequency controlled VSG strategy, the strategy adjusts the output power of the VSG by changing the position of the primary frequency modulation curve. This method can ensure that, after the system is connected to the grid, excess PV power can be sent to the grid, or power can be absorbed from the grid to charge energy storage. In the off-grid state, the strategy uses FPPT technology and superimposes a voltage component onto the voltage loop to quickly balance the DC power and AC power of the inverter. This strategy can improve the reliability of the system’s power supply if the energy storage fails to work normally. Finally, a PV-BES model was built using MATLAB-Simulink, and the simulation results proved the effectiveness of the proposed strategy.
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Chen, Guangwei, Zhitao Liu, and Hongye Su. "An Optimal Fast-Charging Strategy for Lithium-Ion Batteries via an Electrochemical–Thermal Model with Intercalation-Induced Stresses and Film Growth." Energies 13, no. 9 (May 11, 2020): 2388. http://dx.doi.org/10.3390/en13092388.
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Optimal fast charging is an important factor in battery management systems (BMS). Traditional charging strategies for lithium-ion batteries, such as the constant current–constant voltage (CC–CV) pattern, do not take capacity aging mechanisms into account, which are not only disadvantageous in the life-time usage of the batteries, but also unsafe. In this paper, we employ the dynamic optimization (DP) method to achieve the optimal charging current curve for a lithium-ion battery by introducing limits on the intercalation-induced stresses and the solid–liquid interface film growth based on an electrochemical–thermal model. Furthermore, the backstepping technique is utilized to control the temperature to avoid overheating. This paper concentrates on solving the issue of minimizing charging time in a given target State of Charge (SoC), while limiting the capacity loss caused by intercalation-induced stresses and film formation. The results indicate that the proposed optimal charging method in this paper offers a good compromise between the charging time and battery aging.
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Manzhos, Sergei. "Aggregate-State Effects in the Atomistic Modeling of Organic Materials for Electrochemical Energy Conversion and Storage Devices: A Perspective." Molecules 25, no. 9 (May 9, 2020): 2233. http://dx.doi.org/10.3390/molecules25092233.
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Development of new functional materials for novel energy conversion and storage technologies is often assisted by ab initio modeling. Specifically, for organic materials, such as electron and hole transport materials for perovskite solar cells, LED (light emitting diodes) emitters for organic LEDs (OLEDs), and active electrode materials for organic batteries, such modeling is often done at the molecular level. Modeling of aggregate-state effects is onerous, as packing may not be known or large simulation cells may be required for amorphous materials. Yet aggregate-state effects are essential to estimate charge transport rates, and they may also have substantial effects on redox potentials (voltages) and optical properties. This paper summarizes recent studies by the author’s group of aggregation effects on the electronic properties of organic materials used in optoelectronic devices and in organic batteries. We show that in some cases it is possible to understand the mechanism and predict specific performance characteristics based on simple molecular models, while in other cases the inclusion of effects of aggregation is essential. For example, it is possible to understand the mechanism and predict the overall shape of the voltage-capacity curve for insertion-type organic battery materials, but not the absolute voltage. On the other hand, oligomeric models of p-type organic electrode materials can allow for relatively reliable estimates of voltages. Inclusion of aggregate state modeling is critically important for estimating charge transport rates in materials and interfaces used in optoelectronic devices or when intermolecular charge transfer bands are important. We highlight the use of the semi-empirical DFTB (density functional tight binding) method to simplify such calculations.
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Chakraborty, Chaitali, and Chayanika Bose. "Effect of size and position of gold nanocrystals embedded in gate oxide of SiO2/Si MOS structures." Journal of Advanced Dielectrics 06, no. 01 (March 2016): 1650001. http://dx.doi.org/10.1142/s2010135x16500016.
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The influence of single and double layered gold (Au) nanocrystals (NC), embedded in SiO2 matrix, on the electrical characteristics of metal–oxide–semiconductor (MOS) structures is reported in this communication. The size and position of the NCs are varied and study is made using Sentaurus TCAD simulation tools. In a single NC-layered MOS structure, the role of NCs is more prominent when they are placed closer to SiO2/Si[Formula: see text]substrate interface than to SiO2/Al–gate interface. In MOS structures with larger NC dots and double layered NCs, the charge storage capacity is increased due to charging of the dielectric in the presence of NCs. Higher breakdown voltage and smaller leakage current are also obtained in the case of dual NC-layered MOS device. A new phenomenon of smearing out of the capacitance–voltage curve is observed in the presence of dual NC layer indicating generation of interface traps. An internal electric field developed between these two charged NC layers is expected to generate such interface traps at the SiO2/Si interface.
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Rohman, Nurshahirah Athirah, Nor Farahaida Abdul Rahman, and Muhammad Ammirrul Atiqi Mohd Zainuri. "Characteristics of lead-acid and nickel metal hydride batteries in uninterruptible power supply operation." International Journal of Power Electronics and Drive Systems (IJPEDS) 10, no. 3 (September 1, 2019): 1520. http://dx.doi.org/10.11591/ijpeds.v10.i3.pp1520-1528.
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<span>Batteries are one of the main elements in Uninterruptable Power Supply (UPSs). To maintain good operation during power failure, UPSs must have adequate energy for their operation. It depends on the reliability and performance of batteries. Owing to low capital cost and wide availability, lead-acid batteries have been used extensively as the main energy source in UPSs. Nevertheless, as batteries technology grown, Nickel Metal Hydride (NiMH) batteries have offered more promising performance than lead-acid batteries; they are installed in various portable electronic devices. This paper provides an overview of the performance of lead-acid and NiMH batteries during the operation of a single-phase UPS. Their performances are studied based on 2 characteristics which are discharge curve and State of Charge (SOC). Based on those characteristics, both batteries have shown different performances. Simulation results have shown that the NiMH battery exhibits better discharge curve with higher voltage capacity and constant discharge current, and it is more reliable to obtain 12V at minimum percentage of SOC than the lead-acid battery.</span>
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NAZAROV, Vladimir D., Ivan S. ERILIN, Maxim V. NAZAROV, and Olga V. SMORODOVA. "USE OF SOLID OXIDE FUEL CELL FOR INCREASING THE ENERGY EFFICIENCY OF THE ELECTROFLOTATOR." Urban construction and architecture 9, no. 1 (March 15, 2019): 47–51. http://dx.doi.org/10.17673/vestnik.2019.01.8.
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Advances in fuel cells in recent years have made it possible to apply them with high efficiency in various engineering fields. In this paper, a scheme of functioning of an electrofloter was proposed in conjunction with a solid oxide fuel cell. Experimental studies of a hydrogen fuel cell were carried out to obtain a current-voltage characteristic and a curve for the dependence of the fuel cell efficiency on the specific power and current was obtained. The surface efficiency of the electroflater - fuel cell system was built and conclusions were drawn about energy savings and optimal areas of the active surface of the fuel cell under investigation when working with electroflotters with a capacity of up to 3 m3 / h.
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Goff, Daniel T., Steve J. A. Majerus, and Walter Merrill. "A 200 °C Quad-Output Buck Type Switched Mode Power Supply IC." Additional Conferences (Device Packaging, HiTEC, HiTEN, and CICMT) 2014, HITEC (January 1, 2014): 000022–27. http://dx.doi.org/10.4071/hitec-ta16.
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A high temperature (>200 °C), quad-output, buck type switched-mode power supply (SMPS) IC capable of operating over a wide input supply range of 6 V to 15 V is described. The IC is a compact power supply solution for multi-voltage microprocessors, sensors, and actuators. The SMPS topology is a 112 kHz fixed-frequency, synchronous buck converter with slope compensation. A novel internal feedback design enables the output voltages to be pin-programmed to one of three common supply voltages—5 V, 3.3 V, or 1.8 V—while an external resistor divider can also be used for arbitrary voltage programming. Integrated power supply output MOSFET switches minimize the external part count and synchronous rectification reduces power dissipation and improves current capacity. The IC was fabricated in a conventional, low-cost, 0.5 μm bulk CMOS foundry process. Patented circuit design techniques allow the IC to operate in excess of 200 °C and circuit operation was demonstrated at ambient temperatures up to 225 °C. The foundry process is optimized for 5 V applications, however, the IC accepts input voltages up to 15 V and can produce outputs up to 10 V by utilizing extended drain single- and double-sided NMOS and PMOS transistors for the linear regulator pass transistor, error amplifier, and SMPS switches. The high-side FETs are controlled through capacitive coupled level shift circuits to ensure the gate-oxide voltage limits are not exceeded while still maintaining fast signal transitions. The IC also includes a tunable, 25 MHz monolithic oscillator that is programmable over a SPI serial interface. The oscillator bias current is comprised of a programmable constant-gm bias current and a programmable PTAT bias current. The programmability can be used to set the oscillation frequency, but can also be used together with a calibration curve on a microcontroller to achieve a more stable oscillation frequency over temperature. The output current of the quad SMPS was limited to 70 mA by a lower than expected saturation current of the extended-drain PMOS switch devices. The system showed good line regulation (<0.1%) and 50% load step response stability (+/− 100 mV) at a nominal output current of 50 mA when tested at 200 °C ambient.
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Guo, H., J. A. Wasserstrom, and J. E. Rosenthal. "Lactate enhances sodium channel conductance in isolated guinea pig ventricular myocytes." American Journal of Physiology-Heart and Circulatory Physiology 267, no. 4 (October 1, 1994): H1565—H1572. http://dx.doi.org/10.1152/ajpheart.1994.267.4.h1565.
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Myocardial hypoxia and ischemia result in the production of lactate. To study the effect of lactate on the rapid Na+ current (INa), we used the whole cell voltage-clamp technique in enzymatically isolated guinea pig ventricular myocytes. Experiments were conducted at 16 degrees C. Extracellular Na+ concentration ([Na+]o) was maintained in control and test solutions and extracellular pH was 7.4. Lactate (4-10 mM, either sodium lactate or lactic acid) augmented INa in each of eight experiments, increasing the peak Na+ conductance from 75.4 to 84.7 nS (13-16% at all test voltages in the linear portion of the conductance curve). The voltage dependence of steady-state availability and the time course of inactivation remained unchanged. The increase in peak Na+ conductance was concentration dependent, with an apparent dissociation constant of 1.8 mM and Hill coefficient of 1.8. Lactate in the range of 1-10 mM did not significantly reduce the Ca2+ activity of test solutions. These effects of lactate were still observed in Mg(2+)-free test solutions and when the buffering capacity of internal solution was reinforced by increasing N-2-hydroxyethylpiperazine-N'-2-ethanesulfonic acid concentration from 5 to 20 mM. In conclusion, lactate enhances INa via a mechanism that does not involve chelation of Ca2+ or Mg2+ or changes in intracellular pH. These effects of lactate on the Na+ channel might alter electrophysiological properties during myocardial ischemia and could protect the heart from ischemia-induced conduction abnormalities or, alternatively, could lead to arrhythmias.
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Mim, Carsten, Poonam Balani, Thomas Rauen, and Christof Grewer. "The Glutamate Transporter Subtypes EAAT4 and EAATs 1-3 Transport Glutamate with Dramatically Different Kinetics and Voltage Dependence but Share a Common Uptake Mechanism." Journal of General Physiology 126, no. 6 (November 28, 2005): 571–89. http://dx.doi.org/10.1085/jgp.200509365.
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Here, we report the application of glutamate concentration jumps and voltage jumps to determine the kinetics of rapid reaction steps of excitatory amino acid transporter subtype 4 (EAAT4) with a 100-μs time resolution. EAAT4 was expressed in HEK293 cells, and the electrogenic transport and anion currents were measured using the patch-clamp method. At steady state, EAAT4 was activated by glutamate and Na+ with high affinities of 0.6 μM and 8.4 mM, respectively, and showed kinetics consistent with sequential binding of Na+-glutamate-Na+. The steady-state cycle time of EAAT4 was estimated to be >300 ms (at −90 mV). Applying step changes to the transmembrane potential, Vm, of EAAT4-expressing cells resulted in the generation of transient anion currents (decaying with a τ of ∼15 ms), indicating inhibition of steady-state EAAT4 activity at negative voltages (<−40 mV) and activation at positive Vm (>0 mV). A similar inhibitory effect at Vm < 0 mV was seen when the electrogenic glutamate transport current was monitored, resulting in a bell-shaped I-Vm curve. Jumping the glutamate concentration to 100 μM generated biphasic, saturable transient transport and anion currents (Km ∼ 5 μM) that decayed within 100 ms, indicating the existence of two separate electrogenic reaction steps. The fast electrogenic reaction was assigned to Na+ binding to EAAT4, whereas the second reaction is most likely associated with glutamate translocation. Together, these results suggest that glutamate uptake of EAAT4 is based on the same molecular mechanism as transport by the subtypes EAATs 1–3, but that its kinetics and voltage dependence are dramatically different from the other subtypes. EAAT4 kinetics appear to be optimized for high affinity binding of glutamate, but not rapid turnover. Therefore, we propose that EAAT4 is a high-affinity/low-capacity transport system, supplementing low-affinity/high-capacity synaptic glutamate uptake by the other subtypes.
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Nam, Tae Hyun, Soo Moon Park, and Kwon Koo Cho. "Thermal Sulfidation Behavior of Ti-Ni Alloys." Materials Science Forum 486-487 (June 2005): 622–25. http://dx.doi.org/10.4028/www.scientific.net/msf.486-487.622.
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Ti and Ni sulfides were formed on the surface of Ti-Ni alloys by isothermal annealing at various sulfur pressures, and then microstructures of the surface sulfide layers were investigated by means of scanning electron microscopy and X-ray diffractions. Morphology of sulfurized surface changed from granular shape to porous shape at the sulfur pressure of 80 kPa, which is related to the change in sulfide from NiS1.97 to NiS. Two-layered sulfide was observed in which the inner layer was mainly Ti8.2S11 , and the outer layer was a mixture of NiS1.97 and NiS. The discharge curve of the Ti and Ni sulfides cathode formed on the Ti-Ni current collector at the first cycle showed a plateau voltage of 1.6 V, and the discharge capacity was found to be about 530 mAh/g-NiS1.97.
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Lykin, A. V., and E. A. Utkin. "Calculations, norming and reducing of electrical energy losses in city electrical networks." Power engineering: research, equipment, technology 21, no. 3 (November 29, 2019): 46–54. http://dx.doi.org/10.30724/1998-9903-2019-21-3-46-54.
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The article considers the feasibility of changing the structure of a distribution electrical network by transferring points of electricity transformation as close to consumers as possible. This approach is based on installation of pole-mounted transformer substations (PMTS) near consumer groups and changes the topology of the electrical network. At the same time, for groups of consumers, the configuration of sections of the low-voltage network, including service drops, changes. The efficiency of approaching transformer substations to consumers was estimated by the reduction in electrical energy losses due to the expansion of the high-voltage network. The calculation of electrical losses was carried out according to twenty-four hour consumer demand curve. To estimate the power losses in each section of the electrical network of high and low voltage, the calculated expressions were obtained. For the considered example, the electrical energy losses in the whole network with a modified topology is reduced by about two times, while in a high-voltage network with the same transmitted power, the losses are reduced to a practically insignificant level, and in installed PMTS transformers they increase mainly due to the rise in total idle losses. The payback period of additional capital investments in option with modified topology will be significantly greater if payback is assessed only by saving losses cost. Consequently, the determination of the feasibility of applying this approach should be carried out taking into account such factors as increasing the reliability of electricity supply, improving the quality of electricity, and increasing the power transmission capacity of the main part of electrical network.
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Elgammal, Adel, and Curtis Boodoo. "Improving Power Quality and Mitigation of Harmonic Distortion Impact at Photovoltaic Electric Vehicle Charging System." European Journal of Electrical Engineering and Computer Science 5, no. 1 (January 20, 2021): 25–32. http://dx.doi.org/10.24018/ejece.2021.5.1.288.
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This article offers a clear and realistic design for an active power filter to increase reliability and power quality of the photovoltaic charging system and a high-penetration electric vehicle distribution system. The MOPSO algorithm is used as the basis for problems with optimization and filter tuning. A typical regular load curve is used to model the warped power grid over a 24-hour cycle to estimate the total harmonic distortion (THD). For structures with high penetration of electric cars, the probability of minimizing THD (for example to five percent) is explored via optimum capacity active shunt filters and shunt capacitors. To maximize general performance of the charging system, the switching systems are re-scheduled. Moreover, to increase the current control accuracy of shunt active filter, the fuzzy logic controller is utilized. The major drawback to new system is that it would have unrestricted billing for entire day to cope with voltage interruption. In MATLAB / SIMULINK, detailed machine setup and control algorithm experiments are simulated. The simulation findings confirm the efficiency and viability of projected shunt active filter to enhance voltage profile and track power performance of photovoltaic charging system.
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Brañas, Christian, Juan C. Viera, Francisco J. Azcondo, Rosario Casanueva, Manuela Gonzalez, and Francisco J. Díaz. "Battery Charger Based on a Resonant Converter for High-Power LiFePO4 Batteries." Electronics 10, no. 3 (January 23, 2021): 266. http://dx.doi.org/10.3390/electronics10030266.
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A new battery charger, based on a multiphase resonant converter, for a high-capacity 48 V LiFePO4 lithium-ion battery is presented. LiFePO4 batteries are among the most widely used today and offer high energy efficiency, high safety performance, very good temperature behavior, and a long cycle life. An accurate control of the charging current is necessary to preserve the battery health. The design of the charger is presented in a tight correlation with a battery model based on experimental data obtained at the laboratory. With the aim of reducing conduction losses, the general analysis of the inverter stage obtained from the parallel connection of N class D LCpCs resonant inverters is carried out. The study provides criteria for proper selection of the transistors and diodes as well as the value of the DC-link voltage. The effect of the leakage inductance of the transformer on the resonant circuit is also evaluated, and a design solution to cancel it is proposed. The output stage is based on a multi-winding current-doubler rectifier. The converter is designed to operate in open-loop operation as an input voltage-dependent current source, but in closed-loop operation, it behaves as a voltage source with an inherent maximum output current limitation, which provides high reliability throughout the whole charging process. The curve of efficiency of the proposed charger exhibits a wide flat zone that includes light load conditions.
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Lin, Sen, Zhi Cheng Lu, Zhu Bing Zhu, Po Gao, and Sheng Li. "Study of Shaking Table Test on Seismic Performance of 750 kV Post Insulator." Advanced Materials Research 1065-1069 (December 2014): 1491–96. http://dx.doi.org/10.4028/www.scientific.net/amr.1065-1069.1491.
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The applicability of seismic waves for the seismic performance estimation of 750 kV post insulator has been investigated in full-scale shaking table test. the input seismic waves comprise El Centro seismic wave, Landers seismic wave, sine beat wave and artificial standard wave. The testing results indicate that, high dynamic responses of the equipment can be obtained under artificial standard wave condition. In addition, due to comprehensive enveloping ability and gentle spectral curve, artificial standard wave is ideal for the seismic performance evaluation of 750 kV post insulator in the test. An finite element model has been developed and numerical seismic analysis has been performed. Satisfactory match between the simulated and measured results reveals the reliability of the test. The achievements obtained in this paper are helpful in choosing reasonable input wave for shaking table test, and also provide technical support on determining seismic capacity of high voltage electrical equipment.
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Ren, Yuan, Jinhao Wang, Xiao Chang, Yi Du, Ying Zhang, Yizhao Liu, and Gangbin Wang. "An Improved Control Strategy for the Bus Interlinking Converter Based on Three-level Topology in AC-DC Hybrid Microgrid." E3S Web of Conferences 186 (2020): 02002. http://dx.doi.org/10.1051/e3sconf/202018602002.
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Considering the increasing requirements of the AC-DC hybrid microgrid (HMG) for the transmission power capacity and voltage level, the several bus interface converters (BICs) with the two-level PWM converter topology, need to be connected between AC bus and DC bus in parallel, which could generate circulating current and cycle power. The cost of the modular multilevel converter topology based BIC is too high. Hence, this paper proposes to apply the BIC with three-level topology to the HMG, and a droop control strategy with the midpoint potential hysteresis regulation link is designed, which can effectively suppress the fluctuation of midpoint potential without affecting the normal operation of the BIC in the grid connected or off mode. In addition, the principle of neutral point fluctuation and the process of hysteresis control are introduced, and the detailed design of dual-mode control strategy based on droop curve are also given. Finally, the effectiveness of the improved control strategy is verified by simulation.
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Li, Zheng, Yan Qin, Xin Cao, Shaodong Hou, and Hexu Sun. "Wind-Solar-Hydrogen Hybrid Energy Control Strategy Considering Delayed Power of Hydrogen Production." Electrotehnica, Electronica, Automatica 69, no. 2 (May 15, 2021): 5–12. http://dx.doi.org/10.46904/eea.21.69.2.1108001.
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In order to meet the load demand of power system, BP based on genetic algorithm is applied to the typical daily load forecasting in summer. The demand change of summer load is analysed. Simulation results show the accuracy of the algorithm. In terms of power supply, the reserves of fossil energy are drying up. According to the prediction of authoritative organizations, the world's coal can be mined for 216 years. As a renewable energy, wind power has no carbon emissions compared with traditional fossil energy. At present, it is generally believed that wind energy and solar energy are green power in the full sense, and they are inexhaustible clean power. The model of wind power solar hydrogen hybrid energy system is established. The control strategy of battery power compensation for delayed power of hydrogen production is adopted, and different operation modes are divided. The simulation results show that the system considering the control strategy can well meet the load demand. Battery energy storage system is difficult to respond to short-term peak power fluctuations. Super capacitor is used to suppress it. This paper studies the battery supercapacitor complementary energy storage system and its control strategy. When the line impedance of each generation unit in power grid is not equal, its output reactive power will be affected by the line impedance and distributed unevenly. A droop coefficient selection method of reactive power sharing is proposed. Energy storage device is needed to balance power and maintain DC voltage stability in the DC side of microgrid. Therefore, a new droop control strategy is proposed. By detecting the DC voltage, dynamically translating the droop characteristic curve, adjusting the output power, maintaining the DC voltage in a reasonable range, reducing the capacity of the DC side energy storage device. Photovoltaic grid connected inverter chooses the new droop control strategy.
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Caputo, C., and P. Bolaños. "Ultraslow contractile inactivation in frog skeletal muscle fibers." Journal of General Physiology 96, no. 1 (July 1, 1990): 47–56. http://dx.doi.org/10.1085/jgp.96.1.47.
Full textAbstract:
After a contracture response, skeletal muscle fibers enter into a state of contractile refractoriness or inactivation. Contractile inactivation starts soon after membrane depolarization, and causes spontaneous relaxation from the contracture response. Here we demonstrate that contractile inactivation continues to develop for tens of seconds if the membrane remains in a depolarized state. We have studied this phenomenon using short (1.5 mm) frog muscle fibers dissected from the Lumbricalis brevis muscles of the frog, with a two-microelectrode voltage-clamp technique. After a contracture caused by membrane depolarization to 0 mV, from a holding potential of -100 mV, a second contracture can be developed only if the membrane is repolarized beyond a determined potential value for a certain period of time. We have used a repriming protocol of 1 or 2 s at -100 mV. After this repriming period a fiber, if depolarized again to 0 mV, may develop a second contracture, whose magnitude and time course will depend on the duration of the period during which the fiber was maintained at 0 mV before the repriming process. With this procedure it is possible to demonstrate that the inactivation process builds up with a very slow time course, with a half time of approximately 35 s and completion in greater than 100 s. After prolonged depolarizations (greater than 100 s), the repriming time course is slower and the inactivation curve (obtained by plotting the extent of repriming against the repriming membrane potential) is shifted toward more negative potentials by greater than 30 mV when compared with similar curves obtained after shorter depolarizing periods (10-30 s). These results indicate that important changes occur in the physical state of the molecular moiety that is responsible for the inactivation phenomenon. The shift of the inactivation curve can be partially reversed by a low concentration (50 microM) of lanthanum ions. In the presence of 0.5 mM caffeine, larger responses can be obtained even after prolonged depolarization periods, indicating that the fibers maintain their capacity to liberate calcium.
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Frolov, Sergey S., and Dmitry A. Shatilov. "DEPENDENCIES OF THE DISTORTION FACTOR OF THE SINUSOIDALITY OF THE RECOVERY CURRENT ON THE PARAMETERS OF THE PROCESS WHEN CONTROLLING THE FORCED DISCHARGE OF ACCUMULATOR BATTERIES INTO THE NETWORK BY SIGNAL WITH SINGLE-CYCLE ONE-WAY PULSE-WIDTH MODULATION." Vestnik Chuvashskogo universiteta, no. 1 (March 25, 2021): 146–53. http://dx.doi.org/10.47026/1810-1909-2021-1-146-153.
Full textAbstract:
For modern remote and closed systems of uninterruptible power supply, a operation of forced discharge of accumulator batteries is in demand. It is advisable to carry out the specified process of forced discharge with recuperation into the network. This way of leads: firstly, to a decrease in the mass of charging and discharging devices due to the exclusion of powerful resistive loads from the latter; secondly, to noticeable energy savings for closed autonomous objects. At the same time, for the regenerative current, increased requirements are imposed on its sinusoidality, the distortion coefficient of which is significantly influenced by the relationship between the EMF of the battery and the amplitude of the mains voltage, the discharge current and the maximum current of the coil of the active rectifier. The influence the frequency of the PWM control signal and the frequency of the regeneration current (mains frequency) is also possible. In uninterruptible systems, storage batteries are used with different total EMF and capacity that determines the discharge current. In addition, the mentioned values change during operation, and at forced discharge, various technique can be used that differ in the ratio of the discharge current to the capacity of the battery and the law of its change. Therefore, in the development of a universal system for forced discharge of a battery into a network with pulse-width control of the regenerative current shape, is relevant information on the dependences of the distortion factor of the sinusoidality on the above ratios of the battery voltage and the amplitude of the mains voltage, the discharge current and the maximum current of the coil of the active rectifier coil, as well as from the number of pulses for the regeneration current period. The article presents the results of work on obtaining diagrams of these dependencies. To obtain the latter, the function of the output current of the active rectifier is formed – of the regeneration current, then its spectral function. Using the latter, the current waveform distortions are estimated based on the spectral approach. The results obtained are in demand in the development of program modules for microcontrollers of the pulse-width regulators of the regeneration current, which implement algorithms for the formation of a current curve with acceptable values of the distortion coefficient of the sinusoidality when changing the parameters of the battery, network and discharge current.