Discharge Current Value Research Articles

A Novel Spotted Hyena Optimizer for the Estimation of Equivalent Circuit Model Parameters in Li-Ion Batteries

Li-ion batteries possess significant advantages like large energy density, fast recharge, and high reliability; hence, they are widely adopted in electric vehicles, portable electronics, and military and aerospace applications. Albeit having their merits, accurate battery modeling is subjected to problems like prior information on internal chemical reactions, complexity in problem formulation, a large number of unknown parameters, and the need for extensive experimentation. Hence, this article presents a reliable Spotted Hyena Optimizer (SHO) to determine the equivalent circuit parameters of lithium-ion (Li-ion) batteries. The methodology of the SHO is derived from the living and hunting tactics of spotted hyenas, and it is efficiently applied to solve the battery parameter estimation problem. Nine unknown battery model parameters of a Samsung INR 18650-25R are determined using this method. The model parameters estimated are endorsed for five different datasets with various discharge current values. Further, the effect of parameter range and its selection is also emphasized. Secondly, for validation, various performance metrics such as Integral Squared Error, mean best, mean worst, and Standard Deviation are evaluated to authenticate the superiority of the proposed parameter extraction. From the computed results, the SHO algorithm is able to explore the search area up to 89% in the case of larger search ranges. The chosen model and range of the SHO precisely predict the behavior of the proposed Li-ion battery, and the results are in accordance with the catalog data.

Improving the wear and heat resistance of niobium substrate via reactive electrospark treatment using fusible AlCaSiY electrode

Protective coatings with a heterophase layered structure were obtained by reactive electrospark treatment (EST) of niobium substrate with a fusible AlCaSiY electrode. The effect of the frequency–energy modes of EST on the phase composition, structure and properties of the coatings was studied. A combination of high discharge current values (400A) and long pulses (100 μs) yields a double-layer coating with the total thickness of 80 μm, which consists of the (Al) matrix strengthened with Nb2CaAl20 particles and a hard (10 GPa) NbAl3 layer. The results of pin-on-plate tribological testing revealed that this structure made it possible to reduce the coefficient of friction from 0.42 to 0.24 and increase wear resistance 3.5-fold compared to those of niobium. Oxidative annealing of Nb plates in air at 700 °C causes their fracture due to the formation of Nb2O5. Indeed, oxidative annealing of the samples subjected to EST leads to in situ formation of a dense Ca12Al10Si4O35-oxide based near surface layer that inhibits oxygen diffusion into the bulk, thus suppressing Nb2O5 formation. Mass gain of the sample having a protective coating after 300-min isothermal exposure was 2.54 mg/cm2, which is 3.6-fold lower than that for the Nb substrate (9.04 mg/cm2).

Research on SOP Estimation Based on SOC Constraints under Static Operating Conditions

In a battery management system (BMS), accurate estimation of system operating power (SOP) is essential to ensure battery performance and extend service life. In this paper, an SOP estimation method based on open circuit voltage (OCV), state of charge (SOC) and battery current is studied. By analyzing the battery data under dynamic stress test (DST) conditions, the estimated value of continuous peak charge and discharge current is calculated, and the corresponding continuous peak charge and discharge power is estimated accordingly. Comparing the estimated charging and discharging power with the experimental value, the results show that the new algorithm can significantly improve the estimation accuracy of SOP. It not only improves the accuracy of SOP estimates, but also helps to optimize BMS, thereby improving the overall performance and service life of the power battery.

INVESTIGATION OF ELECTROEROSION MACHINING PERFORMANCE OF METAL MATRIX COMPOSITE MATERIALS PRODUCED USING STIR AND INDIRECT SQUEEZE METHOD

In this study, metal matrix composite (MMC) materials were made with an aluminum matrix (AA7075 alloy) and reinforcement silicon carbide (SiC) elements using molten metal stir and indirect squeeze casting. SiC was used as a reinforcing element in the making of MMC material in different amounts (10%, 14%, and 18%) by mass. Electro Discharge Machining (EDM), cut depth (0.5 mm), three different pulse-on times, three different discharge current values, and a fixed pulse-off time (20 s) were used to machine MMC materials. The effects of machining parameters on machining time, average surface roughness, hole diameter, and material wear difference after machining were studied. As a result of the study, the composite material with 75 [Formula: see text]s pulse-on time, 6A current value, and 10% reinforcement element had the lowest machining time, the largest hole diameter, and the smoothest average surface. These machining parameters and materials also had the shortest machining time (5 min). Based on the signal-to-noise ratios, the best parameters for average surface roughness, hole diameter, Processing time, and material wear amount (MMC, discharge current value, and impact time) were found to be [Formula: see text], [Formula: see text], [Formula: see text], and [Formula: see text], respectively. Based on the ANOVA results, the [Formula: see text]2 values for the average surface roughness, hole diameter, machining time, and material wear loss value were 99.3%, 98.7%, 77.8%, and 97.3%, respectively.

Determination of the Pressure and Temperature of the Radiating Arc Plasma from the Measured Photocurrent, Voltage and Discharge Current Values

Determination of the Pressure and Temperature of the Radiating Arc Plasma from the Measured Photocurrent, Voltage and Discharge Current Values

Research on Composite Braking Mode Switching Strategy Based on Fuzzy Algorithm

AbstractAiming at the cruising range of electric vehicles, this paper proposes a control strategy for electric vehicle electromechanical composite braking mode switching based on motor braking force correction. The braking force of the motor is adjusted by factors such as braking intensity to improve the braking energy recovery, and the braking force distribution curve is designed considering the braking energy and braking safety and stability. The research results show the braking time, braking torque, and battery charge. The peak value of discharge current has been improved, and the braking energy recovery efficiency has increased by 9.17% and 3.32% respectively under different working conditions. Under different braking modes with an initial speed of 30 km h−1, the braking energy recovered by the battery has increased by 16.04 , 3.89, 9.63 kJ, the braking time and braking distance are also shorter, which highlights the superiority of this control strategy.

Synthesis of Lithium Phosphorus Oxynitride (LiPON) Thin Films by Li3PO4 Anodic Evaporation in Nitrogen Plasma of a Low-Pressure Arc Discharge.

Thin amorphous films of LiPON solid electrolyte were prepared by anodic evaporation of lithium orthophosphate Li3PO4 in an arc discharge with a self-heating hollow cathode at a nitrogen pressure of 1 Pa. Distribution of the arc current between two electrodes having an anode potential provided independent control of the evaporation rate of Li3PO4 and the density of nitrogen plasma. Stabilization of the evaporation rate was achieved using a crucible with multi-aperture cover having floating potential. The existence of a threshold value of discharge current (40 A) has been established, which, upon reaching ionic conductivity over 10−8 S/cm, appears in the films. Probe diagnostics of discharge plasma were carried out. It has been shown that heating the films during deposition by plasma radiation to a temperature of 200 °C is not an impediment to achieving high ionic conductivity of the films. Dense uniform films of LiPON thickness 1 μm with ionic conductivity up to 1 × 10−6 S/cm at a deposition rate of 4 nm/min are obtained.

Determining V-I characteristics of energy-efficient electrostatic assisted air filtration system by utilizing the back-corona induced current model

The widely utilized high efficient particulate air filters (HEPA) and electrostatic precipitator (ESP) respectively has the shortcomings of relatively high energy consumption and low filtration efficiency. In order to overcome the disadvantages of two traditional air filtration system, electrostatic assisted air filtration system (combining HEPA and ESP) has been proven to achieve high filtration efficiency and low energy consumption simultaneously. Predicting of V-I characteristics of electrostatic filtration system with configuration of “pin to filter medium to grounded device” is very essential and challenging due to the back corona phenomenon. This study utilized the back-corona based current model to predict the V-I characteristics of electrostatic system with different filter medium types and “pin-to-filter” distances. Experiments are conducted to provide data for model validation by changing filter types and locations of discharge pin. The results indicated that both of the predicted values of total discharge current and back-corona induced current agreed well with the experimentally measured data. This validated mathematical model could be used for preliminary design of electrostatic assisted filtration system with configuration of “pin to filter to grounded device”. Based on the V-I characteristics predicted by the semi-empirical model, the electrostatic filtration efficiency could be estimated.

Fluctuations of the plasma potential in atmospheric pressure micro-plasma jets

Fluctuations in plasma floating potential in an atmospheric pressure micro-plasma jet are investigated experimentally. The transport of charged particles toward the ambient air is often seen to be affected by plasma fluctuations. The dependence of fluctuations on operating parameters such as applied voltage, gas flow rate, and gas mixture ratio (He:Ar) is investigated so as to be able to control the fluctuations in the intended application. A single pin probe measures the fluctuations in the jet in a region where the plasma emerges out of the capillary. The fluctuations are characterized by fast Fourier transform and time-frequency analysis (TFA). It is found that with an increase in applied voltage at a fixed flow rate (1 l/min), the fluctuations increase and reach a peak value at ∼11 kV and thereafter decrease at higher voltages due to a high value of discharge current (∼4.77 mA) at 11 kV arising from the intense ionization taking place in the jet. When the gas flow rate is increased at a fixed voltage (14 kV), the fluctuations get enhanced for flow rates beyond 2 l/min due to transition to turbulent flow occurring at a buoyancy induced Reynolds number of ∼474. In the case of gas mixing, an increase in the concentration of Ar and a reduction in He at a fixed applied power (80.6 W) and flow rate (1 l/min) give rise to a higher level of fluctuations, which is considered to be due to lower thermal conductivity and ionization potential of Ar, leading to gas heating, and ponderomotive force, giving rise to filamentation. The TFA shows the time evolution of fluctuation frequencies, which can be tuned by varying the experimental parameters. Understanding the influence of experimental parameters is crucial in controlling the fluctuations in the micro-plasma jet.

Background Pressure Effects on the Performance of a 20 kW Magnetically Shielded Hall Thruster Operating in Various Configurations

The paper reports the characterization results of a 20 kW-class magnetically shielded Hall thruster in three different configurations and operating with a centrally mounted cathode. The characterization was carried out at two different pumping speeds in SITAEL’s IV10 vacuum chamber, resulting in two different background pressure levels for each tested operating point. A linear behavior of discharge current and thrust values versus the anode mass flow rate was noticed for both pumping speeds levels and for all the three configurations. In addition, the thrust and discharge current values were always found to be lower at lower background pressure levels. From the performance levels, a preliminary estimate of the ingested mass flow rates was performed, and the values were then compared to a recently developed background flow model. The results suggested that, for this thruster and in the tested operating regimes, the change in performance due to background pressure could be ascribed not only to the ingestion of external mass flow coming from the chamber but also to other physical processes caused by the flux of residual background neutrals.

Influence Analysis of Current Limiting Reactor on Pole-to-Pole Short Circuit Fault in DC Distribution System

With the development of power electronic technology, flexible DC distribution system has gradually become a research hotspot. Pole-to-pole short circuit fault is the most serious fault type in DC distribution system. When pole-to-pole short circuit fault occurs in DC side, it will produce a large fault current, which will cause serious harm to DC distribution system. Therefore, it is urgent to install current limiting reactor to limit fault over-current. Aiming at the DC distribution system based on half bridge MMC, this paper analyses the fault mechanism and fault characteristics of pole-to-pole short circuit fault, studies the current limiting effect of the installation position and capacity of current limiting reactor on fault current, and carries out simulation verification in PSCAD / EMTDC platform. The analysis and simulation results show that installing a current limiting reactor at the outlet of the DC side can reduce the peak value of capacitor discharge current, and installing a current limiting reactor at the outlet of the AC side can reduce the overall amplitude of fault current.

Study of Solar Radiation Effect on Radio Signal Using Plasma Antenna

Plasma antenna can be formed by energizing glass tubes which are filled with neutral gases. It works similarly as metal antenna where it can transmit and receive wireless signal. This study aims to investigate the effect of weather focused on solar radiation towards the performance of plasma antenna represented by signal strength. Fluorescent lamp was set as plasma because it used ionized gas as its conducting element instead of metal. Execution of electrical properties measurements need to be done first, in order to obtain discharge current and voltage values, that need to be used into Glomac programming for the generation of electron temperature and electron density. Next, calculations of the plasma properties was performed to derive the value of plasma and collision frequencies. The plasma properties are important parameters to design and simulate plasma antenna using Computer Simulation Technology (CST). Antenna parameters in terms of return loss, gain, directivity and radiation pattern can be simulated using CST. Signal strength experiment was conducted to evaluate plasma antenna performance in terms of its capability to capture the signals and analyse the effect of solar radiation on that particular moment through the rate of power level over time versus solar radiation data. It was observed at the highest solar radiation rate which is 920 V/m, the power level recorded is the lowest value at-172.93 dBm. Therefore, the signal strength received by the plasma antenna shows remarkable changes under the influence of solar radiation.

Numerical Suite for Gaseous Plasma Antennas Simulation

A gaseous plasma antenna (GPA) is a device in which a plasma medium is used to transmit or receive electromagnetic (EM) waves. This work is devoted to the presentation of a numerical suite for the simulation of a GPA that consists of a plasma module for the estimation of the plasma parameters (e.g., electron density profile) and its electrical response, along with an EM module to compute the antenna properties (e.g., radiation pattern and input impedance). The two problems are handled separately: first, the plasma discharge is solved, and then, the antenna properties are computed. In particular, the plasma module has been implemented on the C++ library OpenFOAM, whereas the EM module relies on the well-established commercial numerical tool CST Microwave Studio. The results of the plasma module have been compared against experimental measurements performed on a discharge driven by a hollow cathode and a cold cathode fluorescence lamp (CCFL). Finally, the numerical suite has been exploited to characterize a realistic plasma dipole: higher values of discharge current (equivalently of plasma density) allow to achieve higher maximum gain and an input impedance closer to the one of a metallic dipole. Moreover, the possibility of electronically shifting the resonance frequency by tens of megahertz has been proved.

Features of streamer form of corona discharge in respect to electric gas purification

An article briefly describes advantages of streamer form of corona discharge over corona discharge of direct voltage. With the purpose of confirmation of hypotheses about possibility of stabilization of discharge processes in electric fields of streamer form of corona discharge oscillography voltage and current were done, and volt amperage features at various frequencies of pulse voltage were taken. Impact of parameters of electrodes system «Potential plane with corona needles – grounded plane» to value of discharge current was studied. Outcomes of study of power features and character of change in strength of electric fields of streamer form of corona discharge are presented.

Plasma density profile measurements for ultra-short high power laser beam guiding experiments at SPARC _LAB

External injection is a promising method to achieve high accelerating gradients and to control the beam properties. The energy gain of an electron via the wakefield is proportional to the product of the accelerating field multiplied by the effective propagation distance of the laser. Therefore, in order to bring the electron energy in the order of the GeV, a longer propagation length is required, which can be obtained by guiding the laser pulse in a wave-guide. In the case of SPARC_LAB, a 500 μτη diameter hydrogen-filled capillary discharge is used; to guide the laser beam it is necessary to act on the refractive index of the plasma, depending on its density. In this work measurements of the trend over time of the longitudinal profile of the plasma density within the capillary are presented, along with openFOAM simulations of the gas profile distribution. Preliminary test of laser guiding are also shown, detecting the behaviour of the laser beam at the exit of the capillary with respect to the discharge current value.

Investigation of the machinability of SiC reinforced MMC materials produced by molten metal stirring and conventional casting technique in die-sinking electrical discharge machine

In this study, MMC materials were produced by stir casting method using AA7075 alloy matrix and silicon carbide (SiC) as reinforcement elements in order to investigate the effect of die-sinking electric discharge machining (EDM) process parameters for various weight percentage reinforcement (10% 14% and 18%) used MMC. EDM with three different pulse-on time (Time on) (25, 50 &75 µs) and discharge current value (2, 4 & 6 Amperes) and at constant dwell time (20 µs) and depth of cut (0.5 mm). After machining process, the effects of process parameters on processing time, average surface roughness, hole diameter and the weight loss were investigated. As a result of the study, highest values, the lowest values of processing time, hole diameter and average surface roughness were obtained for various weight percentage reinforcement MMC respectively. Ideal MMC, discharge current value and time-on duration for average surface roughness, hole diameter, processing time and material wear loss according to signal to noise ratio were determined. According to ANOVA results, R2 values for the average surface roughness, hole diameter, processing time and material wear loss were calculated as 89.55%, 98.46%, 89.85% and 24.06% respectively.

Simulator of Planar Electrodes Plasma Characteristics using Different Gases

Simulator Plasma Source for Planar Electrodes, SPSPE, is designed to verify the experimental results of planar anode and cathode which are obtained previously using nitrogen gas. Experimentally, the glow discharge is carried out at operating pressure values in the range of 0.1- 0.6 Torr and the disc anode - disc cathode distance equal to 10 cm using nitrogen gas. The comparison between SPSPE and the experimental values at different product of pressure and distance values for breakdown voltage, discharge current and the second Townsend coefficient using nitrogen gas is made. It is found a good match between SPSPE and the experimental values. Also, the first Townsend coefficient is calculated by SPSPE at different product of pressure and distance values using nitrogen gas, while breakdown voltage and discharge current are calculated by SPSPE at different product of pressure and distance values using nitrogen, argon and carbon dioxide gases. It is found that the minimum breakdown voltage values are equal to 472.77, 232.26 and 349.27 volts at minimum product of pressure and distance values equal to 1.5, 1 and 0.75 Torr.cm using nitrogen, argon and carbon dioxide gases, respectively. Also, it is found that the minimum discharge current values are equal to 0.5228 mA and 3.65 mA at minimum product of pressure and distance value equal to 1 Torr.cm using nitrogen and argon gases, respectively. While minimum discharge current value equal to 7.8 mA is obtained at minimum product of pressure and distance value equal to 0.75 Torr.cm using carbon dioxide gas.

Analysis of Generalized Peukert’s Equations for Capacity Calculation of Lithium-Ion Cells

In this paper, the possibility of using generalized Peukert’s equations C =Cm/(1 + (i/i0)n), C = 0.522Cmtanh((i/i0)n/0.522)/(i/i0)n, and C = Cmerfc((i/ik − 1)/(1/n))/erfc(−n) for the calculation of lithium-ion cells’ released capacity at different discharge currents is analyzed. It is proven that these equations correspond well to the experimental data over the entire change range of the discharge currents. Furthermore, it is demonstrated that the parameter n depends on neither cell capacity nor its format or manufacturer; however, it grows with an increase of the ratio i0/Сm (or ik/Сm), which depends on an electrode’s effective thickness and the electrochemical system of the lithium-ion cells. Additionally, it is possible to consider the dependence of a lithium-ion cell’s released capacity on a discharge current value as the statistical phase transition subjected to the normal distribution law. The proposed statistical mechanism explains the changes of the parameters n and i0 (ik) based on the type of battery studied.

Study of fast charging battery

The key to battery management systems (BMS) is an accurate and real-time prediction on State of Charge (SOC) of the power battery. The methods of estimating SOC of power battery were analyzed. The gray neural network model was introduced into the field of SOC estimation. The model is used to establish the relationship of SOC, discharge current and rebound voltage. The model can be used to estimate SOC of battery on line by detecting the values of rebound voltage and discharge current during the discharge process. The model of SOC estimation is proved feasible by comparing the experimental data with calculated data.

Parametric Study of Two Stable Forms of Discharge Burning in a Hall-Effect Thruster

In this paper, we experimentally studied the behavior of the integral operation parameters of a Hall-effect thruster (thrust and specific thrust impulse) in two stable discharge glow modes significantly different from each other in anodic efficiency. The studies were conducted using a laboratory model of a Hall-effect thruster with an extended layer with an average discharge channel diameter of 77 mm in the discharge voltage range of 500–900 V and in the gas-flow rate range from 2 to 5 mg/s. The most striking distinguishing features of the observed glow regimes are the plasma jet shape and the discharge current value at almost identical input parameters (gas flow, discharge voltage, and magnetic field). In the entire studied range of input parameters when changing from the optimal mode (in terms of efficiency) to suboptimal, the main integral characteristics of the engine are shown to undergo a stepwise change: the discharge current increases by 10‒30% with a simultaneous relative drop in thrust by 5–15% and in efficiency by 20–40%. A detailed study of the anodic efficiency structure showed that, at abrupt rebuilding, the efficiency of using the electron current (the ratio of the ion current to the discharge current) changes, i.e., the electron conductivity in the engine discharge channel.