Equal Charge Research Articles

A data-driven fuzzy information granulation approach for battery state of health forecasting

This paper proposes an estimation method for battery state of health (SOH) based on fuzzy information granulation. The time interval of the equal charging current difference (TIECCD) in the constant voltage charging mode is extracted as a feature. Then, grey relational analysis is employed to find the optimal health indicators. After granulating fuzzy information on SOH and health indicators, the three parameters Low, R and Up are obtained to characterize the SOH range. In the implementation, the least squares support vector machine (LSSVM) is selected to construct the nonlinear regression model of the parameters and the granulated feature data to realize the prediction of the trend of battery health. Finally, one reference group is set as contrast, and the prediction results based on experimental data prove the superiority of the proposed method.

Viscous and electro-osmotic effects upon motion of an oil droplet through a capillary

Abstract

Realization of photonic charge-2 Dirac point by engineering super-modes in topological superlattices

Quite recently, an unconventional variety of fourfold linear band degeneracy points has been discovered in certain condensed-matter systems. Contrary to standard 3-D Dirac monopoles, these quadruple points known as the charge-2 Dirac points are characterized by nonzero topological charges, which can be exploited to delve into hitherto unknown realms of topological physics. Here, we report on the experimental realization of a charge-2 Dirac point by deliberately engineering hybrid topological states, called super-modes, in a 1-D optical superlattice system with synthetic dimensions. Utilizing direct reflection and transmission measurements, we propose the existence of the synthetic charge-2 Dirac point in the visible region. We also show an experimental approach to manipulating two spawned Weyl points possessing equal charge. Topological end modes resulting from the charge-2 Dirac point can be delicately controlled within truncated superlattices, opening a pathway to rationally engineer local fields with intense enhancement.

Design of symmetrical half-bridge converter with a series coupling capacitor

Purpose With the advancement of technology, size, cost, and losses of the switched mode power supply (SMPS) have been decreasing. However, due to the high frequency switching, design of magnetic drives and isolation circuits are becoming a crucial factor in SMPS. This paper presents design criteria, procedure and implementation of AC-DC half bridge (HB) converter with lower cost, smaller size and lower voltage stress on the power switch. Design/Methodology/approach The HB converter is designed in a symmetrical mode with a series coupling capacitor. Isolated power supplies are used for the converter and control circuit. Further, a transformer based isolated gate driver is used to drive both MOSFETs. The control IC works in voltage control mode to regulate voltage by controlling the duty cycle of the MOSFETs. Findings Control characteristics and performance of the HB converter is simulated using the MATLAB software and prototype of 170 W HB converter is built to validate the analytical results under variable load current and source voltage. The power quality and variation of load voltage at 2 A, 5 A, 7 A are reported. Originality/value This paper presents the design of a low-cost HB converter in a symmetrical mode which saves the additional cost of symmetric correction circuit normally required in asymmetrical mode design. This paper also focuses on the selection of primary and secondary side switch, series coupling capacitor, commuting diode, isolated drive and charge equalizer resistor.

In vivo microstimulation with cathodic and anodic asymmetric waveforms modulates spatiotemporal calcium dynamics in cortical neuropil and pyramidal neurons of male mice.

Electrical stimulation has been critical in the development of an understanding of brain function and disease. Despite its widespread use and obvious clinical potential, the mechanisms governing stimulation in the cortex remain largely unexplored in the context of pulse parameters. Modeling studies have suggested that modulation of stimulation pulse waveform may be able to control the probability of neuronal activation to selectively stimulate either cell bodies or passing fibers depending on the leading polarity. Thus, asymmetric waveforms with equal charge per phase (i.e., increasing the leading phase duration and proportionately decreasing the amplitude) may be able to activate a more spatially localized or distributed population of neurons if the leading phase is cathodic or anodic, respectively. Here, we use two-photon and mesoscale calcium imaging of GCaMP6s expressed in excitatory pyramidal neurons of male mice to investigate the role of pulse polarity and waveform asymmetry on the spatiotemporal properties of direct neuronal activation with 10-Hz electrical stimulation. We demonstrate that increasing cathodic asymmetry effectively reduces neuronal activation and results in a more spatially localized subpopulation of activated neurons without sacrificing the density of activated neurons around the electrode. Conversely, increasing anodic asymmetry increases the spatial spread of activation and highly resembles spatiotemporal calcium activity induced by conventional symmetric cathodic stimulation. These results suggest that stimulation polarity and asymmetry can be used to modulate the spatiotemporal dynamics of neuronal activity thus increasing the effective parameter space of electrical stimulation to restore sensation and study circuit dynamics.

A Modularized Bidirectional Charge Equalizer for Series-Connected Cell Strings

In this article, a modularized charge equalizer is proposed. In the proposed topology, N series cells are divided into K modules and each module consists of J series cells and its multiplexer switches. A multioutput transformer is used as temporary energy storage. Each of the transformer outputs is connected to one of the K modules and targets the cells in its module. In this way, at the same time K cells are targeted simultaneously and the speed of balancing has increased. In the proposed circuit, energy can be transferred by string to cell, cell to string, and cell to cell methods. In addition, it can be transferred between modules and equalize them. Therefore, the proposed topology is very flexible and can circumvent the limitations of each method and use the appropriate method in the right place. Also, a step-by-step method for command the multiplex switches is proposed. To illustrate the correctness of the circuit operation, a prototype is implemented to balance the charge of four lithium-ion battery cells. The experimental results confirm the correctness of the proposed circuit operation.

Utility-Aware Charging Scheduling for Multiple Mobile Chargers in Large-Scale Wireless Rechargeable Sensor Networks

Mobile charging can provide stable and reliable energy replenishment for wireless rechargeable sensor network (WRSN). However, relatively low charging utility exists in existing solutions. In this paper, we present a utility-based collaborative charging (UBCC) strategy to maximize the charging utility of mobile chargers (MCs) in large-scale WRSNs. Charging MCs and server MCs are employed to jointly achieve our goal by three aspects. First, a path merging scheme is designed to save the traveling paths of MCs. Unlike existing studies with entirely diverse movement trajectories of MCs, the same traveling path is assigned to both the departure charging MCs and the return MCs, which serve different charging areas. Second, an idle-difference alleviating scheme is devised to improve the utilization rate of MCs. Different from current solutions with a large difference of working hours of MCs, each charging MC is assigned the equal charging tasks, resulting in synchronous charging and simultaneous energy replenishment of MCs. Third, an energy-waste averting scheme is designed to maximize the energy utilization of MCs. The energy of each MC is just exhausted until the MC completes its charging tasks and traveling roles. Extensive simulation results demonstrate the advantages of UBCC in the charging cost and charging utility.

Nanomechanics of a hydrogen molecule suspended between two equally charged tips

Geometric configuration and energy of a hydrogen molecule centered between two point-shaped tips of equal charge are calculated with the variational quantum Monte-Carlo (QMC) method without the restriction of the Born-Oppenheimer (BO) approximation. Ground state nuclear distribution, stability, and low vibrational excitation are investigated. Ground state results predict significant deviations from the BO treatment that is based on a potential energy surface (PES) obtained with the same QMC accuracy. The quantum mechanical distribution of molecular axis direction and bond length at a sub-nanometer level is fundamental for understanding nanomechanical dynamics with embedded hydrogen. Because of the tips' arrangement, cylindrical symmetry yields a uniform azimuthal distribution of the molecular axis vector relative to the tip-tip axis. With approaching tips towards each other, the QMC sampling shows an increasing loss of spherical symmetry with the molecular axis still uniformly distributed over the azimuthal angle but peaked at the tip-tip direction for negative tip charge while peaked at the equatorial plane for positive charge. This directional behavior can be switched between both stable configurations by changing the sign of the tip charge and by controlling the tip-tip distance. This suggests an application in the field of molecular machines.

Capacitor discharging calculation application based on android

At this time, there were many small components to make electronic equipment such as TVs, smartphones and others. This electronic equipment uses passive components and active components. The physical size of the capacitor decreases gradually becoming smaller. Capacitors store energy in the form of charge. If there are two equal charges (for example a positive charge and a positive charge) then both charges will refuse. Conversely, if there are two different charges, they will attract each other. The purpose of this research is to create an Android-based software that can calculate the remaining charge after the discharging process. The method used is to use the calculation method of discharging capacitors. The results of this study found that the calculation can be done well and also the presence of errors in the software design process.

An Integrated Cascade Structure-Based Isolated Bidirectional DC–DC Converter for Battery Charge Equalization

In this article, an isolated bidirectional dc-dc converter with an integrated cascade structure is proposed for a centralized charge equalization system. Compared with existing architectures, the proposed converter structure is equivalent to the integration of polarity switches and a bidirectional dc-dc converter. Equalization of cells with different voltage polarities can be realized by controlling the working state of the converter, which further improves the reliability and integration of the equalization system. The integrated cascade structure can not only increase the equalization current and make it work in a continuous state but also achieve a high voltage conversion ratio to improve the efficiency of the transformer. Theoretical derivations of the converter and the conditions of soft-switch implementation are analyzed in detail. Finally, equalization experiments on a 13-cell lithium-ion battery string are carried out, and a quantitative and comprehensive comparison of different centralized equalizer is conducted. The experimental and comparison results validate the superiorities of the proposed equalizer and demonstrate obvious performance enhancement over the conventional method.

Studying the Process of (NH4)2[IrCl6] Thermal Decomposition by X-Ray Photoelectron Spectroscopy and Electron Microscopy

Thermal decomposition of ammonium hexachloroiridate(IV) in inert and reducing atmospheres are studied by X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). Particular attention is paid to the formation of metallic iridium particles. The processes of thermal decomposition proceed similarly in an inert atmosphere and in a vacuum as is evidenced by equal charge states of Ir, Cl, and N at different decomposition stages in these two cases. According to XPS data, the decomposition process can be described as consisting of three main stages. At the first stage, an intermediate product with atomic charge states corresponding to {Ir(NH3)xCl6−x}(x−3) (1 ≤ x ≤ 3) and metallic iridium are formed. At the second stage, atomic charge states indicate formation of {IrClx}3−x, NH4Cl. The metal nanoparticles appearing at these stages have different shapes: spherical, “flakes”, dendritic networks. The final decomposition product (metallic iridium) is agglomerates of regularly shaped spherical nanoparticles of uniform sizes. The process of thermal decomposition in a reducing atmosphere leads to the formation of nanoporous metal crystallites with a shape similar to that of the initial complex salt. Such crystallites are formed as a result of complicated channels that are developed due to the release of gaseous products (N2 and HCl) and are directed from the bulk of the crystallite to its surface. The atomic charge states of the intermediate decomposition product correspond to {IrClx}3−x.

Periodic Coulomb Dynamics of Three Equal Negative Charges in the Field of Equal Positive Charges Fixed in Octagon Vertices

Periodic solutions of the Coulomb equation motion for three equal negative point charges in the field of six equal positive point charges fixed in vertices of a convex octagon are found. The system possesses an equilibrium configuration. The Lyapunov center theorem is applied.

A Layered Bidirectional Active Equalization Method for Retired Power Lithium-Ion Batteries for Energy Storage Applications

The power from lithium-ion batteries can be retired from electric vehicles (EVs) and can be used for energy storage applications when the residual capacity is up to 70% of their initial capacity. The retired batteries have characteristics of serious inconsistency. In order to solve this problem, a layered bidirectional active equalization topology is proposed in this paper. Specifically, a bridge-type equalization topology based on an inductor is adopted in the bottom layer, and the distributed equalization topological structure based on the bidirectional BUCK-BOOST circuit is adopted in the top layer. State of charge (SOC) is used as the equalization target variable, and the bottom layer equalization algorithm based on a “partition” idea and route optimization is proposed. The static equalization experiments and charge equalization experiments are performed by the 12 retired batteries selected from an electric sanitation vehicle. The results show that the proposed equalization method can reduce the SOC difference between retired batteries and can effectively improve the inconsistency of the retired battery pack with a faster equalization speed.

\u03b1\u2032 corrections of Reissner-Nordstr\xf6m black holes

We study the first-order in α′ corrections to non-extremal 4-dimensional dyonic Reissner-Nordström (RN) black holes with equal electric and magnetic charges in the context of Heterotic Superstring effective field theory (HST) compactified on a T6. The particular embedding of the dyonic RN black hole in HST considered here is not supersymmetric in the extremal limit. We show that, at first order in α′, consistency with the equations of motion of the HST demands additional scalar and vector fields become active, and we provide explicit expressions for all of them. We determine analytically the position of the event horizon of the black hole, as well as the corrections to the extremality bound, to the temperature and to the entropy, checking that they are related by the first law of black-hole thermodynamics, so that ∂S/∂M = 1/T. We discuss the implications of our results in the context of the Weak Gravity Conjecture, clarifying that entropy corrections for fixed mass and charge at extremality do not necessarily imply corrections to the extremal charge-to-mass ratio.

On the permselectivity of cation-exchange membranes bearing an ion selective coating

Monovalent ion selective membranes are permeable for monovalent ions while rejecting divalent ions to some extent. Different processes and applications like electrodialysis, microbial fuel cells, and flow batteries utilize such selective properties. Industrial membranes have a specific coating of equal charge to reject the bivalent counter ions. It has been suggested in the past that the current density regime at which such composite ion exchange membranes are operated can strongly influence their ion selectivity towards monovalent ions. Here, we now confirm this observation for a commercial CMS membrane as well as for a novel microgel modified membrane. The higher the applied current density is, the more acute the drop in selectivity becomes as opposed to the unmodified reference membrane where bivalent ions are transported preferentially. This work focuses on the relationship between selectivity and current density regime using (1) a conventional commercial membrane, (2) a commercial monovalent ion selective membranes as well as (3) a tailor-made selective membrane, the latter being surface-modified with quaternized Poly (2-vinylpyridine) (qP2VP) microgels. Experimental electrodialysis results in combination with (a) direct numerical simulations of mixed ion transport through the composite architecture and (b) a swelling analysis of the microgels by ellipsometry reveal that layer responsiveness and structural change of the modification layer is responsible for the decrease in permselectictivity upon an increased current density. The swelling reduces the charge density of the modification and therewith the rejection of divalent ions. It would be highly desirable to synthesize modification layers that have a low ion transport resistance while maintaining its volumetric charge density independent of the current density applied.

Run-to-Run Control for Active Balancing of Lithium Iron Phosphate Battery Packs

Lithium iron phosphate battery packs are widely employed for energy storage in electrified vehicles and power grids. However, their flat voltage curves rendering the weakly observable state of charge are a critical stumbling block for charge equalization management. This paper focuses on the real-time active balancing of series-connected lithium iron phosphate batteries. In the absence of accurate in situ state information in the voltage plateau, a balancing current ratio (BCR) based algorithm is proposed for battery balancing. Then, BCR-based and voltage-based algorithms are fused, responsible for the balancing task within and beyond the voltage plateau, respectively. The balancing process is formulated as a batch-based run-to-run control problem, as the first time in the research area of battery management. The control algorithm acts in two timescales, including timewise control within each batch run and batchwise control at the end of each batch. Hardware-in-the-loop experiments demonstrate that the proposed balancing algorithm is able to release 97.1% of the theoretical capacity and can improve the capacity utilization by 5.7% from its benchmarking algorithm. Furthermore, the proposed algorithm can be coded in C language with the binary code in 118 328 bytes only and, thus, is readily implementable in real time.

Trajectory Taken by Dimeric Cu/Zn Superoxide Dismutase through the Protein Unfolding and Dissociation Landscape Is Modulated by Salt Bridge Formation.

Native mass spectrometry (MS) is a powerful means for studying macromolecular protein assemblies, including accessing activated states. However, much remains to be understood about what governs which regions of the protein (un)folding funnel, which can be explored by activation of protein ions in a vacuum. Here, we examine the trajectory that Cu/Zn superoxide dismutase (SOD1) dimers take over the unfolding and dissociation free energy landscape in a vacuum. We examined wild-type SOD1 and six disease-related point mutants by using tandem MS and ion-mobility MS as a function of collisional activation. For six of the seven SOD1 variants, increasing activation prompted dimers to transition through two unfolding events and dissociate symmetrically into monomers with (as near as possible) equal charges. The exception was G37R, which proceeded only through the first unfolding transition and displayed a much higher abundance of asymmetric products. Supported by the observation that ejected asymmetric G37R monomers were more compact than symmetric G37R ones, we localized this effect to the formation of a gas-phase salt bridge in the first activated conformation. To examine the data quantitatively, we applied Arrhenius-type analysis to estimate the barriers on the corresponding free energy landscape. This reveals a heightening of the barrier to unfolding in G37R by >5 kJ/mol-1 over the other variants, consistent with expectations for the strength of a salt bridge. Our work demonstrates weaknesses in the simple general framework for understanding protein complex dissociation in a vacuum and highlights the importance of individual residues, their local environment, and specific interactions in governing product formation.

A Modular Battery Voltage-Balancing System Using a Series-Connected Topology

A new modular topology and control method is presented for balancing the voltages of a series-connected string of battery cells. The proposed topology has fewer components compared to similar methods and is characterized as “cell to string to cell” category since charge transfer occurs between all cells during a cycle: this increases the speed of the charge equalization process. Two battery cells are connected to a bridge module and bridge modules are connected in series through transformer tertiary windings. This series connection causes all bridges to have the same effect on each other and makes the system operation and analysis more predictable. As waveforms and transferred charge can be predicted accurately through analysis, the equalization time is also optimized through a design procedure. The easy-to-implement distributed controller described requires only one voltage sensor per two battery cells.

Systems for Protecting and Controlling the Lithium Cells

The article presents methods for balancing the cells of batteries made in lithium-ion technology. They have many advantages over the traditional lead-acid batteries. The most important advantages include fast charging, high energy density and power as well as a wider range of operating temperatures. However, they require the use of battery surveillance and management systems (BMS) to increase work safety. One of the most important functions of such a system is the method of balancing, i.e. charge equalization of each cell. This article explains the purpose of balancing, presents the test results, describes the methods for realization of this process, taking into account the advantages and disadvantages of each of them.

Near-Fastest Battery Balancing by Cell/Module Reconfiguration

Charge imbalance is a very common issue in multi-cell /module/pack battery systems due to manufacturing variations, inconsistent charging/discharging, and uneven thermal distribution. As a consequence, the deliverable charge capacity, battery lifespan, and system reliability may all decrease over time. To tackle this issue, various external circuit designs can be attached for charge balance, and the internal battery cell/module/pack connection can also significantly affect the charge balance performance. This paper focuses on minimizing the battery charge equalization (BCE) time by battery cell/module reconfiguration. Specifically, for the reconfigurable module-based BCE system, we propose reconfiguration algorithms for fast charge equalization under different levels of system reconfigurability. For battery systems allowing module reconfiguration and intra-module cell reconfiguration, the proposed module-based bounded reconfiguration algorithm can reach or get very close to the minimum BCE times obtained by exhaustive search. When the reconfigurability level is extended by allowing inter-module cell reconfiguration, the proposed module-based complete reconfiguration algorithm can achieve similar optimality to that of the genetic algorithm (GA). Moreover, as compared to the circuit experiments, exhaustive search, and GA, the proposed algorithms take much less computational time. The optimality and computational efficiency of the proposed algorithms are demonstrated by both circuit and numerical experiments.