Charge Pulse Research Articles

Model predictive controlled pulse current battery charging with power electronic switches thru advanced semiconductor material in DC-DC converter

The pulse charging method is one of the fastest charging methodologies for batteries like lithium ion batteries, which are used in electric vehicle applications. This pulse charging methodology leads to fast charging and has higher energy efficiencies. The aim of the paper is to present an overview of the DC-DC battery charger with a model predective (MP) controller. A MP controller is one that predicts the behaviour of the system with a finite time window. The controlled inputs were generated by the MP controller to have optimal operation with respect to predicted value. The process of prediction and generation of controlled input gets repeated after several intervals of time and whenever the DC voltage is greater than the rated voltage of the battery, the charging circuit is disconnected. The modelling of a closed loop pulse current rechargeable battery converter using a PI controller and an MP controller is the subject of this paper. The goal is to increase output power while lowering steady-state error where the same got reduced to 1.05 V (MP controller) from 2.12 V (PI controller). Similarily, rise, settling and peak times are, 0.21, 0.45 and 0.30 secs respectively in system with MP controller. The results demonstrate the model predictive regulated closed loop pulse current rechargeable battery converter's higher performance. Charging a battery also relies on the performance and efficiency of the power electronic switching devices, which in turn rely on the material qualities. These switches are often made of silicon. Due to improved material technology and a desire for higher performance, wide band-gap semiconductors are used in switching devices. This paper also discusses the semiconductor material used to manufacture the power electronic switches that are cast-off in the DC-DC Converter.

Confined pulsed diffuse layer charging for nanoscale electrodeposition with an STM.

Regulating the state of the solid–liquid interface by means of electric fields is a powerful tool to control electrochemistry. In scanning probe systems, this can be confined closely to a scanning (nano)electrode by means of fast potential pulses, providing a way to probe the interface and control electrochemical reactions locally, as has been demonstrated in nanoscale electrochemical etching. For this purpose, it is important to know the spatial extent of the interaction between pulses applied to the tip, and the substrate. In this paper we use a framework of diffuse layer charging to describe the localization of electrical double layer charging in response to a potential pulse at the probe. Our findings are in good agreement with literature values obtained in electrochemical etching. We show that the pulse can be much more localized by limiting the diffusivity of the ions present in solution, by confined electrodeposition of cobalt in a dimethyl sulfoxide solution, using an electrochemical scanning tunnelling microscope. Finally, we demonstrate the deposition of cobalt nanostructures (<100 nm) using this method. The presented framework therefore provides a general route for predicting and controlling the time-dependent region of interaction between an electrochemical scanning probe and the surface.

Effect of Temperature on the High-Rate Pulse Charging of Lithium-Ion Batteries

Effect of Temperature on the High-Rate Pulse Charging of Lithium-Ion Batteries

The characteristics of microplasma discharge propagation over &#x0D; the titanium surface covered with a thin oxide film

The propagation and structure of a microplasma discharge initiated in vacuum by a pulsed plasma flow with a density of 1013 cm–3 on the surface of a titanium sample covered with a &#x0D; thin continuous dielectric titanium oxide film with a shickness of 2–6 nm were studied experimentally when the electric current of the discharge changes from 50 A to 400 A. &#x0D; It was found that the microplasma discharge glow visually at the macroscale has a branched structure of the dendrite type, which at the microscale consists of a large number &#x0D; of brightly glowing “point” formations – cathode spots localized on the metal surface. The resulting erosion structure on the titanium surface is visually “identical” to the structure of &#x0D; the discharge glow and consists of a large number of separate non-overlapping microcraters with characteristic sizes from 0.1–3 μm, which are formed at the sites of localization of &#x0D; cathode spots at distances of up to 20 μm from each other. It was found that the propagation of a single microplasma discharge over the titanium surface covered with a thin oxide film a &#x0D; thickness of 2–6 nm occurs at an average velocity of 15–70 m/s when the amplitude of the discharge electric current changes in the range of 50–400 A. In this case, the microplasma &#x0D; discharge propagation on the microscale has a “jumping” character: the plasma of “motionless” burning cathode spots, during their lifetime 1 μs, initiates the excitation of new &#x0D; microdischarges, which create new cathode spots at localization distances of 1–20 μm from the primary cathode spots. This process repeated many times during a microplasma dis-&#x0D; charge pulse with a duration from 0.1 ms to 20 ms.

Research on restoration method of nuclear pulse current signal of semiconductor detector based on artificial neural networks

The charge pulse generated by semiconductor detector caused by nuclear event carries nuclide and nuclear reaction information, but the amplified charge pulse amplitude is obviously weak and the noise is so large. Aiming at the difficulty of obtaining the charge signal pulse generated by the detector, a method for recovering the nuclear pulse current signal of semiconductor detector is proposed. Pulse recovery is divided into two parts: pulse shape recovery and pulse amplitude recovery. Point at the pulse shape, a shape recognition network of nuclear pulse current signal based on deep learning is proposed. For pulse amplitude,it can be obtained by Mexican straw hat wavelet forming algorithm. This algorithm can eliminate the baseline fluctuation caused by pulse stacking. The proposed shape recognition network of nuclear pulse current signal is composed of classifier and regressor. The classifier is used to judge whether the data contains a complete rising edge. The data containing the complete rising edge is sent to the regressor for prediction, so as to obtain the parameters related to the current pulse shape. The precision, recall and F-Measure of the classifier in classifying the test set are 98.88%, 98.05% and 98.33%, respectively. The average absolute error of the regressor in predicting the parameters related to the current pulse shape is about 9 ns. The experimental results show that the proposed method can recover the shape and amplitude of the current signal.

Li-Ion Battery and Supercapacitor Modeling for Electric Vehicles Based on Pulse – Pseudo Random Binary Sequence

Energy storage devices such as batteries and supercapacitors are arousing a growing interest in many areas of industrial applications since they allow improving the dynamic response and efficiency. In this sense, the availability of electric models of batteries and supercapacitors is necessary for the correct sizing, control, and energy management of power systems. In order to identify the parameters of the equivalent electric model, the identification current profile is often a pulse of charge or discharge. Subsequently, these models are validated with a current verification profile. However, the verification profile compared to the identification profile is more dynamic in amplitude and frequency, producing validation errors due to the identification signal's limited bandwidth. This paper proposes a novel Pulse – Pseudo Random Binary Sequence (Pulse – PRBS) identification current profile, with similar spectral characteristics to the verification profile, in order to improve the modeling accuracy. The parameters of a Lithium-ion battery and a supercapacitor are obtained with this new identification current profile and the Optimization Toolbox of Matlab, using the electrical models in Simulink or Simscape. Finally, the models are validated with the Urban Driving Cycle ECE-15 and the Hybrid Pulse Power Characterization (HPPC) for electric vehicle applications.

Predicting the impact of formation protocols on battery lifetime immediately after manufacturing

Predicting the impact of formation protocols on battery lifetime immediately after manufacturing

Design and implementation of the distributed dosimetric system based on the principles of IoT

This paper describes the architecture and components of the distributed information and management system for collecting, processing, storing, and distributing data on a radiometric and dosimetric experiment using the principle of the Internet of Things. Data exchange between elements in the system, as well as the analysis of the received information, involves active application of the ThingSpeak cloud service. Two-way communication with the cloud with a 15-second loop has been implemented. Data are processed in the MATLAB (America) environment, integrated into the cloud. The developed hardware and software solutions demonstrate an increased accuracy of measurements due to the use of promising cadmium telluride (CdZnTe) detectors, modern microcontroller and micro communication technology, and a new algorithm for correcting the dependence of detector sensitivity on radiation energy. Measurement with correction by the method of average charge pulse amplitude is carried out in the energy range from 60 keV to 3 MeV. The resolution of the spectrometric channel is 6.5 % at the peak of 662 keV of full absorption from the reference source, Cesium (Сs – 137). The module for a laboratory sensor network, designed to measure the dose of ionizing radiation, has a built-in spectrometric analog-digital converter, microcontroller control, and a communication unit. Constructing the diagrams demonstrates the operation of the interrupt handler in the form of a series of events occurring when requests arrive from a Web server. The peculiarity of the system is the absence of intermediate devices that make it possible to establish a connection with the Internet. The developed system, equipment, algorithms, and programs are used for experimental studies of radiation and nuclear-physical processes. Elements of the system were useful for remote laboratory work by students

An improved electrochemical‐based model to estimate battery equivalent circuit parameters for pulsed discharge scenarios

AbstractLithium‐ion batteries (LIBs) power almost all consumer electronics products these days. High‐energy density and low cost are some of the reasons behind LIBs being used to electrify all modes of transportation. Battery equivalent circuit models enable estimation of the state of battery energy and power. These models also assist in the capturing dynamic and transient operation of electric vehicles (EVs). Researchers have used lumped equivalent circuit models in the past which fail to capture the transient variation of battery capacity during pulsed charging scenarios. In this article, we approach the estimation of battery equivalent circuit parameters from an electrochemical model‐based approach. This is the first research work to employ the single particle model that considers the electrolyte behavior to derive battery equivalent circuit parameters. We evaluate this approach using three different batteries of varying cell capacities. This technique not only improves the accuracy of these models but enables a complete understanding of the transient load operation of these batteries.

Effect of Electrochemical and Mechanical Properties of SEI on Dendritic Growth during Lithium Deposition on Lithium Metal Electrode

In the past three decades, lithium-ion batteries experienced a long series of successful improvements, which nowadays make them a widespread technology. Intercalation electrodes, like graphite in the negative electrode, drove large part of this success. On the other hand, they constitute a limit in terms of energy density, which makes them unlikely to match the increasing demands set by renewable energies and especially electric mobility. Thus, it becomes fundamental to investigate new materials that overcome these limits. Lithium metal represents the optimal candidate for the negative electrode, due to its high theoretical capacity (3860 mAh.g-1) and low potential (-3.04 V SHE). On the other hand, the major drawback of this technology is the formation of dendrites, which are lithium structures that form during its deposition. They can cause thermal runaway and internal short-circuits, potentially leading to explosion. Moreover, during lithium stripping, some parts of the lithium electrode tend to be isolated in the electrolyte. This phenomenon causes a reduction of the electroactive lithium quantity thus a limited lifetime of the cell. Therefore, a deeper comprehension of the interfacial phenomena involved during lithium deposition and stripping is necessary to make lithium metal a viable and competitive option as a negative electrode, fostering the transition towards the next generations of batteries.The proposed model starts from the stability analysis of the electrode interface proposed by Newman and Monroe [1] that considers the effect of the mechanical properties on the lithium deposition. Different from it, the presented model studies a time-dependent variation of the surface and it includes a pseudo-2D representation of the Solid Electrolyte Interface (SEI) component. The approach to model the SEI is based on the work of Liu and Lu [2]; and it includes both SEI creation, due to deposition side reactions, and SEI thickness deformation due to the change in geometry of the underlying electrode. In addition, the model considers the effect of the mechanical properties of the SEI on the surface evolution of the electrode. Therefore, starting from the initial surface geometry and the electrochemical and mechanical properties of the components, the model is able to predict the conditions that favors dendritic growth. The figure shows lithium electrodeposition, starting from the same surface defect, on the lithium metal electrode in a liquid electrolyte. After the same quantity of lithium is deposited, it is possible to distinguish different patterns of surface evolution, due to the difference in magnitude of the current density applied: a quasi-uniform growth at low current density (left), a mossy behavior at medium current density (center) and a branching pattern at high current density (right). The difference in dendritic regime is strictly connected to the local change in the SEI thickness, as shown in the figure, which confirms the importance of this component, often neglected in the literature of dendrites models.Since SEI has a major impact on dendritic growth, a consistent set of experiments has been designed to provide its parameters to the model. Electrochemical Impedance Spectroscopy (EIS) was applied to find the electrochemical parameters of the SEI (e.g. SEI diffusion coefficient, SEI resistivity), while Atomic Force Microscopy (AFM) was conducted to find its mechanical properties (e.g. SEI Young’s modulus). The proposed model has the goal of guiding the experiments in finding ways to avoid or curtail dendrites formation, being able to simulate the effects on dendrites growth of operative conditions, SEI and electrolyte compositions, electrode surface defects and coatings. Starting from the model, innovative ways to increase the lifetime of the lithium metal anodes will be analyzed during the presentation; including coatings, surface morphology modification and pulse charging.[1] C. Monroe, J. Newman, Journal of the Electrochemical Society 151(6), A880-A886 (2004)[2] G. Liu, W. Lu, Journal of the Electrochemical Society 164(9), A1826-A1833 (2017) Figure 1

TCAD investigation of the transport of carriers deposited by alpha particles in silicon carbide power Schottky devices

Radioactive sources and spectroscopy techniques have been proposed in recent publications as an approach to sense the internal electric field and to assess the susceptibility of power semiconductors devices to terrestrial cosmic rays. In this paper, dedicated experiments and advanced TCAD tools are used to understand the formation and the collection of the charge pulses that are generated by alpha particles in SiC Schottky diodes. Special attention is paid to the processes leading to the multiplication of the carriers' species. It is shown that the charge multiplication process is strongly affected by the location of the interaction zone and on impinging angle of the ionizing particle, along with the biasing condition of the device.

Modeling and Simulation of the R5912 Photomultiplier for the LAGO Project

We present the results of the Hamamatsu R5912 photomultiplier tube modelling and simulating. The model can be adapted to any photomultiplier architecture by changing the number of electrodes, voltage distribution, and intrinsic PMT parameters. Our approach solves the use of tapered voltage dividers and allows photomultiplier simulations under stimulation conditions. The model implementation is not limited to SPICE-based software but also be used with compiled and interpreted programming languages. The modeled pulse charge of a vertical muon differs about 4% from the data. The resistive divider model tested reproduces the voltage distribution along the dynodes with a variance of ~3.5%. We compare the photomultiplier model linearity with the data from the operating LAGO's (Latin American Giant Observatory) water Cherenkov detectors installed at Bucaramanga-Colombia and Bariloche-Argentina.

Experimental research on the influence of temperature on the discharge signal of void defects in GIS

Temperature is an important environmental factor during the operation of gas-insulated switchgear (GIS), affecting the evaluation results of the GIS equipment to increase the risk of the power system. However, the influence of temperature on the partial discharge detection signal of GIS is still unclear. Aimed at the common void defects in GIS, the law of change on the number of ultrahigh-frequency (UHF) pulses, the UHF amplitude, the characteristic value of the UHF map, and the maximum apparent charge of a single pulse with temperature are obtained using the UHF method and IEC60270, and corresponding theoretical analysis is carried out. The results show that an increase in temperature leads to a decrease in the void discharge delay time, causing an increase in UHF pulses and a decrease in the apparent charge of a single discharge pulse in the experiment. The increase of temperature makes the void discharge current rise quickly so that the induced UHF amplitude increases. In the range of 40–70°C, the maximum pulse amplitude increases by approximately 30% for every 10°C increase, and the average pulse amplitude increases by approximately 12%. The result of UHF signals affected by temperature obtained in this study has research significance for the realisation of a comprehensive evaluation of the insulation state of GIS equipment considering temperature.

Significantly enhanced energy-storage properties of Bi0.47Na0.47Ba0.06TiO3-CaHfO3 ceramics by introducing Sr0.7Bi0.2TiO3 for pulse capacitor application

The research and development of high-performance lead-free dielectric capacitors with excellent wide temperature stability, large recoverable energy density, ultra-high efficiency, and ultra-high-speed charging and discharging have received extensive attention. However, most lead-free dielectric materials developed at this stage do not meet all these requirements owing to various factors. Herein, a new type of lead-free (1-x)(0.94Bi0.47Na0.47Ba0.06TiO3-0.06CaHfO3)-xBi0.2Sr0.7TiO3 relaxor ferroelectric bulk ceramic was designed and prepared. The doping of Bi0.2Sr0.7TiO3 further refined the sub-micron grains and helped to obtain a wider band gap. Moreover, the ceramic exhibited a polarization response with almost no hysteresis, even under a high electric field because of the large number of randomly distributed nano-scale polar domains. The ceramic with x = 0.4 exhibited an outstanding comprehensive energy-storage performance with an extraordinary Wrec of 6.19 J/cm3 and a superior η of 93.5%. Similarly, another x = 0.45 ceramic also obtained a considerable energy-storage characteristic with an ultra-high η of 94.5% and a large Wrec of 6.02 J/cm3. In addition, the ceramic with x = 0.4 also showed remarkable wide frequency (1–200 Hz) and wide temperature range (20–140 °C) stability. In the pulse charge test, x = 0.4 ceramic exhibited a large discharge energy density of 5.07 J/cm3 under 340 kV/cm and a considerable discharge rate. All these indicate that our work provides a practical and effective idea for the design of application-type dielectric capacitors with an outstanding comprehensive performance.

Pulse-shape discrimination against low-energy Ar-39 beta decays in liquid argon with 4.5 tonne-years of DEAP-3600 data

The DEAP-3600 detector searches for the scintillation signal from dark matter particles scattering on a 3.3 tonne liquid argon target. The largest background comes from ^{39}text{ Ar } beta decays and is suppressed using pulse-shape discrimination (PSD). We use two types of PSD estimator: the prompt-fraction, which considers the fraction of the scintillation signal in a narrow and a wide time window around the event peak, and the log-likelihood-ratio, which compares the observed photon arrival times to a signal and a background model. We furthermore use two algorithms to determine the number of photons detected at a given time: (1) simply dividing the charge of each PMT pulse by the mean single-photoelectron charge, and (2) a likelihood analysis that considers the probability to detect a certain number of photons at a given time, based on a model for the scintillation pulse shape and for afterpulsing in the light detectors. The prompt-fraction performs approximately as well as the log-likelihood-ratio PSD algorithm if the photon detection times are not biased by detector effects. We explain this result using a model for the information carried by scintillation photons as a function of the time when they are detected.

Defect characterization in floating body transistors using a single pulse charge pumping method

Field-effect transistors on a floating body channel have been used for a range of applications, such as three-dimensional nand flash and high-performance devices on silicon-on-insulator wafers. Conventional techniques to characterize the defect states cannot be implemented because those transistors do not have body contacts. A single-pulse charge pumping (SPCP) method was introduced to characterize the defect state distribution of the floating body transistors. The results extracted from the SPCP method on the three-terminal transistors (without body contact) agreed well with those from a conventional charge pumping method or SPCP on four-terminal transistors (with body contact). The validity of the SPCP measurement of the floating body devices was demonstrated by monitoring the increase in the defect state of the three-terminal poly-Si transistors density during the bias stress test. The SPCP method could detect the defect states of floating body transistors with high resolution.

Modelling and Analysis of the Epidemic Model under Pulse Charging in Wireless Rechargeable Sensor Networks.

With the development of wireless sensor networks (WSNs), energy constraints and network security have become the main problems. This paper discusses the dynamic of the Susceptible, Infected, Low-energy, Susceptible model under pulse charging (SILS-P) in wireless rechargeable sensor networks. After the construction of the model, the local stability and global stability of the malware-free T-period solution of the model are analyzed, and the threshold is obtained. Then, using the comparison theorem and Floquet theorem, we obtain the relationship between and the stability. In order to make the conclusion more intuitive, we use simulation to reveal the impact of parameters on . In addition, the paper discusses the continuous charging model, and reveals its dynamic by simulation. Finally, the paper compares three charging strategies: pulse charging, continuous charging and non-charging and obtains the relationship between their threshold values and system parameters.

Single-tone pulse sequences and robust two-tone shaped pulses for three silicon spin qubits with always-on exchange

Quantum computation requires high-fidelity single-qubit and two-qubit gates on a scalable platform. Silicon spin qubits are a promising platform toward realization of this goal. In this paper we show how to perform single-qubit and CZ gates in a linear chain of three spin qubits with always-on exchange coupling, which is relevant for certain dot- and donor-based silicon devices. We also show how to make the CZ gate robust against both charge noise and pulse length error using a two-tone pulse shaping method. The robust pulse maintains a fidelity of 99.99% at 3.5% fluctuations in exchange or pulse amplitude, which is an improvement over the uncorrected pulses where this fidelity can only be maintained for fluctuations in exchange up to 2% or up to 0.2% in amplitude.

Optimal control for fast acquisition of equilibrium voltage for Li-ion batteries

Motivated by the recent electrode health diagnosis method that requires selective open-circuit voltage data, this paper presents a novel approach for the fast acquisition of battery equilibrium voltage using bidirectional current pulses. The proposed method was found by solving a minimum-time optimal control problem. Unlike the conventional pulse-relaxation method which requires a long relaxation period, the use of charge and discharge pulses reduces the testing time by 69%. The given problem is studied numerically and analytically. Analysis based on Pontryagin's minimum principle (PMP) demonstrates that the solution is either bang–bang or bang–off–bang control, depending on the constraints. Furthermore, the optimal control problem is reformulated into a finite-dimensional switching-time optimization problem, making it computationally tractable for on-board applications. Finally, experimental validation is presented for a 4.5 Ah NMC/graphite cell showing a 73% time reduction to reach a new equilibrium voltage.

Gigahertz Frame Rate Imaging of Charge-Injection Dynamics in a Molecular Light Source.

Light sources on the scale of single molecules can be addressed and characterized at their proper sub-nanometer scale by scanning tunneling microscopy-induced luminescence (STML). Such a source can be driven by defined short charge pulses while the luminescence is detected with sub-nanosecond resolution. We introduce an approach to concurrently image the molecular emitter, which is based on an individual defect, with its local environment along with its luminescence dynamics at a resolution of a billion frames per second. The observed dynamics can be assigned to the single electron capture occurring in the low-nanosecond regime. While the emitter’s location on the surface remains fixed, the scanning of the tip modifies the energy landscape for charge injection into the defect. The principle of measurement is extendable to fundamental processes beyond charge transfer, like exciton diffusion.