Observer techniques for estimating the state-of-charge and state-of-health of VRLABs for hybrid electric vehicles

The paper describes the application of observer-based state-estimation techniques for the real-time prediction of state-of-charge (SoC) and state-of-health (SoH) of lead-acid cells. Specifically, an approach based on the well-known Kalman filter, is employed, to estimate SoC, and the subsequent use of the EKF to accommodate model non-linearities to predict battery SoH. The underlying dynamic behaviour of each cell is based on a generic Randles' equivalent circuit comprising of two-capacitors (bulk and surface) and three resistors, (terminal, transfer and self-discharging). The presented techniques are shown to correct for offset, drift and long-term state divergence-an unfortunate feature of employing stand-alone models and more traditional coulomb-counting techniques. Measurements using real-time road data are used to compare the performance of conventional integration-based methods for estimating SoC, with those predicted from the presented state estimation schemes. Results show that the proposed methodologies are superior with SoC being estimated to be within 1% of measured. Moreover, by accounting for the nonlinearities present within the dynamic cell model, the application of an EKF is shown to provide verifiable indications of SoH of the cell pack

A Novel SOC Estimation for Hybrid Energy Pack using Deep Learning

Estimating the state of charge (SOC) of compound energy storage devices in the hybrid energy storage system (HESS) of electric vehicles (EVs) is vital in improving the performance of the EV. The complex and variable charging and discharging current of EVs makes an accurate SOC estimation a challenge. This paper proposes a novel deep learning-based SOC estimation method for lithium-ion battery-supercapacitor HESS EV based on the nonlinear autoregressive with exogenous inputs neural network (NARXNN). The NARXNN is utilized to capture and overcome the complex nonlinear behaviors of lithium-ion batteries and supercapacitors in EVs. The results show that the proposed method improved the SOC estimation accuracy by 91.5% on average with error values below 0.1% and reduced consumption time by 11.4%. Hence validating both the effectiveness and robustness of the proposed method.Comment: 5 pages, 9 figure

Elektrokeemilise voogkondensaatori arendamine ja optimiseerimine

Väitekirja elektrooniline versioon ei sisalda publikatsiooneElektrokeemiline voogkondensaator (EFC) on kontseptuaalne lahendus elektrienergia mastaapseks salvestamiseks. Kõnealune seade sarnaneb tööpõhimõttelt superkondensaatorile, aga olulise erinevusena kasutab tahkete elektroodide asemel süsniniku mikro ja nano-osakestest ning elektrolüüdist koosnevat suspensiooni. Elektrolüüdiga suspensioon on eraldatud poorse, ioonjuhtiva membraaniga ja seadmes on tüüpiliselt mõne millimeetrilise diameetriga kanalid, mille sein on voolkollektoriks ning millest pumbatakse läbi eelpool kirjeldatud suspensiooni. Just nimelt süsinikupõhiste vedelate elektroodide kasutamine võimaldab arendatavat seadet olulisel määral skaleerida ning tulevikus integreerida olemasolevatesse elektrivõrkudesse ja/või rakendada seda efektiivselt taastuvate energiaallikate poolt toodetud elektrienergia salvestamiseks. Doktoritöö keskseks eesmärgiks on EFC-tehnoloogia fundamentaalsete omaduste interpreteerimine. Sellest tulenevalt on töös on läbi viidud EFC elektrokeemilised karakteriseerimised ja arvutisimulatsioonid seadme disainlahenduste optimeerimiseks. Simulatsioonide valdkonnas on sobitatud EFC modelleerimiseks nii olemasolevaid elektrokeemilisi mudeled kui on arendatud ka uudne nn stohhastiline Monte-Carlo põhimõtetel baseeruv mudel. Väljatöötatud mudelid kalibreeriti ja valideeriti põhjalikult võrdluses elektrokeemiliste tulemustega ning neid kasutati voogelektroodide laadimisprotsessi sügavamaks mõistmiseks kolmes fundamentaalses EFC-seadme konstruktsioonis. Sarnaste elektrokeemiliste seadmete modelleerimiseks kasutatakse tihti Nernst-Planki võrranditel või kontsentreeritud lahuse teooriatel baseeruvaid mudeleid. Luuakse teist järku osatuletsitega diferentsiaalvõrrandite süsteemid, mis kirjeldavad nii ioonide kontsentratsioone kui ka seadmes tekkivaid laenguülekande protsesse. Nende mudelite rakendamine iseloomustas ilmekalt difusiooni tõttu seadmes tekkivaid laengu salvestamise ja osakeste transpordi piiranguid. Efektiivne elektroodimaterjali tsirkulatsioon ning piisavalt kiire laengu transport on teineteisele vastanduvad protsessid – kui esimesel juhul on oluliseks näitajaks piisavalt suur elektroodi voolukanalite diameeter, siis teisel juhul on nõutav just nimelt sama kanali diameetri minimiseerimine. Samas ilmnes eksperimentaalsest tulemustest, et mitte ainult difusioonist tingitud nähtused pole olulised, vaid märkimisväärset mõju omavad ka nn kõrvalreaktsioonid. Töö käigus loodud stohhastiline mudel võimaldas saavutada edukalt elektrokeemiliste mõõtmistulemuste ning Nernst-Planki võrranditel baseeruvate mudelitega leitud tulemuste kokkulangevuse. Enamgi, loodud stohhastiline mudel võimaldab edukalt simuleerida vedelate elektroodide laadumise dünaamikat ja kirjeldada suspensioonis asetleidvaid protsesse ning hinnata kõrvalreaktsioonide mõjusid. Kokkuvõtvalt avab loodud lähenemisviis võimaluse leidmaks lahendust voogkondensaatori disaini kesksele probleemile – kuidas tagada seadmest piisav elektroodimaterjali läbivool ning samas hoiduda laengu transpordi limiteerimisest difusiooni tõttu. EFC-tehnoloogia edasise arengu puhul võib eeldada taastuvatest allikatest toodetud energia salvestamisvõimsuse märkimisväärset kasvu. Samas tuleb lisada, et EFC võimsustiheduse parandamiseks, ilma et see kahjustaks nende seadmete energiatihedust ning tsükleeritavust, on vaja jälgida arenduste kooskõla ka muude energiasalvestus- ja muundamis-tehnoloogiatega. Olulisteks faktoriteks on nii seadme töötingimuste valik, elektroodide disain, elektrolüüdi materjalid, kuid samuti ka sobilikud katalüsaatorid.An electrochemical flow capacitor (EFC) is a conceptual approach to meet large-scale electricity storage. This device is similar in operation to a supercapacitor but uses a concentrated solution of carbon micro and nanoparticles and an electrolyte instead of solid electrodes. It typically flows in channels with a diameter of a few millimeters, the wall of which is a flow collector and through which the liquid electrode material is pumped. A porous ion-conducting membrane separates the electrodes. Using carbon-based liquid electrodes in the device under development will allow the technology to be significantly scaled up and integrated into existing electricity grids and used effectively to support renewable energy production. The central goal of the work presented is to understand the fundamental properties of EFC technology. As a result, EFC laboratory tests and computer simulations have been performed to design and optimize the device architecture. In the field of simulations, both existing electrochemical models have been adapted for EFC modeling, and a new stochastic model based on Monte-Carlo principles has been developed. Both implemented and developed models were thoroughly calibrated and validated against laboratory experiments and used to understand the flow electrode charging process in three fundamental EFC device designs. Models based on Nernst-Planck equations or concentrated solution theories are often used to model similar electrochemical devices. Second-order differential equations systems with partial derivatives describe both the ion concentrations and the charge exchange processes occurring in the device. The application of these models was characterized by the limitations of charge storage and transport processes in the device due to diffusion. If the electrode material circulation and sufficiently fast charge transport are critical processes, then a sufficiently large diameter of the electrode flow channels is important. Otherwise, it is necessary to minimize the diameter of the same channel. At the same time, the experimental work showed that the phenomena caused by diffusion are critical side effects and have a significant effect on electrode charging processes. The models based on the Nernst-Planck equations and the stochastic model developed successfully matched the experimental results. Moreover, the developed stochastic model allows to simulate the convection and mixing processes of liquid electrodes successfully and to apply the effects of side reactions. Thus, the developed approach opens the possibility to find a solution to the central problem of the flow capacitor design - how to ensure sufficient flow of electrode material from the device and at the same time avoid limiting the transport of charge due to diffusion. Due to the development of EFC technology, a significant increase in the storage capacity of energy from renewable sources can be expected. At the same time, to improve the power density of EFCs without compromising their high energy density and cyclicality, it is necessary to monitor the coherence of developments with other energy storage and conversion technologies. Important factors are the choice of operating conditions of the device, the design of the electrodes, the materials of the electrolyte, as well as suitable catalysts.https://www.ester.ee/record=b549496

A Hybrid PV-Battery/Supercapacitor System and a Basic Active Power Control Proposal in MATLAB/Simulink

Blaabjerg, Frede/0000-0001-8311-7412; sahin, mustafa ergin/0000-0002-5121-6173WOS: 000516827000129An increase in the integration of renewable energy generation worldwide brings along some challenges to energy systems. Energy systems need to be regulated following grid codes for the grid stability and efficiency of renewable energy utilization. the main problems that are on the active side can be caused by excessive power generation or unregulated energy generation, such as a partially cloudy day. the main problems on the load side can be caused by excessive or unregulated energy demand or nonlinear loads which deteriorate the power quality of the energy networks. This study focuses on the energy generation side as active power control. in this study, the benefits of supercapacitor use in a hybrid storage system are investigated and analyzed. A hybrid system in which photovoltaic powered and stored the energy in battery and supercapacitor are proposed in this study to solving the main problems in two sides. the supercapacitor model, photovoltaic model, and the proposed hybrid system are designed in MATLAB/Simulink for 6 kW rated power. Also, a new topology is proposed to increase the energy storage with supercapacitors for a passive storage system. the instantaneous peak currents energy is aimed to store in supercapacitors temporarily with this topology. the main advantages of this topology are voltage stabilization in two sides by the supercapacitors and a limitation of the battery load, which directly results in longer battery life and decreases the system cost. the simulation results are investigated for this topology.Scientific&Technological Research Council of Turkey (TUBITAK), 2219 postdoctoral research program [1059B191700997]This study was supported through the Scientific&Technological Research Council of Turkey (TUBITAK), 2219 postdoctoral research program with a 1059B191700997 application number

Power Electronics and Energy Management for Battery Storage Systems

The deployment of distributed renewable generation and e-mobility systems is creating a demand for improved dynamic performance, flexibility, and resilience in electrical grids. Various energy storages, such as stationary and electric vehicle batteries, together with power electronic interfaces, will play a key role in addressing these requests thanks to their enhanced functionality, fast response times, and configuration flexibility. For the large-scale implementation of this technology, the associated enabling developments are becoming of paramount importance. These include energy management algorithms; optimal sizing and coordinated control strategies of different storage technologies, including e-mobility storage; power electronic converters for interfacing renewables and battery systems, which allow for advanced interactions with the grid; and increase in round-trip efficiencies by means of advanced materials, components, and algorithms. This Special Issue contains the developments that have been published b researchers in the areas of power electronics, energy management and battery storage. A range of potential solutions to the existing barriers is presented, aiming to make the most out of these emerging technologies

Application of Power Electronics Converters in Smart Grids and Renewable Energy Systems

This book focuses on the applications of Power Electronics Converters in smart grids and renewable energy systems. The topics covered include methods to CO2 emission control, schemes for electric vehicle charging, reliable renewable energy forecasting methods, and various power electronics converters. The converters include the quasi neutral point clamped inverter, MPPT algorithms, the bidirectional DC-DC converter, and the push–pull converter with a fuzzy logic controller