Primary Storage Systems Research Articles

Research of the Primary Electric Energy Storage System of a Traction Photovoltaic Module

Purpose. The main idea of the work is that the electric energy generated by photovoltaic installations is supplied in small parts to capacitive energy storage devices of low power, and then these «portions» of energy are supplied to one common, so-called traction storage device. The research is aimed at obtaining time diagrams of current and voltage changes in the proposed system. Methodology. A review of the world literature on the topic of work was conducted. The basis of this research is the analysis of transient processes in the electrical circuits of the system during the transfer of energy from the photovoltaic module to the traction capacitor under the influence of various control signals: series, parallel, combined. The main research method is computer simulation. The Scilab software environment was used to simulate the operation of the electric energy storage system. Findings. The relevance of the research and development of a primary electric energy storage system using a traction photovoltaic module has been proved. The key mathematical dependencies between the parameters of the constituent elements of electrical circuits are established. The structure of a site with electric energy storage with traction photovoltaic modules and a converter-pulse signal unit is proposed. The graphical characteristics of transient processes that occurred during the transfer of energy from low-power capacitive elements to a high-power capacitive element (traction capacitor) were obtained. Originality. For the first time, graphical dependences of energy transfer between system elements were obtained, which allows for a reasonable choice of the parameters of these elements. Also, for the first time, time dependencies describing the law of control of the process of energy transfer between system links were obtained, which will allow determining the rational modes of its operation. Practical value. The results of the research open up new opportunities in the research field in the development of large-scale experimental models of the maglev path structure in the case of the introduction of a system of distributed primary energy storage in a traction photovoltaic module.

Battery Energy Storage Systems: A Review of Energy Management Systems and Health Metrics

With increasing concerns about climate change, there is a transition from high-carbon-emitting fuels to green energy resources in various applications including household, commercial, transportation, and electric grid applications. Even though renewable energy resources are receiving traction for being carbon-neutral, their availability is intermittent. To address this issue to achieve extensive application, the integration of energy storage systems in conjunction with these resources is becoming a recommended practice. Additionally, in the transportation sector, the increased demand for EVs requires the development of energy storage systems that can deliver energy for rigorous driving cycles, with lithium-ion-based batteries emerging as the superior choice for energy storage due to their high power and energy densities, length of their life cycle, low self-discharge rates, and reasonable cost. As a result, battery energy storage systems (BESSs) are becoming a primary energy storage system. The high-performance demand on these BESS can have severe negative effects on their internal operations such as heating and catching on fire when operating in overcharge or undercharge states. Reduced efficiency and poor charge storage result in the battery operating at higher temperatures. To mitigate early battery degradation, battery management systems (BMSs) have been devised to enhance battery life and ensure normal operation under safe operating conditions. Some BMSs are capable of determining precise state estimations to ensure safe battery operation and reduce hazards. Precise estimation of battery health is computed by evaluating several metrics and is a central factor in effective battery management systems. In this scenario, the accurate estimation of the health indicators (HIs) of the battery becomes even more important within the framework of a BMS. This paper provides a comprehensive review and discussion of battery management systems and different health indicators for BESSs, with suitable classification based on key characteristics.

Investigation of Ultra-Low Temperature Li/CF x Batteries in the Liquefied Gas Electrolyte

Lithium-fluorinated carbon (Li/CFx) is one of the most promising chemistries to serve as a reliable high-energy density primary energy storage system in applications where rechargeability is not required. Though Li/CFx demonstrates high energy density (>2100 Wh kg–1) under ambient conditions, achieving such a high energy density when exposed to subzero temperatures remains challenging, particularly under high current density.Liquefied gas electrolytes (LGE) are regarded as one of the most promising electrolyte systems, offering excellent ionic conductivities at wide temperature ranges from -80 to + 60 oC due to low viscosity and low freezing point of gas molecules. Moreover, the LGE can significantly improve the capacity retention of Li-metal batteries operated at reduced temperatures.Here, we report a liquefied gas electrolyte with an anion-pair solvation structure based on dimethyl ether with a low melting point (−141 oC) and low viscosity (0.12 mPa×S, 20 oC), leading to high ionic conductivity (> 3.5 mS cm–1) between −70 and 60 oC. Besides that, through systematic X-ray photoelectron spectroscopy (XPS) integrated with transmission electron microscopy (TEM) characterizations, we evaluate the CFx interphase from the low-temperature discharge process. We conclude that the fast transport and anion-pairing solvation structure of the electrolyte bring about reduced charge transfer resistance at low temperatures, which resulted in significantly enhanced performance of Li/CFx cells (1690 Wh kg–1, −60 oC;1172 Wh kg–1, −70 oC based on active materials). Utilizing 50 mg cm-2 loading CFx electrodes, the Li/CFx displayed 1530 Wh kg–1 at −60 oC. This work provides insights into the electrolyte design that may overcome the operational limits of batteries in extreme environments.

An adaptive two‐level hierarchical controller for universal power sharing and performance enhancement of hybrid energy storage‐supported AC/DC microgrids

SummaryThe uncertainties in generation from renewable energy sources and randomness in electric vehicle charging/discharging make the generation and load in the grid more volatile. The large‐scale integration of renewable energy sources and electric vehicles has necessitated the remodeling of conventional control schemes in the microgrid. This article presents an adaptive two‐level hierarchical controller that enriches hybrid AC/DC microgrid performance. The virtual synchronous machine‐based primary controller determines the operating mode of the interlinking converter. In addition, it maintains the system's stability by providing virtual inertia support. The communication‐based secondary controller adaptively chooses the scaling factors based on hybrid AC/DC microgrid operating conditions. The adaptive secondary control loop implemented with the primary controller and hybrid energy storage system reduces the frequency/voltage deviations under extreme load volatility and enhances the transient and steady‐state performance. The novelty of the proposed two‐level hierarchical controller is that the general purpose adaptive scheme improves the power sharing in the microgrid under normal and volatile source and load conditions. The simulations and experimental results confirm the efficacy of the proposed controller. Furthermore, the hierarchical two‐level controller performance is validated using real‐time experiments on a hardware‐in‐the‐loop simulator, OPAL‐RT, and Raspberry Pi microcontroller. The real‐time analysis ascertains that the proposed two‐level hierarchical controller effectively preserves the frequency and voltage profiles and provides accurate power sharing between the subgrids.

Solar PV driven hybrid gravity power module—Vanadium redox flow battery energy storage for an energy efficient multi‐storied building

This article presents an innovative perspective of using a gravity energy storage system namely gravity power module (GPM) around a multi-storied building. Two number of GPMs have been vertically fixed around the walls of a multi-storied building and have not been placed underground following the traditional way. The grid-connected proposed hybrid system consisting of solar PV, GPMs and vanadium redox flow battery is focused to supply the maximum possible amount of an essential load of a high-riser, through renewable energy. All of the storage systems are charged through solar PV. Whereas, the grid is used, to procure energy for the unmet load demand and sell the excess renewable energy. Results simulated for each month following seasonal load variation show that net energy supplied by the hybrid system is 99% of the full load demand of essential equipment of the building for the month of February and 90% to 91% for the month of January, November and December. During all the months, the supply of gravity energy storage is restricted to supply within the 18th to 24th hour to reduce the peak demand of the grid. The gravity energy storage is also considered as the primary storage system during those intervals. The yearly average of energy supply from the renewable resource in the proposed system toward the building load is found to be 47.77%. While considering the renewable energy sale toward the grid along the load supply of the building the yearly average of renewable energy penetration becomes 48.89%.

Dual Battery Storage Technique for Remote, Location-Based Solar PV System and Standalone Applications

Nowadays, the usage of renewable energy resources (RER) is growing rapidly, but at the same time, the effective utilization of RER is also a challenging task. For the better usage of RER and the reduction of loss, the dual battery storage is proposed. The main aim of this work is to focus on the design and implementation of a reliable and renewable power generating system under a robust situation, along with a battery storage system. The perturb and observe (P&O) maximum power point tracking (MPPT) technique has been applied to improve the solar photovoltaic power production. In addition, the dual battery storage system is being introduced to improve the life cycle of the primary storage system. The proposed dual storage system is highly preferable for remote, location-based application systems, space applications and military operations. In the dual battery storage system, the batteries are working effectively with a good lifespan, when compared with the existing methods. To determine the state of charge (SOC) and depth of discharge (DOC), those batteries’ input charging and discharging levels were monitored closely. MATLAB Simulink (R2013) is used for simulation; finally, a real-time, three-phase inverter was designed and validated. Under this dual battery storage mode, the life time of battery is improved.

State of health estimation and remaining useful life assessment of lithium-ion batteries: A comparative study

Lithium-ion batteries are widely used due to their attractive features. They have emerged as the primary storage system for electric cars, solar power, and marine vehicles. Consequently, their internal health state estimation has attracted extensive attention. An accurate health assessment results in a safer and more efficient battery management system (BMS), which estimates the battery's state and predicts premature failure. Recurrent neural network (RNN) has been extensively utilized to diagnose and prognosis lithium-ion batteries, as it has demonstrated superior performance. Improving the proficiency of Machine Learning (ML) algorithms has always been a subject of research. Among these attempts, various studies have proposed the combination of RNN and the convolutional neural network (CNN). In this paper, the CNN is combined with the long short-term memory (LSTM) network for the state of health estimation and remaining useful life assessment of lithium-ion batteries. To facilitate the features exploitation procedure for the ML algorithm, a K-means clustering algorithm is proposed for data classification. A comparative study of LSTM and the hybrid CNN-LSTM method is conducted to show the superiority of the proposed method.

Timed Loops for Distributed Storage in Wireless Networks

IoT deployments that have limited memories lack sustained computation power and have limited connectivity to the Internet due to intermittent last-mile connectivity, particularly in rural and remote locations. For maintaining congestion-free operations, most of the collected data from these networks are discarded, instead of being transmitted remotely for further processing. In this article, we propose the paradigm Timed Loop Storage to distribute the data and use the underutilized bandwidth of local network links for sequentially queuing packets of computational data that are being operated on in parts in one of the IoT nodes. While the sequenced packets are executed sequentially on the target IoT device, the remaining packets, which are currently not being operated on, distribute and keep looping over the network links until they are required for processing. A time-synchronized packet deflection mechanism on each node handles data transfer and looping of individual packets. In our implementation, although we observe that the proposed approach requires data rates of 6 Mbps, it incurs only 45 Kb usage of primary storage systems even for sizeable data, ensuring scalability of the connected IoT devices' temporary storage capabilities, thereby making it useful for real-life applications.

Smart Power System for Electric Vehicles Using Three Port Bi-Directional Converter

The proposed system is used to deliver an uninterrupted power supply to the motor in electric vehicle with reduced switching losses. A PV Panel is combined to the load as a secondary power source in addition to the primary Energy Storage System (ESS) which is connected together using a three port DC-DC converter. The converter boosts output from the respective sources and regulates constant supply to the load in a single stage of transmission. Phase shifted Pulse Width Modulation (PPWM) technique reduces the harmonics which in order reduces the switching losses and makes switching instant, resulting in fast dynamic response. The secondary source can also be used to charge the battery through bidirectional converter. A fuel cell connected to a converter which is interfaced with the load through a separate circuit acts as an additional backup at situations to maintain continuous power supply in case of failure in both the primary power source and the panel circuits.

Calcium looping for power generation with CO2 capture: The potential of sorbent storage for improved economic performance and flexibility

Abstract The aim of this work is to investigate the potential of calcium looping (CaL) CO2 capture system for power plants with sorbent storage, for flexible and low-emission power generation from coal. Two different CaL systems have been analyzed for CO2 capture from a reference pulverized coal power plant: (i) a Baseline CaL system and (ii) a FlexiCaL system with sorbent storage. The sorbent storage systems can be exploited in two ways: the primary storage system allows to decouple the carbonator and the calciner load and reduce the size of the calciner island; the secondary storage unit allows to increase/reduce the maximum/minimum power output of the plant for improved grid services. Heat and mass balances have been computed at different loads with process simulation software, considering the off-design operation of the main plant components. A simplified economic analysis has been carried out to compute the cost of electricity and estimate the economic benefits of the primary sorbent storage system for a given power generation profile. The method used in this work allowed to compute the off-design behaviour of the CaL power plant the with the highest accuracy among the literature studies and to understand the potential of the secondary solids storage to provide grid services for the first time. The part-load analysis provided insights on the design of the carbonator reactor, that should limit the heat transfer surface in the riser to avoid excessive reactor cooling at part-load. Conversely, reaction heat should preferably be extracted from the external heat exchangers, where the heat transfer rate can be controlled more easily. From the thermodynamic standpoint, the two CaL plants feature similar efficiency on weekly cycling basis. The secondary storage allows increased operativity of the FlexiCaL plant on the secondary market, thanks to +2% of maximum power and -5% of minimum power output. The primary storage system allows reducing the capital cost of the CaL system, leading to LCOE reduction by 4-5% compared to the Baseline case, in a wide range of carbon tax and plant availability.

Fuzzy Logic-Based Duty Cycle Controller for the Energy Management System of Hybrid Electric Vehicles with Hybrid Energy Storage System

Due to increasing fuel prices, the world is moving towards the use of hybrid electric vehicles (HEVs) because they are environmentally friendly, require less maintenance, and are a green technology. The energy management system (EMS) plays an important role in HEVs for the efficient storage of energy and control of the power flow mechanism. This paper deals with the design, modeling, and result-oriented approach for the development of EMS for HEVs using a fuzzy logic controller (FLC). Batteries and supercapacitors (SCs) are used as primary and secondary energy storage systems (ESSs), respectively. EMS consists of the ultra-power transfer algorithm (UPTA) and FLC techniques, which are used to control the power flow. The UPTA technique is used to charge the battery with the help of a single-ended primary inductor converter (SEPIC) during regenerative braking mode. The proposed research examines and compares the performance of FLC with a proportional integral (PI) controller by using MATLAB (Simulink) software. Three scenarios are built to confirm the efficiency of the proposed design. The simulation results show that the proposed design with FLC has a better response as its rise time (2.6 m) and settling time (1.47 µs) are superior to the PI controller.

Research on a modularized long pulse generator based on anti-resonance network and transmission line transformer.

A modularized generator with three long pulse modules is designed and constructed in this work. The long pulse module consists of a three-section anti-resonance network and a three-stage transmission line transformer. A single module can output a pulse with an amplitude of 33 kV and a full width at half maximum (FWHM) of 400ns, when the primary energy storage system provides a voltage of 24 kV. After the three modules are connected in series in experiment, the modularized long pulse generator delivers a high-voltage pulse to the matched load resistor with a maximum voltage of 96 kV and an FWHM of 400ns. Repetitive experiments at a repetition frequency of 10Hz are also carried out.

Development of an Intelligent Power Management System for Solar PV-Wind-Battery-Fuel-Cell Integrated System

The objective of this work is to develop a power management system that will control the power flow of an integrated renewable energy system with the focus on solar energy and wind energy and dual energy storage systems (batteries are used as the primary energy storage system for short to moderate storage term, whereas hydrogen fuel cell is used as a backup and long-term energy storage). These storage systems are needed to provide high reliability and control systems are necessary for the stable and optimal operation of the whole system. An Intelligent Power Management System (IPMS) is developed to handle various changes in power supply and power demand by managing erratic power and provide suitable control algorithm for the whole system. In order to test and validate the proposed IPMS model, simulations were conducted under various power supply and power demand using power system modeled in HOMER environment. The performed simulations confirm the ability of the IPMS to satisfy the load at all times using solar and wind power (which are unsteady renewables), through the support of batteries and hydrogen fuel cell without a reduction in the power quality or load supply.

Improving the Performance of Primary Storage Systems Using Leveraging Data Deduplication

Data deduplication is a specialised data compression technique used in computers to get rid of redundant copies of repeated data. Intelligent (data) compression and single-instance (data) storage are words that are similar and partly interchangeable. This method may be used to increase storage efficiency and the quantity of data that has to be sent should be reduced over networks. Unique data chunks, or byte patterns, are found and saved throughout the deduplication process through a process of analysis. Recent studies have demonstrated that main storage systems in the Cloud offer moderate to high levels of data redundancy. It demonstrates that as a result of the small I/O requests to redundant data's comparably high temporal access locality, data redundancy displays a substantially greater degree of intensity on the I/O path than that on discs. The system in this project suggests using a performance-oriented I/O deduplication technique known as POD. It is used to increase the I/O performance of main storage systems in the Cloud without compromising the latter's capacity savings.

High-power graphene supercapacitors for the effective storage of regenerative energy during the braking and deceleration process in electric vehicles

The practical applicability of a high-power graphene supercapacitor as an effective primary and auxiliary energy storage system for storing regenerative energy from the braking and deceleration process in electric vehicles (EVs) is studied.

Shutdown-Enabled Electrospun Polyimide Composite Film Prepared By Novel Spin-Coating Method with Polyethylene As Separator for Rechargeable Lithium-Ion Batteries

Global demand for lithium-ion secondary batteries have been increasing due to new market growth from electric vehicles and power storage systems. Lithium-ion batteries possess high power density, energy density and long cycle life without memory effect and little self-discharge, and have been primary energy storage system for commercial electronics. However, recent accidents regarding battery safety, such as Samsung Note 7 issue, has raised doubt among public about lithium-ion batteries as option for energy storage. Separator is one of the primary component for lithium-ion battery safety. Commercial separators like PE or PP not only possess outstanding mechanical and electrochemical performance, but also have thermal shutdown function that provide safety measure by pore—blocking with melted polyolefin materials. Nevertheless, polyolefin materials suffered serious shrinkage at elevated temperature, which cause internal short-circuited of batteries ; also, polyolefin materials have relatively low electrolyte uptake, and could be major obstacle for future lithium-ion battery application. Hence it’s necessary to design new type of separator that guarantee battery safety and demonstrate better electrochemical performance In this study, we proposed a brand-new method to design composite separator with high thermal stability, electrolyte uptake ability and thermal shutdown function. Polyimide(PI) nanofiber film was used as substrate and produced by electrospinning technique, and ultra-thin Low-Density-Polyethylene(LDPE) layer was laid upon PI by simple spin-coating method. Spin-coating method provided unique advantages such as ultra thin coating layer (less than 1 micron), uniform coating structure and simple process, and was yet been applied for construction of composite film as lithium-ion battery separator. Coating parameter was tuned to obtain the optimized composite separator. Field-emission scanning electron microscope (FE-SEM) was used to investigate morphologies of separators ; Contact angle measurement was conducted to verify electrolyte affinity of different separators ; A.C. impedance method was used to measure conductivities and verify thermal shutdown of separators, and electrolyte uptake of different separators were measured by electrolyte soaking method in an argon-filled glovebox. The composite film had sub-micron average pore size, and possessed excellent physical properties, for instance, high porosity(73%), electrolyte uptake(1300%), ion conductivity(4.3*10-4 S/cm), air permeability(gurley value=0), and thermal stability(no shrink up to 150。C). Thermal shutdown function of composite film was also confirmed by impedance measurement at elevated temperature. It was noticed that physical properties between pristine PI and composite film were similar owning to ultra-thin coating layer, which mitigate performance loss from LDPE coating. Afterward, full cell battery tests were conducted with CR2032 type coin cell (Cathode : LFP, anode : MCMB, electrolyte : 1 M LiPF6 in EC/EMC/DMC=1:1:1+1%VC, 1C=2.4mAh/g). The first cycle charge-discharge curves, rate capability and cyclic performance were conducted. The composite film showed flatter first cycle charge-discharge plateau, better capacity retention at higher C-rate (Composite film :102 mAh/g at 1C, 79% retention, Celgard 2500 : 73 mAh/g, 51% retention , w.r.t. 0.1C), and higher discharge capacity at 0.5C 50th cyclic test. The higher porosity and electrolyte uptake of composite film facilitated ion conduction and were the main cause for enhanced battery performance. With enhanced thermal stability and electrochemical performance, we expected this type of composite separator to be promising for future lithium-ion battery application. Figure 1

Reliable access to massive restricted texts: Experience‐based evaluation

SummaryLibraries are seeing growing numbers of digitized textual corpora that frequently come with restrictions on their content. Computational analysis corpora that are large, while of interest to scholars, can be cumbersome because of the combination of size, granularity of access, and access restrictions. Efficient management of such a collection for general access especially under failures depends on the primary storage system. In this paper, we identify the requirements of managing for computational analysis a massive text corpus and use it as basis to evaluate candidate storage solutions. The study based on the 5.9 billion page collection of the HathiTrust digital library. Our findings led to the choice of Cassandra 3.x for the primary back end store, which is currently in deployment in the HathiTrust Research Center.

A Simulation Analysis of Redundancy and Reliability in Primary Storage Deduplication

Deduplication has been widely used to improve storage efficiency in modern primary and secondary storage systems, yet how deduplication fundamentally affects storage system reliability remains debatable. This paper aims to analyze and compare storage system reliability with and without deduplication in primary workloads using public file system snapshots from two research groups. We first study the redundancy characteristics of the file system snapshots. We then propose a trace-driven, deduplication-aware simulation framework to analyze data loss in both chunk and file levels due to sector errors and whole-disk failures. Compared to without deduplication, our analysis shows that deduplication consistently reduces the damage of sector errors due to intra-file redundancy elimination, but potentially increases the damages of whole-disk failures if the highly referenced chunks are not carefully placed on disk. To improve reliability, we examine a deliberate copy technique that stores and repairs first the most referenced chunks in a small dedicated physical area (e.g., 1 percent of the physical capacity), and demonstrate its effectiveness through our simulation framework.

Establishing a publicly available national database of US news articles reporting agriculture-related injuries and fatalities.

The AgInjuryNews system and dataset are a news report repository and information source for agricultural safety professionals, policymakers, journalists, and law enforcement officials. AgInjuryNews was designed as a primary storage and retrieval system that allows users to: identify agricultural injury/fatality events; identify injury agents and emerging issues; provide safety messages for media in anticipation of trends; and raise awareness and knowledge of agricultural injuries and prevention strategies. Data are primarily collected through Google Alerts and a digital media subscription service. Articles are screened, reviewed, coded, and entered into the system. As of January 1, 2018, the system contained 3028 unique incidents. Of those, 650 involved youth, and 1807 were fatalities. The system also had registered 329 users from 39 countries. AgInjuryNews combines injury reports into one dataset and may be the most current and comprehensive publicly available collection of news reports on agricultural injuries and deaths.

Sustainable Cooling with Hybrid Concentrated Photovoltaic Thermal (CPVT) System and Hydrogen Energy Storage

Standalone power systems have vital importance as energy source for remote area. On the other hand, a significant portion of such power production is used for cooling purposes. In this scenario, renewable energy sources provide sustainable solution, especially solar energy due to its global availability. Concentrated photovoltaic (CPV) system provides highest efficiency photovoltaic technology, which can operate at x1000 concentration ratio. However, such high concentration ratio requires heat dissipation from the cell area to maintain optimum temperature. This paper discusses the size optimization algorithm of sustainable cooling system using CPVT. Based upon the CPV which is operating at x1000 concentration with back plate liquid cooling, the CPVT system size is optimized to drive a hybrid mechanical vapor compression (MVC) chiller and adsorption chiller, by utilizing both electricity and heat obtained from the solar system. The electrolysis based hydrogen is used as primary energy storage system along with the hot water storage tanks. The micro genetic algorithm (micro-GA) based optimization algorithm is developed to find the optimum size of each component of CPVT-Cooling system with uninterrupted power supply and minimum cost, according to the developed operational strategy. The hybrid system is operated with solar energy system efficiency of 71%.