Battery Backup Research Articles

Performance Evaluation of Series-Compensated IPT Systems for Transcutaneous Energy Transfer

Today's implantable mechanical circulatory support devices, such as left ventricular assist devices, still rely on a percutaneous driveline, which is a frequent cause of severe infections and which reduces the quality of life for the patients. Inductive power transfer (IPT) is therefore a promising technology to replace the driveline and, hence, reducing the likelihood of an infection. This paper focuses on the series–series compensated IPT system and provides an in-depth comparison of two operating modes, i.e., the operation at resonance and the operation above resonance, and highlights the advantages and disadvantages with respect to the requirements set by the application at hand. In addition, the paper presents the design and the realization of a fully functional transcutaneous energy transfer (TET) implant hardware prototype, which includes the IPT front-end, the control circuit, the backup battery and its charging converter, as well as the communication electronics in a boxed volume of only 10.3 cl. The experimental verification shows that overall dc–dc efficiencies of up to 90% can be achieved for both operating modes when transmitting 25–30 W from the external battery to the implant backup battery, each having a nominal voltage of 14.8 V, using TET coils with 70 mm diameter and 10 mm coil separation distance.

Basic Multi-ampere Solar Mobile Charger

As we know that nowadays usage of smart phones is increasing. Major issue which we are facing is the battery backup of smart-phone is lower comparatively. Another issue we are facing is that the charging rate of battery varies from one company to another thus using charger of one company for another, which causes damage to battery life of smart-phone. In this paper, we have addressed both the problems of charging smart-phones and have suggested various techniques for it. Keywords : Mobile, charger, portable, multi-ampere, solar Cite this Article Devendrasinh Rayjada, Nimit Dhanesha, Prachal Jadeja. Basic Multi-ampere Solar Mobile Charger. Journal of Alternate Energy Sources and Technologies. 2019; 10(1): 39–41p.

Optimal and Economic Evaluation of a Stand-alone Microgrid for Electricity and Water Supply for Namibia’s Rural Village

Stand-alone microgrid hold a primary solution for electricity and water supply in remote areas access to National grid is not possible. This paper presents a detailed optimal sizing and economic evaluations of a stand-alone microgrid for a remote village (Amarika) in Namibia. Several renewable energy sources such as wind turbines and photovoltaic arrays were considered with a battery backup storage system and a reverse osmosis desalination plant for water supply. Modelling of the microgrid was done based on the meteorological data, the daily water and energy demand of the village. Particle swarm optimization was employed for the system techno- economic optimization: to determine a suitable microgrid configuration that can be established at minimum cost. Sensitivity analysis of the system was performed to examine the effect of variation of LPSP on LCOE. The results demonstrate that the optimized microgrid configuration and the optimization algorithm are effective and can be adopted in supplying power and water to the village. The levelized cost of electricity proves the economic feasibility of the microgrid. The levelized cost of electricity falls within a 90% standard deviation (σ=0.065) of the mean. This proved to be economically feasible with a 96.5% reliability of power supply.

Towards Low-Cost Mechanisms to Enable Restoration of Encrypted Non-Volatile Memories

Since Non-Volatile Memories (NVMs) started entering the mainstream memory/storage market, we must consider how to secure NVM-equipped computing systems. Recent Meltdown and Spectre attacks are a strong evidence that security must be intrinsic to computing systems instead of being added as an afterthought. Processor vendors are taking the first steps and are beginning to build security primitives into commodity processors. One security primitive that is associated with the use of emerging NVMs is memory encryption. Memory encryption, while necessary, is very challenging when used with NVMs because it exacerbates the write endurance problem. Secure architectures use cryptographic metadata that must be persisted and restored to allow secure recovery of data in the event of power-loss. Specifically, encryption counters must be persistent to enable secure and functional recovery of an interrupted system. However, the cost of ensuring and maintaining persistence for these counters can be significant. In this paper, we propose a novel scheme to maintain encryption counters without the need for frequent updates. Our new memory controller design, Osiris , repurposes memory Error-Correction Codes (ECCs) to enable fast restoration and recovery of encryption counters. Since different counter-mode encryption schemes are used in industry and research, we provide a versatile Osiris implementation that improves the performance and write-endurance in different memory encryption schemes. To evaluate our design, we use Gem5 to run eight memory-intensive workloads selected from SPEC2006 and U.S. Department of Energy (DoE) proxy applications, and three computation-intensive graph algorithms from CRONO. Compared to a write-through counter-cache scheme, on average, Osiris can reduce 45.8 percent of the memory writes (increase lifetime by 1.86x), and reduce the performance overhead from 44.7 percent(for write-through) to only 4.49 percent. Furthermore, without the need for backup battery or extra power-supply hold-up time, Osiris performs better than a battery-backed write-back (4.4 versus 5.7 percent overhead) and has less write-traffic (1.8 versus 5.4 percent overhead).

Implementation of a wireless charging system for mobile devices

This work describes the implementation of an RF based wireless charging system using RF transmitting and receiving modules. The objective of this work is to implement a system that has the ability to interact and communicate wirelessly within short range. This mobile wireless charging switching system consists of two sections, the transmitting and the receiving section. Each section was interfaced to 433MHz transmitting and receiving modules. The transmitter section of the wireless mobile charging system sends bursts of 433MHz signal through push button switch which is used in the initiation of the charging process to the receiver; when this signal is received by the receiver, it activates a relay which in turn switches on the internal power that comprises the backup battery, DC-to DC converter via a Universal Serial Bus (USB) port to the mobile device to begin charging. This work was able to achieve a wireless transfer of power for distance of about one metre between the transmitter and the receiver.Keywords: wireless charging, radio frequency radiation, electromagnetic induction, inductive coupling, microcontroller,

Economic and resilience benefit analysis of incorporating battery storage to photovoltaic array generation

Power systems with photovoltaic (PV) arrays combined with battery backup storage are becoming increasingly used because of their capability of working in power island mode, especially during grid outages. The problem is to decide the optimal battery sizes for PV + battery systems with given solar array sizes, from both power supply reliability and economical perspectives. An optimization method based on the simulation of system operation during grid interruption is developed to investigate the effects of battery size on system output reliability level of meeting load demand with minimum cost. Case studies are conducted for validation according to actual solar irradiation data, load profiles and realistic power interruption statistics. Sensitivity analysis is also performed to explore how system total cost affects islanding capability of a PV + battery system to supply energy to facilities. The finding shows that the decline of battery price not only reduces the lowest system total cost but also improves islanded system generation reliability. The proposed methodology for optimizing battery capacity added to PV array systems can make them grid-outage resilient and economically viable, which can be utilized as a decision-making tool for future PV + battery system expansion.

A State of Art on Energy Efficient Multipath Routing In Wireless Sensor Networks

Wireless sensor network is the combination of sensor nodes where sensor nodes are distributed all over the network. There are some challenges that come into the wireless sensor network n context to energy efficiency, network lifetime, storage and battery backup. The most important feature of a routing protocol, in order to be efficient for WSNs, is the energy consumption and the extension of the network’s lifetime. In this paper, we have analyzed various routing techniques for WSN that increases the network lifetime and energy consumption.

The Viability of All Renewable Grids with Battery Storage Support

This paper quantifies the practical deliverability of the strategic engineering options proposed to power a future national grid, when fossil fuel use for generation, heating and transport is reducing to zero. The main contenders are the naturally variable renewables with their essential storage for times of low output, and an all base-load nuclear grid, including load balancing use for off-peak surpluses. The measures used are the objectives of government policy - most affordable, adequate, sustainable, with lowest CO2 emissions per unit energy of grid supply, including the effects of subsidies awarded to the available options. The results clearly demonstrate that low-density renewable energy is an inadequate primary energy source to meet UK grid demand. In particular when the true cost of renewable intermittency is considered, in terms of provisioning essential battery backup, or other low-density storage, that naturally variable renewables require to match demand 24/7 without fossil backup. Finally how the approximate cost of 4 years of battery support for an all renewable grid, at today's demand level, would fund a surplus of nuclear plant adequate to power the UK grid at triple today's supply for 60 years, using fuel that is sustainable for the foreseeable future.

Single Step, Electrochemical Preparation of Copper-Based Positive Electrode for Lithium Primary Cells.

Lithium primary cells are commonly used in applications where high energy density and low self-discharge are the most important factors. This include small coin cells for electronics, power backup batteries for complementary metal-oxide-semiconductor memory or as a long-term emergency power source. In our study we present a fast, electrochemical method of the positive electrode preparation for lithium primary cells. The influence of the current density and oxygen presence in a solution on the preparation of the electrode and thus its electrochemical behavior is examined. Electrode compositions were characterized by X-ray photoelectron spectroscopy (XPS). The prepared electrodes may be used in Li cells as competition to Zn-MnO2 primary batteries.

A Novel Approach to Design SRAM Cells for Low Leakage and Improved Stability

The semiconductor electronic industry is advancing at a very fast pace. The size of portable and handheld devices are shrinking day by day and the demand for longer battery backup is also increasing. With these requirements, the leakage power in stand-by mode becomes a critical concern for researchers. In most of these devices, memory is an integral part and its size also scales down as the device size is reduced. So, low power and high speed memory design is a prime concern. Another crucial factor is the stability of static random-access memory (SRAM) cells. This paper combines multi threshold and fingering techniques to propose a modified 6T SRAM cell which has high speed, improved stability and low leakage current in stand-by mode of the memory cell. The simulations are done using the Cadence Virtuoso tool on UMC 55 nm technology.

Battery and backup generator sizing for a resilient microgrid under stochastic extreme events

Owing to the recent power outages caused by extreme events, installing battery energy storage and backup generators is important to improve resiliency for a grid-tied microgrid. In the design stage, the event occurrence time and duration, which are highly uncertain and cannot be effectively predicted, may affect the needed battery and backup generator capacity but are usually assumed to be pre-determined in utility planning tools. This study investigates the optimal battery and backup generator sizing problem considering the stochastic event occurrence time and duration for the grid-tied microgrid under islanded operation. The reliability requirement is quantified by the mean value of the critical customer interruption time in each stochastic islanding time window (ITW), whose length is the duration and the centre is the occurrence time. The stochastic ITW constraint is then transformed to a probability-weighted expression to derive an equivalent Mixed Integer Linear Programming model. Numerical simulations on a realistic grid-tied PV-based microgrid demonstrate that the total cost is reduced by 11.5% considering the stochastic ITW, compared with the deterministic ITW under the same reliability requirement.

Inductive Power Supply for On-line Monitoring Device

The development of power supply technology is the key to improve the on-line monitoring device which ensures the reliability and intelligence of power grid. In this paper, a design scheme of inductive power supply for on-line monitoring device is proposed. The AC/DC converter circuit without rectifier bridge and the black-start circuit are designed. The control module uses the backup battery to solve the problem of insufficient power supply and control strategy adopts the principle of MPPT. The validity of scheme is verified by testing the prototype. Test results shows that prototype can not only work in a wide current range of line current and load but also work at maximum power point and change the working mode following the change of load and line current.

PV fed Water Pumping System in a Smart Home

This paper proposes renewable energy based water pumping system in a smart home using a bidirectional DC-DC converter. A backup battery is connected in the system for uninterrupted power supply to the water pump. Depending upon source availability, DC-DC converter acts either in boost mode or in buck mode to supply uninterrupted power to the water pump. Using MATLAB/Simulink software, the proposed system is simulated and its performance is analyzed for various operating conditions and the results are furnished in this paper. A small scale laboratory prototype is fabricated and tested for the designed system. Experimental results acquired from the prototype testing correlates with the simulation results validating the feasibility of the proposed water pumping system.

Gain Scheduling Algorithm-Based Control of Renewable Energy Systems for Hybrid Standalone DC Grid

In remote locations in India, where the grid is inaccessible, standalone systems can be employed. Due to the abundant availability of solar and wind energy, they are the preferred energy sources in the standalone systems. A battery backup is mandatory as these sources are largely affected by the environmental conditions. Usually, fixed gain proportional-integral controllers are employed to regulate the output voltage of renewable energy and battery systems. Optimal tuning of these controllers is necessary for the desired operation. However, these controllers can be optimally tuned for a specific set of conditions. In order to maintain the voltage regulation in the standalone system over a wide range and under unpredictable atmospheric conditions, the gains must be scheduled dynamically. This paper proposes a hybrid DC local grid where gain scheduled proportional-integral controllers are implemented for the coordinated control of solar, wind, and battery storage under the different operating conditions. The mathematical model of the hybrid DC local grid along with the control system, incorporating proposed GSPI controller for wind, solar, and battery energy systems, is presented in this paper. The performance of the hybrid DC local grid with the proposed GSPI controller is analyzed for the operating conditions experienced in the city of Ahmadabad, Gujarat, India.

Techno-economic study of the impact of blackouts on the viability of connecting an off-grid PV-diesel hybrid system in Tanzania to the national power grid

National electrification plans for many countries with a low level of electrification promote the implementation of centralized and decentralized electrification in parallel. This paper explores different ways of utilizing an established off-grid PV-diesel hybrid system when the national grid becomes available. This is a rather unique starting point within the otherwise well-explored area of rural electrification. With particular focus on the impact of blackouts in the national grid, we evaluate the economic viability of some alternatives: to continue to use the off-grid micro-grid, to connect the existing micro-grid with or without battery backup to the national grid, or to use the national grid only. Our simulation results in HOMER demonstrate that with a grid without blackouts, there are few benefits to maintain the existing system. Low grid-connection fees, low tariffs and low revenues from selling excess electricity to the grid contribute to this result despite the fact that the system does not carry any investment costs. With a grid with blackouts, it is beneficial to maintain the system. The extent of blackouts and the load on the system determine which system configuration is most feasible. The results make clear the importance of taking blackouts in the national grid into consideration when possible system configurations are being evaluated. This is rarely quantified in studies comparing different electrification alternatives, but deserves more attention.

Nature Inspired Power Optimization in smartphones

Good battery backup has always been one of the most desirable features of smartphones since inception. Key subsystems of smartphones include powerful processors (application processors - CPU, communication processors - modem and graphics processors - GPU), large displays and high-speed networks. All these subsystems are very demanding on smartphone battery. Popular smartphone use cases, such as high-resolution video streaming, networked gaming, video calling etc., are power hungry. Due to increased security concerns, smartphone manufacturers have added biometric security features such as fingerprint, IRIS and face recognition etc. in smartphones. There is additional current consumption ranging from 300 mA (mA) to 400 mA (mA) each time smartphone user unlocks the device using any one of these security features. Therefore, it will be in the fitness of the things that smartphone battery lifetime is increased as much as possible. Due to irregular nature of mobile network traffic, it is very difficult to accurately predict battery lifetime or set a deadline up to which battery should last. In this paper, we have addressed both these problems. Here, we present a novel power optimization system called NIPO ( N ature I nspired P ower O ptimization). Our contributions are – i) Present a novel client server based power optimization System, called NIPO. ii) Use nature inspired algorithms - particle swarm optimization (PSO), ant colony optimization (ACO), and cuckoo search algorithm (CSA) with Levy Flights, for power optimization in smartphone displays for the first time. iii) Develop a mathematical model of power consumption for OLED (Organic Light Emitting Diode) displays in smartphones. iv) Implement NIPO system on Android based smartphone and Windows server to validate the effectiveness of proposed system. For experimental purposes, the proposed NIPO system was implemented on smartphone running Android OS for client side and a Windows server for server side. The experimental results validate the effectiveness of the proposed NIPO system. NIPO system successfully meets user defined time-to-last requirement of battery lifetime.

Developing zero energy and sustainable villages – A case study for communities of the future

Abstract Pakistan is an agricultural country and most of its population resides in rural areas. These communities have small power demands which can easily be met through proper utilization of renewable energy technologies such as solar photovoltaic (PV). The focus of this research work is to encourage people and government to develop zero energy communities which will greatly help to achieve sustainable energy infrastructure in the country. In this paper, feasibility of a grid-connected PV power system without battery backup is conducted for the climatic conditions of a rural community located in Toba Tek Singh, Pakistan. RETScreen clean energy simulation tool is used to optimize and carry out feasibility analysis of the proposed PV system. The analysis is carried out based on project finances, fuel saving potential, energy production, capacity factor, and reduction of greenhouse gas emissions. The financial viability of the project is studied by comparing it with the grid electricity. The results indicate that the proposed PV power plant can provide energy in remote areas at relatively better rates as compared to grid electricity. Furthermore, this initiative will help to reduce the emissions of harmful greenhouse gases and to achieve a sustainable development in the country. A sensitivity analysis is also performed to demonstrate and elaborate the effects of government incentives on different decision variables.

MULTIFUNCTIONAL AUTOMATED SYSTEM FOR MONITORING PERFORMANCE OF SOLAR PV PANEL

The utilization of sun energy into electrical or thermal energy is possible only through the help of panels. Solar panel is now widely used for a variety of industrial and domestic applications. A photovoltaic panel converts the sun's radiation to electricity. It is often necessary to monitor health of a solar panel. But it is very difficult to measure the solar parameters manually as every time we need to go on the terrace and measure them using the multimeter. We have implemented the solar panel parameter measurement system. This project helps us in getting those parameters directly on Mobile through GSM and reduces human efforts. Dust will effect on the output parameter of solar panel. This system automatically cleans the dust on the Solar panel. Bidirectional solar panel tracks the sun to harness maximum power. Also this system helps us for detecting any failure in the system as we will come to know within short time due to remotely acquired parameters. This system automatically displays the various parameters of solar panel such as voltage, current, power, sun irradiance and dust level. For this we are using the PIC18F4520 controller for controlling I/O blocks like relays, motors, display, GSM, different sensors like(temperature sensor, dust sensor, light sensor) There is also the voltage divider circuitry along with the controller. We have driven the two loads at the output of system using the backup battery which will be charged by solar panel.

Novel high-efficient large-scale stand-alone solar/wind hybrid power source equipped with battery bank used as storage device

Abstract In this study, a novel large-scale stand-alone solar/wind/battery hybrid power generation system is designed and constructed. It consists of a photovoltaic (PV) array, a wind energy conversion system (WECS), a battery bank, a bidirectional DC/DC converter, two unidirectional DC/DC converters, a unified maximum power point tracking (MPPT) controller, a control unit, and a DC/AC inverter. The stand-alone solar/wind/battery hybrid system presented in this study combines two renewable resources (solar and wind) with a back-up battery bank used as a standby power source to produce electric energy. Moreover, it maximally converts solar and wind energies into electric energy because it uses a novel fast and highly accurate unified MPPT technique that concurrently tracks the maximum power points of both PV system and WECS. Other works reported in the literature are mostly simulation based works (models), and moreover, there is not any new MPPT consideration in them. It is experimentally verified that the large-scale constructed system is a high-efficient stand-alone solar/wind/battery hybrid power generation system that produces electric energy under different environmental conditions such as cloudy sky, so it can be widely used in remote areas.

Modeling and Analysis of a Hydrogen Reformer for Fuel Cell Applications

ABSTRACTFuel cells that utilize hydrogen and oxygen to produce energy are promising power sources. However, there are operational difficulties in storing hydrogen. One way to alleviate this problem is to generate hydrogen in situ from a liquid fuel via steam reforming. In this paper, an ethanol reformer was modeled as a tubular non-isothermal, non-isobaric packed-bed reactor with an annular heat transfer jacket, operating at unsteady state. A suitable heat transfer jacket was designed that provides heat to the reformer by combustion of ethanol. The partial differential equations of the reformer model were solved numerically and model predictions of hydrogen generation were shown to be in good agreement with experimental data available in the literature for a laboratory-scale reformer. A commercial-scale reformer was designed using this high-fidelity model that can produce sufficient hydrogen to generate up to 5 kW of power when used in conjunction with a Ballard Mark V fuel-cell stack. Experimental data from the dynamic power consumption in a 3-bedroom house were used to validate the size of the reformer as well as a back-up battery that supplies power when the reformer is unable to meet the power demand.