Battery Backup Research Articles

A New Analytical MPPT-Based Induction Motor Drive for Solar PV Water Pumping System With Battery Backup

In this article, an analytical method is presented to achieve maximum power point tracking (MPPT) for a solar photovoltaic (PV) array-based water pumping system comprising of an induction motor drive (IMD). The gating signals are generated using the space vector pulsewidth modulation (SVPWM) method for three-phase inverter. This analytical MPPT control (AMPPTC) scheme exhibits fast dynamic performance and minimum overshoot with the IMD-based water pumping system. Additionally, the AMPPTC scheme provides absolute steady-state robustness under variations in solar irradiance/parameters that improves the stability of the system under a wide speed range of IMD and makes the system insensitive toward parameter variations. The dc-link voltage regulation is assured by three-phase inverter, and MPPT regulation is achieved by the boost converter. This two-stage PV system, with MPPT controlled boost converter and SVPWM-based three-phase inverter operating the pump, is modeled and simulated in Simulink environment of MATLAB. The performance and robustness of the AMPPTC-based PV water pumping system are corroborated through the laboratory experimentation.

Enhancing Freshwater Productivity of Twin Wedge Solar Still by Temperature Control Through Thermoelectric Sensors and Modules

Solar stills are zero-emission water desalination devices that utilize the abundantly available solar energy to deliver clean water. In remote locations which are deprived of electricity as well as clean and fresh water, Twin wedge solar stills (TWSS) can be utilized to desalinate saline and brackish water. The productivity of TWSS is depends on the evaporation as well as condensation rate which are subjected to the weather constraints namely, the solar energy radiation, the wind velocity along with the surrounding atmospheric temperature. Monitoring the various temperature parameters in the TWSS and controlling them enables the control of freshwater production. In this paper, the yield of TWSS is monitored and controlled using Seebeck effect-based thermoelectric K-type thermocouple sensors for temperature measurements and reverse seebeck effect based thermoelectric modules for increasing evaporation and condensation rate of the TWSS. A Temperature Control Unit (TCU) is developed to acquire the temperature sensor data and control the operation of thermoelectric modules in order to control the production of the TWSS. The TCU is powered by PV with a battery backup system for remote location operation. The productivity of the system increased from 0.69 – 1.38 liters/m <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> per day to 3.28 – 3.61 liters/m <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> per day, through proposed Temperature Control strategy through Thermoelectric sensors and modules. The proposed system is 1.4 times more profitable than TWSS equivalent to the area of proposed PV powered system.

Design of Low Power and High-Speed Cmos D Flipflop using Supply Voltage Level (SVL) Methods

This Project details about the design of D Flip Flop (DFPFP). This D Flip Flop circuit is analyzed by using the supply voltage level methods. These methods are used mainly to suppress the power consumption caused due to leakage currents. In addition, because of this implemented technique, the time taken for battery backup, and the supply voltage given at standby mode gets minimized. The projected circuit uses a smaller number of transistors, such that power consumption and leakage currents are in prior limit. Mainly, the CMOS D Flip Flops are designed to use them in binary counters, shift registers, Analog and Digital circuit designs. And this circuit design is implemented in 45nm CMOS Technology Cadence Virtuoso Tool.

Single Phase Water Pumping System using Adaptive Neuro Fuzzy Inference MPPT for PV system

The demand for water in India steadily increases as the population grows. Due to its numerous advantages, research in AC motor-based Water Pumping Systems (WPS) has recently got a lot of attention. Because of its natural abundance and ecologically beneficial properties, renewable energy-based solar photovoltaic (PV) generation is the ideal substitute for conventional energy sources. Maximum power extraction from the PV system is critical for increasing solar power generation efficiency. This proposed work presents a solar power system using Adaptive Neuro-Fuzzy Inference System (ANFIS) Maximum Power Point Tracking (MPPT) for pumping system. A MPPT controller based on ANFIS has been introduced in this research. This approach has the advantage of having a higher tracking accuracy. This tracker captures irradiance and temperature from the solar panel as inputs. This system uses a battery backup for energy storage purpose. The battery is recharged using the solar supply. In this system, Pulse Width Modulated (PWM) inverter is used, where it converts the battery voltage (DC), into AC voltage for running the pumping system. For validation, the proposed model is analysed using MATLAB/Simulink.

Development of Grid Tied Inverter for Indian Grid and Operating Environmental Condition

Solar Photovoltaic (PV) technology is one of the renewable energy source technologies to realize the shift to decarbonize energy supply because of availability of safe, limitless, free and reliable long-term sources of power. PV modules/cells are instruments to convert this solar energy to DC energy. Grid interconnection with solar power system is comparatively easier to install as the same do not require storage system. This paper presents injection of 3 kW power generated from solar PV array to 230V grid distribution network. Technique uses phase angle difference between grid voltage and voltage source inverter. The grid acts like a virtual energy storage system with an unlimited storage capacity. Hence, the proposed system is designed without a battery backup. This system is simulated in MATLAB/Simulink to confirm the desire output. In the second step, hardware circuit is designed and implemented based on the simulation results.

Basic Considerations and Conceptual Design of a VSTOL Vehicle for Urban Transportation

On-demand air transport is an air-taxi service concept that should ideally use small, autonomous, Vertical Short Takeoff and Landing (VSTOL), “green”, battery-powered electric aircraft (eVSTOL). In addition, these aircraft should be competitive with modern helicopters, which are exceptionally reliable machines capable of the same task. For certification and economic purposes, mobile tilting parts should be avoided. The concept introduced in this paper simplifies the aircraft and makes it economical to build, certify and maintain. Four contrarotating propellers with eight electric motors are installed. During cruise, only two of the eight rotors available are not feathered and active. In the first step, a commercial, certified, jet-fueled APU and an available back-up battery are used. A second solution uses a CNG APU and the same back-up battery. Finally, the third solution has a high-density dual battery that is currently not available. A conceptual design is shown in this paper.

Security of IoT in 5G Cellular Networks: A Review of Current Status, Challenges and Future Directions

The Internet of Things (IoT) refers to a global network that integrates real life physical objects with the virtual world through the Internet for making intelligent decisions. In a pervasive computing environment, thousands of smart devices, that are constrained in storage, battery backup and computational capability, are connected with each other. In such an environment, cellular networks that are evolving from 4G to 5G, are set to play a crucial role. Distinctive features like high bandwidth, wider coverage, easy connectivity, in-built billing mechanism, interface for M2M communication, etc., makes 5G cellular network a perfect candidate to be adopted as a backbone network for the future IoT. However, due to resource constrained nature of the IoT devices, researchers have anticipated several security and privacy issues in IoT deployments over 5G cellular network. Off late, several schemes and protocols have been proposed to handle these issues. This paper performs a comprehensive review of such schemes and protocols proposed in recent times. Different open security issues, challenges and future research direction are also summarized in this review paper.

Analisis Pengaruh Perbandingan Sistem Hybrid PV-Genset Menggunakan Homer Grid

95% of energy use in Indonesia is still dominated by fossil fuels. One way to meet the increasing energy needs is by using renewable energy.. The most easily available and popular renewable energy today is Solar Power Plants. Currently, solar power plants have various types to maximize their potential, one of which is the hybrid PV-genset system. This research was conducted at SMKN Central Java which has a solar power plant hybrid pv-genset system by connecting the output on grid solar power plants with generators in parallel without battery backup. The study was carried out by reviewing the fuel consumption of the generator through two scenarios without and with battery backup in the system using the HOMER Grid software to run the simulation by entering the required parameters. The results of this study indicate that the system with battery backup has 61.62% greater savings on the fuel consumption side and 61.87% more efficient on the fuel cost side to operate the generator when a blackout occurs.

Autonomous system for in-field observation of responses to vocalizations of Alston’s singing mouse

Ranging throughout central America, Alston’s singing mice (Scotinomys teguina) are known for their long songs, which consist of rapidly repeated, frequency-modulated notes. Singing mice are the first rodents shown to exchange calls at rates resembling human conversation, which are used in mate attraction and male-male competition. Despite being researched in laboratory settings, few studies have examined the impact of the vocalizations in a natural environment. Unlike singing mice, most small rodents make high-frequency sounds at nighttime, to avoid attracting predators. We aim to observe why singing mice can produce long-distance, low-frequency songs, despite the predation risk. To do so, we developed a Raspberry Pi-based system to generate artificial mouse vocalizations at regularly scheduled intervals and record audio data of approaching predators and singing mice. This device was designed to be powered with a standard car battery and a backup lithium-ion battery to function for approximately two weeks in the field without interruption. An Adam A3X studio monitor was deconstructed and retrofitted with a USB microphone, two-terabyte hard drive, backup battery, and amplifier. This presentation will describe the construction of the device and issues with functionality addressed during the design process. [Work supported by UT Integrative Biology Dept., SWAN Howard-McCarley Award.]

Variable operation of a renewable energy-driven reverse osmosis system using model predictive control and variable recovery: Towards large-scale implementation

Powering Reverse Osmosis (RO) systems with Renewable Energy (RE) is essential for decarbonising water production. Integration of RE requires large-scale RO plants to operate efficiently using variable power. Nevertheless, variable operation (involving matching the RO load to available power without battery back-up) has only been implemented for small-scale systems. This paper presents a variable-speed operation technique suitable for large-scale RO systems using an optimised operational strategy and a Model Predictive Controller (MPC). The technique was validated using a laboratory test rig having comparable performance to large-scale systems. A dynamic plant model was used to design the operational strategy and control system. Several operational strategies were explored for varying the operating parameters according to power available from a RE source. An advanced control system based on MPC was designed and compared to a conventional Proportional-Integral-Differential controller. The results showed that operation at variable recovery with constant brine flowrate delivered the lowest specific energy consumption and widest operation range for a system with an isobaric pressure exchanger. The MPC controller improved the settling time for a 10% step-change in permeate flowrate by 47%. Moreover, it improved energy utilisation, giving a 2.35% increase in hourly permeate production for a defined power input time-series.

A Strategy for Grid-Connected PV-Battery System of Mongolian Ger

One of the main sources of energy utilized in the Mongolian Gers is coal and wood mainly for the purpose of heating and other domestic use. This heavily increases the air pollution levels. A viable solution for handling the air pollution is switching to renewable energy sources (RES). Grid-connected photovoltaic (PV) systems with battery back-up provide a reliable solution to the problem addressing the energy demand and pollution control. This paper proposes a grid-connected PV–second-life battery system and its operation strategy. A single Ger, which consists of a PV array, battery energy storage system (BESS), and an electric heater (EH), is modeled and tested. The trading coefficient and selling unit price are calculated based on variables such as loan, selling price, and purchasing price. The advantages of the proposed strategy are its simple design and easy implementation. The economic result shows that there is a significant reduction in the electricity bill during winters, while the bill can be reduced to zero during summers. Furthermore, the annual profit from the proposed system is USD 15. The CO2 emissions are reduced from 32 to 7 tCO2.

A New Switching Strategy for Improving Efficiency and Thermal Distribution of a Three-Port Converter for Solar DC Stand-Alone System

This brief proposes a new switching scheme for a recently published three-port converter to make it suitable for Photo-Voltaic (PV) fed dc stand-alone system with battery backup. The resulted scheme is capable of Maximum Power Point (MPP) Tracking, charging, and discharging of the battery, and can feed power to the load while maintaining the desired load voltage. This scheme, when operated with a saw-tooth or triangle carrier, leads to improved efficiency and dynamic response as compared to existing similar schemes reported in the literature. This brief also proffers toggling between saw-tooth and triangle carriers periodically for better thermal distribution in the switching devices which is envisaged to enhance the reliability of the overall system. A suitable control strategy is also proposed for the complete stand-alone scheme to facilitate operation in various possible modes along with smooth transition between these modes. Small signal analysis is performed based on the proposed switching scheme, and the controller design during various operating modes is discussed. Validation and performance analysis of the overall system are carried out under various operating conditions utilizing a 400W experimental prototype.

Dual Active Bridge Based Reduced Stage Multiport DC/AC Converter for PV-Battery Systems

Standalone power systems are significant for electrifying the remote areas where extending the grid connectivity is not feasible, either economically or logistically. Solar Photovoltaic (PV) systems with battery backup are among the most popular candidates to serve as an energy source in standalone systems. This article presents a novel multiport converter (MPC) for PV-battery systems powering standalone loads. The proposed converter is a reduced stage power converter based on current fed dual active bridge (CF-DAB) topology. CF-DAB offers galvanic isolation and a high voltage ratio without sacrificing efficiency. Switching losses are further reduced by a modified modulation scheme that reduces the average switching frequency of some of the switches. The proposed converter performs the functions of tracking maximum power point of the solar panel and regulating the load voltage while using fewer power conversion stages. This is done by sharing components among the various stages performing maximum power point tracking, voltage boosting, and dc/ac conversion. A small-signal model of the proposed MPC required for its closed-loop control is also proposed, which can also be utilized for other CF-DAB-based converters. A lab prototype of the proposed MPC has been fabricated and its operation has been validated under various static and dynamic conditions.

AC network centennial: Years of distribution networks [History

Automatic AC secondary distribution networks are the norm in urban areas of dense load concentration; no electrical distribution engineer could imagine any other technique. A century ago, dc distribution predominated in such urban areas. Alternating current distribution was minimal, with radial feeders from transformer substations to the local transformers that supplied customers. It was not as efficient or reliable as dc and lacked battery backup. Direct current distribution systems were expensive, and ac promised a potential 500% reduction in distribution costs by elimination of the substations and heavy cables required by dc systems if reliability and efficiency could be improved.

Chemistry Options for Lithium-Ion UPS and BBU [Expert View

Industrial rack-mounted uninterruptible power supplies (UPS) or battery backup units (BBU) are used in data centers or telecom central offices to provide backup power for servers and switching equipment in the event of power failure. Historically, these UPS’s have relied on lead-acid as the predominant battery type. Currently, lithium-ion (Li-ion) batteries are gaining market share over the incumbent lead-acid battery technology. To differentiate UPS from BBU power sources, we define a typical UPS as double-conversion with ac-dc-ac power conversion, while BBU is the embedded battery with dc voltage input and output. While the input/output of a UPS is more universal by providing either single-phase 120–240 V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">AC</sub> or three-phase 208–480 V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">AC</sub> , the BBU dc output voltage is typically matched to the equipment it is powering. DC powered equipment is gaining acceptance in multiple industries for the simplicity, and efficiency. More and more installations are relying on BBU’s and dc plants to power their equipment directly. <xref ref-type="fig" rid="fig1" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Figure 1</xref> presents a BBU and a dc plant installed in a telecom rack with space for other equipment that needs a backup power source.

Designing and Sensitivity Analysis of an Off-Grid Hybrid Wind-Solar Power Plant with Diesel Generator and Battery Backup for the Rural Area in Iran

Because of the lack of transmission and distribution grid of electricity in remote and inaccessible areas due to the high cost of construction of the transmission line along with the unsuitable geographical conditions and taking into account the factors affecting sustainable energy production, renewable energy seems like a sensible solution. Therefore, in this paper, considering the solar and wind potential of Turkalan village located in East Azerbaijan Province, the combined solar-wind-diesel generator system with battery bank and independent of the grid was evaluated. Sensitivity analysis and optimal measurement of the studied system were performed by HOMER software. Sensitivity analysis was performed on the parameters of solar radiation, light reflection from the environment, and wind speed. The goal was to supply 22 kWh/d of energy with a maximum load demand of 2.5 kW. The four hybrid systems proposed by the software considering the total net present cost (NPC) were solar-generator-battery, solar-wind-generator-battery, solar-battery, and solar-wind-battery, respectively. The studies were conducted to determine which of the systems is more suitable for the area.

Using a computer based selection model for sizing of solar panels and battery back-up systems for use in a floating in-pond raceway

The In-pond Raceway (IPR) is a relatively new option for production aquaculture, which depends on water moving devices to provide constant flow. Failure of these devices will often result in a catastrophic loss of fish in the system. Thus, robust power backup systems are necessary to mitigate risk in the event of prolonged power outage. Because these systems must be dependable and many suitable locations for these raceways are in ponds in remote locations, farmers have considered utilizing off-grid solar photovoltaic (PV) systems with battery storage. PV with battery storage eliminates the expense of running utility power to remote areas and eliminates the associated risk of power failure when these lines go down. However, the PV and battery storage must be properly sized to ensure continuously available power. This study modeled energy requirements using a daily energy balance for these unique systems. The model was then utilized to determine whether sized systems could withstand varying electric loads based on monitored hourly climatological conditions at seven different locations within the state of Kentucky in the United States. Determining the appropriate size was an iterative process, where the battery storage and PV array were incrementally increased until the model predicted that the system would provide continuous power year-round. The model was also used to examine the effects of undersized systems. Energy depletion events (when not enough energy remained to drive the water moving device) were clustered in groups of multiple days in winter months over the twenty-two-year dataset. Therefore, undersized systems may be appropriate if there was no intention of stocking fish in winter. Establishing this model led to the development of a design decision support tool aimed at potential new Aquaculture producers and a series of recommendation tables, with the intention of streamlining the initial design process for this novel technology.

Readiness to implement on-site molecular testing for tuberculosis in community health centers in Uganda

BackgroundNewer molecular testing platforms are now available for deployment at lower-level community health centers. There are limited data on facility- and health worker-level factors that would promote successful adoption of such platforms for rapid tuberculosis (TB) testing and treatment initiation. Our study aimed to assess readiness to implement onsite molecular testing at community health centers in Uganda, a high TB burden country in sub-Saharan Africa.MethodsTo understand implementation readiness, we conducted a qualitative assessment guided by the Consolidated Framework for Implementation Research (CFIR) at 6 community health centers in central and eastern Uganda between February and April 2018. We conducted 23 in-depth, semi-structured interviews with health workers involved in TB care at each health center to assess TB-related work practices and readiness to adopt onsite molecular testing using the GeneXpert Edge platform. Interviews were transcribed verbatim and coded for thematic analysis.ResultsParticipants (N=23) included 6 nurses/nursing assistants, 6 clinicians, 6 laboratory directors/technicians, 1 medical officer, 2 health center directors, and 2 other health workers involved in TB care. Health workers described general enthusiasm that on-site molecular testing could lead to greater efficiencies in TB diagnosis and treatment, including faster turn- around time for TB test results, lack of need for trained laboratory technicians to interpret results, and reduced need to transport sputum specimens to higher level facilities. However, health workers also expressed concerns about implementation feasibility. These included uncertainty about TB infection risk, safety risks from disposal of hazardous waste, a lack of local capacity to provide timely troubleshooting and maintenance services, and concerns about the security of GeneXpert devices and accessories. Health workers also expressed the need for backup batteries to support testing or charging when wall power is unstable.ConclusionOur study generated a nuanced understanding of modifiable contextual barriers and led to direct revisions of implementation strategies for onsite molecular testing. The findings highlight that novel diagnostics should be implemented along with health system co-interventions that address contextual barriers to their effective uptake. Pre-implementation assessment of stakeholder perspectives, collaborative work processes, and institutional contexts is essential when introducing innovative technology in complex health care settings.

IoT Based Ventilator

Abstract: We propose the design and development of an Internet of thing based ventilator system. The ultimate vision of IoT is to upscale communication mechanisms with a highly distributed and significantly dense heterogeneous devices network. Recently world is under stress due to the COVID-19 pandemic, which causes severe respiratory distress. Therefore, it is essential to develop low-cost and high-efficiency technologies for real-time health detection and continuous treatment system. The IoT-based ventilator is a low-cost, respiratory monitoring, and controlling system. The designed and developed ventilator delivers breaths by compressing a conventional Ambu bag with the help of a fixed arm connected to a servo motor. It eliminates the need for a human operator for the bag valve mask. Tidal volume and number of breaths per minute are set via user-friendly input modes, which help in customizing the pressure according to the real-time requirements of the patient. It has a safety mode that is when the power supply goes down; the backup battery automatically kicks in. A built-in alerts system is embedded to activate and warn the local and the remote locations about any malfunctioning for immediate attention.

Quantitative analysis of DC–DC converter models: a statistical perspective based on solar photovoltaic power storage

Abstract Photovoltaic (PV) systems have paved their way into general households due to their high efficiency, low deployment cost and huge power savings. These advantages combined with Government incentives further assist in wide-scale adoptability of the solar powered systems. PV systems generate direct current (DC) outputs, which needs to be converted into alternating current (AC) via inverters. The efficiency of inverter design decides the overall efficiency of the PV system, which allows effective utilization of the solar power for feeding to grid or for local usage. In order to design effective inverter models, a large number of electrical configurations are designed by researchers over the years. These include, stand-alone inverters, grid-tie inverters, battery backup inverters and hybrid inverters, each of which are further divided into multiple sub-categories. Each of these sub-categories have a different application, for instance, string-converters are used for moderate power applications up-to 150k W, while central converters are used for high power applications above 80k W, etc. Apart from power capabilities, these designs vary in terms of efficiency of conversion, usability, cost, etc. Due to so many parametric variations, effective selection of these converters for a given PV application becomes ambiguous. In order to reduce this ambiguity, the underlying text statistically evaluates performance of some of the most efficient PV converter models, and compares them on the basis of power capabilities, accuracy of conversion, converter used, control model used, etc. This review will assist researchers and system designers to select the best suited models for their given applications, and thus reduce the time needed for efficient PV inverter system design. This text also recommends future research which can be adopted for improving efficiency of these systems.