Power Supply Fluctuations Research Articles

Power Supply Fluctuation and Sales Performance of Frozen Foods Business: A Study of ABA Metropolis. Nigeria

One of the essential requirements for output growth in the frozen food business is adequate electricity supply. The electricity supply bane has brought about the acquisition of expensive power back up facilities in the form of plants, generators, and inverters to augment stable electricity supply. The study therefore, investigated power supply fluctuation and sales performance of frozen foods in Nigeria. In line with the objectives of the study, two hypotheses were formulated. The descriptive survey research design was adopted for the study. The population of the study comprised of twenty (20) frozen food firms in Aba with a sample size of sixty (60) respondents which was conveniently drawn from our population of interest. A structured questionnaire based on the five-point Likert scale was used in data collection. Frequency and percentages were used in analysing both the personal data of the respondents. While Kendall tau_b was employed in analyzing the hypotheses formulated. The findings revealed that a significant relationship exists between erratic power supply and profitability; alternative source of power supply and profitability. We therefore, recommended amongst others that, Government should encourage competition in the power sector, rather than the monopoly the electricity company is currently enjoying. They need to be proactive and embrace the renewable energy which would lead to decentralization of power supply, create more jobs, lead to lower costs, and cleaner environments. Keywords: Power, supply, fluctuation, erratic power supply, alternative power supply, profitability, sales performance DOI: 10.7176/EJBM/13-15-02 Publication date: August 31 st 2021

Model-Based Optimization of Solid Oxide Electrolysis Cells and Stacks for Power-to-Gas Applications

The temporarily fluctuating power supply produced by renewable energy sources (RES) forces the integration of energy storage technologies in our energy network at a massive scale, in order to make future scenarios of a sector-coupling and distributed clean energy supply feasible. Power-to-Methane (PtM) chemical storage concepts are very attractive in this regard, since the production of synthetic CH4 has the advantages of a high-energy density carrier that is easily transportable within the existing pipeline infrastructure and that is a feedstock for various applications in the form of compressed or liquefied natural gas (CNG/LNG). However, in all these scenarios, the levelized cost of the synthetic fuel is a major obstacle due the relatively inefficient conversion chain, i.e. energy losses associated with the fuel production plus consumption. Thermal integration of high-temperature (HT) steam electrolysis based on solid oxide electrolysis cells (SOECs) with the exothermic catalytic methanation is a very promising concept to boost the system’s efficiency by making use of the intrinsically favored thermodynamics and kinetics of HT-electrolysis for H2 generation. On stack level, electrical efficiencies (based on the lower heating value (LHV)) of 96% and specific energy consumptions of 3.3 kWh per Nm3 of H2 were reported for HT-steam electrolysis [1], whilst net system PtM efficiencies of ~80% could be demonstrated in a pilot project [2].Still, there exists the fundamental question on how to optimize the cell design and the operating conditions in terms of balancing area-specific power density, efficiency, degradation rates, and costs, i.e., how to use this synergy optimally in a future real-world application.Here, we use a detailed multi-physics and multi-scale SOEC simulation tool alongside initial and long-term experiments performed on commercial electrolyte- (ESC) and anode-supported cells (ASCs) to make further strikes towards this question. Firstly, a planar single cell model coupling 1D+1D gas transport and spatially-resolved charge transfer across the electrode thickness is calibrated based on polarization curves recorded at different temperatures (600-900 °C) and inlet compositions (80-95% H2O, balance H2). By accounting for realistic microstructural cell data acquired from Scanning Electron Microscopy (SEM), a nearly quantitative accordance with the experimental data could be achieved. Subsequently, by incorporating a 2D heat transport model, adiabatic simulations are performed to identify optimal operation conditions in a parametric study, which are used as a basis for the long-term degradation experiments. It is demonstrated how the selection of the cell design affects the selection of optimal operation points, and how the creation of reactant starvation zones within the cell can severely impact the electrical efficiency. A scale-up to the stack level is performed afterwards by applying a 3D stack model [3], which considers heat loss to the surroundings across a thermal insulation layer. This enables to realize system-oriented simulations with conditions experienced by the stack that are close to the real-world application. In this way, the implications of scaling-up on (i) the SOEC performance depending on the cell design, and (ii) the selection of optimal operation conditions from an electrolyzer point-of-view in the context of PtM are illustrated on the basis of industrially-scaled stacks. Acknowledgements Financial support by the federal ministry for economic affairs and energy (Bundesministerium für Wirtschaft und Energie, BMWi) under Grant Numbers 03EIV041D and 03EIV041E in the “MethFuel” group of the collaborative research project “MethQuest” is gratefully acknowledged.

A Comparison of Generalized Unified Power Flow Controller and Load Tap Changing Transformer for Voltage Stability Enhancement in a Power System

The continuous increase in power demand and huge power losses in modern power systems have been a growing concern to power utilities. Such phenomenon often results in epileptic power supply, power system instability, supply fluctuations and security problems in many parts of the globe. Identification of suitable places for the installation of reactive power compensators to minimize voltage drop and system power losses in a power system becomes imperative. In this paper, the Newton-Raphson iterative method was used for the power flow solution of the 28 bus Nigerian 330KV grid system. The Generalized Unified Power flow Controller (GUPFC) is installed at identified weak load buses of the Nigerian 28-bus power system to reduce the losses and voltage drop of the system. A comparative analysis of the GUPFC with Load Tap Changing Transformers (LTCT) is also performed. Result obtained shows that the GUPFC can largely (effectively) improve the system power stability and selectively balance the power flow of multi-lines power flows when placed at identified weak buses compared with LTCT. Thus, GUPFC can be used to reduce overall power losses along transmission lines as well as improve stability overall reliability of the power grid system.

Construction of Distributed Cooperative EMS in Multiple Homes Based on EV State Prediction and MPC

In this paper, we propose a novel energy management system (EMS) in which multiple homes cooperate. A buffer with a storage battery is needed to realize efficient power control in response to fluctuations in power demand and supply. Since there are problems such as economic cost and securing of installation place to apply the storage battery, it is conceivable to use electric vehicles (EV) instead. However, EVs need to be charged or discharged at home in preparation for traveling. The purpose of this paper is to propose a distributed cooperative energy management method for multiple homes based on EV state prediction and model predictive control (MPC). Finally, numerical simulation results show the effectiveness of the proposed algorithm.

Enhancing Energy Flexibility through the Integration of Variable Renewable Energy in the Process Industry

Energy flexibility plays a crucial role in the current energy transition, as it can contribute to a stabilization of the grid. The integration of electricity from renewable energy sources leads to large fluctuations in power supply, compromising the reliability of supply and the grid stability. Employing surplus of variable renewable energy (VRE) to cover the industrial demand can on one hand reduce the need for grid upgrade on a long term. On the other hand, integrating VRE can contribute to fulfill decarbonisation targets in the industrial sector. As a consequence, the share of renewable energy in the total energy consumption can be increased. This paper aims at assessing the role of VRE integration in the process industry as a mean to leverage energy flexibility. The assessment consists of a scenario-based evaluation, complemented by a simulation model, able to quantify the reduction of specific CO2 emissions. The developed approach is demonstrated within a case study in the paper industry.

Uninterruptible Power Supply Improves Precision of Telomere Length Measurement via qPCR

Epidemiological literature has produced robust associations between telomere length (TL) and health, wherein individuals with shorter TL are at increased risk for chronic disease and death. Even so, technical challenges associated with TL measurement have led some to question their utility as a biomarker of aging. Several pre-analytical factors influence TL assessment via qPCR including tissue source, sample storage, and DNA extraction method. Additional work has investigated how conditions within the PCR run (e.g. mastermix reagents) influences precision and reproducibility of TL measurements. However, the impact of power supply remains unclear. Momentary fluctuations in power supply can affect the functioning of high-performance electronics, including real-time thermocylers. These fluctuations can be mitigated by using an uninterruptible power source (UPS), an electronic apparatus capable of supplying constant, uninterrupted voltage to high-performance electronics. The current study investigated how using a UPS influenced TL assessment via qPCR. Standard deviation and coefficient of variation across replicates were compared for samples assessed with or without the use of a UPS. Samples run with a UPS had significantly lower standard deviation (p<0.001) and coefficient of variation (p=0.002) than those run without a UPS. Notably, neither the efficiency of exponential amplification (p=0.674) nor the standard curve R2 (p=0.638) varied as a function of UPS status. Thus, UPS status decreases variability within sample replicates while maintaining the overall quality of the qPCR assay. *The work presented was supported by the Telomere Research Network, an NIH-sponsored working-group recently established to coordinate best practices for measuring telomere length in population-based research.

A novel phase-locked loop applied on frequency fluctuation of EAST power supply

The excellent performance of synchronous phase locked technology is the basis of improving the power quality of Experimental Advanced Superconducting Tokamak (EAST) power system. The conventional synchronous reference frame phase-locked loop (SRF-PLL) with low pass filter (LPF) has a poor filter capacity for the 2nd harmonic component as the fundamental frequency fluctuation due to the high-power, high-parameter operation of the EAST. To improve accuracy of the phase estimation, adaptive notch filter (ANF) will be introduced into the LSRF-PLL to reject the disturbance of 2nd harmonic component, which can adaptively track the fluctuation of fundamental frequency with least mean square (LMS) algorithm. A novel composite algorithm of LPF and ANF SRF-PLL (LASRF-PLL) is presented to suppress the disturbance of the frequency fluctuation and harmonic pollution. At the last, the performance of the proposed LASRF-PLL is finally validated by simulation results of MATLAB software.

Power Control Framework for Green Data Centers

In recent years, renewable energy, such as wind and photovoltaic electric power has been increasingly integrated into data center power provisioning systems to address high energy consumption of data centers. However, in reality, the intermittency and randomness of renewable energy (power supply fluctuation) is detrimental to the reliable operation of sophisticated IT equipment in those so-called green data centers. In this article, we address the problem of data center power regulation explicitly taking into account the unreliability and instability of renewable energy sources. To this extent, we design a novel data center power control framework that smoothens the power fluctuation and instability of renewable energy sources. The core of our framework is two power regulation optimization algorithms. In particular, a server workload scheduling algorithm deals with high frequency fluctuations while an Uninterruptable Power Supply (UPS) power regulation algorithm handles low frequency and large extent power fluctuations. These algorithms are also designed to satisfy service level agreement (SLA) and standby power supply capacity. We have conducted an extensive evaluation study using trace data of a real data center of 30000-node cluster with 50 x 250 UPS battery groups and 24-hour power generation data from real wind farm and photovoltaic power station. The experimental results show our framework effectively smoothens fluctuations of data center power supply, more effective use of renewable energy, and extend the UPS batteries’ lives to reduce the skyrocketed data center operating expenses.

Self-charging wearables for continuous health monitoring

Remarkable advances in wearable electronics have brought numerous multi-functionalities in health monitoring, but demanded more power, necessitating larger batteries and frequent recharging. Replacement or recharging of batteries, however, poses undesirable downtime in health monitoring. Thermoelectrics are promising in sustainably supplying power by converting body heat but wearable thermoelectrics have not been capable of producing power large or stable enough for the continuous operation of commercial health monitoring sensors. Here synergistic integration of a wearable thermoelectric generator (WTEG) and an emerging Li-S battery has delivered power sustainably and continuously, overcoming the biggest hurdle in utilizing thermoelectrics for wearable electronics in practice. The major drawback of low thermoelectric output voltage for charging batteries has been greatly alleviated with the high-performance Li-S battery whose charging voltage is only a half those of Li-ion batteries. The WTEG continuously produces large power up to 378 µW, operating a commercial glucose sensor (64 µW) and storing the remainder in the Li-S batteries for providing a stable voltage of 2 V even under large fluctuations in power supply and demand. This work demonstrates feasibility of operating a commercial glucose sensor only with body heat for the first time, to our best knowledge, engendering sustainable operation of wearables without interruption and tedious recharging/replacement of batteries. Integrated wearable thermoelectric-battery system for a continuous glucose monitoring sensor and the infrared image of the integrated system worn on a human wrist. • Synergistically integrated wearable thermoelectric-battery system. • Demonstrated feasibility of operating a commercial glucose sensor only with body heat for the first time. • Designed high energy density Li-S batteries for wearables with 3D porous carbon nanotubes. • Developed self-sustainable and continuous health monitoring systems.

Utilization of Information and Communication Technologies (ICTs) Tools for Sharing of Agricultural Related Information in Osun State: Implications for Rural Information Needs

The study was motivated by the need to harness technological advancement to enhance agricultural production in Osun State. The study assessed the utilization of Information and Communication Technologies (ICTs) tools for sharing of agricultural related information in Osun State, Nigeria. The study illustrated the socio economic characteristics of the Respondent, identified the available ICT tools for sharing of various agricultural related information, identified agricultural related information shared through various available ICT tools, measured the frequency of utilization of the identified ICT tools and assessed the severity of challenges encountered by Respondent in the utilization of ICT tools in the study area. Sixty percent of Extension Agents in each of the three zones in the study area were sampled. The data collected were examined using descriptive statistics tools while regression analysis was used to test the significant relationship between the socio-economic characteristics of Respondents and their frequency of utilization of ICT Tools for sharing of agricultural related information in the study areas. The analysis of the data was carried out with the use of SPSS version 22. The findings revealed that the average age of Respondents was 39 years; more than half of the respondent (67.1%) were male; most (81.4%) of the respondent were married; majority (68.6%) of the respondent were Christian; about (70%) of the respondent had tertiary education. The mean household size was 5 members per household; majority of the respondents belonged to one association or the other and they access the internet with their own data plan. Radio (wms 2.7) was ranked first as most available ICT tools for sharing information in the study area. Furthermore, information on availability and sources of farm inputs (wms2.3) was ranked most shared information while information on storage facilities (wms1.0) was ranked the least shared information by the Respondents. Also, the initial cost of procurement of ICT gadgets, cost of maintenance, risk of theft of gadget, and fluctuating power supply were the major challenges encountered with the use of various ICT tools. Regression analysis identified a significant relationship between selected socio-economic characteristics of the Respondents and frequency of Utilization of ICT Tools for sharing Agriculture related information. The study recommended use of Radio as medium through which agricultural related information should be shared bearing in mind its ease of access, little cost of procurement and maintenance, extent of reach and frequency of usage among the respondents. Provision of access to internet facility was recommended in order to afford respondents a limitless right to use information on the World Wide Web. Finally, alternative source of power to enable respondents recharge their ICT gadgets was recommended to make up for unreliable electricity supply.

Research on capacity planning and optimization of regional integrated energy system based on hybrid energy storage system

Some regional integrated energy systems (RIES) have installed equipments such as wind turbine and photovoltaic, but the fluctuation of these intermittent power supply is large, resulting in a certain amount of energy waste. Because energy storage can improve the utilization rate of renewable energy, this paper establishes a storage capacity expansion planning model considering multiple functions of hybrid energy storage in the RIES. In this model, the wavelet packet decomposition method is used to reasonably decompose the high-frequency fluctuation and low-frequency fluctuation of renewable energy to achieve the function of stabilizing fluctuation. Meanwhile, an operation strategy for hybrid energy storage to participate in demand response is proposed. Rain flow counting method is used to research the life of hybrid energy storage system, which improves the accuracy of energy storage annual cost calculation. In the Simulation and Analysis section, the genetic quantum algorithm is used for simulation and analysis of the role and benefits of hybrid energy storage. The simulation results show that the benefit of hybrid energy storage in capacity expansion construction is increased by 10.4%, and when the electricity and gas prices fluctuate by ±20%, the hybrid energy storage configuration proposed in this paper has a stable advantage in more than 95%.

Preservative Effect of Newbouldia laevis (Boundary Tree) Leaf Extract on Shelf-Life of Fresh Chicken Meat under Tropical Conditions

The shelf life of chicken meat has been rapidly reduced as a result of high environmental temperatures prevalent in the tropics which favored the activities of spoilage micro-organisms, and reactive oxygen species that function in oxidative damage. Newbouldia laevis (N. laevis) possess valuable antioxidant and antibacterial properties. However, information on the effect of aqueous extracts of dry and wet leaves of N. laevis on preservation of fresh chicken meat under tropical condition is scanty and thus, investigated. Broiler chicken meat (10kg weight) was obtained immediately after slaughter and were randomly allotted to three treatments (T1- control; T2- aqueous extract of wet leaves of N. laevis; and T3- aqueous extract of dry leaves of N. laevis) in a Randomized Complete Block Design. Tropical plant, such as Newbouldia laevis with relatively high resistance to heat stress, possesses viable bioactive compounds that can lower the growth of spoilage micro-organisms and activities of reactive oxygen species on fresh chicken meat under tropical conditions for 48 hours. Hence, poultry farmers in developing nations with fluctuating power supply can adopt the quick meat shelf life enhancement technique, while commercial poultry farmers across the globe can embark on product fortification using extracts of Newbouldia laevis.

Reducing Fluctuations in Slow-Extraction Beam Spill Using Transit-Time-Dependent Tune Modulation

Slow extraction of beam from synchrotrons or storage rings as required by many fixed target experiments is performed by controlled excitation and feeding of a structural lattice resonance. Due to the sensitive nature of this resonant extraction process, the temporal structure of the extracted beam is modulated by the minuscule current fluctuations present on the quadrupole magnet power supplies. Such a modulation lead to pile-ups in detectors and a significant reduction in accumulated event statistics. This contribution proposes and experimentally demonstrates that by an introduction of further modulation on quadrupole currents with a specific amplitude and frequency, the inherent power supply fluctuations are mitigated leading to a smoothening of the beam temporal structure. The slow extraction beam dynamics associated with this method are explained along with the operational results.

A Versatile Design of Low Power and High-Speed Operational Amplifier using Nano Scale Transistors

This paper illustrates the design of low power and high-speed operational Amplifier using Nanoscale Transistors. The proposed design introduces biasing block, for generating I=10uA for Channel length=180nm Technology. Adding biasing block to two-stages operational Amplifier current is constant i.e. there are no fluctuations in power supply, increase in bandwidth and power dissipation is less as compared the previous result. The design is simulated in p-spice tool and performed AC analysis. After analysis, the design achieved the parameter like Gain = 40db, Phase Margin=90º, Unity Gain Band Width=13MHz, Output Swing=0.1v to 1.7v and Power Dissipation=0.145mW.

Research on ADRC of Double Buck Inverter

The traditional double buck full bridge inverter adopts the hysteresis current control mode, and the current is in the half cycle. Because of its no bridge arm through, high voltage utilization and high efficiency, it is widely used. Based on the disturbance caused by power supply fluctuation, external noise and system parameter change, this paper proposes an auto disturbance rejection control (ADRC) strategy. The simulation results show that the ADRC strategy can make the double buck full bridge inverter have good waveform tracking performance, good robustness, stability and high accuracy.

Sizing and Allocation of Battery Energy Storage Systems in Åland Islands for Large-Scale Integration of Renewables and Electric Ferry Charging Stations

The stringent emission rules set by international maritime organisation and European Directives force ships and harbours to constrain their environmental pollution within certain targets and enable them to employ renewable energy sources. To this end, harbour grids are shifting towards renewable energy sources to cope with the growing demand for an onshore power supply and battery-charging stations for modern ships. However, it is necessary to accurately size and locate battery energy storage systems for any operational harbour grid to compensate the fluctuating power supply from renewable energy sources as well as meet the predicted maximum load demand without expanding the power capacities of transmission lines. In this paper, the equivalent circuit battery model of nickel–cobalt–manganese-oxide chemistry has been utilised for the sizing of a lithium-ion battery energy storage system, considering all the parameters affecting its performance. A battery cell model has been developed in the Matlab/Simulink platform, and subsequently an algorithm has been developed for the design of an appropriate size of lithium-ion battery energy storage systems. The developed algorithm has been applied by considering real data of a harbour grid in the Åland Islands, and the simulation results validate that the sizes and locations of battery energy storage systems are accurate enough for the harbour grid in the Åland Islands to meet the predicted maximum load demand of multiple new electric ferry charging stations for the years 2022 and 2030. Moreover, integrating battery energy storage systems with renewables helps to increase the reliability and defer capital cost investments of upgrading the ratings of transmission lines and other electrical equipment in the Åland Islands grid.

Research and Simulation of DC Microgrid Three-Phase AC-DC Converter Control Strategy Based on Double Loop

The new voltage and current double loop control strategy is proposed to solve the DC microgrid bus voltage fluctuation caused by loads fluctuation, parameters perturbation and unbalanced three-phase power supply. Firstly, the $dq$ axis mathematical model of three-phase AC-DC bidirectional converter in DC microgrid is analyzed and established, and then the controllers are designed according to the $dq$ axis mathematical model. The outer loop is a voltage loop based on variable gain linear extended state observer (VGLESO) and sliding mode theory. VGLESO can not only effectively overcome the problem of peak output of traditional high-gain LESO in the initial stage of operation, and ensure that the system has good startup characteristics, but also quickly track and compensate the total disturbance of the system without additional current sensors. The inner loop is a current loop based on adaptive PI, which can eliminate the influence of system parameters perturbation on bus voltage and improve the system’s adaptability. Under the action of the inner and outer loops, the system has good dynamic and static characteristics. Finally, the feasibility and correctness of the control strategy are verified by Matlab/Simulink.

Oxygen Evolution Reaction of Titanium Oxide-Based Materials with and without Doping in Alkaline Solution

Introduction Water electrolysis technology has paid attention to recent developing with Power-to-gas (PtG). Especially, technologies of alkaline water electrolysis (AWE) is one of essential component for PtG. Ni of the AWE anode is already reported that it is afraid to occur the degradation by the fluctuating power produced from renewable energy1, so that it should be required alternative anode with high durability. From our previous research, it was found that group 4, 5 transition metal oxides has catalytic activity for not only oxygen reduction reaction2 but also oxygen evolution reaction (OER) in alkaline solution3. In this study, we have focused on the titanium oxide-based material4 and the catalytic activity and durability of Ti oxide-based electrocatalyst with and without doping for the OER have investigated in the alkaline solution. Experimental Four types of TiOx doping with 1 mol% of Zr, Ce, and Ta (Zr-TiOx, Ce-TiOx, and Ta-TiOx as shown in the following section) and without doping were prepared under oxygen starvation atmosphere, and then formed as rod shape (φ = 5.0 mm, Toshima manufacturing Co., Ltd.). Electrochemical measurements were performed at 30 ± 0.5°C using a TiOx rod described in above, reversible hydrogen electrode (RHE) and glassy carbon plate as working, reference and counter electrodes in a three-electrode cell filled with 7 mol dm-3 KOH solution. After the pretreatment, cyclic voltammetry (CV) was carried out for the scan rate of 50 mV s-1, and the electric double layer capacity was calculated from the current data. In order to evaluate the catalytic activity for the OER, slow scan voltammetry (SSV) was performed in the potential range of 1.2 to 2.0 V for the scan rate of 5 mV s-1. For the simulation durability of fluctuation power supply, the potential cycling was performed for 5000 cycles with 500 mV s-1 in the range of 0 to 2.0 V by triangular wave, and then SSV measurement was demonstrated to evaluate the OER activity of TiOx samples. Results and discussion Each electrical resistivity of the sample was around 1 to 5 Ω cm, and no significant difference was observed depending on the presence or absence of doping other elements. In addition, although the resistance after electrochemical measurement has increased for all samples, the order of magnitude has not changed. Fig. 1 shows Tafel plots of OER on TiOx before the potential cycling test. The vertical axis uses the pseudo current density, i*, that was normalized by the electric double layer capacity. Since Tafel region of each sample was observed from 1.5 to 1.6 V, Tafel slope was calculated in range of these potential. In addition, the i* at 1.6 V was used as an index to estimate the OER activity in this study. The i* at 1.6 V of Zr-TiOx was 1.4×10-1 A F-1 and it was higher than that of initial TiOx of 3.9×10-2 A F-1. The Tafel slope of Zr-TiOx was 94 mV dec-1 while that of TiOx was 203 mV dec-1. As a result, the OER activity was improved by doping with Zr. In the case of Ce-TiOx and Ta-TiOx, both i*s at 1.6 V was similar to that of TiOx, and no significant change of Tafel slope were observed. According to both results, the effect of doping Ce and Ta was not found. The durability of sample was evaluated by the comparison between initial OER activity and that after potential cycling. We also used i* at 1.6 V as an index of OER activity. The i* at 1.6 V after potential cycling was obtained as following; TiOx: 2.7 × 10-2 A F-1, Zr-TiOx : 6.3 × 10-2 A F-1; Ce-TiOx : 6.1 ×10-3 A F-1, Ta-TiOx : 1.3 ×10-2 A F-1. The reduction rate from the initial activity was 31% for TiOx, 55% for Zr-TiOx, 74% for Ce-TiOx, and 47% for Ta-TiOx, respectively. Acknowledgment This work is partially supported by Toyota Mobility Foundation and the Suzuki Foundation. References 1) H. Ichikawa. K. Matsuzawa, Y. Kohno, I. Nagashima, Y. Sunada, Y. Nishiki, A. Manabe, and S. Mitsushima, ECS Trans., 58 (33), 9 (2014). 2) K. Matsuzawa, A. Ishihara, Y. Kohno, K. Ota, S. Mitsushima, and G. Jerkiewicz, Abst. 65th Annual Meeting of ISE, s04-001, Lausanne, Switzerland (2014). 3) A. Oishi, K. Matsuzawa, Y. Kohno, A. Ishihara, and S. Mitsushima, Abst. ECS 228th Meeting, #1890, Phoenix, Az (2015). 4) R. Suzuki, K. Matsuzawa, and A. Ishihara, Proc. 38th Meeting of Hydro. Ener. Sys. Soc. Jpn, p.95 (2018) (in Japanese). Figure 1

Parameters for Stability of Reconfigurable Memory and 6T SRAM Cell

As the technology is improving, channel length of MOSFET is scaling down. In this environment stability of SRAM becomes the major concern for future technology. Static noise margin (SNM) plays a vital role in stability of SRAM. This paper gives an introduction to the reconfigurable memory and 6T SRAM cell. It includes the implementation, characterization and analysis of reconfigurable memory cell and its comparison with the conventional 6T SRAM cell for various parameters like read margin, write margin, data retention voltage, temperature and power supply fluctuations and depending upon these analysis we find SNM for 6T and 8T SRAM cell. The tool used for simulation purpose is IC Station by Mentor Graphics using 350nm technology at supply voltage of 2.5volts.

Modeling and control of DC microgrid system based on hydrogen production load

For the intermittent output of wind turbine and photovoltaic power, aming at the problem of abandoning wind and abandoning light, this paper proposes a DC microgrid system model and control strategy based on hydrogen production load. The DC microgrid system consists of a permanent magnet direct drive wind power system, a photovoltaic power generation system, a buffer energy storage system and an alkaline water electrolysis cell hydrogen production load. The hydrogen production load can adapt to the intermittent fluctuation power supply, make better use of the abandoned wind and light power and be environmentally friendly. Both wind power system and photovoltaic power generation system adopt MPPT control. The battery buffer energy storage device adopts constant voltage charge and discharge control. They are all controlled by their own converters to the DC bus, by producting hydrogen to store the unstable electrical energy generated by distributed generation in the DC microgrid. Based on Matlab/Simulink, results show that the system operates flexibly, the control strategy adopted by the system can maintain the stable operation and load of the system under various power fluctuations and different power supply combinations.