13,668 research outputs found
A novel high-voltage gain step-up DC–DC converter with maximum power point tracker for solar photovoltaic systems
In order to generate electricity from solar PV modules, this study proposed a novel high-voltage gain step-up (HVGSU) DC–DC converter for solar photovoltaic system operation with a maximum power point (MPP) tracker. The PV array can supply power to the load via a DC–DC converter, increasing the output voltage. Due to the stochastic nature of solar energy, PV arrays must use the MPPT control approach to function at the MPP. This study suggests a novel HVGSU converter that uses the primary boost conversion cell and combines switched capacitors and voltage multiplier cells. The proposed topology is upgradeable for high-voltage gain step-up and can be incorporated as well. A clamp circuit reuses the energy that leaks out so that the switch voltage stress and power loss are kept to a minimum. One thing that makes it stand out is that the voltage stress on the diodes and switch stays low and constant even as the duty cycle changes. Additionally, the inductor greatly reduces the diodes’ reverse recovery losses. There is a lot of information about steady-state analyses, operation principles, and design guidelines. A prototype circuit is built to test the maximum power point tracking operation with voltage conversion from 20–40 V to 380 V at 150 W. The results of the experiments support the theoretical analysis and claimed benefits. The proposed converter has the ability to track the maximum power point and a high conversion efficiency over a wide range of power. A weighted efficiency of 90–96% is shown by the prototype
Control-mode as a Grid Service in Software-defined Power Grids: GFL vs GFM
In power systems with high penetration of power electronics, grid-forming
control is proposed to replace traditional Grid-Following Converter (GFL) in
order to improve the overall system strength and resist small-signal
instability in weak grids by directly forming the terminal voltage. However,
sufficient headroom of both active and reactive power must be made available
for Grid-Forming Converter (GFM) to operate, potentially leading to sub-optimal
operation in steady states. This presents a new research problem to optimally
allocate between GFM and GFL to balance the ability of GFMs to improve the grid
strength and the potential economic loss resulting from reserved headroom. An
optimization framework under software-defined grids is proposed, for the first
time, to dynamically determine the optimal allocation of GFMs and GFLs in power
systems at each time step of system scheduling according to system conditions,
which ensures both system stability and minimum operational cost. To achieve
this, the system scheduling model is expanded to simultaneously consider the
constraints related to active and reactive power reserves for GFMs, as well as
the system level stability. Case studies conducted on the modified IEEE 30-bus
system demonstrate significant economic benefits in that the optimal proportion
of GFMs in the power system can be dynamically determined while ensuring power
reserve and grid stability constraints
Livelihood Information Endowment as a Correlate of Material Quality of Life among Rural Women in Southwest, Nigeria
This study examined the livelihood information endowment (LIE) as a correlate of Material Quality of life (MQoL) among rural Women in Southwest Nigeria. Multistage sampling procedure was used to select 384 respondents using interview schedule. Data collected on socioeconomic characteristics, LIE (livelihood information sought and sources of information); constraints to LIE and MQoL were analysed with percentages, weighted mean score, mean, standard deviation, Pearson Product Moment Correlation and Chi-square at ?0.05. Result showed that most of the respondents were cooperative society members (51.6%) with mean year of former education being 8.0±4.62 years. The mostly accessible information source was Radio (1.43); with LIE being high for 55.7%. However, respondents’ most prominent constraint to LIE was network problem (0.40); which was high for 53.4%. The respondents’ MQoL status was low for 52.1%, as most did not possess landed properties (58.1%); with the most material possessed compared with peers being kitchen utensils (0.90). Significant relationship existed between respondents’ MQoL and years of experience of non-agricultural activities (r=0.137), LIE (r=0.134), social group belonged (r=0.153), cosmopoliteness (?2=2229.870) and constraint to LIE (r=-0.017). Constraints to LIE inform the respondents’ MQoL status. Therefore, appropriate strategies to combat constraints to the LIE should be embarked on
Detail or uncertainty? Applying global sensitivity analysis to strike a balance in energy system models
Energy systems modellers often resort to simplified system representations and deterministic model formulations (i.e., not considering uncertainty) to preserve computational tractability. However, reduced levels of detail and neglected uncertainties can both lead to sub-optimal system designs. Herein, we present a novel method that quantitatively compares the impact of detail and uncertainty to guide model development and help prioritisation of the limited computational resources. By considering modelling choices as an additional ‘uncertain’ parameter in a global sensitivity analysis, the method determines their qualitative ranking against conventional input parameters. As a case study, the method is applied to a peer-reviewed heat decarbonisation model for the United Kingdom with the objective of assessing the importance of spatial resolution. The results show that while for the optimal total system cost the impact of spatial resolution is negligible, it is the most important factor determining the capacities of electricity, gas and heat networks
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A Survey of Quantum-Cognitively Inspired Sentiment Analysis Models
Quantum theory, originally proposed as a physical theory to describe the motions of microscopic particles, has been applied to various non-physics domains involving human cognition and decision-making that are inherently uncertain and exhibit certain non-classical, quantum-like characteristics. Sentiment analysis is a typical example of such domains. In the last few years, by leveraging the modeling power of quantum probability (a non-classical probability stemming from quantum mechanics methodology) and deep neural networks, a range of novel quantum-cognitively inspired models for sentiment analysis have emerged and performed well. This survey presents a timely overview of the latest developments in this fascinating cross-disciplinary area. We first provide a background of quantum probability and quantum cognition at a theoretical level, analyzing their advantages over classical theories in modeling the cognitive aspects of sentiment analysis. Then, recent quantum-cognitively inspired models are introduced and discussed in detail, focusing on how they approach the key challenges of the sentiment analysis task. Finally, we discuss the limitations of the current research and highlight future research directions
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Assessment of Voltage Fluctuations for Battery Storage Systems Providing Frequency Response Services †
† This paper Is an extended version of our paper published in IEEE.Data Availability Statement: No new data were created.This article belongs to the Special Issue Advances in Electrical Power Engineering—Selected Papers from 57th International Universities Power Engineering Conference (UPEC2022)Copyright © 2023 by the authors. This paper investigates voltage fluctuations caused by the operation of battery energy storage (BES) units which provide frequency response (FR) and fast frequency response (FFR) services using a test network based on a typical part of the United Kingdom (UK) mainland system. This paper provides an overview of current FR/FFR services currently used in the UK, and a summary of their typical modes of operation. Using DIgSILENT Powerfactory, the paper introduces a simple frequency disturbance generator to mimic typical frequency disturbances that would occur in the UK network, and then subsequently uses a representative test distribution network to show how voltage disturbances associated with BES units can develop across the electrical network. The paper provides a contribution to knowledge by creating a systematic approach for assessing voltage disturbance and flicker concerns for BES units on island networks, using a simple control algorithm and novel frequency disturbance generator.This research received no external funding
Proceedings of the 10th International Scientific-Practical Conference “Formation of the mechanism of national economic systems competitive positions strengthening in global, regional and local dimensions”
Розвиток соціально-економічних систем мікро-, мезо- і макрорівня: конфлікт традиційних моделей та економічних реалій 21 століття
Особливості інтеграції держави, бізнесу, науки, освіти в умовах цифровізації суспільства
Роль і потенціал вітчизняного підприємництва у розвитку економічно стійкої держави
Сучасний розвиток фінансового ринку України: можливості, виклики, загрози
Інновації у глобальній біржовій сфері та банківській діяльності
Страховий ринок України – каталізатор чи стримувач прогресивних змін у вітчизняній економічній системі?
Економічно ефективна торгівля: розуміння суті та сучасні підходи до її ведення
Майбутнє конкурентоспроможності: розумне управління, розумні території, розумний бізнес
Трансформація бізнес-процесів у контексті сталого розвитк
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Modeling, Oscillation Analysis and Distributed Stabilization Control of Autonomous PV-based Microgrids
Driven by rising energy demand and the goal of carbon neutrality, renewable energy generations (REGs), especially photovoltaic (PV) generations, are widely used in the urban power energy systems. While the intelligent control of microgrids (MG) brings economic and efficient operation, its potential stability problem cannot be ignored. To date, most of the research on modeling, analyzing and enhancing the stability of MG usually assume the DC-link as an ideal voltage source. However, this practice of ignoring the dynamics of DC-link may omit the latent oscillation phenomena of autonomous PV-based MG. First, this paper establishes a complete dynamic model of autonomous PV-based MG including PV panels and DC-link. Different from previous conclusions of idealizing DC-link dynamics, participation factor analysis finds the potential impact of DC-link dynamics on system dynamic performance, and different influence factors including critical control parameters and non-linear V-I output characteristic of PV array are considered to further reveal oscillation mechanisms. Second, based on the average consensus algorithm, a distributed stabilization controller with strong robustness is proposed to enhance stability of the PV-based MG, which does not affect the steady-state performance of the system. Finally, the correctness of all theoretical analysis and the effectiveness of the proposed controller are verified by time domain simulation and hardware-in-loop tests.10.13039/501100001809-National Natural Science Foundation of China (Grant Number: 51907031
Architecture and Advanced Electronics Pathways Toward Highly Adaptive Energy- Efficient Computing
With the explosion of the number of compute nodes, the bottleneck of future computing systems lies in the network architecture connecting the nodes. Addressing the bottleneck requires replacing current backplane-based network topologies. We propose to revolutionize computing electronics by realizing embedded optical waveguides for onboard networking and wireless chip-to-chip links at 200-GHz carrier frequency connecting neighboring boards in a rack. The control of novel rate-adaptive optical and mm-wave transceivers needs tight interlinking with the system software for runtime resource management
Design of One-Phase Inverter Using EGS002 with SPWM
The more advanced the development of the technological world in Indonesia, the needs of the community in the use of electrical energy are also higher so that an alternative tool is needed that can produce a voltage source such as PLN. In this thesis, a 1-phase inverter will be designed that can produce output in the form of an AC voltage of 220 volts with a frequency of 50 Hz and has a good feedback voltage so that the inverter output voltage can be stable at an AC voltage value of 220 volts. The 1-phase inverter is made using a full bridge inverter circuit, the SPWM (sinusoidal pulse width modulation) signal is generated using EGS002 by ASIC (Application Specific Integreted Circuit), and the voltage correction transformer used has a maximum working power of 600 watts. According to the results of the no-load test the 1-phase inverter can produce an AC voltage on the output side of 220 to 230 volts with 50 Hz frequencys and the results of the load test show that the inverter has a good feedback voltage so that even when the input voltage drops, the inverter output voltage value is still above 220 volts
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