scholarly journals Review of Control Strategies for DC Nano-Grid

2021 ◽  
Vol 9 ◽  
Author(s):  
Hong Fan ◽  
Weinan Yu ◽  
Shiwei Xia
Keyword(s):  
Cooperative Control ◽  
Control Strategies ◽  
High Reliability ◽  
Renewable Energy Sources ◽  
Current Control ◽  
Power Sharing ◽  
Research Progress ◽  
Control Technology ◽  
Advantages And Disadvantages ◽  
Control Technologies

As an emerging energy management technology, the DC nano-grid coordinates renewable energy sources output through demand-side management which would provide more options and flexibility for the dispatch of smart buildings and communities with high reliability and efficiency. In this context, this article has analyzed the structure and components of the DC nano-grid. The role and components in DC nano-grid are reviewed in this article. Then the crucial control technologies for the DC nano-grid in recent years are investigated from two aspects: local control and coordinated control, which contains control schemes such as voltage/current control technology, power-sharing technology and cooperative control technology. Different control strategies at various levels are compared and their application scenarios, advantages and disadvantages are also analyzed. The current research progress and challenges are summarized at the end of this article.

scholarly journals The State of the Art of the Control Strategies for Single-Phase Electric Springs

2018 ◽  
Vol 8 (11) ◽  
pp. 2019 ◽  
Author(s):  
Qingsong Wang ◽  
Panhong Chen ◽  
Fujin Deng ◽  
Ming Cheng ◽  
Giuseppe Buja
Keyword(s):  
Power Generation ◽  
Critical Loads ◽  
Single Phase ◽  
Reactive Power ◽  
State Of The Art ◽  
Control Strategies ◽  
Renewable Energy Sources ◽  
Advantages And Disadvantages ◽  
Load Demand ◽  
Active And Reactive Power

The concept of electric springs (ESs) has been proposed as a new solution for stabilizing power grid fed by intermittent renewable energy sources. With a battery or active power source (DC, on the inside), the ESs can provide both active and reactive power compensations. So far, three typical topologies of single-phase ESs have been reported. Unlike traditional devices where power generation follows the load demand, the ESs are associated with non-critical loads form the so-called smart loads that transfer the fluctuated power to the non-critical loads, adaptively, according to the intermittent nature of power generation. After reviewing the main control strategies of single-phase ESs, the paper analyzes their advantages and disadvantages as well as their suitable applications. Comparisons among different control strategies on a specific topology version are implemented. Finally, conclusions and possible future trends are pointed out.

scholarly journals A Cooperative Control Scheme for AC/DC Hybrid Autonomous Microgrids

Processes ◽  
2020 ◽  
Vol 8 (3) ◽  
pp. 311 ◽  
Author(s):  
Wanxing Sheng ◽  
Yinqiu Hong ◽  
Ming Wu ◽  
Yu Ji
Keyword(s):  
Cooperative Control ◽  
Control Strategies ◽  
Power Sharing ◽  
Secondary Control ◽  
Hybrid Microgrid ◽  
Bidirectional Converter ◽  
Global Power ◽  
Control Scheme ◽  
Droop Characteristic ◽  
High Flexibility

The AC/DC hybrid microgrid (MG) has been widely promoted due to its high flexibility. The capability to operate in islanding mode is an appealing advantage of the MG, and also sets higher requirements for its control system. A droop control strategy is proposed on account of its distinguishing feature of automatic power sharing between distributed generations (DGs), but it introduces some drawbacks. Therefore, distributed cooperative secondary control is introduced as an improvement. In order to optimize the active power sharing in AC/DC hybrid microgrids, a number of cooperative control strategies have been proposed. However, most studies of AC/DC hybrid microgrids have mainly focused on the control of the bidirectional converter, ignoring the effects of secondary control within subnets, which may make a difference to the droop characteristic. This paper extends the cooperative control to AC/DC hybrid microgrids based on normalizing and synthesizing the droop equations, and proposes a global cooperative control scheme for AC/DC autonomous hybrid microgrids, realizing voltage restoration within AC and DC subnets as well as accurate global power sharing. Ultimately, the simulation results demonstrate that the proposed control scheme has a favorable performance in the test AC/DC hybrid system.

scholarly journals A Comprehensive Motivation of Multilayer Control Levels for Microgrids: Synchronization, Voltage and Frequency Restoration Perspective

2020 ◽  
Vol 10 (23) ◽  
pp. 8355
Author(s):  
Ronald Jackson ◽  
Shamsul Aizam Zulkifli ◽  
Mohamed Benbouzid ◽  
Suriana Salimin ◽  
Mubashir Hayat Khan ◽  
...  
Keyword(s):  
Control Method ◽  
Control Strategies ◽  
Renewable Energy Sources ◽  
Hierarchical Control ◽  
Control Level ◽  
Point Of View ◽  
Power Sharing ◽  
Grid Synchronization ◽  
Future Prediction ◽  
And Control

The current paradigm in integrating intermittent renewable energy sources into microgrids presents various technical challenges in terms of reliable operation and control. This paper performs a comprehensive justification of microgrid trends in dominant control strategies. It covers multilayer hierarchical control schemes, which are able to integrate seamlessly with coordinated control strategies. A general overview of the hierarchical control family that includes primary, secondary, tertiary controls is presented. For power sharing accuracy and capability, droop and non-droop-based controllers are comprehensively studied to address further development. The voltage and frequency restoration techniques are discussed thoroughly based on centralized and decentralized method in order to highlights the differences for better comprehend. The comprehensive studies of grid synchronization strategies also overviewed and analyzed under balanced and unbalanced grid conditions. The details studies for each control level are displayed to highlight the benefits and shortcomings of each control method. A future prediction from the authors’ point of view is also provided to acknowledge which control is adequate to be adopted in proportion to their products applications and a possibility technique for self-synchronization is given in this paper.

scholarly journals Grid-forming control strategies for black start by offshore wind power plants

2020 ◽  
Vol 5 (4) ◽  
pp. 1297-1313 ◽  
Author(s):  
Anubhav Jain ◽  
Jayachandra N. Sakamuri ◽  
Nicolaos A. Cutululis
Keyword(s):  
Power System ◽  
Wind Power ◽  
Power Plants ◽  
Large Scale ◽  
Control Strategies ◽  
Renewable Energy Sources ◽  
Stability Limit ◽  
Offshore Wind ◽  
Advantages And Disadvantages ◽  
Wind Power Plants

Abstract. Large-scale integration of renewable energy sources with power-electronic converters is pushing the power system closer to its dynamic stability limit. This has increased the risk of wide-area blackouts. Thus, the changing generation profile in the power system necessitates the use of alternate sources of energy such as wind power plants, to provide black-start services in the future. However, this requires grid-forming and not the traditionally prevalent grid-following wind turbines. This paper introduces the general working principle of grid-forming control and examines four of such control schemes. To compare their performance, a simulation study has been carried out for the different stages of energization of onshore load by a high-voltage direct-current (HVDC)-connected wind power plant. Their transient behaviour during transformer inrush, converter pre-charging and de-blocking, and onshore block-load pickup has been compared and analysed qualitatively to highlight the advantages and disadvantages of each control strategy.

Comparison of Acid Gas Control Technologies in EFW Facilities

2010 ◽  
Author(s):  
Craig Kedrowski ◽  
Donald Hug ◽  
Reudi Frey ◽  
Adrian Kaspar
Keyword(s):  
Packed Bed ◽  
Control Technology ◽  
Air Pollution Control ◽  
Acid Gas ◽  
Advantages And Disadvantages ◽  
The World ◽  
Emission Regulation ◽  
Gas Control ◽  
Cost Efficient ◽  
Control Technologies

As Energy-from-Waste (EfW) facilities make the leap into the twenty-first (21st) century, so does the demand for cost efficient air pollution control technology. In an effort to meet this rising demand, companies have to develop concepts that remove acid gases in an efficient, sustainable, and reliable way. The current market trend to provide the best available control technology (BACT) leads people searching for technologies that are: • Proven and have extensive records of success. • Highly efficient, resulting in low emission to the atmosphere, but requiring minimal investment. • Compact in design, simple, and low maintenance. • Offering high availability, low reagent consumption, and low residue levels. • Resulting in either clean or suppressed liquid effluents. This paper will specifically discuss the three main types of acid gas control technologies available in today’s marketplace, which include dry, semi-dry, and wet scrubbers. It will first focus on the acid gas control technology most commonly used in the US, the spray dryer absorber, followed by a typical Ring Jet® wet scrubber with packed bed, and finally, the Turbosorp® system. For each of the above technologies, this paper will present the concepts, advantages and disadvantages, achievable emissions, and capital and operating costs. It will then look at how each of these technologies is utilized at existing EfW facilities operating throughout the world and provide information on how each facility has been operating. Lastly, it will look towards the future of acid gas control technologies and provide insight into what advances are being made to meet the most stringent air emission regulation all over the world.

scholarly journals Structural Improvements in Consensus-Based Cooperative Control of DC Microgrids

Electronics ◽  
2019 ◽  
Vol 8 (2) ◽  
pp. 187 ◽  
Author(s):  
Muhammad Adnan Mumtaz ◽  
Muhammad Mansoor khan ◽  
Xiangzhong Fang ◽  
Muhammad Umair Shahid ◽  
Muhammad Talib Faiz
Keyword(s):  
Cooperative Control ◽  
Voltage Regulation ◽  
Current Control ◽  
Power Sharing ◽  
System Stability ◽  
Control Loop ◽  
Dc Microgrid ◽  
Dc Microgrids ◽  
The Stability ◽  
Finite Gain

This study is dedicated to establishing a comparative analysis of the performance ofdifferent local controllers on the cooperative control of DC microgrids. One of the elementary andchallenging issues in DC microgrids is the assurance of fairness in proportional current sharingwhile accomplishing voltage regulation in parallelly connected distributed energy sources. In thiswork, structural improvements are proposed to enhance the system stability and controlperformance. A finite-gain controller was employed in the outer voltage control loop with a simpleproportional (P) controller in the inner current control loop of a converter. Due to the finite-gaincontroller, droop-like power sharing was achieved without droop coefficient. In order to furtherenhance the power-sharing accuracy and DC voltage regulation, a different method was adopted inconsensus-based cooperative control to estimate the average current and average voltage difference.Moreover, small signal analysis was used to scrutinize the stability and control performance of thelocal controller, while different communication delays and current disturbances were applied toexamine the performance of the controller. Finally, a four-node-based DC microgrid setup wasdeveloped in MATLAB/Simulink environment, and simulation results of the proposed and existingtechniques were scrutinized. The simulations results demonstrated the effectiveness of the proposedcontroller.

scholarly journals Combating mosquito-borne diseases using genetic control technologies

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Guan-Hong Wang ◽  
Stephanie Gamez ◽  
Robyn R. Raban ◽  
John M. Marshall ◽  
Luke Alphey ◽  
...  
Keyword(s):  
Disease Burden ◽  
Genome Engineering ◽  
Mosquito Control ◽  
Control Strategies ◽  
Current Control ◽  
Transmission Risk ◽  
Control Methods ◽  
Control Technologies ◽  
Health Burdens ◽  
Gene Drives

AbstractMosquito-borne diseases, such as dengue and malaria, pose significant global health burdens. Unfortunately, current control methods based on insecticides and environmental maintenance have fallen short of eliminating the disease burden. Scalable, deployable, genetic-based solutions are sought to reduce the transmission risk of these diseases. Pathogen-blocking Wolbachia bacteria, or genome engineering-based mosquito control strategies including gene drives have been developed to address these problems, both requiring the release of modified mosquitoes into the environment. Here, we review the latest developments, notable similarities, and critical distinctions between these promising technologies and discuss their future applications for mosquito-borne disease control.

Recent Patents on Valve Mechanism Device

2020 ◽  
Vol 13 (3) ◽  
pp. 230-241
Author(s):  
Ye Dai ◽  
Hui-Bing Zhang ◽  
Yun-Shan Qi
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Flow Direction ◽  
Research Progress ◽  
Valve Mechanism ◽  
Advantages And Disadvantages ◽  
Valve Structure ◽  
Valve Leakage ◽  
Safety And Reliability

Background: Valves are an important part of nuclear power plants and are the control equipment used in nuclear power plants. It can change the cross-section of the passage and the flow direction of the medium and has the functions of diversion, cutoff, overflow, and the like. Due to the earthquake, the valve leaks, which will cause a major nuclear accident, endangering people's lives and safety. Objective: The purpose of this study is to synthesize the existing valve devices, summarize and analyze the advantages and disadvantages of various devices from many literatures and patents, and solve some problems of existing valves. Methods: This article summarizes various patents of nuclear-grade valve devices and recent research progress. From the valve structure device, transmission device, a detection device, and finally to the valve test, the advantages and disadvantages of the valve are comprehensively analyzed. Results: By summarizing the characteristics of a large number of valve devices, and analyzing some problems existing in the valves, the outlook for the research and design of nuclear power valves was made, and the planning of the national nuclear power strategic goals and energy security were planned. Conclusion: Valve damage can cause serious safety accidents. The most common is valve leakage. Therefore, the safety and reliability of valves must be taken seriously. By improving the transmission of the valve, the problems of complicated valve structure and high cost are solved.

scholarly journals Phylogenetic Complexity of Morphologically Identified Anopheles squamosus in Southern Zambia

Insects ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 146
Author(s):  
Jordan Hoffman ◽  
Ilinca Ciubotariu ◽  
Limonty Simubali ◽  
Twig Mudenda ◽  
William Moss ◽  
...  
Keyword(s):  
Phylogenetic Relationships ◽  
Catchment Area ◽  
Control Strategies ◽  
Light Trap ◽  
Current Control ◽  
Control Measures ◽  
Morphological Identification ◽  
The Past ◽  
Blood Meal Source ◽  
Residual Malaria Transmission

Despite dramatic reductions in malaria cases in the catchment area of Macha Hospital, Choma District, Southern Province in Zambia, prevalence has remained near 1–2% by RDT for the past several years. To investigate residual malaria transmission in the area, this study focuses on the relative abundance, foraging behavior, and phylogenetic relationships of Anopheles squamosus specimens. In 2011, higher than expected rates of anthropophily were observed among “zoophilic” An. squamosus, a species that had sporadically been found to contain Plasmodium falciparum sporozoites. The importance of An. squamosus in the region was reaffirmed in 2016 when P. falciparum sporozoites were detected in numerous An. squamosus specimens. This study analyzed Centers for Disease Control (CDC) light trap collections of adult mosquitoes from two collection schemes: one performed as part of a reactive-test-and-treat program and the second performed along a geographical transect. Morphological identification, molecular verification of anopheline species, and blood meal source were determined on individual samples. Data from these collections supported earlier studies demonstrating An. squamosus to be primarily exophagic and zoophilic, allowing them to evade current control measures. The phylogenetic relationships generated from the specimens in this study illustrate the existence of well supported clade structure among An. squamosus specimens, which further emphasizes the importance of molecular identification of vectors. The primarily exophagic behavior of An. squamosus in these collections also highlights that indoor vector control strategies will not be sufficient for elimination of malaria in southern Zambia.

scholarly journals Home Energy Management for Community Microgrids Using Optimal Power Sharing Algorithm

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 1060
Author(s):  
Md Mamun Ur Rashid ◽  
Majed A. Alotaibi ◽  
Abdul Hasib Chowdhury ◽  
Muaz Rahman ◽  
Md. Shafiul Alam ◽  
...  
Keyword(s):  
Energy Storage ◽  
Real Time ◽  
Energy Management ◽  
Cost Minimization ◽  
Renewable Energy Sources ◽  
Storage System ◽  
Power Sharing ◽  
Optimal Power ◽  
Time Operation ◽  
Home Energy Management

From a residential point of view, home energy management (HEM) is an essential requirement in order to diminish peak demand and utility tariffs. The integration of renewable energy sources (RESs) together with battery energy storage systems (BESSs) and central battery storage system (CBSS) may promote energy and cost minimization. However, proper home appliance scheduling along with energy storage options is essential to significantly decrease the energy consumption profile and overall expenditure in real-time operation. This paper proposes a cost-effective HEM scheme in the microgrid framework to promote curtailing of energy usage and relevant utility tariff considering both energy storage and renewable sources integration. Usually, the household appliances have different runtime preferences and duration of operation based on user demand. This work considers a simulator designed in the C++ platform to address the domestic customer’s HEM issue based on usages priorities. The positive aspects of merging RESs, BESSs, and CBSSs with the proposed optimal power sharing algorithm (OPSA) are evaluated by considering three distinct case scenarios. Comprehensive analysis of each scenario considering the real-time scheduling of home appliances is conducted to substantiate the efficacy of the outlined energy and cost mitigation schemes. The results obtained demonstrate the effectiveness of the proposed algorithm to enable energy and cost savings up to 37.5% and 45% in comparison to the prevailing methodology.

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