Design and control of grid connected inverter for harmonic suppression

2020 ◽  
Vol 18 (5) ◽  
pp. 1349-1356
Author(s):  
Congliang Fei ◽  
Pengfei Xiahou ◽  
Fujun Wang
Keyword(s):  
Design Methodology ◽  
Harmonic Distortion ◽  
Pi Control ◽  
Harmonic Suppression ◽  
Test Results ◽  
Current Waveform ◽  
Content Type ◽  
Simulation And Experiment ◽  
Grid Connected Inverter ◽  
And Control

Purpose This study aims to focus on the grid connected inverter. Design/methodology/approach The grid connected inverter for harmonic suppression was designed, the topological structure of the inverter and the design of LCL filter were analyzed, then a PIR controller was proposed and finally simulation and experiment were carried out. Findings The simulation results showed that the distortion rates of the 5th, 7th and 11th harmonics under PIR control were 0.14%, 0.13% and 0.06%, respectively, which were significantly lower than that under PI control. The system test results also showed that the current waveform under PI control was rough and total harmonic distortion (THD) content was 3.8%; under PIR control, the grid connected current waveform was relatively smooth, with fewer spikes and burrs, and the THD content was 1.9%, indicating that the harmonics were effectively suppressed. Originality/value The experimental results verify that the inverter and PIR controller designed in this study are effective for harmonic suppression. This work makes some contributions to the improvement of the effect of harmonic suppression and promotion of the better application of grid connected inverter.

G-GERT network model of online public opinion reversal based on kernel and grey degree

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Shuli Yan ◽  
Xiangyan Zeng ◽  
Pingping Xiong ◽  
Na Zhang
Keyword(s):  
Public Opinion ◽  
Network Model ◽  
Design Methodology ◽  
Average Frequency ◽  
Decision Makers ◽  
Content Type ◽  
Gert Network ◽  
Frequency Probability ◽  
And Control ◽  
Difficult Issue

PurposeIn recent years, online public opinion reversal incidents have been occurring frequently, which has increased the complexity of the evolution of online public opinion, and they have become a difficult issue for public opinion management and control. It is of great significance to explore the regularity of online public opinion reversal.Design/methodology/approachCombined with the grey characteristics of online public opinion information, a grey graphical evaluation review technique (G-GERT) network model is constructed based on kernel and grey degree, and the frequency, probability and time of online public opinion reversal nodes are calculated using C-marking method and Z-marking method.FindingsThroughout the online public opinion reversal events, there are all repeated outbreak nodes occurring, so the authors regard the repeated occurrence of outbreak nodes as reversal. According to the average frequency, probability and time of repeated outbreak nodes in the G-GERT network model, the authors predict the corresponding key information of reversal. It can simulate the evolution process of public opinion events accurately.Originality/valueThe G-GERT network model based on kernel and grey degree reveals the regulation of public opinion reversal, predicts the frequency, probability and time of reversal nodes, which are the most concerned and difficult issues for decision-makers. The model provides the decision basis and reference for government decision-making departments.

Harmonic suppression of LCL grid-connected inverter based on PI control

2021 ◽  
Author(s):  
Hao Hou ◽  
Shengguo Zhang ◽  
Jiawei Yang ◽  
Weiwen Hu
Keyword(s):  
Pi Control ◽  
Harmonic Suppression ◽  
Grid Connected Inverter

Hong Kong’s response to COVID-19: a glance to the control measures and their enforcement

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Ka Ki Lawrence Ho ◽  
Ying-Tung Chan
Keyword(s):  
Hong Kong ◽  
Infection Rate ◽  
Government Policy ◽  
Design Methodology ◽  
Control Measures ◽  
Content Type ◽  
The Government ◽  
And Control ◽  
Viral Outbreak

Purpose This study aims to examine Hong Kong’s responses to COVID-19, arguing that Hong Kong’s relatively low infection rate is due to self-discipline of citizens together with the enforcement measures introduced by the government. Design/methodology/approach This study reviewed the government policy announcements and the prevailing scholarly analyses on Hong Kong society during COVID-19. Findings It starts by examining the partial lockdown and control measures since mid-January, and the roles of different government units in enforcement were examined and assessed. Suppression of viral outbreak in Hong Kong should primarily be attributed to the appropriate lockdown and quarantine actions of the government. Originality/value However, outperformance of the frontline professionals and the highly aware, self-disciplined and mutually aided citizens in the community are also the key to the “interim success” by June 2020 in the highly accessible and densely populated city.

scholarly journals Evaluation and control of opinion polarization and disagreement: a review

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Yuejiang Li ◽  
Hong Zhao
Keyword(s):  
Design Methodology ◽  
Crucial Importance ◽  
Content Type ◽  
Recent Advances ◽  
And Control

Purpose The purpose of this paper is to review the recent studies on opinion polarization and disagreement. Design/methodology/approach In this work, recent advances in opinion polarization and disagreement and pay attention to how they are evaluated and controlled are reviewed. Findings In literature, three metrics: polarization, disagreement and polarization-disagreement index are usually adopted and there is a tradeoff between polarization and disagreement. Different strategies have been proposed in literature which can significantly control opinion polarization and disagreement based on these metrics. Originality/value This review is of crucial importance to summarize works on opinion polarization and disagreement and to the better understanding and control of them.

Spaces of performance: a storytelling approach to learning in higher education

2018 ◽  
Vol 25 (6) ◽  
pp. 410-421 ◽  
Author(s):  
Kenneth Mølbjerg Jørgensen
Keyword(s):  
Higher Education ◽  
Learning Organization ◽  
Design Methodology ◽  
Theoretical Discussion ◽  
Content Type ◽  
Approach To Learning ◽  
Conditions For Learning ◽  
Research And Teaching ◽  
And Control ◽  
Practical Implications

Purpose The purpose of the paper is to provide a framework for reflecting on how different ways of configuring spaces in higher education (HE) condition the possibilities of learning. Second, the purpose is to construct a storytelling approach for the configuration of such spaces. Design/methodology/approach The paper’s conceptual purpose is achieved through a theoretical discussion of three concepts: performance, politics and storytelling. Findings Learning in HE needs reconsideration in terms of what kinds of learning are made possible through the discursive and material configuration of the spaces of research and teaching. In particular, the focus to some extent should move away from the management and control of learning toward what enables learning. Practical implications The literature on organizational learning and the learning organization comprise concepts, methods and tools that play different roles with regard to controlling, shaping and enabling learning. When the focus is on learning in HE, it is important to be aware of the tracks of learning these technologies enable. Social implications The interest in managing and controlling learning is often problematic in relation to the potential of HE to produce new and innovative forms of learning. Originality/value This paper introduces the term “spaces of performance,” which directs attention toward the material, discursive and relational conditions for learning. It also introduces a space of storytelling as a new principle for learning in HE.

scholarly journals Composite Control Strategy of Output Current of LCL Photovoltaic Grid-Connected Inverter

2021 ◽  
Vol 2136 (1) ◽  
pp. 012015
Author(s):  
Shengqing Li ◽  
Xinluo Li ◽  
Qiang Wu ◽  
Xiafei Long
Keyword(s):  
Control Strategy ◽  
Block Diagram ◽  
Harmonic Distortion ◽  
Harmonic Suppression ◽  
Output Current ◽  
Control Block ◽  
Current Harmonics ◽  
Suppression Effect ◽  
Composite Control ◽  
Grid Connected Inverter

Abstract In order to further optimize the output current harmonic suppression effect of photovoltaic grid-connected inverters, a composite control strategy of LCL type photovoltaic grid-connected inverter output current is proposed. This strategy combines proportional complex integral (PCI) control and repetitive control (RC) in parallel, draws a composite control block diagram, introduces a transfer function, and designs PCI and RC control parameters. Prove that the compound control can reduce current harmonics, achieved the purpose of reducing the steady-state error of the fundamental frequency. And adopts a new PCI composite control strategy, which helps to save the cost of the control system. By building the MATLAB/Simulink simulation platform and establishing the PCI+RC composite control model of LCL photovoltaic grid-connected inverter, the comparison of the simulation results shows that compared with the PI+RC control strategy, the total harmonic distortion rate of the grid-connected current is reduced by 25.77. %, significantly improving the quality of grid-connected current.

Impact of AI regulation on intention to use robots

2019 ◽  
Vol 8 (2) ◽  
pp. 97-114
Author(s):  
Sheshadri Chatterjee
Keyword(s):  
Quality Of Life ◽  
Artificial Intelligence ◽  
Design Methodology ◽  
Regulatory Control ◽  
Control Beliefs ◽  
Intention To Use ◽  
Content Type ◽  
And Control ◽  
The Impact

Purpose The purpose of this paper is to identify the factors influencing the citizens to use robots that would improve the quality of life of the citizens. Design/methodology/approach With the help of different adoption theories and models and with the support of background studies, some hypotheses have been formulated and a conceptual model has been developed with the consideration of the impact of artificial intelligence regulation (IAR) that controls the use of robots as a moderator. The model has been validated and the hypotheses have been tested by statistical analysis with the help of survey works involving consideration of feedbacks from 503 usable respondents. Findings The study reveals that the use of robots by the citizens would appreciably increase if government imposes strict artificial intelligence (AI) regulatory control concerning the use of robots, and in that case, it appears that the use of robots would improve the quality of life of the citizens. Research limitations/implications The duly validated model would help the authority to appropriately nurse and nurture the factors such as ethical dilemma, perceived risks and control beliefs for enhancing the intention of the citizens to use robots for many purposes including domestic usage in the context of appropriate restrictions imposed through AI regulation. Such use of robots would eventually improve the quality of life. Originality/value There are a few studies covering analysis of IAR as a moderator on the linkages of the predictors with the intention of the citizens to use robots. In this context, this study is claimed to have offered a novel contribution.

In-flight reconfiguration of lithium-ion cells aimed at extending flight times and range of electrically powered UAVs

2019 ◽  
Vol 7 (3) ◽  
pp. 98-111 ◽  
Author(s):  
Svetoslav Zabunov ◽  
Garo Mardirossian
Keyword(s):  
Design Methodology ◽  
Lithium Ion ◽  
Test Results ◽  
Content Type ◽  
Test Setup ◽  
Lithium Ion Cells ◽  
Battery Design ◽  
Novel Design ◽  
Battery Module

Purpose The purpose of this paper is to disclose a novel reconfiguration battery design suitable for electrically powered UAVs. Design/methodology/approach A design of a reconfigurable battery module is presented. Test setup with prototype battery module is developed and described. Test results of measurements are shown and discussed. Findings The results ascertain the benefits of implementing a reconfigurable battery in small electrically powered UAVs and specifically prove the efficiency of the proposed design. Originality/value The proposed novel design is compared to previous work while advances from the latter and the gained advantages were established.

scholarly journals Enhancing cognitive and entrepreneurship competencies through EBL

2019 ◽  
Vol 4 (2) ◽  
pp. 280-292
Author(s):  
Kholilah ◽  
Vega Wafaretta ◽  
Dian Syariati
Keyword(s):  
Cognitive Abilities ◽  
Design Methodology ◽  
Industrial Revolution ◽  
Content Type ◽  
Whitney Test ◽  
Entrepreneurial Skills ◽  
Learning Challenges ◽  
The World ◽  
Student Center ◽  
And Control

Purpose Entrepreneurship-based learning (EBL) is one of the student-center learningmethods that can answer learning challenges in the era of industrial revolution 4.0. EBL is expected to improve students’ competencies and make students more adaptable to the changes in the world of work in the future. The paper aims to discuss this issue. Design/methodology/approach This study uses quasi-experiments and divides classes into project class and control class. The project consists of making business proposals, conducting business, liquidating the partnership, and recording business transaction using the Xero platform. The Wilcoxon Signed Ranks Test, Mann–Whitney Test and independent t-test were carried out to test whether there are differences of cognitive abilities and entrepreneurial (general, social and functional) competencies between the project class and control class. Findings The results of the study shows there are differences of understanding of partnership accounting and the achievement of social and functional entrepreneurial competencies between the project class and control class. Research limitations/implications This study implies in using EBL to improve entrepreneurial skills for students beyond cognitive abilities. Originality/value The novelty of this research is the implementation of EBL in partnership accounting topics.

Operating performance of acquirers after acquisition: evidence from India

2019 ◽  
Vol 12 (3) ◽  
pp. 327-341
Author(s):  
Bipin Kumar Dixit
Keyword(s):  
Design Methodology ◽  
Operating Performance ◽  
Difference In Difference ◽  
Return On Assets ◽  
Content Type ◽  
Acquisition Period ◽  
Acquiring Firms ◽  
Book To Market Ratio ◽  
Matching Criteria ◽  
And Control

Purpose The purpose of this paper is to examine the operating performance of Indian using difference-in-difference (DD) methodology. It, further, examines whether there is a difference in the operating performance of acquirers doing partial and full acquisitions. Design/methodology/approach Four different benchmark criteria are used to select control firms, namely, size, size and industry, size and leverage, and size and book-to-market ratio. To measure the operating performance, return on assets (ROA) is calculated as the ratio between earnings before depreciation, interest, tax and amortization (EBDITA) and total assets (TA), expressed in percentage. This paper examines the ROA of event and control firms for three years in each pre- and post-acquisition period and finally compares them using the DD method. Findings Using a sample of Indian acquirers, the results show that the operating performance of Indian acquirers neither improves nor deteriorates after accounting for an appropriate benchmark. Operating performance of event firms significantly reduces in the post-acquisition period. However, non-acquiring firms of similar size and pre-operating performance also exhibit similar results. Finally results show that, the operating performance of acquirers making full acquisitions deteriorates. Originality/value It provides insights into the operating performance of Indian acquirers with an improved methodology, which accounts for the performance of control firms. The author also uses multiple matching criteria to find control firms to overcome the possible bias of the results dependent on the matching criteria. To the best of the author’s knowledge, the author could not find other studies comparing the operating performance of acquirers making partial and full acquisitions.

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