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Sag and Flicker Reduction Using Hysteresis-Fuzzy Control-Based SMES Unit

Canadian Journal of electrical and computer engineering 2019年第1期42卷 52-57页

作者： Yunus, A. M. Shiddiq Habriansyah, Imran Abu-Siada, Ahmed Masoum, Mohammad A.S. Energy Conversion Study Program Mechanical Engineering Department State Polytechnic of Ujung Pandang Makassar90245 Indonesia Mechatronics Study Program Mechanical Engineering Department State Polytechnic of Ujung Pandang Makassar90245 Indonesia Electrical and Computer Engineering Department University of Curtin University BentleyWA6102 United States Department of Engineering Utah Valley University OremUT84058 United States

The issue of power quality is one of the prominent factors in determining the reliability of power systems. It is inevitable to consider power quality issues and include appropriate mitigation techniques in the design of any future power system project construction. Voltage sag and flicker are the two most common short disturbance types of power quality issues that frequently occur in power systems. A widely accepted mitigation strategy to enhance the power quality of disturbed networks is by connecting a flexible ac transmission system. In this paper, a superconducting magnetic energy storage (SMES) unit along with hysteresis-fuzzy controller to suppress the severe impacts of voltage sag and flicker events on the power quality of a power system is proposed, implemented, and tested. The proposed SMES configuration with hysteresis current control and fuzzy logic controller is effective, simple, and easy to implement. Simulation results show the ability of the proposed SMES controller in compensating sag and/or flicker distortions. © 2003-2010 IEEE Canada.

关键词： Power quality

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Computational Performance of a LES Solver for Supersonic Jet Flow Applications

arXiv

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arXiv 2023年

作者： Junqueira-Junior, Carlos Azevedo, João Luiz F. Yamouni, Sami Wolf, William R. Instituto de Aeronáutica e Espaço SP São José dos Campos12228-904 Brazil Instituto Tecnológico de Aeronáutica SP São José dos Campos12228-900 Brazil Universidade Estadual de Campinas SP Campinas13083-970 Brazil Aerodynamics Division Departamento de Ciência e Tecnologia Aeroespacial DCTA/IAE/ALA Brazil Graduate Program on Computer Sciences and Electrical Engineering Departamento de Ciência e Tecnologia Aeroespacial DCTA/ITA Brazil Faculty of Mechanical Engineering

An in-house large eddy simulation tool is developed in order to reproduce high fidelity results of compressible jet flows. The large eddy simulation formulation is written using the finite difference approach, with an explicit time integration and using a second order spatial discretization. The energy equation is carefully discretized in order to model the energy equation of the filtered Navier-Stokes formulation. Such numerical studies are very expensive and demand high performance computing. Message passage interface protocols are implemented into the code in order to perform parallel computations. The present work addresses the computational performance of the solver running on up to 400 processors in parallel. Different mesh configurations, whose size varies from approximately 5.9 million points to approximately 1.0 billion points, are evaluate in the current paper. Speedup and efficiency curves are evaluated in order to assess the strong scalability of the solver. © 2023, CC BY.

关键词： Large eddy simulation

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Development of teaching materials for improving motivation to learn electromagnetics using ict

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IEEJ Transactions on Fundamentals and Materials 2020年第4期140卷 171-178页

作者： Ohtaki, Yu Ohchi, Masashi Master's Program in Electrical Electronics and Computer Engineering Graduate School of Engineering Chiba Institute of Technology 2-17-1 Tsudanuma Narashino275-0016 Japan Department of Electrical and Electronic Engineering Faculty of Engineering Chiba Institute of Technology 2-17-1 Tsudanuma Narashino275-0016 Japan

In this research, we have been developed teaching materials for electromagnetics that demonstrate theories using real-world actual applications (capacitors, coils, piezoelectric elements, Wireless Power Transfer(WPT), WiFi, direct-current motor, etc.) presented as animations and video data via Web services. Hypertext Markup Language (HTML) and JavaScript were used to create the Web services for teaching materials. Recently, the lack of academic ability of Japanese engineering course students has become a large social problem at Japanese higher education. In particular, in the field of electrical engineering education, the visualization and mathematical abilities of students have been declining remarkably. In addition, today's teaching materials for educational institutions in Japan tend to reply primarily on rote learning. However, we consider that rote learning is not the primary method for university education. We tested our new developed materials on students learning motivation of electromagnetics and evaluated their effectiveness with some questionnaires. It was clear that the new teaching method has effectiveness for increasing learning motivation of Electromagnetics. © 2020 The Institute of electrical Engineers of Japan.

关键词： Web services

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Observation of Temporal Reflections and Broadband Frequency Translations at Photonic Time-Interfaces

arXiv

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arXiv 2022年

作者： Moussa, Hady Xu, Gengyu Yin, Shixiong Galiffi, Emanuele Ra'di, Younes Alù, Andrea Photonics Initiative Advanced Science Research Center City University of New York New YorkNY10031 United States Department of Electric Engineering City College of City University of New York New YorkNY10031 United States Department of Electrical Engineering and Computer Science Syracuse University SyracuseNY13244 United States Physics Program Graduate Center City University of New York New YorkNY10016 United States

Time-reflection is a uniform inversion of the temporal evolution of a signal, which arises when an abrupt change in the properties of the host material occurs uniformly in space.1-3 At such a time-interface, a portion of the input signal is time-reversed, and its frequency spectrum is homogeneously translated while its momentum is conserved, forming the temporal counterpart of a spatial interface. Combinations of time-interfaces, forming time-metamaterials and Floquet matter4, exploit the interference of multiple time-reflections for extreme wave manipulation, leveraging time as a new degree of freedom5. Here, we report the observation of photonic time-reflection and associated broadband frequency translation in a switched transmission-line metamaterial whose effective capacitance is homogeneously and abruptly changed via a synchronized array of switches. A pair of temporal interfaces are combined to demonstrate time-reflection-induced wave interference, realizing the temporal counterpart of a Fabry-Perot cavity6. Our results establish the foundational building blocks to realize time-metamaterials and Floquet photonic crystals, with opportunities for extreme photon manipulation in space and time7-8 © 2022, CC BY.

关键词： Metamaterials

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Set-theoretic detection of data corruption attacks on cyber physical power systems

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Journal of Modern Power Systems and Clean Energy 2018年第5期6卷 872-886页

作者： Efstathios KONTOURAS Anthony TZES Leonidas DRITSAS Electrical and Computer Engineering Department University of Patras Electrical and Computer Engineering Program New York University Abu Dhabi Department of Electrical and Electronic Engineering Educators School of Pedagogical and Technological EducationASPETE 14121 Athens Greece

This paper addresses a set-theoretic method for the detection of data corruption cyber-attacks on the load frequency control loop of a networked power system. The system consists of several interconnected control areas forming a power grid. Based on the overall discrete-time network dynamics, a convex and compact polyhedral robust invariant set is extracted and is used as a set-induced anomaly detector. If the state vector exits the invariant set,then an alarm will be activated, and the potential threat is considered disclosed. The attack scenario used to assess the efficiency of the proposed anomaly detector concerns corrupted frequency sensor measurements transmitted to the automatic generation control unit of a compromised control area. Simulation studies highlight the ability of a set-theoretic approach to disclose persistent and intermittent attack patterns even when they occur at the same time with changes in the power load demand.

关键词： Power systems Load frequency control Cyber-attacks Set-theoretic methods

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Voltage Levels and Reactive Power in Distribution Networks with High Integration of Distributed Photovoltaic Generation

Voltage Levels and Reactive Power in Distribution Networks w...

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2019 IEEE PES Conference on Innovative Smart Grid Technologies, ISGT Latin America 2019

作者： Darui, Caroline B. F. Lucca, Tiago G. Abaide, Alzenira Da R. Da Veiga, Matheus F. Da Cruz, Matheus S. Knak Neto, Nelson Wüst, Lucas L. Figueiró, Iuri C. Federal University of Santa Maria Graduate Program in Electrical Engineering Santa Maria Brazil URI Santo Ângelo Department of Engineering and Computer Science Santo Ângelo Brazil

ISBN: (纸本)9781538695678

The Brazilian electrical system is undergoing many changes due to the exponential growth of photovoltaic systems connected to the grid (PV). This increase may affect power quality parameters, such as reduction of power factor and increase of voltage levels. This work aims to model and simulate a low voltage distribution network with high levels of integration of PV systems in order to verify how the voltage and reactive parameters behave in these cases. It was used new load curve models, the Monte Carlo method and the OpenDSS software. © 2019 IEEE.

关键词： Monte Carlo methods

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Nematoelasticity of hybrid molecular-colloidal liquid crystals

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Physical Review E 2021年第1期104卷 014703-014703页

作者： B. Senyuk H. Mundoor I. I. Smalyukh H. H. Wensink Department of Physics University of Colorado Boulder Colorado 80309 USA Department of Electrical Computer and Energy Engineering Materials Science and Engineering Program and Soft Materials Research Center University of Colorado Boulder Colorado 80309 USA Chemical Physics Program Departments of Chemistry and Physics University of Colorado Boulder Colorado 80309 USA Renewable and Sustainable Energy Institute National Renewable Energy Laboratory and University of Colorado Boulder Colorado 80309 USA Laboratoire de Physique des Solides Université Paris-Saclay & CNRS UMR 8502 91405 Orsay France

Colloidal rods immersed in a thermotropic liquid-crystalline solvent are at the basis of so-called hybrid liquid crystals, which are characterized by tunable nematic fluidity with symmetries ranging from conventional uniaxial nematic or antinematic to orthorhombic [Mundoor et al., Science 360, 768 (2018)]. We provide a theoretical analysis of the elastic moduli of such systems by considering interactions between the individual rods with the embedding solvent through surface-anchoring forces, as well as steric and electrostatic interactions between the rods themselves. For uniaxial systems, the presence of colloidal rods generates a marked increase of the splay elasticity, which we found to be in quantitative agreement with experimental measurements. For orthorhombic hybrid liquid crystals, we provide estimates of all 12 elastic moduli and show that only a small subset of those elastic constants play a relevant role in describing the nematoelastic properties. The complexity and possibilities related to identifying the elastic moduli in experiments are briefly discussed.

关键词： Biaxial liquid crystals Liquid crystals

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Unique material modifications of Ga2O3 enabled by ultrafast laser irradiation 11

Unique material modifications of Ga2O3 enabled by ultrafast ...

引用

Oxide-based Materials and Devices XI 2020

作者： Ahn, Minhyung Sarracino, Alex Ansari, Abdul Torralva, Ben Yalisove, Steven Phillips, Jamie Department of Electrical Engineering and Computer Science University of Michigan Ann ArborMI48109 United States Applied Physics Program University of Michigan Ann ArborMI48109 United States Department of Climate and Space Sciences and Engineering University of Michigan Ann ArborMI48109 United States Materials Science and Engineering Department University of Michigan Ann ArborMI48109 United States

ISBN: (纸本)9781510633254

Ultrafast (femtosecond pulse) laser irradiation provides unique laser-material interactions associated with high instantaneous electric fields and short timescales that lead to a nonequilibrium state between excited electrons and phonons. These interactions result in material modifications that differ from conventional chemical, physical, and thermal processing at much longer timescales, and an opportunity to address material and device processing challenges associated with wide-bandgap materials such as Ga2O3. In this work, we explore ultrafast laser irradiation (Ti:sapphire, 150 fs pulse width) of bulk (010) Sn-doped β-Ga2O3 under two different wavelengths, fundamental (780 nm) and frequency-doubled (390 nm), and a range of laser fluences. We identified a regime for laser-induced damage threshold resulting in material ablation, thermally-induced straight crack formation, and recrystallization. Rastering on a β-Ga2O3 substrate created surface nanostructures including laser-induced periodic surface structures at a high spatial frequency (period ∼250 nm). These highly aligned periodic structures can be controlled by laser polarization and wavelength, presenting a means for direct writing of surface nanostructures. Enhanced atomic movement associated with a transient metallic state can provide a means for intentional generation of point defects via the laser irradiation. These point defects may offer a means of electrical modification, which was demonstrated as more than five orders of the magnitude enhancement of lateral conductance on rastered β-Ga2O3. Moreover, a hydrophobic surface of β-Ga2O3was achieved by ultrafast laser irradiation. © COPYRIGHT SPIE. Downloading of the abstract is permitted for personal use only.

关键词： Hydrophobicity

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A Light Weight Multi-Head SSD Model For ADAS Applications

A Light Weight Multi-Head SSD Model For ADAS Applications

引用

Pervasive Artificial Intelligence (ICPAI), International Conference on

作者： Chun-Yu Lai Bo-Xun Wu Tsung-Han Lee Vinay Malligere Shivanna Jiun-In Guo National Chiao Tung University Hsinchu Taiwan College Doctoral Program of Electrical and Computer Engineering National Chiao Tung University Hsinchu Taiwan

ISBN: (数字)9781665404839

ISBN: (纸本)9781665404846

Moving objects detection is considered as one of the prime safety indicators in the Advanced Driver Assistance System (ADAS). For implementing on resource-limited embedded platforms and still yield sufficient frame rate and quality, the paper proposes a lightweight multi-head single shot detector (SSD) model that strengthens the moving object detection significantly. The paper also introduces focal loss method to deal with imbalance problem of detecting pedestrians and bikes in training datasets (vehicles, bikes, and pedestrians). Lastly, the proposed lightweight network can be deployed on low-power embedded devices to achieve real-time processing performance (512x256) yielding 30fps.

关键词： Conferences Artificial intelligence

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Spatial atlas of the mouse central nervous system at molecular resolution (vol 622, pg 552, 2023)

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NATURE 2024年第7993期625卷 E6-E6页

作者： Shi, Hailing He, Yichun Zhou, Yiming Huang, Jiahao Maher, Kamal Wang, Brandon Tang, Zefang Luo, Shuchen Tan, Peng Wu, Morgan Lin, Zuwan Ren, Jingyi Thapa, Yaman Tang, Xin Chan, Ken Y. Deverman, Benjamin E. Shen, Hao Liu, Albert Liu, Jia Wang, Xiao Broad Institute of MIT and Harvard Cambridge MA USA Department of Chemistry Massachusetts Institute of Technology Cambridge MA USA John A. Paulson School of Engineering and Applied Sciences Harvard University Boston MA USA Computational and Systems Biology PhD Program Massachusetts Institute of Technology Cambridge MA USA Department of Electrical Engineering and Computer Science Massachusetts Institute of Technology Cambridge MA USA Department of Biology Massachusetts Institute of Technology Cambridge MA USA Klarman Cell Observatory Broad Institute of MIT and Harvard Cambridge MA USA Department of Chemistry and Chemical Biology Harvard University Cambridge MA USA Stanley Center for Psychiatric Research Broad Institute of MIT and Harvard Cambridge MA USA

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