• Title/Summary/Keyword: Fundamental Circuit

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Incremental Passivity Based Control for DC-DC Boost Converters under Time-Varying Disturbances via a Generalized Proportional Integral Observer

  • He, Wei;Li, Shihua;Yang, Jun;Wang, Zuo
    • Journal of Power Electronics
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    • v.18 no.1
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    • pp.147-159
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    • 2018
  • In this paper, the voltage tracking control of a conventional DC-DC boost converter affected by unknown, time-varying circuit parameter perturbations is investigated. Based on the fundamental property of incremental passivity, a passivity based control law is designed. Then, to obtain a better disturbance rejection property, two generalized proportional integral (GPI) observers are employed to estimate the time-varying uncertainties in the output voltage and inductor current channels, and the estimated values are applied as feedforward compensation. Moreover, the global trajectory tracking performance of a system with disturbances is ensured under the composite controller. Finally, simulation and experiment studies are provided to demonstrate the feasibility and effectiveness of the proposed method. The results show that the proposed controller delivers a promising disturbance rejection capability as well as a good nominal tracking performance.

Estimation of Fault Location on Transmission Lines using Current Phasor (전류 페이저를 이용한 송전선로 고장점 추정 알고리즘)

  • Yeo, Sang-Min;Kim, Chul-Hwan
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.58 no.11
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    • pp.2095-2100
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    • 2009
  • Since most of the Extra High Voltage (EHV) transmission lines are untransposed and multi-circuits, errors are occurred inevitably because of the unbalanced impedances of the lines and so on. Therefore, a distance relaying algorithm applicable to the untransposed multi-circuits transmission lines needs to be developed. The proposed algorithm of fault location estimation in the paper uses the fundamental phasor to reduce the effects of the harmonics. This algorithm also analyzes the second-order difference of the phasor to calculate the traveling times of waves generated by faults. The traveling time of the waves generated by faults is derived from the second-order difference of the phasor. Finally, the distance from the relaying point to the faults is estimated using the traveling times. To analyze the performance of the algorithm, a power system with the EHV untransposed double-circuit transmission lines are modeled and simulated under various fault conditions such as several fault types, fault locations, fault inception angles and fault resistances. The results of the simulations show that the proposed algorithm has the capability to estimate the fault locations quickly and accurately.

Real-Time Plasma Process Monitoring with Impedance Analysis and Optical Emission Spectroscopy

  • Jang, Hae-Gyu;Kim, Dae-Kyoung;Kim, Hoon-Bae;Han, Sa-Rum;Chae, Hee-Yeop
    • Proceedings of the Korean Vacuum Society Conference
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    • 2010.02a
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    • pp.473-473
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    • 2010
  • Plasma is widely used in various commercial etchers and chemical vapor deposition. Unfortunately, real-time plasma process monitoring is still difficult. Some methods of plasma diagnosis is improved, however, it is possible for real-time plasma diagnosis to use non-intrusive probe only. In this research, the object is to investigate the suitability of using impedance analysis and optical emission spectroscopy (OES) for real-time plasma process monitoring. It is assumed that plasma system is a equivalent circuit. Therefore, V-I probe is used for measuring impedance, which can be a new non-intrusive probe for plasma diagnosis. From impedance data, we tried to analyse physical properties of plasma. And OES, the other method of plasma diagnosis, is a typical non-intrusive probe for analyzing chemical properties. The amount of the OES data is typically large, so this poses a difficulty in extracting relevant information. To solve this problem, principal component analysis (PCA) can be used. For fundamental information, Ar plasma and $O_2$ plasma are used in this experiment. This method can be applied to real-time endpoint and fault detections.

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Thrust Bearing Design for High-Speed Composite Air Spindles (고속 복합재료 공기 주축부를 위한 추력베어링 설계)

  • Bang, Kyung-Geun;Lee, Dai-Gil
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.26 no.10
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    • pp.1997-2007
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    • 2002
  • Composite air spindles are appropriate for the high-speed and the high-precision machining as small hole drilling of printed circuit board (PCB) or wafer cutting for manufacturing semiconductors because of the low rotational inertia, the high damping ratio and the high fundamental natural frequency of composite shaft. The axial load and stiffness of composite air spindles fur drilling operation are determined by the thrust ben ring composed of the air supply part mounted on the housing and the rotating part mounted on the rotating shaft. At high-speed rotation, the rotating part of the thrust bearing should be designed considering the stresses induced by centrifugal force as well as the axial stiffness and the natural frequency of the rotating shaft to void the shaft from failure due to the centrifugal force and resonant vibration. In this work, the air supply part of the thrust bearing was designed considering the bending stiffness of the bearing and the applied load. The rotating part of the thrust bearing was designed through finite element analysis considering the cutting forces during manufacturing as well as the static and dynamic characteristics under both the axial and con trifugal forces during high-speed rotation.

Identifications and Reduction Methods of Aerodynamic Noise Sources in High Speed Rotating Optical Disk Drive (고속으로 회전하는 광디스크 드라이브의 공력 소음원 규명 및 소음저감방법)

  • Kim, Yong-Seok;Lee, Duck-Joo
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.17 no.6 s.123
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    • pp.477-483
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    • 2007
  • Major noise source in high speed rotating optical disk drives (CD and DVD-ROM) arises due to the high-speed airflow produced from the upper and lower surfaces on the rotating disk. The present paper deals with the experimental approach how to identify the noise source based on the fundamental principles of aeroacoustics and to propose a reduction method of the noise source. The CD-ROM device is composed of disk, window tray, motors at the bottom place and electronic circuit plate also located below the window plate. The window is cut in the tray to read the disk information using the optical device located below the tray and moving linearly from the center of the disk through the end of the disk. All components are possible noise generators. Experimental studies were carried out in the anechoic room with various design modifications, such as tray geometry, window size and hole location on tray, to identify the major aerodynamic noise source and significant reductions of the aerodynamic noise were obtained.

Indices Characterizing Road Network on Geo-Spatial Imagery as Transportation Network Analysis

  • Lee, Ki-Won
    • Korean Journal of Remote Sensing
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    • v.20 no.1
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    • pp.57-64
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    • 2004
  • In GIS-based network analysis, topological measure of network structure can be considered as one of important factors in the urban transportation analysis. Related to this measure, it is known that the connectivity indices such as alpha index and gamma index, which mean degree of network connectivity and complexity on a graph or a circuit, provide fundamental information. On the other hand, shimbel index is one of GIS-based spatial metrics to characterize degree of network concentration. However, the approach using these quantitative indices has not been widely used in practical level yet. In this study, an application program, in complied as extension, running on ArcView- GIS is implemented and demonstrated case examples using basic layers such as road centerline and administrative boundary. In this approach, geo-spatial imagery can be effectively used to actual applications to determine the analysis zone, which is composed of networks to extract these indices. As the results of the implementation and the case examples, it is notified that alpha and gamma indices as well as shimbel index can be used as referential data or auxiliary information for urban planning and transportation planning.

Three-coil Magnetically Coupled Resonant Wireless Power Transfer System with Adjustable-position Intermediate Coil for Stable Transmission Characteristics

  • Chen, Xuling;Chen, Lu;Ye, Weiwei;Zhang, Weipeng
    • Journal of Power Electronics
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    • v.19 no.1
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    • pp.211-219
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    • 2019
  • In magnetically coupled resonant (MCR) wireless power transfer (WPT) systems, the introduction of additional intermediate coils is an effective means of improving transmission characteristics, including output power and transmission efficiency, when the transmission distance is increased. However, the position of intermediate coils in practice influences system performance significantly. In this research, a three-coil MCR WPT system is adopted as an exemplification for determining how the spatial position of coils affects transmission characteristics. With use of the fundamental harmonic analysis method, an equivalent circuit model of the system is built to reveal the relationship between the output power, the transmission efficiency, and the spatial scales, including the axial, lateral, and angular misalignments of the intermediate and receiving coils. Three cases of transmission characteristics versus different spatial scales are evaluated. Results indicate that the system can achieve relatively stable transmission characteristics with deliberate adjustments in the position of the intermediate and receiving coils. A prototype of the three-coil MCR WPT system is built and analyzed, and the experimental results are consistent with those of the theoretical analysis.

Neuroscience and the Social Powers of Narrative: How Stories Configure Our Brains

  • Armstrong, Paul B.
    • Journal of English Language & Literature
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    • v.64 no.1
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    • pp.3-24
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    • 2018
  • Stories are important instruments for configuring our cognitive and social worlds, but they do not necessarily make us more caring or less aggressive and self-involved. The ability to tell and follow a story requires cognitive capacities that are basic to the neurobiology of mental functioning, and so it would stand to reason that our experiences with stories would draw on and re-shape patterns of interaction that extend beyond the immediate experience of reading or listening to a narrative. Our intuitive, bodily-based ability to understand the actions of other people is fundamental to social relations, including the circuit between the representation of a configured action emplotted in a narrative and the reader's or listener's activity of following the story as we assimilate its patterns into the figures that shape our worlds. The activity of following a narrative can have a variety of beneficial or potentially noxious social consequences, either promoting the shared intentionality that neurobiologically oriented cultural anthropologists identify as a unique human capacity supporting culturally productive collaboration, or habitualizing and thereby naturalizing particular patterns of perception into rigid ideological constructs. The doubling of "me" and "not-me" in narrative acts of identification may promote the "we-intentionality" that makes socially beneficial cooperation possible, or it can set off mimetic conflict and various contagion effects. Neuroscience cannot predict what the social consequences of narrative will be, but it can identify the brain- and body-based processes through which (for better or worse) stories exercise social power.

Recent Advances in a-IGZO Thin Film Transistor Devices: A Short Review

  • Jingwen Chen;Fucheng Wang;Yifan Hu;Jaewoong Cho;Yeojin Jeong;Duy Phong Pham;Junsin Yi
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.36 no.5
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    • pp.463-473
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    • 2023
  • In recent years, the transparent amorphous oxide thin film transistor represented by indium-gallium-zinc-oxide (IGZO) has become the first choice of the next generation of integrated circuit control components. This article contributes an overview of IGZO thin-film transistors (TFTs), including their fundamental principles and recent advancements. The paper outlines various TFT structures and places emphasis on the fabrication process of the active layer. The result showed that the size of the active layer including the length-to-width ratio and the width could have a significant effect on the mobility. And the process of TFT could influence the crystal structure of IGZO thin film. Furthermore, the article presents an overview of recent applications of IGZO TFTs, such as their use in display drivers and TFT memories. At last, the future development of IGZO TFT is forecasted in this paper.

A Dynamic Modeling & State Sensitivity Analysis of the Surface Mounting Device (Surface Mounting Device의 동역학적 모델링 및 상태 민감도 해석)

  • Jang, Jinhee;Han, Changsoo;Kim, Jungduck
    • Journal of the Korean Society for Precision Engineering
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    • v.13 no.7
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    • pp.90-99
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    • 1996
  • In the area of assembly process of micro-chips and electronic parts on the printed circuit board, surface mounting device(SMD) is used as a fundamental tool. Generally speaking, the motion of the SMD is based on the ball screw system operated by any type of actuators. The ball screw system is a mechanical transformed which converts the mechanical rotational motion to the translational one. Also, this system could be considered as an efficient motion device against mechanical backlash and friction. Therefore a dynamic modeling and state sensitivity analysis of the ball screw system in SMD have to be done in the initial design stage. In this paper, a simple mathematical dynamic model for this system and the sensit- ivity analysis are mentioned. Especially, the bond graph approach is used for graphical modeling of the dynamic system before analysis stage. And the direct differentiation method is used for the state sensit- ivity analysis of the system. Finally, some trends for the state variables with respect to the design variables could be suggested for the better design and faster operating based on the results of dynamic and state sensitivity.

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