• Title/Summary/Keyword: impedance characteristics

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Analysis of Energy Conversion Efficiency in Micro Power Generation using Vibrating Piezoelectric Cantilever (압전빔의 진동을 이용한 마이크로 동력원의 에너지 변환 해석)

  • Lee, Heon-Ju;Chang, Young-Soo;Lee, Yoon-Pyo
    • Proceedings of the KSME Conference
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    • 2007.05b
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    • pp.3365-3370
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    • 2007
  • We developed micro power generation system using piezoelectric materials. In our system, the ambient vibrating energy is converting to electric energy by deflection of piezoelectric beams. The system consists of energy generating parts, converting enhancement parts, electric regulation and charging parts, and interface with small-energy-consuming mobile devices. The geometry of piezoelectric beams, the source of vibrating energy, and the electric load of target application determine the characteristics of generating electric power, such as impedance, voltage, current and power density. Therefore, we made a model for analysis of generating power with given information such as piezoelectric materials, geometry, vibration type, and mass. With this model, we can calculate capacitance of piezoelectric beams, generating voltage, current, and power. To obtain maximum energy transfer efficiency, we approached this study in the view of material, electrical, and mechanical engineering

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Modified Wilkinson Power Divider for Multiple Harmonics Suppression

  • Kang In-Ho;Xu Hai-Yan
    • Journal of Navigation and Port Research
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    • v.29 no.7
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    • pp.615-618
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    • 2005
  • A new structure of the Wilkinson power divider that can suppress multiple harmonics output is presented The power divider consists of T-type or $\pi$-type capacitive loads and shunt resistors. Experimental results show that this power divider suppresses the second and the third harmonic components to less than -38dB, while maintaining the characteristics of a conventional Wilkinson power divider, featuring an equal power split, a simultaneous impedance matching at all ports and a good isolation between output ports.

Synthesis and Electrochemical Characterization of Polypyrrole/Multi-walled Carbon Nanotube Composite Electrodes for Supercapacitor Applications

  • Paul, Santhosh;Lee, Yoon-Sung;Choi, Ji-Ae;Kang, Yun-Chan;Kim, Dong-Won
    • Bulletin of the Korean Chemical Society
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    • v.31 no.5
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    • pp.1228-1232
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    • 2010
  • The nanocomposites of polypyrrole (PPy) and multi-walled carbon nanotube (MWCNT) with different composition are synthesized by the chemical oxidative polymerization method. In these composites, the MWCNTs are uniformly coated by PPy with different thickness. The electrochemical properties of the composite electrodes are investigated by cyclic voltammetry, galvanostatic charge-discharge cycling and electrochemical impedance spectroscopy. The full cells assembled with the PPy/MWCNT composite electrodes deliver initial specific capacitances ranging from 146.3 to 167.2 F/g at 0.5 mA/$cm^2$ and exhibit stable cycling characteristics. The effect of content of MWCNT in the composite on cycling performance of the cells is also investigated.

High-Frequency Analysis Modeling of Hybrid Vehicle Battery (하이브리드 자동차 배터리의 고주파 해석 모델링)

  • Lee, Jae-Joong;Lee, June-Sang;Kim, Mi-Ro;Kweon, Hyck-Su;Nah, Wan-Soo
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.61 no.2
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    • pp.263-269
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    • 2012
  • In order to present that the electromagnetic compatibility standards following the frequency goes up which is based automotive electronics, in this paper, a hybrid/electric vehicle battery which reflects the frequency of the equivalent circuit model is introduced. By using this circuit modeling, the impedance characteristics can be analysed and an analyze of battery one cell is finished. Using this model, each different from the discharging situation, the discharge characteristic curve could be led. Basic theoretical approaches and measuring results through MATLAB and experimental validation of the EIS measurement equipment was used.

Active Microstrip Antenna for Mobile Communication

  • Nakasuwan, J.;Rakluea, P.;Songthanapituk, N.
    • 제어로봇시스템학회:학술대회논문집
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    • 2004.08a
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    • pp.28-31
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    • 2004
  • This paper describe analysis active microstrip antenna with low noise amplifier at 900 MHz for mobile communication. The microstrip patch antenna is integrated with low noise amplifier on a permittivity 4.5 (Epoxy-FR4) and thickness of substrate 1.6 mm. Low noise amplifier is designed by using GaAs FETs. The analysis characteristics of antenna include return loss, input impedance, vswr, radiation pattarn, bandwidth and gain of antenna. Mesurement gain of antenna is shown 19.2435 dBi.

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High-Speed Signaling in SDARM Bus Interface Channels : Review

  • Park, Hong-June;Sohn, Young-Soo;Park, Jin-Seok;Bae, Seung-Jun;Park, Seok-Woo
    • JSTS:Journal of Semiconductor Technology and Science
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    • v.1 no.1
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    • pp.50-69
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    • 2001
  • Three kinds of high-speed signaling methods for synchronous DRAM (SDRAM) bus interface channels (PC-133, Direct-Rambus, and SSTL-2) were analyzed in terms of the timing budget and the physical transmission characteristics. To analyze the SDRAM bus interface channels, loss mechanisms and the effective characteristic impedance method were reviewed and the ABCD matrix method was proposed as an analytic and yet accurate method. SPICE simulations were done to get the AC responses and the eye patterns of the three SDRAM bus interface channels for performance comparisons. Recent progress and future trend for SDRAM bus interface standards were reviewed.

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Voltage Estimation Method for Distribution Line with Irregularly Dispersed Load (부하가 불규칙하게 분포된 배전선로의 전압추정 방법)

  • Park, Sanghyeon;Lim, Seongil
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.67 no.4
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    • pp.491-497
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    • 2018
  • Most of the applications for distribution system operation highly rely on the voltage and current managements from the field devices. Voltage from the remote controlled switch contains unacceptably large measurement error due to the nonlinear characteristics of the bushing potential transformer. This paper proposes a new voltage magnitude estimation method by calculating voltage drop using current measurement, line impedance and loads deployment data. Contract demand power and pole transformer capacity managed by NDIS are used as a key element to improve accuracy of the proposed method. Various case studies using Matlab simulation have been performed to verify feasibility of the propose voltage estimation method.

Structural Characterization and Dielectric Studies of Superparamagnetic Iron Oxide Nanoparticles

  • Sivakumar, D.;Naidu, K. Chandra Babu;Nazeer, K. Prem;Rafi, M. Mohamed;kumar, G. Ramesh;Sathyaseelan, B.;Killivalavan, G.;Begam, A. Ayisha
    • Journal of the Korean Ceramic Society
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    • v.55 no.3
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    • pp.230-238
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    • 2018
  • Superparamagnetic iron oxide nanoparticles (SPIONs) have been prepared without using surfactants to assess their stability at different time intervals. The synthesized particles were characterized by X-ray diffraction, Fourier-transform infrared spectroscopy, ultraviolet-visible-near infrared spectroscopy, and energy dispersive spectroscopy. Field emission scanning electron microscopy and high-resolution transmission electron microscopy images of the samples were also investigated. The average particle size was measured to be 12.7 nm even in the polydispersed form. The magnetic and dielectric characteristics of the $Fe_3O_4$ nanoparticles have also been studied and discussed in detail.

Compact-Size Fractal Antenna with Stable Radiation Properties for Wi-Fi and WiMAX Communications

  • Abed, Amer T.;Singh, Mandeep S.J.;Islam, Mohammad Tariqul
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.12 no.6
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    • pp.2734-2747
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    • 2018
  • In this study, a novel fractal ring antenna with a compact size of $24{\times}9{\times}0.8mm^3$ was configured using three iterations. Low profile, circular polarization, and measured operating bands (4.5-6.5 GHz) meet specifications of the upper band used in Wi-Fi and WiMAX applications. The antenna featured, stable radiation properties, especially gain and efficiency, in the notched band (92%). In deep, the antenna impedance, reflection coefficients, surface current distribution and circular polarization for the three iterations had been studied to improve the process of antenna design and its radiation characteristics.

A Study On the Output Voltage and Power Factor of the Three-Phase Four Switches Z-Source PWM Rectifier (3상 4 스위치 Z-소스 PWM정류기의 출력전압과 역률에 관한 연구)

  • Qiu, Xiao-Dong;Eom, Jun-Hyun;Jung, Young-Gook;Lim, Young-Cheol
    • Proceedings of the KIPE Conference
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    • 2013.11a
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    • pp.48-49
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    • 2013
  • In this paper, the four switches three-phase Z-source rectifier is studied. The conventional three-phase four switches rectifier can only either perform buck or boost operation, distortion and unbalance of the input current are serious. Therefore, we proposed the four switches three-phase Z-source rectifier which can realize buck function simply by applying the Z-impedance network. We will verify characteristics of Z-network by the simulation and experiment.

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