• Title, Summary, Keyword: Equivalent Circuit

Search Result 1,717, Processing Time 0.048 seconds

Investigation of Equivalent Circuit for PEMFC Assessment (고분자 전해질 FC 평가용 등가회로 검토)

  • Myong, Kwang-Jae
    • Transactions of the Korean Society of Mechanical Engineers B
    • /
    • v.35 no.9
    • /
    • pp.897-902
    • /
    • 2011
  • Chemical reactions occurring in a PEMFC are dominated by the physical conditions and interface properties, and the reactions are expressed in terms of impedance. The performance of a PEMFC can be simply diagnosed by examining the impedance because impedance characteristics can be expressed by an equivalent electrical circuit. In this study, the characteristics of a PEMFC are assessed using the AC impedance and various equivalent circuits such as a simple equivalent circuit, equivalent circuit with a CPE, equivalent circuit with two RCs, and equivalent circuit with two CPEs. It was found in this study that the characteristics of a PEMFC could be assessed using impedance and an equivalent circuit, and the accuracy was highest for an equivalent circuit with two CPEs.

Equivalent Circuit Modeling of Rosen-type Multilayer Piezoelectric Transformer (Rosen형 적층 압전변압기의 등가회로 모델링)

  • Shin, Hoon-Beom;Lee, Yong-Kuk;Yu, Young-Han;Ahn, Hyung-Keun;Han, Deuk-Young
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
    • /
    • v.19 no.12
    • /
    • pp.1099-1105
    • /
    • 2006
  • In this paper, the equivalent circuit model of a Rosen-type multilayer piezoelectric transformer(MPT) has been proposed based on the Mason's equivalent circuit model and the principle of single layer piezoelectric plate. From the piezoelectric direct and converse effects, the symbolic expressions between the electric inputs and outputs of the MPT have been derived from the equivalent circuit model. A simplified equivalent circuit model of the MPT whose driving part has a single input form has been proposed. The symbolic expressions of the driving part have been derived from the simplified equivalent circuit model and the model was compared with the multi-input equivalent circuit model through the simulation. In the comparisons between the simulation results and the experimental data, output voltage is 630 Vp-p in case of 11-layered MPT and 670 Vp-p for 13-layered MPT over the experiment range. As the load resistance increases, output voltage increases and saturates over $300k{\Omega}$ and the resonant frequency changes from 102 kHz to 103 kHz. The simulation and the experimental results agree well over different load resistances and frequencies.

Estimation of Equivalent Circuit Parameters of Underwater Acoustic Piezoelectric Transducer for Matching Network Design of Sonar Transmitter (소나 송신기의 정합회로 설계를 위한 수중 음향 압전 트랜스듀서의 등가회로 파라미터 추정)

  • Lee, Jeong-Min;Lee, Byung-Hwa;Baek, Kwang-Ryul
    • Journal of the Korea Institute of Military Science and Technology
    • /
    • v.12 no.3
    • /
    • pp.282-289
    • /
    • 2009
  • This paper presents an estimation technique of the equivalent circuit parameters for an underwater acoustic piezoelectric transducer from the measured impedance. Estimated equivalent circuit can be used for the design of the impedance matching network of the sonar transmitter. A fitness function is proposed to minimize the error between the calculated impedance of the equivalent circuit and the measured impedance of the transducer. The equivalent circuit parameters are estimated by using the fitness function and the PSO(Particle Swarm Optimization) algorithm. The effectiveness of the proposed method is verified by the applications to a sandwich-type transducer and a dummy load. In addition, the impedance matching network is also designed by using the estimated equivalent circuit model.

An Equivalent Circuit Model for a Dumbbell-Shaped DGS Microstrip Line

  • Woo, Duk-Jae;Lee, Taek-Kyung
    • Journal of electromagnetic engineering and science
    • /
    • v.14 no.4
    • /
    • pp.415-418
    • /
    • 2014
  • This paper presents an equivalent circuit model for a dumbbell-shaped defected ground structure (DGS) in a microstrip line. The effects of equivalent circuit elements of a dumbbell-shaped DGS and their magnetic coupling to the host transmission line are modeled as a simple lumped-element circuit. In addition, simple approximate expressions to determine the main circuit parameters for this model are presented. The transfer characteristic calculated by the proposed circuit model is compared with the results of EM simulation and measurement.

Wall Voltage Characteristics Simulated Using an Equivalent Circuit Model for AC POPs

  • Kim, Joon-Yub;Lim, Jong-Sik
    • 한국정보디스플레이학회:학술대회논문집
    • /
    • /
    • pp.317-320
    • /
    • 2003
  • As a convenient means for the characterization of the wall voltage and wall charge of AC PDPs during the sustain period, an equivalent circuit model for AC PDPs is presented. The equivalent circuit model for AC PDPs consists of capacitors and thyristors. The equivalent circuit model is based on the physical structure of the AC PDP and the I-V characteristic of the discharge space. This equivalent circuit model can be easily implemented in the standard simulators such as SPICE and can easily simulate the variation of the current, charge and voltage involved in AC PDPs as the supply voltage varies.

  • PDF

Equivalent Circuit Modeling of Wideband Underwater Acoustic Piezoelectric Vibrator (광대역 수중 음향 압전 진동체의 등가회로 모델링)

  • 조치영;김원호;윤형규
    • Journal of KSNVE
    • /
    • v.6 no.5
    • /
    • pp.645-652
    • /
    • 1996
  • In this paper an identification method is presented to obtain the equivalent electric circuit model of a wideband underwater acoustic piezoelectric vibrator. Unknown parameters involved in the equivalent circuit are indentified using the measured electrical admittances in air. The proposed method is applied to an example transducer. The validity of equivalent circuit model is demonstrated by the comparison between the experimental measurements and analytical calculations of TVR(transmitting voltage response) in water.

  • PDF

Equivalent Circuit Parameters of S-band 1.5 Cell RF Gun Cavity

  • Kim, Ki-Young;Kang, Heung-Sik;Tae, Heung-Sik
    • Journal of electromagnetic engineering and science
    • /
    • v.4 no.1
    • /
    • pp.30-36
    • /
    • 2004
  • We determined equivalent circuit parameters of a 1.5 cell S-band RF gun cavity from the resonant characteristics of its decoupled cavities(half cell and full cell) using the code SUPERFISH. Equivalent circuit parameters of the 1.5 cell RF gun cavity resonated in the 0-mode were obtained easily from the circuit parameters of each decoupled cavities. In order to obtain equivalent circuit parameters for the $\pi$ -mode cavity, we calculated the differences of the resonant frequencies and the equivalent resistances between the 0- and $\pi$ -modes with slight variations of the radius and thickness of the coupling iris. From those differences, we obtained R/Q value and equivalent resistance of the $\pi$ -mode, which are directly related to the equivalent circuit parameters of the coupled cavity. Using calculated R/Q value, we can express equivalent inductance, capacitance and resistances of the RF gun cavity resonated in the $\pi$ -mode, which can be useful for analyzing coupled cavities in a steady state.

Analysis of the Transient State of the Squirrel Cage Induction Motor by Means of the Magnetic Equivalent Circuit Method

  • Jeong Jong-Ho;Lee Eun-Woong;Cho Hyun-Kil
    • KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
    • /
    • v.5B no.1
    • /
    • pp.34-38
    • /
    • 2005
  • The finite element method is very flexible for new shapes and provides flux distribution, magnetomotive force, eddy currents, and torques. However, it requires lengthy computational time in order to achieve desired accuracy. The magnetic equivalent circuit method takes less computation time than the finite element method. Therefore, the finite element method is mainly used to confirm the completed design. The magnetic equivalent circuit method is convenient for complicated analysis of the transient state of the induction motor. The magnetic equivalent circuit method is restricted to only one direction of magnetic flux. In this paper, the construction elements (that is, stator iron, rotor iron, yoke, air gap, etc.) of the squirrel cage induction motor were represented by a flux tube and the air gap magnetomotive force was calculated by the magnetic equivalent circuit method. Starting transient torque and phase current of the squirrel cage induction motor were verified by the theoretical calculation and the experiment.

Calculation of the Parameter according to the Slip in Squirrel-Cage Induction Motor (Slip에 따른 농형유도전동기의 회로정수 산정)

  • Lee, Su-Jin;Lee, Jeong-Jong;Kim, Sung-Il;Hong, Jung-Pyo
    • Proceedings of the KIEE Conference
    • /
    • /
    • pp.738_739
    • /
    • 2009
  • This paper describes the calculation of the equivalent circuit parameters according to the slip in squirrel-cage induction motor. Recently, the induction motor is demanded of the various operation condition. In order to acquire the accurate characteristic for the operation condition of the motor, equivalent circuit parameters have to be calculated accurately. So the equivalent circuit parameters are computed by using the finite element method, the reliable characteristic analysis is carried out by application of the parameter to the equivalent circuit analysis. From the analysis result using this combined equivalent circuit and finite element method is compared with the experimental results by a detailed equivalent circuit, the validity of the method is proved.

  • PDF

Proposed Equivalent Circuit and Parameter Identification Method for Electro-Magnetic Resonance Based Wireless Power Transfer

  • Kawamura, Atsuo;Kim, Tae-Woong
    • Journal of Electrical Engineering and Technology
    • /
    • v.8 no.4
    • /
    • pp.799-807
    • /
    • 2013
  • The proper equivalent circuit is newly presented for electro-magnetic resonance based wireless power transfer. Based on the proposed equivalent circuit of open-ended helical antennas, the parameter identification of helical antennas can be well derived for highly efficient wireless power transfer. The well-established equivalent circuit in high frequency ranges is developed for analyzing a resonance enhanced-electromagnetic coupling helical antennas and the unknown parameters for helical antennas are identified by experiments. The effectiveness based on the proposed equivalent circuit is verified through experiments.