• 한국소음진동공학회논문집
• /
• 제21권2호
• /
• pp.99-105
• /
• 2011

The magnetic circuit analysis excluding flux loss and fringing effect often gives a result with unignorable error, when compared with real system. But, it is not easy to make a complete magnetic circuit model with the loss effects. This paper introduces a relatively simple method to build the model including the flux loss and fringing effect, in which the paths of leaked flux are simplified in terms of circular arcs and straight lines. After modification of the model, the error of about 36 % in maximum between the magnetic circuit analysis and FEM analysis is reduced to about 7 %.

• Journal of Welding and Joining
• /
• 제18권5호
• /
• pp.41-48
• /
• 2000

Dynamic behaviors of the GMAW system are simulated using the short-circuit transfer model and the characteristic equations fir the power supply, wire system and arc. The conventional wire equation, which relates the rate change of the wire extension to the wire feed rate and melting rate, is modified to include effects of the molten drop attached at the wire tip. The modified wire equation describes behaviors of the GMAW system more precisely and provides information about the initial bridge volume for short-circuit transfer. The proposed short-circuit model predicts the variation of parameters such as the current, voltage, short-circuit frequency and time considering the effects of the surface tension and electromagnetic force due to current. The calculated results are in broad agreements with the experimental results under the argon shielding condition.

• Journal of electromagnetic engineering and science
• /
• 제11권3호
• /
• pp.156-160
• /
• 2011

We have proposed and analyzed an equivalent circuit for a magnetically coupled wireless power transmission (WPT) system between two loop resonators by considering its coupling coefficient and radiation-related parameters. A complete formulation is provided for all the necessary circuit parameters. The mechanism of radiation loss is sufficiently explained. The circuit and electromagnetic (EM) simulation results have been shown to be in good agreement. Based on the proposed circuit formulation, a specific load impedance for maximum WPT efficiency was found to exist. The proposed modeling of the WPT in terms of circuit characterizations provides sufficient insight into the problems associated with WPT.

• 전기학회논문지
• /
• 제56권9호
• /
• pp.1626-1631
• /
• 2007

This paper presents a new modeling method using lamp output power and the modeling coefficients of the lamp. The proposed method utilizes the lamp modeling coefficients such as equivalent impedance Z(p), coupling coefficient of the transformer k(p), turns ratio of the transformer n(p), and plasma resistance Rp(p) as a function of lamp output power. The equivalent impedance Z(p) was developed from the equivalent resistance Req(p) and equivalent inductance Leq(p) of the lamp. Simulation and experimental results of the proposed model are presented in order to validate the proposed method. The modeling method can use to design an impedance matching circuit for a Class-D inverter.

• 한국항행학회논문지
• /
• 제24권4호
• /
• pp.314-321
• /
• 2020

LASAR (logic automated stimulus and response) 소프트웨어는 디지털 전자 회로 카드에 대한 로직 기능시험 및 고장검출을 위한 자동점검프로그램 개발도구이다. LASAR 소프트웨어는 소자의 논리회로 기능 및 입·출력 정의된 정보가 필요하다. 소자 정보가 없으면 정상적인 부품 모델링이 불가능하다. 따라서 본 논문에서는 소자 정보가 없는 PLD (programmable logic device) 소자를 역설계 방법을 통하여 부품 모델링을 수행한다. 개발된 LASAR 프로그램은 고장 시뮬레이션 결과와 단일 고착 고장삽입 방법을 통해 고장 검출율을 확인하였다. 고장 검출율은 기존의 제한적인 모델링은 91%, 역설계를 통한 모델링은 94%로 3% 상승하였다. 또한, EP 310 PLD 소자에 대한 입·출력핀에 대한 22가지 고착결함의 경우 100% 검출하여 양호한 성능을 확인하였다.

• 한국지능시스템학회논문지
• /
• 제25권2호
• /
• pp.161-167
• /
• 2015

본 논문에서는 응축수를 활용하는 새로운 열전 냉각장치를 소개하고 이 냉각장치에 대한 전기적 등가회로 모델을 제안한다. 소개된 냉각장치는 수집된 응축수를 히트싱크로 분무함으로써 응축수를 처리함과 동시에 냉각 효율을 향상시킬 수 있다. 기존의 열전 냉각장치에 대한 회로 모델과 열전소자-응축수 간의 열교환 방정식을 결합함으로써 소개된 냉각장치의 전기적 등가회로 모델을 유도한다. 유도된 모델의 파라미터는 별도의 실험을 통한 데이터 측정 없이 열전소자의 데이터시트 정보만으로 결정되기 때문에 소개된 냉각장치의 제어기를 설계하는 단계에서 해당 모델이 유용하게 사용될 수 있다. 제안된 모델의 타당성을 모의실험을 통해 확인하고 기존의 열전 냉각장치와 성능을 비교함으로써 응축수를 활용한 열전 냉각장치의 우수성 또한 검증한다.

• 한국군사과학기술학회지
• /
• 제11권5호
• /
• pp.5-11
• /
• 2008

Recently developed radars use the solid-state power amplifier to amplify the RF signal. The stability of RF signal directly depends on that of the electric power. So the stable and reliable electric power should be needed. When the electric power switch is tuned on for the first time in order to operate the radar system, the in-rush current is generated because of the capacitive characteristic. The excess in-rush current breaks the element. Therefore, the analysis about the in-rush current to design the electric power system is necessary. In this paper, modeling and simulation on the whole power system is carried out and the necessity of limiting the in-rush current is verified. After the analysis, the circuit to limit the in-rush current is designed and examined to verify the analysis. The circuit is good enough to limit the in-rush current.

• 한국전자파학회논문지
• /
• 제29권9호
• /
• pp.677-684
• /
• 2018

본 연구는 S-parameter를 이용한 변압기의 고주파 모델링 방법을 제시한다. 1차측과 2차측을 단락 또는 개방 회로를 구성하여 각 상태에서의 반사계수를 Vector Network Analyzer로 측정하였다. 측정 결과로부터 등가회로 소자를 추출하여 고주파 등가회로를 모델링하고, 2-port 회로에서 측정한 S-parameter 측정치와 시뮬레이션 결과를 비교함으로써 타당성을 검증하였다. 이는 정확하고 예측 가능한 고주파 변압기를 설계하는데 적용될 수 있다.

• 전기학회논문지P
• /
• 제59권4호
• /
• pp.473-476
• /
• 2010

In this paper, we analyzed the short circuit current of a low voltage direct current distribution system. For the analysis, we performed the modeling of the low voltage direct current distribution system with a 6-pulse three-phase thyristor rectifier using the PSCAD/EMTDC, surveyed impedance of sources, transformers and distribution lines to run a simulation. A result of the simulation is that short circuit currents of the direct current distribution system with the rectifier decreased due to a thyristor-ON-resistance(Ron). But in case of the low thyristor-ON resistance, output fault current of the rectifier increased over three-phase short circuit current of an AC power system without a rectifier by regular ratio of the rectifier. Because the output fault current of the rectifier can increase over interrupting the capacity of circuit breakers, studying short circuit currents of a low voltage direct current distribution system with a rectifier is necessary for introducing the direct current distribution systems.

• 한국공작기계학회:학술대회논문집
• /
• 한국공작기계학회 1995년도 춘계학술대회 논문집
• /
• pp.34-39
• /
• 1995

To reduce the shock in shifting the clutches and the brakes in automatic transmission have to be connected smoothly and disconnected rapidly. It is PCSV(Pressure Control Solenoid Valve) that play this role of automatic transmission. In this paper there were two steps in the analysis of the PCSV. The first step was modeling the elctromagnet by the permeance method. The second step was modeling the hydraulic circuit by the pressure differential equation. In addition to this modeling a experiment was performed and the commercial package program was used in order to justify modeling. The result of modeling coincide with the result of experiment and commercial package program. As a result this modeling is usable in analysis of dynamic characteractic of the PCSV.