• 한국조명전기설비학회:학술대회논문집
• /
• 한국조명전기설비학회 2004년도 춘계학술대회 논문집
• /
• pp.506-510
• /
• 2004

A multi-phase interleaved buck converter is used to reduce current ripples and filter size of a power supply. This paper addresses the modelling and steady-state analysis of the multi-phase interleaved buck converter operated in discontinuous inductor current mode. The model is derived using an averaging technique in steady state. The do voltage ratio and the range of the discontinuous inductor current mode(DICM) and the continuous output current mode(COCM) are derived from the averaged state-space model. In addition, the efficiency is investigated according to the number of phase.

• Journal of Magnetics
• /
• 제22권1호
• /
• pp.104-108
• /
• 2017

Induction motors have wide applicability in many fields, both in industrial sectors and households, for their advantages of a high efficiency and robust structure. The introduction of power-source-containing harmonics into the induction motor winding lowers its efficiency and increases its temperature, greatly affecting its operation characteristics. In this study, we performed an electromagnetic field analysis using the time-difference finite-element method with the purpose of analyzing the steady-state current characteristics of an induction motor. Additionally, we calculated the steady-state current with a method combining an electromagnetic field equation and a circuit equation. In the electromagnetic field analysis, the nonlinearity was taken into account using the Newton-Raphson method, and a backward time-difference method was employed for the time derivative term. Then, we compared the steady-state current of the induction motor obtained by calculation with the experimentally measured values, thus validating the proposed algorithm. Furthermore, we analyzed the impacts of the shape and material of the rotor conductor bar of the induction motor on the steady-state current of the main winding.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2006년도 제37회 하계학술대회 논문집 B
• /
• pp.982-983
• /
• 2006

This paper deals with an analysis and design of the state feedback current controller's gain in the three-phase current control systems. First, this paper derives the transfer function of the closed loop current control system and also compares the state feedback current controller with the conventional proportional integral controller. A new pole placement method by using the pole/zero cancellation method is proposed to give a simple and concrete concept with respect to the pole selection. Experimental results on the permanent magnet synchronous motor show that the proposed method is very useful to design the gain of the state feedback current controller.

• 전기학회논문지
• /
• 제59권7호
• /
• pp.1194-1198
• /
• 2010

A high temperature superconducting power cable (HTS power cable) was applied large current capacity by no resistance in normal state. Fault state was risen out of over-current but, it was limited to resistance. this study was modeling equivalence, and unbalanced state analyzed operating charateristics of HTS power cable. The equivalence model was composed superconductor, shield, and former part. This model simulation was appeared conductor and shield current in normal state, but fault state was appeared former current as rise current by resistance. so it need to sufficiently influenced the quench characteristic when the former design.

• 대한전기학회논문지:전력기술부문A
• /
• 제53권1호
• /
• pp.38-42
• /
• 2004

In this paper we analyzed the electromagnetic behavior of a superconducting fault current limiter (SFCL) under the quench state using FEM. The analysis model used in this work is 5.5 KVA meander-line type SFCLs which are currently developed by Superconductor Power System Lab in Korea Electric Power Research Institute. Meshes of 3,650 triangular elements were used in the analysis of this SFCL. Analysis results showed that the distribution of current density was concentrated to inner curved line in meander-line type SFCL and the maximum current density was 14.61 A/$m^2$ and also the maximum Joule heat was 2,030 W/$m^2$ in this region. We think that the new and the modified structure must be considered for an uniform distribution of the electromagnetic field.

• 전기학회논문지
• /
• 제59권10호
• /
• pp.1748-1753
• /
• 2010

This paper suggests an improved technique to establish the modeling regarding steady and transient state on three phase-in one cryostat type HTS(High Temperature Superconducting) cable. The proposed modeling is established using EMTP/ATPDraw and TACS and MODELS provided by that. It has higher accuracy than the conventional method, as the actual HTS cable is modelled. Steady and transient state analysis performed by EMTP/ATPDraw calculate the current of conductor, shield and former, respectively. In case of the transient state modeled quench state occurred by a single line-to-ground fault, current of conductor shield and former are also calculated, respectively. Especially, various fault resistances and angles are considered to improve the reliability during transient state analysis. Analysis results reveal that the proposed technique improves the accuracy of modeling.

• E2M - 전기 전자와 첨단 소재
• /
• 제9권5호
• /
• pp.450-454
• /
• 1996

Maxwell-Displacement-Current(MDC) measuring technique has been applied to the study of monolayers of Dilauroylphosphatidylcholine (L-.alpha.-DLPC) and Dimyristoylphosphatidylcholine (L-.alpha.-DMPC). The displacement current was generated from monolayers on a water surface by monolayer compression. Displacement current was generated when the area per molecule was about 250.angs.$^{2}$, 280.angs.$^{2}$. Displacement current was generated in the gas state, gas/liquid state, and liquid state in the course of monolayer compression. The orientational change of molecules in monolayers was discussed on the basis of the MDCs obtained. Finally, we measured differential thermal analysis of sample.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
• /
• 제52권2호
• /
• pp.53-60
• /
• 2003

This paper deals with steady-state analysis of a single-phase line-start permanent magnet synchronous motor. In order to analyze the steady-state characteristics, the asymmetric single-phase line-start synchronous motor is converted to the symmetric two-phase synchronous motor, that is, the asymmetric magnetic field is separated from the positive and the negative symmetric components using symmetrical-component theory. The analysis method of the synchronous motor on the d-q axis coordinates is used for the positive component and the equivalent circuit of the induction motor is applied for the negative component analysis. Moreover, d-q axis inductance considering current phase angle is applied to positive component analysis for precise characteristic analysis. In order to validate the proposed analysis method, the analysis results are compared with the experimental results.

• 전기학회논문지
• /
• 제57권10호
• /
• pp.1713-1719
• /
• 2008

A high temperature superconducting power cable (HTS power cable) was applied large current capacity by no resistance in normal state. Fault state was risen out of over-current but, it was limited to resistance. This study was modeling equivalence, and unbalanced state analyzed operating characteristic of HTS power cable. The equivalence model was composed superconductor, shield, and former part. This model simulation was appeared conductor and shield current in normal state, but unbalanced state was appeared former current as rise current by resistance. So it need to sufficiently influenced the quench characteristic when the former design.

• 전기학회논문지P
• /
• 제51권4호
• /
• pp.186-192
• /
• 2002

In this paper, interleaved boost power factor corrector(IBPFC) is applied as a pre-regulator in switch mode power supply. IBPFC can reduce input current ripple and effectively increase the switching frequency without increasing the switching losses, because input current is divided each 50% by two switching devices. IBPFC can be classified as three cases by duty ratio condition in continuous current mode and be carried out state space average modeling. According to the modeling, steady and transient state analysis is performed by steady elements and perturbation element. Control transfer function is derived for design of control system.