• 대한전자공학회논문지SD
• /
• 제43권12호
• /
• pp.23-32
• /
• 2006

다층 고속 디지털 보드에 대한 빠르고 정확한 전압 버스 설계 방법은 정확하고 정밀한 고속 보드에 전원 공급망 설계 방법을 위해 고안되었다. FAPUD는 PBEC(Path Based Equivalent Circuit)모델과 망 합성 방법의 두 중요 알고리즘을 기반으로 구성된다. PBEC 모델 기반의 회로 레벨의 2차원 전원 분배 망의 전기적 값으로부터 lumped 1차원 회로 모델로 간단한 산술 표현들을 활용한다 제안된 PBEC 기반인 회로 단계 설계는 제안한 지역 접근법을 이용해 수행된다. 이 회로 단계 설계는 온칩 디커플링 커패시터의 크기, 오프칩 디커플링 커패시터의 위치와 크기, 패키지 전압 버스의 유효한 인덕턴스를 직접 결정하고 계산한다. 설계 출력에 따라 모든 디커플링 커패시터가 포한된 lumped 회로 모델과 전압 버스의 레이아웃은 FAPUD 방법을 이용한 후 얻을 수 있다. 미세조정 과정에서, I/O Switching에 의해 덧붙여진 Simultaneous Switching Noise(SSN)를 고려한 보드 재 최적화가 수행될 수 있다 이는 전원 공급 잡음에 I/O 동작 효과가 lumped 회로 모델을 가지고 전 동작 주파수 범위에 대해 추산될 수 있기 때문이다. 게다가 만약 설계에 조정이 필요하거나 교체해야 한다면, FAPUD 방법은 다른 전면 설계변경 없이 디커플링 커패시터들을 대체하여 설계를 수정하는 것이 가능하다. 마지막으로 FAPUD 방법은 전형적인 PEEC 기본설계 방법과 비교해 정확하고 FAPUD 방법의 설계 시간은 전형적인 PEEC 기본 설계 방법의 시간보다 10배가 빠르다.

• Journal of Electrical Engineering and Technology
• /
• 제13권6호
• /
• pp.2276-2283
• /
• 2018

A 50kW-4000rpm interior permanent magnet synchronous machine (IPMSM) applied to the high-performance electric vehicle (EV) is introduced in this paper. The main work of this paper is that a 2-D T-type lumped-parameter thermal network (LPTN) model is presented for IPMSM temperature rise calculation. Thermal conductance matrix equation is generated based on calculated thermal resistance and loss. Thus the temperature of each node is obtained by solving thermal conductance matrix. Then a 3-D liquid-solid coupling model is built to compare with the 2-D T-type LPTN model. Finally, an experimental platform is established to verify the above-mentioned methods, which obtains the measured efficiency map and current wave at rated load case and overload case. Thermocouple PTC100 is used to measure the temperature of the stator winding and iron core, and the FLUKE infrared-thermal-imager is applied to measure the surface temperature of IPMSM and controller. Test results show that the 2-D T-type LPTN model have a high accuracy to predict each part temperature.

• 재활복지공학회논문지
• /
• 제5권1호
• /
• pp.59-64
• /
• 2011

인공 중이 (IMEHD, implantable middle ear hearing device)용 플로팅 매스 트랜스듀서는 제작 과정상에서 발생하는 구조적 오차 및 제작 결합시의 문제점들로 인해 설계 시 의도와 다른 진동 특성을 가질 수 있게 되고, 이렇게 제작된 진동 트랜스듀서는 향후 실제 환자에게 이식되었을 때의 진동체 진동 성능을 예측하기 어려운 문제점이 있다. 본 연구에서는 제작된 플로팅 매스형 트랜스듀서에 대해 설계값과의 비교 평가 및 향후 컴퓨터 모델화된 청각 중이 집중 소자 모델에 적용이 가능하도록 기 제작된 진동체의 집중 소자 모델 파라미터들을 추정할 수 있는 방법을 제안하였으며, 제안된 방법을 LabVIEW 기반의 그래픽 유저 인터페이스 소프트웨어로 구현하였다. 제안된 방법은 실제 제작된 플로팅 매스형 진동체의 진동 변위 및 위상 데이터를 이용하여 해당 진동체의 집중 모델 파라미터들을 순차적 이차 프로그래밍 (SQP, sequential quadratic programming) 방법으로 추정하는 방식이다. 구현된 방법을 이용하여 측정 데이터에 가해지는 잡음의 양에 따른 플로팅 매스형 진동 트랜스듀서의 집중 모델 파라미터 추정 시의 발생 오차 변화를 컴퓨터 시뮬레이션을 통해 조사하여 본 방법의 파라미터 추정 정확도를 확인하였다. 또한, 실제로 제작한 인공중이용 진동 트랜스듀서에 대해 측정된 진동 변위 및 위상 데이터를 이용하여 진동체의 집중 모델 파라미터들을 추정하였으며, 기존 설계값들과 비교를 통해 제안된 방법의 유용성을 평가하였다.

• 한국초전도ㆍ저온공학회논문지
• /
• 제21권1호
• /
• pp.31-35
• /
• 2019

The lumped-parameter circuit model for a no- insulation (NI) high temperature superconductor (HTS) magnet has been well understood after many experimental and analytic studies over a decade. It successfully explains the non-linear charging behaviors of NI magnets. Yet, recently, multiple groups reported that the post-quench electromechanical behaviors of an NI HTS magnet may not be well explained by the lumped circuit model. The characteristic resistance of an NI magnet is one of the key parameters to characterize the so-called "NI behaviors" of an NI magnet and recently a few groups reported a potential that the characteristic resistance of an NI magnet may substantially vary during a quench. This paper deals with this issue, the increment of contact resistance of the no-insulation (NI) REBCO magnet during a quench and its impact on the post-quench behaviors. A 7 T 78 mm NI REBCO magnet that was previously built by the MIT Francis Bitter Magnet Laboratory was chosen for our simulation to investigate the increment of contact resistance to better duplicate the post-quench coil voltages in the simulation. The simulation results showed that using the contact resistance value measured in the liquid nitrogen test, the magnitude of the current through the coil must be much greater than the critical current. This indicates that the value of the contact resistance should increase sharply after the quench occurs, depending on the lumped circuit model.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2004년도 추계학술대회 논문집
• /
• pp.1236-1239
• /
• 2004

The object of this study is to develop a model of the cardiovascular system capable of simulating the short-term transient and steady-state hemodynamic responses such as hypotention and disequilibrium syndrome during hemodialysis or hemofiltration. The model consists of a closed loop 12 lumped-parameter representation of the cardiovascular circulation connected to set-point models of the arterial and cardiopulmonary baroreflexes and 3 compartmental body fluid and solute kinetic model. The hemodialysis model includes the dynamics of sodium, urea, and potassium in the intracellular and extracellular pools, fluid balance equations for the intracellular, interstitial, and plasma volumes. We have presented the results of many different simulations performed by changing a few model parameters with respect to their basal values.

• Journal of Mechanical Science and Technology
• /
• 제14권2호
• /
• pp.188-196
• /
• 2000

In this paper, our aim is to develop a model for two cooperating flexible manipulators handling a rigid object by using lumped parameters. This model is in turn analyzed on MATLAB. In order to validate the model, a precise simulation model is developed using $ADAMS^{TM}$ (Automatic Dynamic Analysis of Mechanical System). Moreover, to clarify the discussion, the motions of a dual-arm experimental flexible manipulator are considered. Using the developed model, we control a robotic system with a symmetric hybrid position/force control scheme. Finally, experiments and simulations are performed, and a comparison of simulation results with experimental results is given to a rerify the validity of our model.

• International Journal of Air-Conditioning and Refrigeration
• /
• 제9권3호
• /
• pp.46-56
• /
• 2001

The present study concerns the numerical simulation of a supply airflow control in a variable air volume (VAY) system. A stratified thermal model (multi-zone model) is suggested to predict a local thermal response of an air-conditioned space. The effects of various thermal parameters such as the cooling system capacity, the thermal mass of an air-conditioned space, the time delay of thermal effect, and the building envelope heat transmission are investigated. Further, the influence of control parameters such as the supply air temperature, the PI control factor and the thermostat location on a VAV system is quantitatively delineated. The results obtained show that the previous homogeneous lumped thermal model (single zone model) may overestimate the time taken to the set point temperature. It is also found that there exist the appropriate ranges of the control parameters for the optimal airflow control of the VAV system.

• 한국초전도저온공학회:학술대회논문집
• /
• 한국초전도저온공학회 1999년도 제1회 학술대회논문집(KIASC 1st conference 99)
• /
• pp.153-156
• /
• 1999

In this paper, the inertance tube is modeled by the distributed impedance model. This model is verified by the analytical solutions for the long tube without the reservoir. In this model the distributed impedace effect of the inertance tube is included and mass flow rate and pressure distributions are calculated along the inertance tube for various inertance tube lengths. Mass flow rate at the inlet of the inertance tube is also calculated by this model and compared to the lumped impedance method. Mass flow rate by the distributed model shows quite different behaviors from the lumped model when the operating frequency is high and the length of the tube becomes large.

• 한국군사과학기술학회지
• /
• 제2권2호
• /
• pp.92-98
• /
• 1999

Dynamic behavior of missile which is fired in canister is analyzed by flexible multibody dynamics. The bending elasticity of missile is very important in case that missile is fired in the inclined launcher. In this paper, the force element model for the missile launching stage and the finite element model of missile are developed. The FEA model of missile is condensed into five lumped mass element model and the consistence between FE model and lumped mass model of missile is verified by modal analysis. As a result of analysis, sabot reaction force and pitch rate of missile for the variation of gap size and force element are obtained.

• 한국물환경학회지
• /
• 제36권5호
• /
• pp.373-384
• /
• 2020

Hydrological models are based on a combination of parameters that describe the hydrological characteristics and processes within a watershed. For this reason, the model performance and accuracy are highly dependent on the parameters. However, model uncertainties caused by parameters with stochastic characteristics need to be considered. As a follow-up to the study conducted by Choi et al (2020), who developed a relatively simple semi-distributed hydrological model, we propose a tool to estimate the posterior distribution of model parameters using the Metropolis-Hastings algorithm, a type of Markov-Chain Monte Carlo technique, and analyze the uncertainty of model parameters and simulated stream flow. In addition, the uncertainty caused by the parameters of each version is investigated using the lumped and semi-distributed versions of the applied model to the Hapcheon Dam watershed. The results suggest that the uncertainty of the semi-distributed model parameters was relatively higher than that of the lumped model parameters because the spatial variability of input data such as geomorphological and hydrometeorological parameters was inherent to the posterior distribution of the semi-distributed model parameters. Meanwhile, no significant difference existed between the two models in terms of uncertainty of the simulation outputs. The statistical goodness of fit of the simulated stream flows against the observed stream flows showed satisfactory reliability in both the semi-distributed and the lumped models, but the seasonality of the stream flow was reproduced relatively better by the distributed model.