• Journal of the Institute of Electronics Engineers of Korea SC
• /
• v.48 no.6
• /
• pp.71-81
• /
• 2011

Unlike a typical internal combustion engine vehicle, the powertrain system of the pure electric vehicle, consisting of battery, inverter and motor, has direct effects on the vehicle performance and dynamics. Then, the specific modeling of such complex electro-mechanical components enables the insight into the longitudinal dynamic outputs of the vehicle and analysis of entire powertrain systems. This paper presents the dynamic model of electric vehicle powertrain systems based on theoretical approaches to predict and analyze the final output performance of electric vehicles. Additionally, the correlations between electric input signals and the final output of the mechanical system are mathematically derived. The proposed model for powertrain dynamics of electric vehicle systems are validated with a reference electric vehicle model using generic simulation platform based on Matlab/Simulink software. Consequently, the dynamic analysis results are compared with electric vehicle simulation model in some parameters such as vehicle speed/acceleration, and propulsion forces.

• KIISE Transactions on Computing Practices
• /
• v.21 no.9
• /
• pp.587-595
• /
• 2015

Several fields of science have traditionally demanded large-scale workflow support, which requires thousands of central processing unit (CPU) cores. In order to support such large-scale scientific workflows, large-capacity cluster systems such as supercomputers are widely used. However, as users require a diversity of software packages and configurations, a system administrator has some trouble in making a service environment in real time. In this paper, we present a container-based cluster management platform and introduce an implementation case to minimize performance reduction and dynamically provide a distributed computing environment desired by users. This paper offers the following contributions. First, a container-based virtualization technology is assimilated with a resource and job management system to expand applicability to support large-scale scientific workflows. Second, an implementation case in which docker and HTCondor are interlocked is introduced. Lastly, docker and native performance comparison results using two widely known benchmark tools and Monte-Carlo simulation implemented using various programming languages are presented.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.40 no.9
• /
• pp.801-805
• /
• 2016

In this paper, engine clutch engagement shock is analyzed during the mode change of plug-in hybrid electric vehicles. Multi-driving mode includes the EV (electric vehicle) mode, HEV (hybrid electric vehicle) mode, and engine operating mode. Depending on the mode change, the engine clutch is either engaged or disengaged. The magnitude of shock during clutch engagement is very important because it impacts vehicle acceleration and clutch synchronization speed, which affects ride comfort substantially. The performance simulator of plug-in hybrid electric vehicles was developed using MATLAB/Simulink. The simulation results show that the mode change control algorithm is necessary for minimizing shock during clutch engagement.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.29 no.6
• /
• pp.659-665
• /
• 2023

The exciter of a ship generator adjusts the magnetic flux through excitation current control to maintain the output terminal voltage constant. The voltage controller inside the exciter typically uses a proportional integral control method. however, the response characteristics determined by the gain and time constant produce unwanted output owing to an inappropriate setting value that can reduce the quality and stability of power within the ship. In this study, a neural network circuit is learned using stable input/output data that can be obtained through the AC4A type exciter model provided by IEEE, and the simulation is performed by replacing the existing proportional integral control type voltage controller with the learned neural network circuit controller. Consequently, overshooting was improved by up to 9.63% compared with that of the previous model, and excellence in stable response characteristics was confirmed.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.18 no.2
• /
• pp.27-34
• /
• 2014

Buzz margin scheduling and control technique which are suitable to regulate stable and high pressure air in wide range of Mach number are suggested for fixed geometry of a supersonic intake. From the analysis of preceding study, most effective control variable is induced and scheduling law is newly suggested in a real application point of view. The appropriateness of the control law in wide range of Mach number is addressed by numerical simulation of controlled propulsion system. Also, the simulation for stabilization and tracking performances of the controller are studied to investigate the phenomena under flight maneuver and disturbances.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.23 no.6
• /
• pp.39-50
• /
• 2019

Modeling and Simulation(M&S) for a liquid propellant supply system is a technique to predict the performance of components and systems under certain conditions based on mathematical modeling for each component of the engine. In this paper, the basic structure of M&S for the supply system applied to liquid rocket engines was obtained by analyzing the related research conducted. The basic mathematical modeling of components was organized and the characteristics of each study result were analyzed. Based on the analysis and validation results, M&S method of advanced foreign research institutes was also identified, and factors related to its accuracy were described.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2017.05a
• /
• pp.131-136
• /
• 2017

High speed under water vehicle by using solid rocket motor, which is a natural cavitation type, was tested. The vehicle's speed and running distance was measured, and pressure sensors installed on the surface of the vehicle show pressure-time history of pressures according to the development of the supercavitation. Underwater cameras installed on the wall of the test pool recorded whole processes from the onset of the supercavitation to fully developed one. CNU-SuperCT based on 2-dimensional inviscid theoretical analysis was used to simulate the test result. In consideration of CNU-SuperCT does not include the control fins of the vehicle, simulation results agree with test results very well. Also, pictures from underwater cameras support the test results.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.22 no.4
• /
• pp.12-17
• /
• 2018

A natural cavitation-type high-speed underwater vehicle with solid rocket motor is tested, and its speed and running distance are measured. The outputs from pressure sensors on the surface of the vehicle reveal a pressure-time history reflecting the development of supercavitation. Underwater cameras installed on the wall of the test pool record the entire process from the onset of supercavitation to its full development. CNU-SuperCT, based on two-dimensional inviscid theoretical analysis, is used to simulate test results. Considering CNU-SuperCT does not include the control fins of the vehicle, simulation results agree with test results very well. Additionally, pictures from underwater cameras support the test results.

• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.20 no.6
• /
• pp.162-176
• /
• 2021

Recently, Autonomous Vehicle(AV) has been expected to solve various transportation problems. s the problem of environmental pollution become serious, research to reduce pollution is needed. However, empirical research on AV related pollution is insufficient. Based on this background, this study analyzed network performance changes and CO₂ emissions introduc AVs and Electric Vehicles(EV) in eight intersections. The results show that when AVs with internal combustion engines were, the effect of carbon reduction over the network was insignificant. On the other hand, it was that the total amount of CO₂ generated in the network decreased significantly when EVs and autonomous electric vehicles were emissions in the transportation sector.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2002.04a
• /
• pp.59-59
• /
• 2002

램제트 추진기관은 압축과정을 별도의 부품 없이 형상에 의해서 감속하여 연소 압력비를 얻는다. 따라서 구동 마하수와 형상에 의해 흡입과정의 압축 효율이 결정된다. 설계점은 충분한 유량을 확보 할 수 있는 유량과 충격파 각을 조절하여 전압력 손실을 줄이도록 고려되어야 한다. 또한 연소가 일어나면 연소실 압력이 배압으로 작용하고 비행시에 받음각은 변하므로 이에 따른 성능 분석도 고려 되어야 할 사항이다. 본 연구는 국내에서 실험한 형상에 대해 수치계산을 수행하여 코드의 검증과 아울러 램제트 유동장의 수치적 시뮬레이션도 설계단계에서 하나의 도구로 이용할 수 있음을 보여준다. 실험에서는 배압 조건을 얻기 위해 유동 블록키지를 유로 내에 두어 상응하는 배압을 얻었지만 본 계산에서는 압력 경계조건을 직접 사용하였다. 유동이 비정상 특성을 가지므로 시간 정확도를 이차로 가지도록 이중시간 전진법을 사용하였다. 사용한 압력비는 충격파가 카울 끝에 닿는 임계상태에 가까운 12, 13, 14에 대해 계산을 수행하였고 부스터모드로 흡입구 끝이 막혀 있다가 램제트 모드로 바뀌어 연소실 압력이 위의 압력비라고 가정할 때의 비정상 천이 과정을 계산해 보았다. 본 계산은 흡입구 부분만을 떼어놓고 적절한 가정 하에 수행되었지만 연소실 내부도 비정상 특성을 가지므로 흡입구와 연소실을 동시에 같이 계산해야한다. 추후에 전체적인 계산을 진행하기 위한 전 단계로 흡입구 계산만을 수행하여 실험과 잘 일치하는 계산 결과를 얻었고 전체 계산을 위한 연구는 진행 중에 있다.