• 한국수소및신에너지학회논문집
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• 제26권2호
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• pp.184-191
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• 2015

As the power electronics system increases the frequency, the power loss and thermal management are paid more attention. This research presents a real time model of dissipation power with junction temperature response for 120kw IGBT inverter which is applied to the thermal management of high power IGBT inverter. Since the computational time is critical for real time simulation, look-up tables of IGBT module characteristic curve are implemented. The power loss from IGBT provides a clue to calculate the temperature of each module of IGBT. In this study, temperature of each layer in IGBT is predicted by lumped capacitance analysis of layers with convective heat transfer. The power loss and temperature of layers in IGBT is then communicated due to mutual dependence. In the dynamic model, PWM pulses are employed to calculation real time IGBT and diode power loss. Under Matlab/Simulink$^{(R)}$ environment, the dynamic model is validated with experiment. Results showed that the dynamic response of power loss is closely coupled with effective thermal management. The convective heat transfer is enough to achieve proper thermal management under guideline temperature.

• 제어로봇시스템학회논문지
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• 제22권7호
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• pp.570-577
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• 2016

This paper proposes the design of a novel distributed message management scheme using a message-oriented management and analysis tool (MOMAT) for naval combat system (NCS) middle-ware. If a message is not guaranteed real-time of the NCS with each node, it causes the loss of data and decreases the reliability of systems. To solve these problems, improved message management schemes are proposed. Message management schemes are considering a real-time user management scheme and a real-time traffic management scheme. The proposed schemes are simulated with a developed simulation tool, data publisher, and subscriber connected through nodes in middle-ware. The simulation results show improved results in terms of message round-trip time (RTT), End-to-End delay, and throughput.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 추계학술대회 논문집 Vol.14 No.1
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• pp.46-51
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• 2001

For Fast Real-time Recognition of Nonlinear Error Data, a new Neural Network algorithm which recognized the map in real time is proposed. The proposed neural network technique is the real time computation method through the inter-node diffusion, In the network, a node corresponds to a state in the quantized input space. Each node is composed of a processing unit and fixed weights from its neighbor nodes as well as its input terminal. The most reliable algorithm derived for real time recognition of map, is a dynamic programming based algorithm based on sequence matching techniques that would process the data as it arrives and could therefore provide continuously updated neighbor information estimates. Through several simulation experiments, real time reconstruction of the nonlinear map information is processed,

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 추계학술대회 논문집
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• pp.46-51
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• 2001

For Fast Real-time Recognition of Nonlinear Error Data, a new Neural Network algorithm which recognized the map in real time is proposed. The proposed neural network technique is the real time computation method through the inter-node diffusion. In the network, a node corresponds to a state in the quantized input space. Each node is composed of a processing unit and fixed weights from its neighbor nodes as well as its input terminal. The most reliable algorithm derived for real time recognition of map, is a dynamic programming based algorithm based on sequence matching techniques that would process the data as it arrives and could therefore provide continuously updated neighbor information estimates. Through several simulation experiments, real time reconstruction of the nonlinear map information is processed.

• 한국자동차공학회논문집
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• 제11권4호
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• pp.173-179
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• 2003

In this paper, a real-time multibody vehicle dynamics and control model has been developed for a virtual reality intelligent vehicle simulator. The simulator consists of low PCs for a virtual reality visualization system, vehicle dynamics and control analysis system a control loading system, and a network monitoring system. Virtual environment is created by 3D Studio Max graphic tool and OpenGVS real-time rendering library. A real-time vehicle dynamics and control model consists of a control module based on the sliding mode control for adaptive cruise control and a real-time multibody vehicle dynamics module based on the subsystem synthesis method. To verify the real-time capability of the model, cut-in, cut-out simulations have been carried out.

• 전자공학회논문지C
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• 제35C권4호
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• pp.38-49
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• 1998

A fossil power plant can be modeled by a lot of algebraic equations and differential equations. When we simulate a large, complicated fossil power plant by a computer such as workstation or PC, it takes much time until overall equations are completely calculated. Therefore, new processing systems which have high computing speed is ultimately needed for real-time or high-speed(faster than real-time) simulators. This paper presents an enhanced strategy in which high computing power can be provided by parallel processing of DSP processors with communication links. DSP system is designed for general purpose. Parallel DSP system can be easily expanded by just connecting new DSP modules to the system. General urpose DSP modules and a VME interface module was developed. New model and techniques for the task allocation are also presented which take into account the special characteristics of parallel I/O and computation. As a realistic cost function of task allocation, we suggested 'simulation period' which represents the period of simulation output intervals. Based on the development of parallel DSP system and realistic task allocation techniques, we cound achieve good efficiency of parallel processing and faster simulation speed than real-time.

• 한국군사과학기술학회지
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• 제8권4호
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• pp.58-67
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• 2005

To overcome limitations of test scope, schedule and cost, M&S(Modeling & Simulation) technique has been applied for T&E(Test and Evaluation) of the state-of-art weapon systems. This paper proposes an air defense simulation software framework to reduce both redundancy an[1 programming errors in system simulator. The proposed framework consists of a 'model' and a 'middleware' The 'middleware' is a reliable communication service layer that supports not only HLA(High Level Architecture) which is an international standard in M&S but also TCP/IP, UDP and etc. The main role of 'model' is to schedule and to run the real-time distributed simulation. The proposed framework has been applied to M-SAM(Middle range Surface to Air Missile) system simulator. The proposed framework's scheduling and communication performance results are satisfactory and were measured by hardwired NTP(Network Timer Protocol) time-stamp with GPS(Global Positioning System) timer for better precision.

• 한국자동차공학회논문집
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• 제18권4호
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• pp.92-98
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• 2010

Virtual ground modeling is one of key topic for real-time vehicle dynamic simulation. This paper discusses about the virtual 3D road modeling process using parametric surface concept. General road data is a type of lumped position vector so interpolation process is required to compute contact of internal surface. The parametric surface has continuity and linearity within boundaries and functions are very simple to find out contact point. In this paper, the parametric surface formula is adopted to road modeling to calculate road hight. Position indexing method is proposed to reduce memory size and resource possession, and a simple mathematical method for contact patch searching is also proposed. The developed road process program is tested in dynamic driving simulation on off-road. Conclusively, the new virtual road program shows high performance of road hight computation in vast field of off-road simulation.

• Journal of Power Electronics
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• 제17권6호
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• pp.1535-1544
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• 2017

Advances in FPGA technology have enabled fast real-time simulation of power converters, filters and loads. FPGA based HIL (Hardware-In-the-Loop) simulators have revolutionized control hardware and software development for power electronics. Common time step sizes in the order of 100ns are sufficient for simulating switching frequency current and voltage ripples. In order to keep the time step as small as possible, ideal switching function models are often used to simulate the phase legs. This often produces inferior results when simulating the discontinuous conduction mode (DCM) and disabled operational states. Therefore, the corresponding measurement and protection units cannot be tested properly. This paper describes a new solution for this problem utilizing a discrete-time PI controller. The PI controller simulates the proper DC and low frequency AC components of the phase leg voltage during disabled operation. It also retains the advantage of fast real-time execution of switch-based models when an accurate simulation of high frequency junction capacitor oscillations is not necessary.

• 한국정보과학회논문지:컴퓨팅의 실제 및 레터
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• 제11권2호
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• pp.149-156
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• 2005

HLA는 시뮬레이션 표준 아키텍처로서 민수 및 국방 시뮬레이션 분야에서 관심이 높아가고 있다. 국내외에서 워게임과 같은 구조적 시뮬레이션에서는 HLA를 적용한 성공적인 개발사례를 찾아 볼 수 있다. 그러나 네트워크 시율레이터나 인터넷 게임과 같은 실시간 분산 시뮬레이션에서는 그 적용 사례가 아직까지 관찰되고 있지 않다. 그 이유는 실시간 분산 HLA 시뮬레이션에서는 네트워크 수준에서 RTI를 통한 메시지 전송시간이 컴퓨팅 능력, 시뮬레이션 노드 개수, 전송방식, 전송패킷의 크기에 영향을 받고, 응용 수준에서 메시지의 사건처리시간이 메시지 처리방식에 의존하여 실시간 제약조건을 설정하기가 어렵기 때문이다. 따라서 본 논문에서는 차후 M-SAM 시뮬레이터의 개발을 위하여 RTI의 실시간 제약 조건의 수준을 고찰하고자 한다. 이를 위하여 1.Af 환경에서 6대의 PC상에 HLA 기반의 실험용 시뮬레이터를 개발하고 RTI의 성능을 측정하고 분석하였다. 본 연구의 결과로서 이전의 연구에서 제시되지 않았던 다수 노드 환경에서 실제 운용 시나리오와 부하에 따른 메시지 지연시간, RTI 부하 및 RTI 패킷전송 비율에 대한 정량적인 특성 값을 얻을 수 있었고, 이 결과는 향후 M-SAM 시뮬레이터 또는 유사 응용체 계의 개발에서 표적 수, 전송주기 및 메시지 처리방식에 대한 설정지침으로 활용이 기대된다.