• 항공우주기술
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• 제3권1호
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• pp.109-116
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• 2004

일반적으로 위성에 장착된 GPS 수신기는 GPS 위성으로부터 항법 신호를 받아서 위성의 위치, 시간 및 속도 정보를 제공하는 것을 주요 목적으로 하고 있다. 이러한 정보를 근거로 위성의 현재 위치정보 및 임무 수행을 위한 정보를 유도하게 된다. 2005년 발사예정인 아리랑 위성2호는 GPS 수신기에서 나오는 IPPS 신호를 위성체 각 프로세서의 기준시간으로 사용되며 DPLL, FEP회로 및 운용소프트웨어(FSW)에 의하여 동작된다. 본 논문에서는 아리랑 위성2호(KOMPSAT-2,이하 K2)의 시간동기구조에 대한 구조 및 설계에 대한 뿐 아니라 정밀도 분석 및 시험결과등 전 과정에 대한 내용을 기술하였다.

• International Journal of Automotive Technology
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• 제8권5호
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• pp.637-650
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• 2007

A new on-line fault detection and isolation(FDI) scheme has been proposed for engines using an adaptive neural network classifier; this paper investigates the robustness of this scheme by evaluating in a wide range of operational modes. The neural classifier is made adaptive to cope with the significant parameter uncertainty, disturbances, and environmental changes. The developed scheme is capable of diagnosing faults in the on-line mode and can be directly implemented in an on-board diagnosis system(hardware). The robustness of the FDI for the closed-loop system with crankshaft speed feedback is investigated by testing it for a wide range of operational modes, including robustness against fixed and sinusoidal throttle angle inputs, change in load, change in an engine parameter, and all changes occurring simultaneously. The evaluations are performed using a mean value engine model(MVEM), which is a widely used benchmark model for engine control system and FDI system design. The simulation results confirm the robustness of the proposed method for various uncertainties and disturbances.

• 전기전자학회논문지
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• 제24권2호
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• pp.385-391
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• 2020

배전계통에서의 과전류 및 이상 전압 현상은 전력설비에 부담을 줄 뿐만 아니라 수용가에 치명적인 피해를 입힐 수 있다. 그로 인해 실시간 배전계통 시뮬레이터를 활용하여 신속한 고장처리와 정전구간 축소 및 고장복구를 통한 전력공급의 신뢰도를 높이는 배전자동화 관련 연구가 활발히 진행되고 있다. 기존의 디지털 시뮬레이터를 이용한 배전계통 모의시스템은 고가의 설비로 시스템 구축에 제약이 있고 실 배전계통을 통한 검증 또한 불가능하다. 본 논문에서는 배전계통 디지털 시뮬레이터의 계통해석결과를 기반으로 배전자동화용 단말장치와의 연동을 통해 실시간 시뮬레이션 및 기능검증이 가능한 시스템을 개발하였다. 제안한 시스템의 효용성은 실험을 통해 검증하였다.

• Nuclear Engineering and Technology
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• 제56권3호
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• pp.1037-1051
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• 2024

This paper presents the construction results and design of the UNIST Reactor Innovation platform for small modular reactors as a versatile testbed for exploring innovative technologies. The platform uses simulant fluids to simulate the thermal-hydraulic behavior of a reference small modular reactor design, allowing for cost-effective design modifications. Scaling analysis results for single and two-phase natural circulation flows are outlined based on the three-level scaling methodology. The platform's capability to simulate natural circulation behavior was validated through performance calculations using the 1-D system thermal-hydraulic code-based calculation. The strategies for evaluating cutting-edge technologies, such as the integration of a solid oxide electrolysis cell for hydrogen production into a small modular reactor, are presented. To overcome experimental limitations, the hardware-in-the-loop technique is proposed as an alternative, enabling real-time simulation of physical phenomena that cannot be implemented within the experimental facility's hardware. Overall, the proposed versatile innovation platform is expected to provide valuable insights for advancing research in the field of small modular reactors and nuclear-based hydrogen production.

• 전력전자학회논문지
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• 제26권2호
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• pp.75-81
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• 2021

This study analyzes the resonance characteristics caused by the mutual interference between LCL filters and the grid impedance under the parallel operation of the grid-connected inverter using the LCL filter. These characteristics are verified through simulation and experiment. Two inverters are used to connect to the grid in parallel, and the system parameters, including the LCL filter, are set to the same conditions. In the case of inverters running in parallel at the point of common coupling, the presence of grid impedance causes mutual interference between the LCL filters of each inverter, and the deviation of the filter resonance frequency is analyzed to understand the parallel inverter. The correlation between the number of devices and the size of grid impedance is simulated by PSIM and verified by MATLAB. By connecting the real-time digital simulator Typhoon HILS to the DSP 28377 control board, the mutual interference characteristics are tested under the condition of two inverters running in parallel. The experimental and analysis results are the same, indicating the validity of the analysis.

• 항공우주시스템공학회지
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• 제13권6호
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• pp.36-42
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• 2019

본 논문은 유/무인 항공기 복합운용체계 검증을 위한 시뮬레이션 환경 구축 및 통합 시험에 대하여 다룬다. 유/무인 항공기 지상 시뮬레이션 환경 구축을 위해서 유인기용 시뮬레이터인 X-Plane과 무인기용 시뮬레이터 HILS를 연동하여 상호 복합운영이 가능한지 시뮬레이션으로 검증하였다. 실제 비행시험 전 유/무인 항공기 및 지상통제실 간 C Band 및 UHF 채널을 이용한 통신 가능성을 확인하기 위하여 통신장비를 제작하고 유인 항공기를 이용한 검증을 수행하였다.

• 한국자동차공학회논문집
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• 제23권1호
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• pp.25-33
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• 2015

This paper presents the d-q axis equivalent circuit model of an interior permanent magnet (IPM) which includes the iron loss resistance. The model is implemented to be able to run in real-time on the FPGA-based HIL simulator. Power electronic devices are removed from the motor control unit (MCU) and a separated controller is interfaced with the real-time simulated motor drive through a set of proper inputs and outputs. The inputs signals of the HIL simulation are the gate driver signals generated from the controller, and the outputs are the winding currents and resolver signals. This paper especially presents iron loss prediction which is introduced by means of comparing the torque calculated from d-q axis currents and the desired torque; and minimizing the torque difference. This prediction method has stable prediction algorithm to reduce torque difference at specific speed and load. Simulation results demonstrate the feasibility and effectiveness of the proposed methods.

• 전력전자학회논문지
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• 제26권4호
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• pp.294-297
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• 2021

A grid voltage estimation method for modular plug-in active power decoupling (APD) circuits is proposed in this study as direct replacements of electrolytic capacitors. Since modular plug-in APD circuits cannot have additional grid voltage sensors and should be operated independently without information exchange with the front-end converter, it is impossible to obtain the phase information of the grid directly. Therefore, the proposed method uses the second-order harmonic component of the DC-link voltage to estimate the grid voltage necessary to control the APD circuit. By employing the proposed method, the concept of modular plug-in APD circuits can be realized and implemented without direct detection of the grid voltage. The experimental results based on hardware-in-the-loop simulation (HILS) validate the effectiveness of the proposed control method.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회A
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• pp.849-854
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• 2007

This paper describes design and tuning of a full-range Adaptive Cruise Control (ACC) with collision avoidance. The control scheme is designed to control the vehicle so that it would feel natural to the human driver and passengers during normal safe driving situations and to avoid rear-end collision in vehicle following situations. In this study, driving situations are determined using a non-dimensional warning index and time-to-collision (TTC). A confusion matrix method based on natural driving data sets was used to tune control parameters in the proposed ACC System. An ECU-Brake Hardware-in-the-loop Simulation (HiLS) was developed and used for an evaluation of ACC System. The ECU-Brake HiLS results for alternative driving situation are compared to manual driving data measured on actual traffic way. The ACC/CA control logic implemented in an ECU was tested using the ECU-Brake HiLS in a real vehicle environment.

• 한국항해항만학회지
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• 제35권4호
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• pp.303-316
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• 2011

With the development of mechatronics technology in the transporter industry, the electric power assisted steering (EPAS) system has many advantages compared to the hydraulic system. Many manufacturers are developing and applying EPAS systems to improve the performance of the transporter. Using the HILS system developed in the paper, an adaptable EPAS system was developed for real transporter. It was installed in a real, KIA Rio, and tested. Results indicated outstanding performance. Therefore, the developed EPAS can be applied via HILS system.