• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.7
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• pp.1098-1105
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• 2021

The International Maritime Organization has steadily strengthened environmental regulations on nitrogen oxides and carbon dioxide emitted from marine vessels. Consequently, the demand for electric propulsion vessels based on eco-friendly elements has increased. To this end, research and development has been steadily conducted for various vessels. In electric propulsion systems, a redundancy configuration is typically adopted to increase reliability and facilitate the onboard arrangement. Furthermore, studies have been actively conducted to ensure the safety of electric propulsion systems through the combination with digital twin technology. A digital twin can be used to predict outcomes in advance by implementing real-world equipment or space in a virtual world like twins, integrating real-world information and data with the virtual world, and performing computer simulations of situations that can occur in a real environment. In this study, we perform failure modes and effects analysis (FMEA) to validate the electric power management system (PMS) redundancy scheme for the digital twin technology development of electric propulsion vessels. Then, we propose the role and algorithm of PMS as a compensation function for preventing primary and secondary damages caused by a single equipment failure of the PMS and preventing additional damages by analyzing the impact on the entire system under real vessel operating conditions based on the redundancy FMEA suggested for the ship classification and certification. We verified the improvement in propulsion conservation through tests.

• The Journal of the Korea institute of electronic communication sciences
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• v.12 no.1
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• pp.85-92
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• 2017

Recently, electric propulsion systems are used for unmanned surface vehicle, fish finder boat, etc. Some of these propulsion systems can be constructed of two electric motors and propellers for advanced impellent force. In this case, the speed difference generated between two propellers, namely, the synchronous error has a bad influence on the energy efficiency and course error. In this study, a synchronous control system is designed to restrain synchronous error caused by disturbance and mismatched dynamic characteristics. The control system is composed of the reference model, pre-filters, speed controllers, and synchronous controllers. The reference model is used for calculating the decoupled synchronous error and control input for each propulsion system. The pre-filters and speed controllers are designed in order that the propulsion system may follow the reference signal without overshoot and input saturation. And the synchronous controllers are designed from the viewpoint of stable and quick synchronization through root locus mothed approach. Finally, the simulation results show that the designed control system is effective for the disturbance.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.23 no.8
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• pp.923-929
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• 2019

The stability of the propulsion system is crucial for the autonomous vessel. Multiple power generation and propulsion systems should be provided for the stability of the propulsion system. High power generation capacity is calculated for stability, resulting in economical decline due to low load operation. To solve this problem, we need to optimize the power system. In this paper, an OPMS for electric propulsion ship is constructed. The OPMS consists of a hybrid power generation system, an energy storage system, and a control load system. The power generation system consists of a dual fuel engine, the energy storage system is a battery, and the control load system consists of the propulsion load, continuous load, intermittent load, cargo part load and deck machine load. The power system was constructed by modeling the characteristics of each system. For the experiment, a scenario based on ship operation was prepared and the stability and economical efficiency were compared with existing electric propulsion ships.

• Journal of the Korean Society for Railway
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• v.13 no.2
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• pp.166-172
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• 2010

Currently, vector control is used for speed control of trains because induction motor has high performance is installed in Electric railroad systems. Also, control of the induction motor is possible through various methods by developing inverters and control theory. Presently, rolling stocks which use the induction motor are possible to brake trains by using AC motor. Therefore model of motor block and induction motor is needed to adapt various methods. There is Variable Voltage Variable Frequency (VVVF) as the control method of the induction motor. The torque and speed is controlled in the VVVF. The propulsion system model in the electric railroad has many sub-systems. So, the analysis of performance of the speed control is very complex. In this paper, simulation models are suggested by using Matlab/Simulink in the speed control characteristic. On the basis of the simulation models, the response to disturbance input is analyzed about the load. Also, the current, speed and flux control model are proposed to analyze the speed control characteristic in the train propulsion system.

• Proceedings of the KIEE Conference
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• 2008.10b
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• pp.253-257
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• 2008

지능형교통시스템 (Intelligent Transportation System: ITS) 은 도로 및 교통관리, 교통정보제공, 대중교통 및 화물차량의 운영 등 교통의 전 분야에 걸쳐 정보통신 기술, 센서 및 제어 기술을 접목함으로써 교통의 효율화와 물류비용의 절감을 목표로 하고 있다. 특히, 최근에는 전자 및 통신 기술 등 첨단기술을 활용하여 현행 교통체계를 첨단화하기 위한 노력이 빠르게 진행되고 있으며, ITS는 최근 위치정보의 폭넓은 보급과 유 무선통신기술의 발전에 따라 위치정보서비스, 텔레매틱스 서비스 등과의 결합을 통해 새로운 비즈니스 모델들을 탄생시키고 있다. 또한 기존에 중점적으로 추진되어 왔던 도로 및 차량 영역뿐만 아니라 ITS 아키텍처를 구성하는 다양한 하위 시스템들간의 통신 및 정보체계 표준화와 관계된 기술, 시스템, 서비스 등의 시장이 형성되기 시작하고 있다. 이중에서도 최근에는 이동통신기술의 발전과 복합단말의 발전을 통해 통합된 기능을 갖는 이동전화, PDA, 스마트단말 등의 개인단말 뿐만 아니라 도로와 차량내의 통신을 위한 차량탑재형 단말 등의 보급으로 단거리 무선통신기술과 스마트차드 기술을 이용한 자동요금징수시스템, 위치정보기술을 이용한 위치기반서비스, GPS를 이용하여 실시간 교통정보 서비스가 가능한 텔레매틱스 서비스 등은 본격적으로 시장을 형성해 나가고 있다. 이는 기존의 ITS 분야가 ETCS(Electric Toll Collection System), AVHS(Advanced Vehicle & Highway System), CVO(Commercial Vehicle Operation)등 교통 인프라에 초점을 맞추고 있었으나 그동안의 수익모델 부재 등으로 인해 사업자들의 적극적인 투자가 이루어지지 않아 ITS 시장 활성화에 어려움이 있어 왔다는 점을 고려해 볼 때 최근 위치정보를 이용한 사용자 서비스를 통해 민간 기업의 투자 참여와 일반 사용자들의 ITS 에 대한 관심이 매우 높아지고 있다는 점은 ITS 시장의 확대에 있어 매우 긍정적인 요인될 것으로 예상되고 있다. 본 논문에서는 이러한 ITS의 세계적인 개발 및 투자 추세, 국내의 추진 동향을 통해 살펴보고 이에 따른 국내 적용에 대한 시사점을 살펴보았다.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.2004_2006
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• 2009

2009년 기준으로 국내 전력회사에서 관리 운영하고 있는 전력량계는 약 1,800 여 만대로 이중 약 16만 여대의 고압용 전력량계는 전자식화를 완료하였고 기타 저압용 전력량계는 2015년 이내에 전자식화를 완료할 예정이다. 국내에 전자식 전력량계가 본격적으로 도입된 지 채 10여년이 되지 않은 상황에서 국내의 전력계량 기술분야는 단순한 전자식화의 틀을 벗어나 국가적 스마트그리드 사업의 추진과 연계하여 지능화된 스마트 전력계량시스템으로 급격하게 진보하고 있다. 본 논문 에서는 최근 사내 현안 연구과제로 수행된 '전자식 전력량계를 활용한 부가서비스 시행방안 연구'의 연구결과를 토대로 하여, 국외 주요국가의 차세대 전자식 전력량계 부가서비스 기술개발 추세를 조망하고 향후 국내환경에 적합한 차세대 스마트급 전력량계의 부가서비스 도출방안과 항목선정을 위한 평가 그리고 구체적 적용전망을 살펴보고자 한다.

• Journal of the Korean Society for Railway
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• v.13 no.2
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• pp.173-178
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• 2010

Electric railroad systems consist of supply system of electric power and electric locomotive. The electric locomotive is adapted to high speed driving and mass transportation due to obtaining high traction force. The electric locomotive is operated by motor blocks and traction motors. Train speed is controlled by suppling power from motor blocks to traction motors according to reference speed. Speed control of the electric locomotive is efficient by spending minimum energy between motor blocks and traction motors. Recently, induction motors have been used than DC and synchronized motors as traction motors. Speed control of induction motors are used by vector control techniques. In this paper, speed of the induction motor is controlled by using the vector control technique. Control system model is presented by using Simulink. Pulse is controlled by PI and hysteresis controller. IGBT inverter is used for real-time control and system performance is demonstrated by simulating the induction motor which has 210[kW] on the output power.

• Aerospace Engineering and Technology
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• v.5 no.2
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• pp.126-133
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• 2006

This paper deals with technological and design skills for all pneumatical, hydraulical, mechanical and electrical parts related to control valve. Especially, a variety of dynamic characteristics, which are not easily extracted from field tests using control valves, are studied by system-simulation code, AMESim. The simulated results are also compared and examined with actual testing results in terms of physical dynamic characteristics. In addition, this paper contains the simulated system characteristics including dynamic characteristics in component level of valve itself. Based on the results, it is applied to control system of propellant feeding system in liquid-propellant engine of satellite launcher.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.35-36
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• 2015

21세기 들어 지구온난화 현상이 심각해지면서 세계 각국의 온실가스 감축 노력이 추진되고 있다. 특히, 2005년 2월에 공식 발효한 교통의정서(Kyoto Protocol)에서 온실가스 배출에 실질적인 책임이 있는 38개 선진국을 대상으로, 2012년까지 1990년의 온실가스 배출량 대비 평균 5.2%의 감축을 의무화 한 것이다. 한국 정부 또한 2009년 11월 온실 가스 감축목표를 2020년 배출전망치(BAU : Business As Usual) 대비 30%로 결정하고 저탄소 녹색성장기본법에 명시하는 등 국제적 감축 행렬에 동참하였다. 한국 정부는 2009년 12월부터 2013년 5월까지 42개월간 제주도에서 스마트그리드 실증사업을 시행하였다. 본 논문에서는 제주 실증단지에서 개발된 기술을 이용하여 건물단위 에너지 통합관리를 할 수 있는 시스템으로서 스마트그리드 스테이션을 개발하여 현장에 적용하였고 이를 활용한 확산방안을 제시하고자 한다.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.32 no.6
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• pp.126-133
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• 2004

MRE-1 Dual Thruster Module(DTM), which will be used in KOMPSAT(Korea Multi-Purpose Satellite), can provide reliable and cost-effective means for attitude and maneuvering control system. Thruster heat shield, one of the main components of DTM, is designed to prevent the critical radiative heat exchange between thruster and satellite during firing. To overcome the manufacturing difficulties, a electroforming process is preferred to classical welding process. In this case, an inner diameter of a new shield will be decreased a little due to the change of manufacturing process. Therefore, the interference problem between thruster nozzle and heat shield is investigated through structural analysis and their results are described in this paper.