• 한국철도학회:학술대회논문집
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• 한국철도학회 2004년도 추계학술대회 논문집
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• pp.1437-1443
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• 2004

In this paper, AC electric vehicle propulsion system(Converter/Inverter) using high power semiconductor, IPM(Intelligent Power module) is proposed. 2-Parallel operation of two PWM converter is adopted for increasing capacity of system and the VVVF inverter control is used a mixed control algorithm, where the vector control strategy at low speed region and slip-frequency control strategy at high speed region. The proposed propulsion system is verified by experimental results with a 1,350kW converter and 1.100kVA inverter with four 210kW traction motors.

• International Journal of Naval Architecture and Ocean Engineering
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• 제7권2호
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• pp.390-398
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• 2015

Energy-saving devices for 317K VLCC have been developed from a propulsion standpoint. Two ESD candidates were designed via computational tools. The first device WAFon composes of flow-control fins adapted for the ship wake to reduce the loss of rotational energy. The other is WAFon-D, which is a WAFon with a duct to obtain additional thrust and to distribute the inflow velocity on the propeller plane uniform. After selecting the candidates from the computed results, the speed performances were validated with model-tests. The hydrodynamic characteristics of the ESDs may be found in improved hull and propulsive efficiencies through increased wake fraction.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 B
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• pp.1343-1345
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• 2005

In this paper, control schemes are proposed for a propulsion system(Converter/Inverter) of the TTX(Tilting Train express). In developed traction converter, unity power factor control, compensation method of dc link voltage have been applied. Output current of converter contains harmonics ripple at twice input ac line frequency, which causes a ripple in the dc link voltage so that control scheme is developed in inverter system to reduce the pulsating torque current. At low speed region, vector control scheme is applied and slip frequency control is adopted at high speed region. The performance of propulsion system will be verified by simulation and prototype experimental results.

• 한국추진공학회지
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• 제17권4호
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• pp.49-55
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• 2013

한국항공우주연구원 (이하 항우연)에서 개발중인 중형 전기동력 무인기 EAV2의 추진시스템에 대한 비행시험결과에 대하여 기술 하였다. EAV2는 날개 길이 6.9 m, 무게 18 kg의 저속 장기 체공형 무인기이다. 전기 동력원으로는 태양전지, 연료전지, 배터리의 세 가지를 동시에 사용한다. EAV2는 2012년 6월에 22시간 이상 체공 비행에 성공하였다. 시험 결과, 전기추진 시스템은 비행 중 일어나는 여러 상황에서 필요한 동력을 성공적으로 공급하였으며, 각 동력원들은 설계된 목적에 부합하게 작동되었다.

• 대한조선학회논문집
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• 제47권2호
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• pp.163-177
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• 2010

This article examines hydrodynamic characteristics and speed performances of a ship attached with a full spade and a twisted rudder based on a computational method. For this study, a 13,100 TEU container carrier is selected. The turbulent flows around a ship are analyzed by solving the Reynolds-averaged Navier-Stokes equation together with the application of Reynolds stress turbulence model. The computations are carried out at the conditions of rudder, bare hull, hull-rudder and hull-propeller-rudder. An asymmetric body-force propeller is applied. The speed performance is predicted by the model-ship performance analysis method of the revised ITTC'78 method. The hydrodynamic forces are compared in both rudder-open-water and self-propulsion conditions. The flow characteristics, the speed performance including propulsion factors and the rudder-cavitation performance are also compared. The model tests are conducted at a deep-water towing tank to validate the computational predictions. The computational predictions show that the twisted rudder is superior to the full spade rudder in the respect of the speed and the cavitation performances.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2009년도 춘계학술대회 논문집
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• pp.376-381
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• 2009

The increasing needs for higher cargo capacity in the container vessels' fleet has led to ship builder's demand for higher power output rating engine to meet the propulsion requirement, thus, leading to the development of super large two stroke low speed diesel engines. This large sized bore engines with more than 12 cylinders are capable of delivering power output up to more than 100,000 bhp at maximum continuous rating. The thrust variation force due to axial vibration occurring in propulsion shafting of these ships are transmitted to ship structure via thrust bearing. This force may vibrate the super structure of ship in the fore-aft direction and the fatigue strength of crank shaft can be decreased by additional bending stress increase in crank shaft pin and journal. In this paper, the axial vibration of propulsion shafting system on the 14RT-flex96C super large diesel engine with 14 cylinders is identified by theoretical analysis and vibration measurement.

• 한국마린엔지니어링학회:학술대회논문집
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• 한국마린엔지니어링학회 2002년도 춘계학술대회논문집
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• pp.121-127
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• 2002

Environmental protection on the ocean has been interested and nowadays the International Maritime Organization(IMO) has advanced on the prevention of air pollution from ships. This study presents the emission characteristics of 4 stroke propulsion diesel engine in E2 cycle (constant speed) and E3 cycle (propeller curved speed). Also the effects of important operating parameters in terms of intake air pressure and temperature, and maximum combustion pressure are described on the specific emissions. Emissions measurement and calculation are processed according to IMO Technical Code. The results show that NOx emission level in E3 cycle is higher than E2 cycle due to lower engine speed and lower maximum combustion pressure by retarding fuel injection timing. Intake air temperature has strong influence on NOx emission production. And CO, HC emissions are not affected by maximum combustion pressure and intake air pressure and temperature.

• 전기학회논문지
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• 제63권10호
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• pp.1467-1472
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• 2014

This paper study on powering characteristic on speed variation of propulsion system of prototype 8200 electric locomotive propulsion system through simulation modeling. For this purpose, it being applied in the field of railway IGBT (Insulated Gate Bipolar Transistor) elements are used. Converter was performed PLL (Phase-Locked Loop) control method that is used to control the phase and output voltage, and the inverter was carried an indirect vector control method to control the speed of traction motor. The results of simulation by modeling and experimental unit, we was confirmed that converter is controlled a unity power factor and output voltage by reference voltage. Also traction motor was controlled by indirect vector control and SVPWM inverter switching method very well.

• Journal of Power Electronics
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• 제19권3호
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• pp.761-770
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• 2019

This paper proposes a hybrid phase windings excitation method for improving the efficiency of a 7-phase brushless DC (BLDC) motor in the electric propulsion system of a ship. The electrical losses of a BLDC motor system depend on the operating region and the number of excited phase windings (2-phase, 4-phase or general 6-phase windings). In this paper the operating region and torque/speed characteristics according to the motor rotation speed and propeller load are analyzed for a number of excitation methods. In addition, it analyzes the electrical losses of the system under each of the excitation methods in the entire operating region of the motor. In every sampling time, the proposed control method calculates the electrical loss of the system for each of the excitation methods and operates a 7-phase BLDC motor by selecting the excitation method that results a decreased electrical loss at the operating speed. The usefulness of the proposed control algorithm is verified through experimental results.

• 전력전자학회논문지
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• 제10권3호
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• pp.233-240
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• 2005

본 논문은 현재까지 전적으로 수입에 의존하던 국내 교류 전동차용 추진제어장치(Converter/Inverter)를 대용량 IPM 스위칭 소자를 적용하여 개발된 시스템을 제안한다. 컨버터의 용량을 향상시키기 위해 2대의 PWM 컨버터를 병렬 운전하고 병렬 운전 시 각각의 컨버터 스위칭 각을 다르게 제어하여 고조파 함유를 줄였으며 DC-Link 단의 Beatless 제어를 수행하였다. VVVF 인버터 제어의 경우, 저속의 운전영역에서는 순시 토크 제어가 가능한 백터제어를 적용하고, 고속 운전 영역에서는 슬립 주파수제어를 적용하는 백터 제어와 스칼라 제어의 병용 제어기법을 제시하였다. 제시된 추진제어장치는 4대의 210kW 유도전동기를 이용하여 철도차량용 추진제어장치에 적용되는 관련 규격의 각종 시험을 통해 그 성능을 검증하였다.