• 한국소음진동공학회논문집
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• 제20권12호
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• pp.1183-1189
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• 2010

Shock-resistance test for a real equipment for a normal vessel is one of the difficult problem in many cases because of terrible cost and weight. An analysis technique to evaluate the shock resistance in a design stage is necessary, instead In this paper, the process to evaluate the shock resistance of a propulsion motor for naval vessels was presented based on German navy's BV043 regulation. The shock signal to impose the equipment under the test was first evaluated, and was then applied to the structural FE model of the equipment. From the transient FEA, the time history of von-Mises stress was obtained by the mode superposition method. The shock resistance was evaluated using the peak value of the von-Mises stress.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.1838-1844
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• 2011

In this paper, the propulsion control of a high-speed maglev train is studied. Electromagnetic suspension is used to levitate the vehicle, and linear synchronous motors (LSM) are used for propulsion. In general, a low-speed maglev train uses a linear induction motor (LIM) for propulsion that is operated under 300[km/h] due to the power-collecting and end-effect problem of LIM. In case of the high-speed maglev train over 500[km/h], a linear synchronous motor (LSM) is more suitable than LIM because of a high-efficiency and high-output properties. An optical barcode positioning system is used to obtain the absolute position of the vehicle due to its wide working distance and ease of installation. However, because the vehicle is working completely contactless, the position measured on the vehicle has to be transmitted to the ground for propulsion control via wireless communication. For this purpose, Bluetooth is used and communication hardware is designed. A propulsion controller using a digital signal processor (DSP) in the ground receives the delayed position information, calculates the required currents, and controls the stator currents through inverters. The performance of the implemented propulsion control is analyzed with a small maglev train which was manufactured for experiments, and the applicability of the high-speed maglev train will be explored.

• 한국항공운항학회지
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• 제23권3호
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• pp.1-7
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• 2015

In the present study, we conducted the research on the high efficiency propulsion system for the development of long-endurance UAV with an electric propulsion system. For the long endurance UAV, fair aerodynamic characteristics with the high efficiency of the propulsion system is required because the flight power and the duration time of the long-endurance UAV vary greatly depending on the efficiency of the propulsion system. Therefore, in this study, the tracking program which records the performance of motor, propeller was developed because of their wide variation in the efficiency depending on the using condition, and records from the existing flight test program were utilized to check the accuracy of the program we had developed. For the development of future long-endurance solar UAV, we confirmed the applied voltage of motor, the optimal rotation of propeller and the gear ratio of reduction gear in order to get the highest efficiency on the propulsion system at the optimal flying condition.

• 전력전자학회논문지
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• 제20권4호
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• pp.351-355
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• 2015

This paper explained the application of a lithium-ion battery energy storage system to electric propulsion ships. The power distribution in electric propulsion ships has low power quality because of the variation in the power consumption of the propulsion motor. For proper operation of the ship, the power quality needs to be improved, and the battery energy storage system is used to solve power-quality problems. The simulation models of electric propulsion ship and battery energy storage systems are constructed on MATLAB/Simulink to verify the improvement in power quality. The proposed system is applied in various scenarios of the propulsion motor state. The power quality achieved by using the battery energy storage system in both voltage and frequency satisfies the standards set by IEC-60092/101.

• International Journal of Railway
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• 제3권2호
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• pp.54-59
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• 2010

In order to develop the deep-underground GTX (Great Train eXpress) in domestic, the running performance analysis of the propulsion system by a variety of route condition must be carried out before studying the specification and the development of the high-speed propulsion system with inverter and traction motor. Then it is necessary to study the running resistance properties of the high-speed traction system for the variety of tunnel type and vehicle organization method at first. In addition, the properties of the power requirement of the traction motors needed to maintain the balanced speed of the high-speed traction system are next studied. We need to study properties of the emergency braking distance caused by the highest operation speed of the high-speed traction system and present the fundamental design technologies to develop the high-speed traction system for the deep-underground GTX. Finally, the paper analyzes the applicability of the conventional Korean Tilting Train eXpress (TTX) propulsion system on the high-speed propulsion system for the deep-underground GTX.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2011년도 제36회 춘계학술대회논문집
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• pp.228-231
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• 2011

추진제의 연소속도는 추진기관을 설계할 때 반드시 필요한 요소이다. 추진제의 연소속도는 중립적 압력선도를 얻을 수 있는 추진제 그레인을 설계/제작하여 지상연소시험을 통해 압력을 확인하고 연소 속도 계산식의 계산을 통해 얻는다. 이렇게 얻어진 계산된 연소속도 값은 표준화된 추진제의 시편을 제작하여 스트렌드 버너에서 연소시켜 얻어진 추진제의 연소속도 값과 비교하여 정확한 연소속도 값을 확인하게 된다. 본 연구는 추진기관 설계에 필수요소인 추진제 조성에 따른 연소속도를 효율적으로 얻고자 소형 추진기관을 설계/제작/시험/분석 하였다.

• 전력전자학회논문지
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• 제12권4호
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• pp.277-284
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• 2007

본 논문은 전기추진시스템에 사용되는 BLDC 전동기 중에서 최대 토크 특성을 갖는 독립상 BLDC 전동기의 제어 특성에 대하여 기술하고자 한다. 독립 상 전동기는 각 상이 전기적으로 분리된 형태로 구성된 것이 특징이다. 이러한 특징을 분석하기 위하여 Y결선 3상 BLDC 전동기와 독립 3상 BLDC 전동기를 모델링하고, 시뮬레이션을 통하여 비교하였다. 시뮬레이션 결과 Y결선 3상 BLDC 전동기에 비하여 독립 3상 BLDC 전동기가 상전압이 높았다. 고정자 저항 및 인덕턴스가 일정할 때, 높은 상전압은 최대 상전류의 증가를 가져왔고, 이러한 전류 증가는 최대 토크를 증가시킨다. 그러므로 독립상 BLDC 전동기의 상전류를 제어함으로써 독립상 BLDC 전동기의 전류 맥동이 저감됨을 확인하였다.

• 한국추진공학회지
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• 제18권5호
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• pp.19-28
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• 2014

핀틀 노즐 기술을 적용한 고체 추진기관의 지상 연소시험을 수행하여 내탄도 성능 해석과 비교하였다. Baffle이 없는 핀틀-노즐 추진기관 시험 결과 초기 압력은 내탄도 성능 해석 결과와 유사하였으나 점진적으로 압력이 증가하는 현상이 나타났다. 또한, 핀틀 주변으로 공급되는 유동을 균일하게 형성하기 위하여 baffle을 추가하여 시험을 수행하였다. 시험 결과 예측되는 압력보다 40% 높은 압력이 측정되었으며 CFD 유동해석을 통하여 baffle에 의한 전압력 손실이 발생하며 10%의 전압력 손실을 고려하여 예측된 연소실 압력이 측정 압력과 유사함을 확인하였다.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2009년도 춘계학술대회 논문집
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• pp.215-218
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• 2009

A design of a subscale solid propellant rocket motor was conducted to do the similitude experiments for the large scale rocket motor. One of the main factor to subscale was the mach number of the solid propellant flume through a nozzle exit The analysis of the flume flow was done to obtain the mach number for the large and subscale rocket motor. The flume shapes on the non dimensional axises by the nozzle exit diameter was matched each other. The propellant grain of a subscale solid rocket motor was designed by the profile of pressure vs time obtained by the mach number of the flume shape. Some analyses of the theoretical solution were compared with the results of the ground static test.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2007년도 제29회 추계학술대회논문집
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• pp.211-214
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• 2007

추진제 원료로 알루미늄 분말을 사용하는 고체추진기관은 지상연소시험을 수행하면 slag가 생성되어 연소관 내부에 쌓이게 된다. 연소시간이 긴 대형추진기관은 slag 양이 많아 취약부위에 쌓이게 되면 자칫 추진기관 폭발이 발생할 수도 있다. 이를 개선하고자 본 논문에서는 고체추진기관에서 slag가 축적되기 쉬운 부분에 라이너를 충진하는 공정을 개발하여 소개하려고 한다.