• 한국항해항만학회지
• /
• 제42권6호
• /
• pp.437-445
• /
• 2018

국제해사기구(IMO)에서는 해양 환경보호를 위해 황산화물($SO_X$), 질소산화물($NO_X$), 이산화탄소($CO_2$) 등의 선박 배기가스 배출 규제를 강화하고 있으며, 특히 미국, 유럽을 중심으로 배출가스통제구역(Emission Control Area, ECA)을 설정하여 운용하고 있다. 이러한 환경 규제의 대응방법으로서 친환경 고효율 선박에 대한 요구가 커지면서 배출가스를 줄일 수 있는 전기추진시스템 관련 연구 및 기술에 대한 관심이 늘어나고 있다. 컨테이너선과 같은 상선은 경제속도 운항의 이유로 전기추진시스템의 적용대상에서 벗어나 있었으나, 앞으로 배기가스 배출 규제가 강화되고 4차 산업혁명 기술로 대표되는 빅데이터, IoT 기술을 적용한 자동화 시스템이 선박에 적용되기 위해서는 모니터링 및 제어가 쉬운 전기추진시스템이 필요할 것으로 전망된다. 따라서 본 논문에서는 6,800TEU 컨테이너 선박을 대상으로 전기추진시스템을 적용하기 위해서 기존 컨테이너 선박의 부하분석을 통해 부하분석 기반의 발전기 및 배터리 용량 설계를 목표로 연구를 진행하였다. 부하분석기반으로 설계된 시스템은 배터리를 이용한 부하분배제어를 통해 발전기가 높은 효율구간에서 운용할 수 있다는 장점이 있다.

• 한국추진공학회:학술대회논문집
• /
• 한국추진공학회 2000년도 제14회 학술강연논문집
• /
• pp.6-6
• /
• 2000

On-orbit thermal behavior of KOMPSAT (Korea Multi-purpose Satellite) propulsion system employing hydrazine (N$_2$H$_4$) liquid monopropellant is addressed. Thermal control performance to prevent propellant freezing in spacecraft-operational orbit was verified by flight telemetry data obtained during LEOP (Launch and Early Operation Phase). Results are depicted in terms of temperature history during several orbits selected and are compared with acceptable temperature ranges of system components. Cyclic behavior of temperature is reduced into duty cycles of the avionics heaters and subsequently converted into the electrical power required to keep away from propellant freezing. Temperature of each component which was achieved under on-ground thermal-balanced condition of spacecraft, is presented for comparison with the flight data, additionally.

• International Journal of Aeronautical and Space Sciences
• /
• 제13권4호
• /
• pp.421-427
• /
• 2012

Solar Sail propulsion has been validated in space (IKAROS, 2010) and soon several more solar-sail propelled spacecraft will be flown. Using sunlight for spacecraft propulsion is not a new idea. First proposed by Frederick Tsander and Konstantin Tsiolkovsky in the 1920's, NASA's Echo 1 balloon, launched in 1960, was the first spacecraft for which the effects of solar photon pressure were measured. Solar sails reflect sunlight to achieve thrust, thus eliminating the need for costly and often very-heavy fuel. Such "propellantless" propulsion will enable whole new classes of space science and exploration missions previously not considered possible due to the propulsive-intense maneuvers and operations required.

• 유체기계공업학회:학술대회논문집
• /
• 유체기계공업학회 2006년 제4회 한국유체공학학술대회 논문집
• /
• pp.45-46
• /
• 2006

Usual LEO satellite for earth observation use a blowdown hydrazine monopropellant propulsion system for attitude hold and orbit maintenance. For precision control, thruster valve has very short closing time, but this can cause water hammering and pressure surge. Since water hammering and pressure surge can cause damage of propulsion system and ununiform thrust, Thruster valve closing is one of the special concern during satellite propulsion system design. In this paper, an analysis for propellant feed system is conducted using the method of characteristics. The results represent water hammer effect is negligible even at the worst case and pressure surge can be decreased effectively with a trim orifice.

• 한국전산유체공학회:학술대회논문집
• /
• 한국전산유체공학회 2005년도 춘계 학술대회논문집
• /
• pp.173-181
• /
• 2005

A fluid transient analysis for the propellant flow in a monopropellant propulsion system is conducted using the method of characteristics (MOC). Algebraic simultaneous equations method and Clamor's rule method utilized to drive the compatible and characteristic equations are reviewed to understand MOC more extensively. The identification of fluid transient phenomena of propulsion system of Koreasat 1 is carried out through parametric studies. Also this work describes the reason that the propulsion system of Koreasat 1 has no orifice to control flow transients or to limit the initial hydrazine flow rate for the first-pulse firing.

• 한국마린엔지니어링학회:학술대회논문집
• /
• 한국마린엔지니어링학회 2005년도 전기학술대회논문집
• /
• pp.1113-1119
• /
• 2005

The power electric system is one of the most concerning factor for the reliability of the electric propulsion ship. operation in higher temperature decreases the device's reliability and power efficiency. the management of power loss and temperature of switching devices is indispensable for the reliability fo the power electric system. In this paper, IGBT chip of the switching devices is modeled and MIIR(Motor with Inverter Internal to Rotor)type of the propulsion motors is used. these parts interact with each other to calculate the loss and temperature of device. calculated Results is modeled and designed of the control and monitoring system for the electric propulsion system.

• 대한조선학회 특별논문집
• /
• 대한조선학회 2008년도 특별논문집
• /
• pp.38-45
• /
• 2008

The application of the electric propulsion system to the vessels has recently become common due to the latest technology for controlling the electric motors with variable speed. However it has been found that harmonic distortion exists in the electric propulsion system, which consists of an electric motor, a converter and an inverter, and this harmonic distortion has a harmful effect on the system. In this paper, the definition of the harmonic distortion and problems caused by the harmonic distortion in the electric propulsion of the vessels are introduced and the practical solutions for the problems are investigated.

• 한국추진공학회:학술대회논문집
• /
• 한국추진공학회 2004년도 제22회 춘계학술대회논문집
• /
• pp.601-604
• /
• 2004

Precise position and attitude control of pico-satellite requires huge number of impulses of the order of 10$^{-6}$ Ns. MEMS solid rocket array is a promising propulsion system but the higher degree of miniaturization causes unreliable operation mainly due to quenching. In order to breakthrough this situation, a novel design of solid micro-rocket is proposed, which generates tiny impulses repetitively from a single rocket not from array. This unique micro-rocket is based on the utilization of quenching, which causes propellant reaction to sustain only in a small area. A test chip of a micro solid propellant tank and micro heater array is fabricated and ignition test is conducted. Obtained results show the feasibility of this concept and future direction of this quenching-based propulsion is discussed.

• 항공우주시스템공학회지
• /
• 제15권4호
• /
• pp.21-29
• /
• 2021

As global environmental regulations have been strengthened, the eco-friendly market has grown rapidly. In the field of aircraft, research on electric vertical take-off and landing aircraft that can enter city centers and perform personal air transportation using electric propulsion is ongoing. For aircraft using electric propulsion methods to operate reliably, electric power thrust systems are a key factor. Electric aircraft require a high power density for propulsion systems with strict limits on volume and weight. The efficient control of inverter systems is essential for achieving high power density. Therefore, in this paper, the characteristics of inverters and motors were analyzed through simulations based on the space vector pulse width modulation (PWM) and discontinuous PWM methods for controlling inverter systems.

• 한국해양공학회지
• /
• 제32권1호
• /
• pp.68-75
• /
• 2018

This study deals with the heading angle and depth keeping control technique for an ROV with multiple horizontal and vertical thrusters by thrust allocation. The light work class ROV URI-L, which is under development at KRISO, is a redundant actuating system with multiple thrusters that are larger than the ROV's degree of freedom. In the redundant actuating system, there are several solutions for a specific ROV motion to be performed. Therefore, a thrust allocation algorithm that considers the entire propulsion system should be regarded as important. First, this paper describes the propulsion system of the ROV and introduces the thrust allocation method of each motion controller. In addition, the performance of the controller is examined using a heading angle and depth keeping control test in a stationary state.