• Journal of the Korean Society for Railway
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• v.20 no.3
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• pp.339-348
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• 2017

Power supply for railway cars can be divided into propulsion system power supply and auxiliary power units (APU). The propulsion system power supply is for propulsion of railway cars, and regenerative braking; the APU provides power for the air compressor, lighting, car control and other auxiliary parts. According to high voltage and high current specifications, generally, an insulated-gate bipolar transistor (IGBT) is adopted for the switching component. For appropriate switching operation, a gate driver unit (GDU) is essentially required. In this paper, the technical trends of GDU for railway cars are analyzed and a design consideration for IGBT GDU is described.

• Journal of the Korean Society of Propulsion Engineers
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• v.25 no.5
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• pp.36-52
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• 2021

As the application of nano-satellites constellation increases worldwide in the wake of New Space era, there is growing demand for the development of thrusters for precise attitude and orbit control of small satellites. Field Emission Electric Propulsion(FEEP) thruster uses a liquid metal as a propellant and accelerates the ionized liquid metal through a strong electric field at the tip of the metal surface. FEEP thruster technology is suitable for nano-satellites which require various missions for attitude and orbit control, because it provides thrust ranging from 1 µN to 1 mN with high specific impulse up to about 10,000 s and can be miniaturized due to its simple structure. In this paper, the basics of FEEP thrusters are introduced, then the current status of research and development of FEEP thrusters are presented.

• Journal of Satellite, Information and Communications
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• v.11 no.1
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• pp.58-62
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• 2016

The satellite propulsion system provides the required thrust to insert a satellite into the desired orbit after separation from the launch vehicle and to control orbit inclination or compensate altitude loss due to drag after inserted into the desired orbit. The on-orbit performance of LEO satellite propulsion system according to operation mode was verified based on the results analysis for early on-orbit operation. The temperature trends of components and tubing were checked and the resultant trends were within the normal range as well.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.05a
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• pp.295-298
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• 2008

In this paper, prototype dynamic modeling scheme to control ramjet propulsion systems were proposed. From the physical understandings of engine system, a typical 2nd-order system model was applied to simulate the dynamic characteristics of fuel supply system. The shock location varience in diffuser to chamber pressure fluctuation is calculated so that the out of phase between two signals was observed.

• Aerospace Engineering and Technology
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• v.3 no.1
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• pp.97-102
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• 2004

Propulsion System provides the required velocity change impulse for orbit transfer from parking orbit to mission orbit and three-axis vehicle attitude control impulse. KOMPSAT-2 propulsion system(PS) is an all-welded, monopropellant hydrazine system. The PS consists of the subassemblies and components such as Thrusters, Propellant Tank, Pressure Transducer, Propellant Filter, Latching Isolation Valves, Fill/Drain Valves, interconnecting propellant line assembly, and thermal hardwares for operation-environment control of the PS. This paper summarizes a development process of the liquid propulsion system from the design engineering up to the test and evaluation.

• The Transactions of the Korean Institute of Power Electronics
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• v.4 no.6
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• pp.491-499
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• 1999

This paper is on the high perfonnance propulsion IGBT VVVF inverter adopted new technique for railways. To prove the high performance and stabilit~r of traction, running tests are carried out under the simulated condition alike real field. The tests are perfonned on not only a steady states but also a transient states such a as input voltage variation using inertia load equivalent to 160tons train. The vector control technique is a adopted to improve traction for 4 motors. The low switching synchronous PW1\l method based on a space v voltage vector modulation is pro\XlSed as the optimal method for propulsion system railway. The output voltage l is controlled continuously to six step by prolxlsed ovennodu]ation technique without sudden torque variation.

• Journal of the Korean Society of Propulsion Engineers
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• v.18 no.1
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• pp.91-96
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• 2014

KSLV-I (Korea Space Launch Vehicle-I) upper stage KM (Kick Motor) is a solid propulsion system which consists of igniter, SAD (Safety Arming Device), composite case, and submerged nozzle capable of TVC (Thrust Vector Control) actuation. Each subsystem of KM fulfilled development requirements for achieving a flight mission successfully. We confirmed the successful development of KM from the $3^{rd}$ flight test results of NARO on January 30, 2013. This article deals with the requirements of KM and the results on configuration management, mass variation, thrust axis alignment, and major test results and so on.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2006.05a
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• pp.41-44
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• 2006

The propulsion system of VIA-50A airship consists of engine, generator, inverter, motor and propeller. The motor and propeller was designed that can be tilted to $120^{\circ}$ for thrust vector control. When the flight test was performed, various condition data of the airship were obtained by wireless telecommunication and analyzed in real-time. In this paper, we presented flight test results of propulsion system. Considering the designed requirement and normal range, we verified that all constituent part was operated in normal condition during the high altitude flight test.

• Journal of the Korean Society of Propulsion Engineers
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• v.2 no.3
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• pp.80-89
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• 1998

Propulsion subsystem transfers KOMPSAT into mission orbit and controls its attitude. Design factor consists of structure safety, electrical circuit design, consumable power estimation of thermal hardwares, damping device design of fuel transient pressure, and system configuration design by considering plume effect from thruster firing. System level analysis should be performed for verification of system design under launch vehicle and orbital environment. Electrical functional test of thermal control hardware, proof pressure test, cleanliness verification test, and internal/external leakage test of fuel feeding system should be carried out for performance estimation of propulsion system. Design and assembly process of propulsion subsystem was depicted and reliability of system was verified by test analysis in this paper.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.1200-1203
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• 2017

Propulsion system test complex (PSTC) is designed to verify propulsion system of KSLV-II. It is composed of hydraulic and pneumatic system, test stand system, control/measurement system, and flame deflector and safety system. In this study, kerosene filling system of hydraulic and pneumatic system is introduced. It performs store and chilling of kerosene, chilling and purging of filling line, and filling and retrieval of the kerosene. The kerosene supply requirements of 1, 2 and 3 stages of KSLV-II are considered in design process.