• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2007.11a
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• pp.35-38
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• 2007

Aiming at time-dependent performance prediction of Liquid Rocket Engine(LRE) system, Modular Program for Conceptual Design of LRE is reviewed, and a modeling and dynamic analysis of rocket engine system with reference to Rocket Engine Dynamic Simulator(REDS) is outlined. Component modeling is based on classical thermodynamic and inviscid theories, and were formulated mathematically in terms of essential parameters. Essential design parameters are addressed. The rocket engine is modeled as a system of pipes with various hydraulic elements, and then the operate characteristic of that elements are simulated by solving conservation equation sequentially.

• Proceedings of the KIEE Conference
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• 2000.07b
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• pp.1140-1142
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• 2000

This paper describes a down-scaled model for a high-speed railway train. The propulsion system of simulator consists of four line-side converters four induction motors driven by two inverters, an eddy current braking system, two dynamic braking systems. The control algorithm of traction and braking including anti-skid control can be developed using the simulator. Simulator design procedure. control algorithm and some experimental waveforms are presented in this paper.

• Proceedings of the KIEE Conference
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• 2001.07b
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• pp.1079-1081
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• 2001

A propulsion system apparatus is needed for a railroad vehicle to test and estimate propulsion performance. The electrical inertia simulator to facilitate the development and testing of propulsion systems, is presented in this paper. It is based on a vector-controlled induction motor drive supplied from the AC mains through a double PWM converter that provides desirable features such as bi-directional power flow, nearly unity power factor and low harmonic factor at the AC mains. A theoretical analysis is first presented, followed by a detailed simulation study to assess the overall system performance under dynamic conditions.

• Proceedings of the KSR Conference
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• 2006.11a
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• pp.161-169
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• 2006

To develop a Maglev successfully, it is necessary to develop the core technologies such as levitation and propulsion system and construct engineering system which can integrally evaluate performances of Maglev and provide technical reviews parametrically In this paper, we designed the Maglev running performance simulator which can provide decision-making Information for direction of development of Maglev and examination for running performance about the change of various design parameters such as safety and stability, noise, and ride quality. The designed system is an engineering-based system and can be developed using engineering framework by KIMM which can integrate diverse CAE systems in distributed environments and provide systematic information management. And it also provides VR-based visualization and web-based user interface except VR system which requires special hardware system.

• Journal of Hydrogen and New Energy
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• v.35 no.2
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• pp.230-239
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• 2024

Efforts are being made to replace ship diesel engines with electric propulsion motors in response to emission regulations. In particular, in the case of short-range small ships, research is being conducted to replace polymer electrolyte membrane fuel cells (PEMFC) with power sources. However, PEMFC has problems such as slow dynamic response characteristics and reduced durability at high temperatures. To solve this problem, a high-precision ship model was developed with power distribution and thermal management strategies applied, and through this, the required power, heat, and power characteristics of the propulsion system according to the ship's speed profile were analyzed.

• Journal of the Korean Society of Propulsion Engineers
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• v.19 no.5
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• pp.62-70
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• 2015

A liquid rocket engine system can cause rapid pressure and temperature variations during the startup period. Thus the startup analysis is required to reduce time and expense for successful development of liquid rocket engine through the startup prediction. In this study, a startup analysis simulator is developed for a staged combustion cycle engine powerpack. This simulator calculates propellant flow rates using pressure and flow rate balances. In addition, a rotational speed of turbopump is obtained as a function of time by mathematical modeling. A startup analysis result shows that the time to reach a steady-state and a rotational speed at the steady-state are 1.3 sec and 27,500 rpm, respectively. Moreover it can indicate proper startup sequences for stable operation.

• Proceedings of the KSR Conference
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• 1999.05a
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• pp.291-298
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• 1999

TCMS(Train Control ＆ Management System) is the management system of train information which intensively control, monitor and test the main on-board equipments including propulsion/brake unit by the serial transmission line. TCMS reduces interface circuits and number of train lines by the software logic and utilizing serial communication method. This paper describes the method of powering and braking control by TCMS software logic, in comparison with the powering/braking control by conventional relay logic/hardwire circuits, and the software logic was verified by simulation test with TCMS simulator.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2009.05a
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• pp.417-418
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• 2009

Aiming at time-dependent performance prediction of Liquid Rocket Engine(LRE) system, Program for Dynamic Characteristic Prediction of LRE is overviewed, and a modeling and dynamic analysis of rocket engine system with reference to developed transient simulator for LRE is outlined.

• The Transactions of the Korean Institute of Power Electronics
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• v.7 no.1
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• pp.74-80
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• 2002

A propulsion system apparatus for railroad vehicle is estimated it's performance because of safety and confidence. In general, flywheel type testing method is widely used in the equipment. However, mechanical inertia generated by the flywheel can not be varied (or controlled) and can not be represent actual running resistance. In this study, we have focused on the development of variable vehicle load generation. Therefore, we have proposed the method which uses variable vehicle load controlled by vector motor to get the characteristics of the real vehicle load and confirmed the results with those of computer simulations.

• Journal of Power Electronics
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• v.14 no.2
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• pp.402-412
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• 2014

This paper proposes a novel electric propulsion system for naval ships, which consists of Active Front End (AFE) converters directly connected to battery Energy Storage Modules (ESMs). Employing the proposed AFE converters with ESMs in the power systems of naval ships can enhance the reliability and quality of the electric power. Furthermore, the fuel-efficiency of the generator can be improved by a higher loading factor of the generator and its prime movers. The proposed AFE configuration does not require an additional dedicated DC/AC converter for the ESMs. Instead of that, the AFE converter itself can control the DC link voltage and the discharging and/or charging of the ESMs. A control scheme to achieve these control objectives is also presented in this paper. The overall power system, including the generators and electrical loads of a naval ship, is implemented by a small scaled Power Hardware-In-the-Loop (PHIL) simulator. Through this experimental setup, the proposed system configuration and the power control strategies are verified. It is shown that the fuel-efficiency and transient dynamics can be improved in the normal and contingency operation modes.