• International Journal of Naval Architecture and Ocean Engineering
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• v.9 no.4
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• pp.351-372
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• 2017

Propulsion in waves is a complex physical process that involves interactions between a hull, a propeller, a shaft and a prime mover which is often a diesel engine. Among the relevant components, the diesel engine plays an important role in the overall system dynamics. Therefore, using a proper model for the diesel engine is essential to achieve the reasonable accuracy of the transient simulation of the entire system. In this paper, a simulation model of a propulsion system in waves is presented with emphasis on modeling a two-stroke marine diesel engine: the framework for building such a model and its mathematical descriptions. The models are validated against available measurement data, and a sensitivity analysis for the transient performance of the diesel engine is carried out. Finally, the results of the system simulations under various wave conditions are analyzed to understand the physical processes and compare the efficiency for different cases.

• The Transactions of the Korean Institute of Power Electronics
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• v.10 no.3
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• pp.233-240
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• 2005

In this paper, AC electric vehicle propulsion system(Converter/Inverter) using high power semiconductor, IPM is proposed. 2-Parallel operation of two PWM converter is adopted for increasing capacity of system and the harmonic content is eliminated by the phase shaft between two PWM converters switching phase. 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.

• Journal of the Korean Society of Propulsion Engineers
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• v.15 no.6
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• pp.63-69
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• 2011

The Smart UAV must have the control characteristics of propulsion system necessary for both rotary aircraft and fixed wing aircraft though it equips turbo-shaft engine. To develop an electronic engine controller in the future, it is necessary to accumulate the experience of engine operation and data of tilt rotor aircraft. For this purpose, the computer programs which predict engine performance in the steady state and transient state can be utilized for the supplementation of flight test data. In this work, we developed a dynamic analysis program using engine performance data gathered during the flight tests. In addition the accuracy of the program was verified through comparison with flight test data and the results of steady-state performance analysis program.

• Journal of Advanced Marine Engineering and Technology
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• v.33 no.8
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• pp.1152-1161
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• 2009

The power measurement of main propulsion system on the new vessels can be classified with the direct method acquired from the shaft's strain using strain gauge and the indirect method converted and summed from all of cylinders combustion pressure using mechanical or electrical pickup device during the sea trial. This power is fluctuated by external factors which was influenced by various sea motions with long time interval and by internal factors which was influenced by varying torques of torsional vibration and bending moment, due to mis-aligned shaft and whirling vibration with short time interval. In this paper, the statistical analysis method for the shaft power measurement and assessment using strain gauge in marine vessels are introduced. And these are identified by the low speed two stroke diesel engine model and four stroke medium speed diesel engine model including reduction gear.

• Journal of Advanced Navigation Technology
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• v.27 no.1
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• pp.63-70
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• 2023

In this work, a capacitive wireless power transfer (C-WPT) system is presented for wireless sensor system (WSS) applications in marine propulsion shafts. For a single Q factor on both sides of the coupling capacitor and reactive power removal from the circuit, a double-sided LCLC converter and transformers topology are designed to drive the rotary C-WPT system for WSS on the shaft. Parallel-connected parallel plate rotating capacitors with a capacitance of 170 pF are designed and implemented for the C-WPT system on a snow rotating shaft. In the experimental results, the C-WPT system achieved a transmission efficiency of 66.67% with 7.8 W output power at 3 mm distance and 1 MHz operating frequency. Therefore, it was proved that the fabricated C-WPT system can supply power to the WSS of the rotating shaft.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.22 no.1
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• pp.46-52
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• 2012

Since the engine and reduction gear in a naval vessel are usually supported by the mounting system separately, the misalignment between the input shaft of the reduction gear and the output shaft of the engine should occur caused by ship motion. In this study, this misalignment is estimated from the linear static analysis assuming that the phase of movements of the engine and reduction gear at low frequency range is same and the dynamic effect is not affect to them. Through comparing the relative displacement of the engine and reduction gear calculated from linear static analysis to that from dynamic analysis as well as experiment, the assumption in this study could be verified.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.9
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• pp.1808-1817
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• 2017

Duties required for naval ship such as anti-submarine, anti-ship, and supply, etc are diversified, so the ECS (Enfineering Control System) is required for executing the mission effectively. The ECS monitors and controls the propulsion system in order that naval ship can perform the mission. As the in-country development of ECS is progressed, a test system for ECS is needed, and a naval ship propulsion system simulator based on CODOG was developed on this study. The naval ship propulsion system simulator based on CODOG which is divided into gas turbine model, diesel engine model, reduction gear model and controllable pitch propeller model, simulates to feedback of control commands of ECS. As a result of the experiment, it is able to confirm speed, torque and power, etc. of the gas turbine, diesel engine and shaft according to ECS propulsion mode.

• Journal of the Korean Society of Propulsion Engineers
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• v.2 no.2
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• pp.38-46
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• 1998

A theoretical and an empirical application of the speed control of a single-shaft turbo-jet engine was done using an observer for Linear Quadratic Gausian(LQG) that is one of the robust control fields. Based on a general controller design with state feedback, a controller with output feedback was designed to find out a sufficient condition in finding an Asymptotic Stability After defining of the total system through the modeling of a real turbo-jet engine, a Tracking Control was carried out. Furthermore, a saturation of the control input was theoretically considered in the output feedback controller to simulate more similar real condition.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• v.y2005m4
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• pp.248-251
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• 2005

In this paper, health monitoring technique has been studied for performance deterioration caused by the defects of the gas turbine. The parameters for performance diagnostics have been extracted by using GSP program for modeling the target engine. The virtual sensor model for the health monitoring has been built of those data. The position and magnitude of the defects of the engine components have been determined by using Multiple Linear Regression technique and the method using the weight in order to diagnose the single and multiple defects.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2006.05a
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• pp.209-212
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• 2006

In this study, Support Vector Machine(SVM) and Artificial Neural Network(ANN) are used for developing the defect diagnostic algorithm of the aircraft turbo-shaft engine. Effect of altitude variation on the Defect Diagnostics algorithm has been included and evaluated. Separate learning Algorithm(SLA) suggested with ANN to loam the performance data selectively after classifying the position of defects by SVM improves the classification speed and accuracy.