• The Transactions of the Korean Institute of Power Electronics
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• v.17 no.2
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• pp.114-120
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• 2012

Recently, integrated electric propulsion system has been vigorously adopted into naval vessels. To enhance effectiveness and efficiency of power management in these propulsion systems, this paper investigates necessity of energy storage devices and their operation strategies. By introducing the energy storage devices, engine can operate at higher efficiency point and accordingly costs for fuel and maintenance are significantly reduced. In addition, transient performance can also be improved with support of the devices and it leads to stable operation of shipboard power bus. To validate the proposal of this paper, computer simulation has been conducted with real load data of existing electric propulsion system.

• Journal of the Korean Society of Propulsion Engineers
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• v.14 no.6
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• pp.1-8
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• 2010

In this paper, we present some results of technical surveys, power analyses, and weight estimation on electric propulsion systems for 1-ton class Personal Air Vehicles(PAV) applications. When hybrid electric propulsion is adopted, its power performance using fuel cells and batteries in inferior to that of internal combustion engines. However, hybrid electric propulsion systems may replace IC engines when energy density and power density reach 0.75 kW$^*$hr/kg and 2.5 kW/kg, respectively.

• International Journal of Naval Architecture and Ocean Engineering
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• v.11 no.2
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• pp.765-781
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• 2019

This study predicts the power consumption of an Electric Propulsion Ship (EPS) in marine environment. The EPS is driven by a propeller rotated by a propulsion motor, and the power consumption of the propeller changes by the marine environment. The propulsion motor consumes the highest percentage of the ships' total power. Therefore, it is necessary to predict the power consumption and determine the power generation capacity and the propeller capacity to design an efficient EPS. This study constructs a power estimation simulator for EPS by using a ship motion model including marine environment and an electric power consumption model. The usage factor that represents the relationship between power consumption and propulsion is applied to the simulator for power prediction. Four marine environment scenarios are set up and the power consumed by the propeller to maintain a constant ship speed according to the marine environment is predicted in each scenario.

• Journal of the Korean Society of Propulsion Engineers
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• v.12 no.3
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• pp.76-86
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• 2008

The EP(electric propulsion) is unique in that several energy sources can be utilized to produce the electric energy and that high exhaust velocity can be achieved compared to the conventional chemical propulsion. Though a lot of variety of non chemical propulsion are under study, the fact that the EP's specific impulse ranges widely from 200s to 5000s led most research to concentrate on the electric propulsion research. This paper, therefore, is aimed to introduce the up-todate existing EP family such as electrothermal, electrostatic and electromagnetic thrusters where its operating concepts, characteristics and possible variants are presented for future applications.

• The Transactions of the Korean Institute of Power Electronics
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• v.20 no.4
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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.

• Journal of Navigation and Port Research
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• v.32 no.10
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• pp.765-770
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• 2008

This paper presents the power control for the hybrid electric propulsion system. In this paper, the hybrid propulsion system consists cf the generator and battery as power supply system in ship. The hybrid control system is designed with energy saving algorithm for decreasing the power consumption of power supply system. This paper suggests the method to increase efficiency of hybrid electric propulsion system by developing battery charging system. The performance of power control system is analyzed with the experiment equipment for hybrid propulsion system, and the results showed a good property.

• Journal of IKEEE
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• v.15 no.1
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• pp.96-103
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• 2011

This paper deals with the characteristic analysis of the integrated power system applied for the electric propulsion ships. This includes the electric power system modeling which is accomplished with the electric power network mainly composed of generators, switchboards, variable frequency devices, electric motors, and etc. In addition, performance comparison between the permanent magnet synchronous motor (PMSM) and the induction motor (IM) for 3.7MW ship propulsion has been done. In order to investigated the main performance of propulsion motor, a coupled model taking into account torque density, copper loss, iron loss, efficiency, power factor, and torque ripple using finite element analysis (FEA) has been employed.

• Journal of Advanced Marine Engineering and Technology
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• v.32 no.8
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• pp.1296-1302
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• 2008

This paper deals with modeling and dynamic characteristic analysis of a large-powered LNG electric ship propulsion system. Basically, we perform to verify the adequacy of system modeling on the sea going mode and LNG unloading mode based on load flow analysis. And then, we observe the dynamic characteristic of system to perform motor starting analysis and transient stability analysis. Particularly, this paper examine analysis results in comparison with the IEEE standard 141 and the class rule. Hence, this paper has evaluated stability of the electric ship propulsion system at static and dynamic conditions.

• Proceedings of the KIEE Conference
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• 2001.07b
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• pp.632-634
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• 2001

Recently, almost cruise are manufactured with electric propulsion system. The characteristics and types of the electric propulsion motors, which is one of the most important component in electric propulsion system for ships, are examined and compared. And a trend on the recent technical development of electric propulsion motors for ships is introduced.

• Journal of Ocean Engineering and Technology
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• v.33 no.5
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• pp.447-453
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• 2019

Recently, environmental regulations have been strengthened for SOX, NOX, and CO2, which are ship exhaust gases. In addition, according to the 4th Industrial Revolution, research on autonomous ship technology has become active and interest in electric propulsion systems is increasing. This paper analyzes the power load characteristics of an electric propulsion ship, which is the basic technology for an autonomous ship, in terms of energy management. For the load analysis, data were collected for a 6,800 TEU container ship with a mechanical propulsion system, and the propulsion load was converted to an electric power load and clustered according to the characteristics using a SOM (Self-Organizing Map). As a result of the load analysis, it was confirmed that the load characteristics of the ship could be explained by the operation mode of the ship.