• Special Issue of the Society of Naval Architects of Korea
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• 2008.09a
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• pp.38-45
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• 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.

• Journal of Power System Engineering
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• v.15 no.2
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• pp.78-83
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• 2011

This paper aims at investigation some operating characteristics and energy usage efficiency of a induction motor and a BLDC motor considering electric propulsion system in a small ship based on battery source. At first, performance curves of discharge voltage from the battery and current from each motor according to the load variations were analyzed. Next, variations of motor torque and rotational speed versus load change at each motor were analyzed. Finally, efficiency of energy usage of the battery and available navigation distance were compared each other. Through some comparisons and analyses, it was cleared that the BLDC motor is more suitable for the motor of the electric propulsion system in small ships based on battery source. It is expected that the results can be used as useful data for design of the electric propulsion system with batteries.

• Journal of the Korean Society of Propulsion Engineers
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• v.25 no.6
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• pp.53-59
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• 2021

The ROK Navy operates many war ships despite its short history. Various types of war ships, such as submarines, destroyers, frigates, corvette etc., use suitable propulsion systems for the operational requirements of each war ship. A hybrid propulsion system was introduced to change from the current mechanical propulsion system to an electric propulsion system according to the changing patterns of naval warfare, and it is expected that an integrated electric propulsion system will also be introduced. Therefore, this paper investigates the propulsion system of major ships operated by the Korean Navy, predicts the changes in future naval warfare, and proposes a propulsion system for future ships.

• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.7
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• pp.1238-1243
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• 2022

The International Maritime Organization is at the forefront of strengthening gas emission regulations for ships globally. The Korean government needs to apply measures to reduce emissions, such as setting a basic roadmap for greenhouse gas reduction. In addition, there is an urgent need to introduce a new efficient propulsion system that can reduce gas emissions. This includes applications to fishing vessels, which account for 90.6% of the greenhouse gas emissions from ships sailing along domestic coasts. In this study, an electric-combined propulsion system applicable to domestic coastal fishing vessels was developed. The target ship to which the electric-combined propulsion system could be applied was selected. A simulation system was constructed using MATLAB/Simulink to compare the expected fuel consumption when applying the developed complex electric propulsion system to the propulsion system mounted on the selected target fishing vessel. Through simulations, the differences in fuel consumption between the mechanical propulsion system and the electric hybrid propulsion system (both when charging and not charging the battery on land) were confirmed. The results show that fuel consumption can be decreased by approximately 13% and 16% when applying the electric-combined propulsion system.

• Journal of Power System Engineering
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• v.15 no.5
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• pp.16-21
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• 2011

The large scale decisive battle will be gradually reduced on the sea in the future and surface combatant ship installed advanced weapon units as well as propulsion system will be continuously increased. The high level of military technology leads to appear state-of-the-art weapon system using high power energy. As a results, fossil fuel powered main prime mover as diesel engine and gas turbine which are composed of mechanical propulsion system should be decreased from combatant ship in the near future. The new building naval combatant ship with the latest technology has electric based propulsion method of the hybrid type combined with mechanical and electrical drive. U.S. and Royal Navy, especially, select the integrated fully electric based propulsion system for the next generation combat ship and play an important roll for developing them. In this context, this paper was focused on the deduction of implications through analyzing the combatant ship propulsion system using diesel and gas turbine engine which are promoted on the worldwide.

• Proceedings of the KIEE Conference
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• 2003.04a
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• pp.40-43
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• 2003

An electric propulsion system integrated with the ship service distribution system offers the naval architect considerable flexibility, and often the choice of a more affordable ship to acquire and operate as compared to a segregated mechanical drive option. United States of America navy announced in 2000 that they selected the electric propulsion system on next generation warship. Specially there is excellent advantages in superconductivity motors which can have higher efficiency, less vibration and noise, smaller dimensions compared with the conventional motors. The 5 MW HTS motor for warship test of electric propulsion was developed and tested. Also it was contracted between AMSC and United States of America navy to develop a 36.5 MW HTS motor in 3 years since March 3, 2003. This paper deals with the technical development tendency of HTS motors in foreign countries as well as in domestic, and it is focused on the application of HIS motors to the electrical propulsion system.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.544-547
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• 2011

This paper describes on hardware simulation of passive power control of propulsion system for electric propulsion aircraft of KARI. The propulsion system uses hybrid power system that is composed of solar cell, fuel cell and battery. The fuel cell is replaces by simulator due to its difficulty in handling while the other components are the same as that will be used on board. As the result, reliable power supply for propulsion is confirmed and each power source is well operated showing its characteristics.

• Journal of the Korean Society for Precision Engineering
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• v.33 no.6
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• pp.499-508
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• 2016

This paper describes a study of performance prediction of an electric propulsion system for multirotor UAVs. The electric propulsion system consists of motors, propellers, batteries and speed controllers, and significantly affects performance characteristics of the platform. The performance of the electric propulsion system for multirotor UAVs was predicted using an analytical model derived from the characteristics of each component, operation experiments and statistical analyses. Ground performance tests and endurance flights were performed to verify the reliability of the proposed performance prediction method. A quadrotor platform was designed to demonstrate the parcel delivery service used in the endurance flight. From the result of verification tests, it was confirmed that the proposed method has a good agreement.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.5
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• pp.777-781
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• 2012

In this paper, an electrical power simulation program was developed to predict the energy consumption of the electrical railway propulsion system, which considered the actual operating conditions of the electric railway vehicles. The developed program was designed to predictable the energy consumption during a virtual driving in the actual route of the virtual railway vehicles equipped with a propulsion system consisting of power conversion equipments and traction motors. In addition, the accuracy verification of the electrical power simulation program for a propulsion system was performed by using a real power consumption data, which was measured during the driving of the railway vehicles in the Gyeongui Line. In conclusion, the electrical power simulation program for a propulsion system was validated throughout a comparative investigation between the simulated values and the experimental values and the energy consumption characteristics of electric railway vehicles on the existing route or the new route will be possible to predict throughout the virtual simulation considering the driving conditions of the electric railway vehicles.

• 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.