• Proceedings of the KSME Conference
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• 2004.04a
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• pp.1250-1254
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• 2004

To develop more compact and light generators which have high capacity, the most important thing that should be considered is the inner cooling system. Under all circumstances, the temperature of rotor and stator windings must be kept below the maximum temperature of insulation to maintain reliability and prolong durability of the machine. Therefore, the development of more effective cooling system and the exact prediction of windings are essential to produce our unique generator model which is reliable and competitive in international market. In this study, the flow of cooling air and the temperature distribution of winding is analyzed by using computational fluid dynamics. This analysis can lead to optimize the structure of cooling system and predict a local temperature rise.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2012.10a
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• pp.777-778
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• 2012

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.4
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• pp.412-417
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• 2015

The IMO MEPC has been increasingly strengthening the emission standard for marine environment protection. In particular, nitrogen oxide (NOx) emissions of all ocean-going ships built from 2016 will be required to comply with the Tier-III regulation. In this study, a vanadia based SCR (Selective Catalytic Reduction) system developed for ship application was installed on a diesel engine for power generation of the training ship T/S SAENURI in Mokpo National Maritime University. For the present study, the exhaust pipeline of the generator diesel engine was modified to fit the urea SCR system. This study investigated the NOx reduction performance according to the two kind of injection method of urea solution (40%): Auto mode through the PLC (Programable Logic Control) and Manual mode. We were able to find the ammonia slip conditions when in manual mode method. So, the optimal urea injection quantity can be controlled at each engine load (25, 35, 50%) condition. It was achieved 80% reduction on nitrogen oxide. Furthermore, we found that the NOx reduction performance was better with the load up-down (while down to 25% from 50%) than the load down-up (while up to 50% from 25%) test.

• Proceedings of the KWS Conference
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• 2001.10a
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• pp.140-142
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• 2001

항공기의 제트 엔진을 비롯하여 육상용 발전기, 선박용 엔진, 로켓 엔진 등에 널리 사용되는 터빈 블레이드를 포함한 고온용 가스터빈 부품은 최대 온도 120$0^{\circ}C$ 이상의 고온에 노출되어 가혹한 기계적 응력을 받는 동시에 고온에서의 표면 안정성이 요구되므로 초내열 니켈 합금(superalloy), 티타늄 합금, 내열강 등의 고온강도가 우수한 합금이 사용된다. 그런데 합금성분이 많이 첨가된 내열 합금을 용접하는 경우, 미세균열, 용접부의 기계적 성질의 저하, 용접열영향부의 내식성과 내산화성의 저하, 용접외부 결함에 의한 피로강도 저하 등의 문제가 발생하므로 이를 해결해야 한다. 본고에서는 생산성과 용접품질이 우수한 고밀도 에너지빔 용접의 적용 현황에 관하여 고찰코자 한다.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.05a
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• pp.648-655
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• 2005

The resilient mounts of a diesel engine installed onboard a ship should be designed for both static and dynamic loads. If possible, the resonance frequencies of the six rigid body modes of the installation and the flexible modes of the engine support structure should not lie within the engine operation range. In this paper a design criterion is proposed to evaluate an isolation system which involves the summation of dynamic forces transmitted through the resilient mounts and elastic potential energy index stored in the mounts. A case study is also presented in which a diesel engine generator, which had an elastic foundation and was mounted in a 5500 TEU container vessel, was studied both theoretically and experimentally. The theoretical analysis of the test model was performed by using a single mass 6 degree of freedom system. Actual measurements of mechanical vibration of the Engine and its foundation onboard were carried out, which showed the importance of including the flexibility of the engine support structure in the mode

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.16 no.4 s.109
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• pp.329-338
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• 2006

The resilient mounts of a diesel engine installed onboard a ship should be designed for both static and dynamic loads. If possible, the resonance frequencies of the six rigid body modes of the installation and the flexible modes of the engine support structure should not lie within the engine operation range. In this paper a design criterion is proposed to evaluate an isolation system which involves the summation of dynamic forces transmitted through the resilient mounts and elastic potential energy index stored in the mounts. A case study is also presented in which a diesel engine generator, which had an elastic foundation and was mounted in a 5500 TEU container vessel, was studied both theoretically and experimentally. The theoretical analysis of the test model was performed by using a single mass 6 degree of freedom system. Actual measurements of mechanical vibration of the engine and its foundation onboard were carried out, which showed the importance of including the flexibility of the engine support structure in the mode.

• Proceedings of the KIEE Conference
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• 2005.10c
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• pp.47-49
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• 2005

최근의 선박 추진시스템은 기존의 엔진, 터빈 둥의 구동 원에서 선박의 발전기로부터 선체 외부의 프로펠러와 일체형으로 구성된 모터를 구동하여 추진하는 전기추진식으로 변화되고 있다. 특히, 히토류계 영구자석재질의 발달로 인하여 대형선박의 추진을 위한 대용량 자석계자형 BLDC와 영구자석형 동기전동기의 설계 연구가 활발히 이루어지고 있다. 그러나 여전히 MW급 대용량 BLDC 추진전동기의 설계 연구는 미흡한 실정이다. 이에 본 연구에서는 5MW급 대용량 BLDC 추진전동기 설계 연구를 진행하였으며, 그 결과 슬롯 수에 의한 고정자 형상이 다른 3가지 타입의 인버터 내장형 MW급 모델을 설계하였다. 그리고 이들 모델들을 정자계 유한요소법을 이용하여 해석함으로써 고정자 형상에 따른 회전특성을 분석하였고, 이를 바탕으로 본 설계 조건에 적합한 고정자 형상 설계 방향을 제시하였다.

• Journal of Advanced Marine Engineering and Technology
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• v.38 no.7
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• pp.909-915
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• 2014

Terminal voltage of the Automatic Voltage Regulator(AVR) of brushless synchronous generator is generally being controlled by PID Control way in shore and ship field. However, in case of changeable large load on power system, PID control method is deficiency to respond output voltage with settling time. Hence, taking into consideration this situation, it is required new control method. In this thesis, we propose Fuzzy Logic Control(FLC) which has more optimal robust control way in order to respond varying values of terminal voltage to the brushless synchronous generator through simulation of MATLAB/SIMULINK and prove Fuzzy logic control more optimal compared with PID control.

• 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.40 no.1
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• pp.39-44
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• 2016

Automated voltage regulators (AVRs) are used on ships and offshore to automatically adjust the voltage based on real-time output voltage readings of the generator engine. Analog-type AVR was previously more commonly used, but is slowly being replaced with digital-type AVR because of increased demands of response time. This study presents a new digital AVR system that contains appropriate features of the AVR with respect to offshore unstable load conditions and poor operating conditions. Furthermore, experiments of load and voltage change prove the excellence of stability and response of the proposed system compared to previous AVR systems. Additionally, an integrated control system for a monitoring the output voltage and field current was developed to easily set the gain value.