• Journal of Electrical Engineering and Technology
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• 제6권6호
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• pp.750-759
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• 2011

This paper focuses on the control of bidirectional power flow in the electric shipboard power systems, especially in the Medium-Voltage Direct Current (MVDC) shipboard power system. Bidirectional power control between the main MVDC bus and the local zones can improve the energy efficiency and control flexibility of electric ship systems. However, since the MVDC system contains various nonlinear loads such as pulsed power load and radar in various subsystems, the voltage of the MVDC and the local zones varies significantly. This voltage variation affects the control performance of the bidirectional DC-DC converters as exogenous disturbances. To improve the control performance regardless of uncertainties and disturbances, this paper proposes a novel controller design method of the bidirectional DC-DC converters using $L_1$ control theory and intelligent optimization algorithm. The performance of the proposed method is verified via large-scale real-time digital simulation of a notional shipboard MVDC power system.

• 전력전자학회논문지
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• 제17권2호
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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.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 1997년도 춘계학술대회논문집; 경주코오롱호텔; 22-23 May 1997
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• pp.545-550
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• 1997

It is well known that Statistical Energy Analysis(SEA) is one of very attractive analytical methods to solve shipboard noise problems. With reasonable successes, many applications of SEA to shipboard noise prediction have been reported. However when one wishes to obtain theoretical predictions by using SEA in practical systems, he will find difficulty in modeling of source systems, that is, foundations where to place main engine, generator, compressor, and so on. Also, he will find that it is hard to determine the amount of power flow from machinery to structures. In this paper, SEA of a simple foundation model was carried out using the estimated amount of power flow from source; the estimated mobility method. The comparison between the estimated and measured results is presented. That comparison shows a method to get structure-borne noise power from the combination of machinery and foundation. This prediction method gave a good results for a air-compressor mounted on a model foundation. The method is expected to give a reasonable power output in practical problems.

• International Journal of Naval Architecture and Ocean Engineering
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• 제10권1호
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• pp.37-47
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• 2018

Dynamic simulation is critical for electrical ship studies as it obtains the necessary information to capture and characterize system performance over the range of system operations and dynamic events such as disturbances or contingencies. However, modeling and simulation of the interactive electrical and mechanical dynamics involves setting up and solving system equations in time-domain that is typically time consuming and computationally expensive. Accurate assessment of system dynamic behaviors of interest without excessive computational overhead has become a serious concern and challenge for practical application of electrical ship design, analysis, optimization and control. This paper aims to develop a systematic approach to classify the sophisticated dynamic phenomenon encountered in electrical ship modeling and simulation practices based on the design intention and the time scale of interest. Then a novel, comprehensive, coherent, and end-to-end mathematical modeling and simulation approach has been developed for the latest Medium Voltage Direct Current (MVDC) Shipboard Power System (SPS) with the objective to effectively and efficiently capture the system behavior for ship-wide system-level studies. The accuracy and computation efficiency of the proposed approach has been evaluated and validated within the time frame of interest in the cast studies. The significance and the potential application of the proposed modeling and simulation approach are also discussed.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2016년도 전력전자학술대회 논문집
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• pp.431-432
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• 2016

본 논문에서는 선박 전력 응용을 위해 가스터빈에 대한 Rowen 모델을 채택하여 유도 전동기로 그 특성을 모의하는 시뮬레이터를 개발하고자 한다. PSIM을 이용한 시뮬레이션 결과가 제시된다.

• 한국소음진동공학회논문집
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• 제20권7호
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• pp.685-692
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• 2010

A hybrid mount for shipboard machinery installed on naval ships was developed. The mount is combined with a rubber mount and a piezostack actuator. The rubber mount is one of the most popular and effective passive mounts to have been applied to various vibration systems to date. The piezostack actuator is featured by a fast response time, small displacement and low power consumption. Through a series of experimental tests conducted in accordance with MIL-M-17185A(SHIPS), MIL-M-17508F(SH), and MIL-S-901D which are US military specifications related to the performance requirements of the mount, it has been confirmed that the hybrid mount shows more effective performance for use in naval ships.

• 한국군사과학기술학회지
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• 제24권1호
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• pp.50-60
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• 2021

For conventional AESA radars, DC-DC power modules using 300 Vdc have low efficiency, high volume, heavy weight, and high price, which have problems in modularity with T/R module groups. In this paper, to improve these problems, we propose a distributed DC-DC power module with high-voltage 800 Vdc and high-efficiency Step-down Converter. In particular, power requirements for modern and future marine weapons systems and sensors are rapidly evolving into high-energy and high-voltage power systems. The power distribution of the next generation Navy AESA radar antenna is under development with 1000 Vdc. In this paper, the proposed highvoltage, high-efficiency DC-DC power modules increase space(size), weight, power and cooling(SWaP-C) margins, reduce integration costs/risk, and reduce maintenance costs. Reduced system weight and higher reliability are achieved in navy and ground AESA systems. In addition, the proposed architecture will be easier to scale with larger shipboard radars and applicable to other platforms.

• Journal of Advanced Marine Engineering and Technology
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• 제32권8호
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• pp.1278-1284
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• 2008

Electric propulsion motors are operated from a variable frequency drive, which supplies power to motors at a frequency appropriate to the desired speed. The objective of this study was to evaluate power converters for shipboard applications and to recommend converters that meet lower harmonic distortion levels and torque ripples. Two systems were studied in detail : Cyclo-converters and PWM-converters. Cyclo-converters are the obvious choice where size, weight and efficiency are the most critical issues. However they have a disadvantage in power factor and they produce severe torque ripples in the motor which makes them unacceptable without special systems. PWM-converters produces better motor current waveform and eliminates common mode voltage issues at the motor, but suffers a multiple stages of power conversion and the isolating transformer. Results of this case study show that PWM-converters are more advanced and efficient drives for induction motor of electric propulsion ship.

• 한국정보통신학회논문지
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• 제13권12호
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• pp.2618-2624
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• 2009

전기추진선박의 추진시스템에서 중요하게 고려해야 할 사항이 전력변환장치에 의해 전동기에 공급되는 전압 및 전류에 포함되는 고조파 성분을 억제하는 것이다. 근래에 특수선박의 전기추진시스템에서 속도 및 토크제어기법으로 많이 사용하고 있는 벡터제어방식이 많은 제어기와 복잡한 연산을 요구하고 토크의 동적 특성이 전동기의 정수변화에 영향이 큰 단점을 가지고 있어서 대안으로 제시되고 있는 제어기법 중에 하나가 직접토크제어방식이다. 하지만 직접토크제어방식은 영벡터를 인가하지 않으므로 토크리플이 심하여 공급 전류파형에 고조파 성분이 포함되는 단점을 가지고 있으므로 이를 해결해야 한다. 본 논문에서는 유도전동기를 추진기로 채용하고 있는 LNG 선박의 전기추진시스템에서 직접토크제어방식을 사용하는 경우에 고조파 발생을 저감하기 위한 제어방식을 제시한다. 새로운 직접토크제어방식은 샘플링 주파수의 변화없이 복잡한 제어기를 사용하지 않고 인버터 스위칭 주파수를 일정하게 유지한 채 개선된 공간벡터 변조법에 의해 인버터를 제어하는 방식이다. 제안된 방식의 유효성은 추진기에 공급되는 전류파형에 포함된 고조파 성분의 분석과 속도제어 특성을 통해 입증한다.

• Strategy21
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• 통권34호
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• pp.178-206
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• 2014

The battlefield environment in the maritime has been changed by advanced IT technology, variation of naval warfare condition, and developed military science and technology. In addition, state-of-the-art surface combatants has become to multi-purpose battleship that is heavily armed in order to meet actively in composed future sea battlefield condition and perform multi-purpose missions as well as having capability of strategic strike. To maximize the combat strength and survivability of ship, it is not only possible for Zumwalt(DDG-1000) class combatant to conduct multi-purpose mission with advanced weapon system installation, innovative hull form and upper structure such as deckhouse, shipboard high-powered sensor, total ship computing environment, and integrated power control but it was designed so that can be installed with energy based weapon systems in immediate future. Zumwalt class combatant has been set a high value with enormous threatening surface battleship in the present, it seems to be expected that this ship will be restraint means during operation in the littoral. The advent of Zumwalt class battleship in the US Navy can be constructed as a powerful intention of naval strength building for preparing future warfare. It is required surface ship that can be perform multi-purpose mission when the trend of constructed surface combatants was analyzed. In addition, shipboard system has been continuously modernized to keep the optimized ship and maximize the survivability with high-powered detection and surveillance sensor as well as modularity of combat system to efficient operation.