• 전력전자학회논문지
• /
• 제22권4호
• /
• pp.353-359
• /
• 2017

To take advantage of electric propulsion, several large vessel kinds, namely, cruise vessels, icebreakers, drill ships, and warships, have been generally designed with Integrated Power System (IPS). Although most of these vessels have adopted AC distribution IPS, DC distribution IPS ships have recently emerged as a new promising technology thanks to the availability of the products related to the DC distribution system, in which the system's major advantages over AC distribution are reduced weight and fuel consumption. This paper presents the comparison results of a 10-t class fishing boat for the AC distribution and DC distribution cases. By replacing AC distribution system with DC distribution, 31-41% reduction in the weight of the electrical equipment weight and 20-25% reduction in the fuel consumption are expected.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2005년도 추계학술대회 논문집 전력기술부문
• /
• pp.20-23
• /
• 2005

This paper introduces the latest discussions on the Integrated Dispatch Center (IDC, or Integrated Control Center: ICC) for the Northeast Asia Region Interconnected Power System (NEAR-IPS). The IDC is for the safety and economical operation of the NEAR-IPS. The status and plans of the EPSs and the control systems (or dispatch centers) to be interconnected shall be reviewed and the consideration on the IDC to be built in the future shall be discussed.

• 대한산업공학회지
• /
• 제42권2호
• /
• pp.151-164
• /
• 2016

In this paper, we deal with a risk analysis for an IPS (Integrated power system) and propose a simulation model combining the fault tree and event tree in order to estimate the system availability and risk level, together. Firstly, the basic information such as operational scenarios, physical structure, safety systems is explained in order to make the fault tree and event tree of the IPS. Next, we propose a discrete-event simulation model using a next-event time advance technique to advance the simulation time. Also the state transition and activity diagrams are explained to represent the relationship between the objects. By numerical examples, the redundancy allocation is considered in order to decrease the risk level of the IPS.

• Journal of Advanced Marine Engineering and Technology
• /
• 제38권9호
• /
• pp.1070-1074
• /
• 2014

IEEE 1662(2009)에 따르면 통합 전력 시스템(이하 IPS)은 함정의 모든 동력기관(Prime mover)이 전력만을 생산하고 생산된 전력을 통합하여 추진과 무기체계, 함정 내 소요처에 공급하는 체계를 말한다. IPS의 특징은 원동기 배치의 유연성, 원동기와 추진기의 기계적인 분리, 에너지전환 및 전달의 여유 증가 그리고 미래 전자무기의 사용을 위하여 재분배가 가능한 전력의 유연성들이다. IPS는 동력기관이 최적부하에서 운전될 수 있도록 전력생산단계를 다양하게 가질 수 있다. 본 연구는 IPS의 원동기 구성 방식에 따른 적합성을 정량적으로 평가할 수 있는 평가 인자와 평가 방법에 대한 연구이다. 즉, 구축함급 함정에 발전용 디젤 기관과 발전용 가스터빈 기관으로 구성되는 IPS를 운용할 경우를 가상하여, IPS 동력 시스템의 다양한 구성 방법들의 특징을 비교 분석하여 평가함으로써 IPS를 최적화할 수 있는 방안에 관하여 연구하였다. 평가 인자는 동력 시스템의 최적화 대상인 전투 능력과 경제성 두 요소를 고려하여 검토하였다.

• 전력전자학회논문지
• /
• 제20권1호
• /
• pp.45-50
• /
• 2015

The simulation model of All-Electric-Ship consists of electrical and mechanical systems. Running the total simulation requires considerable time and causes a lack of computer memory, because the two systems have different dynamic characteristics. Therefore, integrated simulation is practically impossible. This paper proposes the simplified model of electrical system to reduce simulation time significantly, compared to the detailed model. The validity of the proposed simplified model is verified by comparing detailed and simplified simulation results. Thus, the simplified models are applied to the integrated system. As a result, total system simulation can be implemented.

• Journal of Power Electronics
• /
• 제18권6호
• /
• pp.1844-1854
• /
• 2018

Isolated power systems (IPS) are often characterized by a weak grid due to small power grids. The grid side voltage is no longer equivalent to an ideal voltage source of an infinitely big power grid. The conversion control of new energy sources, parameter perturbations as well as the load itself can easily cause the system voltage to oscillate or to become unstable. To solve this problem, increasing the energy-storage power sources is usually used to improve the reliability of a system. In order to provide support for the voltage, the energy-storage power source inverter needs an method to control the voltage source. Therefore, this paper has proposed the active damping control of a voltage source inverter (VSI) based on virtual compensation. By simplifying the VSI double closed-loop control, two feedback compensation channels have been constructed to reduce the VSI output impedance without changing the characteristics of the voltage gain of a system. This improvement allows systems to operate stably in a larger range. A frequency-domain analysis, and simulation and experimental results demonstrate the feasibility and effectiveness of the proposed method.

• Journal of Power Electronics
• /
• 제17권2호
• /
• pp.380-388
• /
• 2017

Since the carrier sequence is not reproducible in a period of the random carrier pulse width modulation (RCPWM) and a higher harmonic spectrum amplitude is likely to affect the quality of the power supply. In addition, electromagnetic interference (EMI) and mechanical vibration will appear. To solve these problems, this paper has proposed an optimal RCPWM based on a genetic algorithm (GA). In the optimal modulation, the range of the random carrier frequency is taken as a constraint and the reciprocal of the maximum harmonic spectrum amplitude is used as a fitness function to decrease the EMI and mechanical vibration caused by the harmonics concentrated at the carrier frequency and its multiples. Since the problems of the hardware make it difficult to use in practical engineering, this paper has presented a hardware system. Simulations and experiments show that the RCPWM is effective. Studies show that the harmonic spectrum is distributed more uniformly in the frequency domain and that there is no obvious peak in the wave spectra. The proposed method is of great value to research on RCPWM and integrated power systems (IPS).

• 한국추진공학회지
• /
• 제25권6호
• /
• pp.53-59
• /
• 2021

한국 해군은 짧은 역사에도 불구하고 많은 전함을 운용하고 있다. 잠수함, 구축함, 호위함, 고속함 등 다양한 유형의 함정을 보유하고 있다. 각각의 함정은 운영 요구 사항에 적합한 추진시스템을 사용한다. 하이브리드 추진시스템은 함정의 기술발전에 따라 기계추진시스템에서 기계-전기추진시스템으로 발전하고 있으며, 향후 통합 전기추진시스템도 도입될 것으로 기대된다. 따라서 본 논문에서는 한국 해군이 운용하는 주요 함정의 추진체계를 조사하고, 향후 해군력의 변화를 예측하여 향후 해군 함정추진체계를 제안한다.

• 전기학회논문지
• /
• 제66권1호
• /
• pp.33-39
• /
• 2017

A top priority in the design of underwater vehicle is to guarantee the dependability of the electric system because failure of the electrical power supply system is directly related to the life of the passengers. In this paper, we present four kinds of alternative designs to improve reliability of electrical system in underwater vehicle. To reduce the risk and to increase availability of the electrical system, we use the redundancy of the grid structure and power converter. For all design alternatives, we carry out Fault Tree Analysis. Based on the FTA result, we implement RAM simulation to compare the risk and availability for the proposed design alternatives.

• Nuclear Engineering and Technology
• /
• 제53권1호
• /
• pp.148-163
• /
• 2021

Timely fault identification is important for safe and reliable operation of the electric valve system. Many research works have utilized different data-driven approach for fault diagnosis in complex systems. However, they do not consider specific characteristics of critical control components such as electric valves. This work presents an integrated shallow-deep fault diagnostic model, developed based on signals extracted from DN50 electric valve. First, the local optimal issue of particle swarm optimization algorithm is solved by optimizing the weight search capability, the particle speed, and position update strategy. Then, to develop a shallow diagnostic model, the modified particle swarm algorithm is combined with support vector machine to form a hybrid improved particle swarm-support vector machine (IPs-SVM). To decouple the influence of the background noise, the wavelet packet transform method is used to reconstruct the vibration signal. Thereafter, the IPs-SVM is used to classify phase imbalance and damaged valve faults, and the performance was evaluated against other models developed using the conventional SVM and particle swarm optimized SVM. Secondly, three different deep belief network (DBN) models are developed, using different acoustic signal structures: raw signal, wavelet transformed signal and time-series (sequential) signal. The models are developed to estimate internal leakage sizes in the electric valve. The predictive performance of the DBN and the evaluation results of the proposed IPs-SVM are also presented in this paper.