• Proceedings of the KIPE Conference
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• 2012.07a
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• pp.132-133
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• 2012

마이크로그리드에서 계통 연계 운전시 분산발전시스템은 계통과 함께 부하의 수요를 담당하게 된다. 그러나 계통사고로 인해 시스템이 단독 운전모드로 동작시에는 계통과의 연결 없이 분산 발전만으로 부하의 수요를 담당해야한다. 이때 드룹제어방식은 적절한 부하 sharing을 가능케하고 전압과 주파수를 안정적으로 유지할 수 있게해준다. 따라서 본 논문에서는 드룹제어방식의 단독운전모드시의 인버터 병렬 운전 제어를 통한 13kW급 풍력발전 시스템을 제안하였고 PSIM을 이용한 시뮬레이션을 통해 이를 검증하였다.

• Journal of the Korean Society for Precision Engineering
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• v.30 no.10
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• pp.1103-1109
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• 2013

This paper presents an optimal capacity design of a Hybrid generation system based on economical evaluation for various loads. Optimal sizes of a standalone and grid connection wind- PV hybrid systems were designed for normal, residential and industrial loads using HOMER (Hybrid Optimization Model for Electronic Renewable). Their economical evaluation were performed and compared with a diesel generation system that covers the same loads. The results showed that the stand alone hybrid generation system can be more economical than a diesel generation system for long term operation.

• Proceedings of the Korean Society of Computer Information Conference
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• 2022.07a
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• pp.493-494
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• 2022

본 논문에서는 독립형 하이브리드 발전을 위한 효율적안 운영방법을 제안한다. 별도의 정원이 없는 오지에서 독립적으로 동작하기 위해 태양광과 풍력 또는 소수력을 활용하여 두 가지 이상의 발전을 이용하여 발전할 수 있는 하이브리드 발전을 이용한다. 또한 발전된 전원을 야간에도 사용할 수 있도록 저장할 수 있는 배터리를 내장하여 동작할 수 있도록 한다, 배터리의 이용은 발전이 발생되는 구간과 발전이 되지 않는 구간으로 나누어 설계하였다. 발전이 이루어지는 구간은 하나의 발전과 2개의 발전으로 분리하여 하나의 발전만 이루어지는 구간은 일반적인 CC/CV(정전류/전전압) 방식을 이용하여 일반 충전을 수행하고 두 개의 발전이 동시에 이루어지는 구간은 CC(전전류) 모드를 최대한 활용하는 급속 충전을 수행한다. 본 논문에서 제안한 방법은 2개 이상의 발전을 활용하여 독립적인 기능 수행이 가능한 하이브리드 발전을 이용한 독립형 장치로서 장소와 환경의 제한이 적어 실용가능성을 나타내었다.

• Journal of Power Electronics
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• v.15 no.5
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• pp.1318-1328
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• 2015

The photovoltaic (PV) power conditioning system for small-scale applications has gained significant interest in the past few decades. However, the standalone mode of operation has been rarely approached. This paper presents a two-stage multi-level micro-inverter topology that considers the different operation modes. A multi-output flyback converter provides both the DC-Link voltage balancing for the multi-level inverter side and maximum power point tracking control in grid connection mode in the PV stage. A modified H-bridge multi-level inverter topology is included for the AC output stage. The multi-level inverter lowers the total harmonic distortion and overall ratings of the power semiconductor switches. The proposed micro-inverter topology can help to decrease the size and cost of the PV system. Transient analysis and controller design of this micro-inverter have been proposed for stand-alone and grid-connected modes. Finally, the system performance was verified using a 120 W hardware prototype.

• Convergence Security Journal
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• v.24 no.2
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• pp.175-180
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• 2024

Future warfare is evolving with advanced science and technology, introducing a variety of unmanned and manned combat systems. These systems generate and exchange massive amounts of information, challenging current tactical communication systems as a foundation for future communication infrastructure. To analyze the information distribution capability of the Army TIGER corps, this paper examines four scenarios: standalone ground network operation, integrated network operation, load distribution, and error recovery. Utilizing M&S results, we highlight the potential of a multilayer integrated command and control network, incorporating ground, air, and space networks, to enhance the reliability and stability of the overall communication network.

• The Journal of the Korea institute of electronic communication sciences
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• v.14 no.2
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• pp.351-360
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• 2019

Recently, the use of ESS facilities has been increased under the government's energy policy and at the same time, the various accident incidents such as fire and explosion occurred. Currently the ESS is installed as integrated ESS which includes PMS(: Power Management System), However, when the accident occurs, this system has high possibilities of losing the data due to oxidization, and the administrator cannot respond promptly. Therefore, in this paper, by constructing a separate WAS and data storage, it is possible to separate the main functions of the conventional system, to enable external EMS operation, and at the same time to quickly respond to the cause and cause of the accident occurrence. We will propose the development of a standalone PMS that is possible to respond.

• The Transactions of the Korean Institute of Power Electronics
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• v.18 no.6
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• pp.579-586
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• 2013

This paper proposes a mode transition algorithm between the grid-tied and the stand-alone operations for the single-phase inverter with the energy storage system. For the grid-tied operation, the dc-link voltage and the output current are required to be control. For the stand-alone mode, both the output voltage and the output current should be regulated. In order to mitigate a falling-off in control performance during transients in mode change, the load power estimation and the current selection schemes are proposed. The proposed method allows an optimized current reference is selected to reduce an output voltage drop and an excessive over-current in transient. To verify the effectiveness of the proposed method, both the simulation and the experiments for a 3kW single-phase inverter with the energy storage system have been conducted. From the results, it has been confirmed that the proposed method reduces a transient error as well as implementing smooth mode transition.

• Journal of Electrical Engineering and Technology
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• v.11 no.1
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• pp.117-124
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• 2016

Solar photovoltaic pumping system is one of most important of renewable energy applications especially in rural areas. Besides, the control strategy for standalone solar pumping system based on induction motor and without DC/DC converter has been widely studied and discussed in the literature. This topology is of great concern due its economic issues, especially when a standard frequency converter (SFCs) with scalar control is used instead of a dedicated PV inverter. This paper proposes an external control module to generate SFCs frequency reference in order to ensure both maximum power point tracking (MPPT). We present method of modeling and control of photovoltaic pumping system based centrifugal pump controlled by new improved incremental conductance in order to optimize the price and operation of pumping system this MPPT algorithm have many advantages like can be eliminate proportional integral controller It is a low cost solution since it requires no additional power equipment. The induction motor driven pump that is powered by a solar array is controlled by the indirect field oriented control (IFOC). The effectiveness of the proposed approach is illustrated by simulations carried out under Matlab Software. The experimental results are compared with simulation results.

• Journal of Advanced Navigation Technology
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• v.18 no.4
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• pp.268-277
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• 2014

It is very important to correlate flight plan for safe and prompt ATC(air traffic control) operation. In this paper, we design CWP(controller working position) MRT(multi radar tracking) processing module to achieve improvement of overall ATC automation system's performance by minimizing network traffic overload when correlating MRT with flight plan. This implemented module can guarantee efficiency and safety of ATC automation system by applying distributed correlated manner, and reduce network usage by using encoded flight plan correlated MRT data format. We found that this module has 8.54~12.11% lower network usage and 8.37~11.27% higher network traffic fairness than the module using standalone manner.

• Ceramist
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• v.22 no.1
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• pp.56-69
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• 2019

Recent advances in low-power sensors and transmitters are driving the search for standalone power sources that utilize unused ambient energy. These energy harvesters can alleviate the issues related to the installation and maintenance of sensors. Particularly piezoelectric energy harvesters, with the ability to convert ambient mechanical energy into useful electricity, have received significant attention due to their high energy density, low cost and operational stability over wide temperature and pressure conditions. In order to maximize the generated electrical power, the natural frequency of the piezoelectric energy harvester should be matched with the dominant frequency of ambient vibrations. However, piezoelectric energy harvesters typically exhibit a narrow bandwidth, thus, it becomes difficult to operate near resonance under broadband ambient vibration conditions. Therefore, the resonating of energy harvesters is critical to generate maximum output power under ambient vibration conditions. For this, energy harvesters should have broadband natural frequency or actively tunable natural frequency with ambient vibrations. Here, we review the most plausible broadband energy harvesting techniques of the multi-resonance, nonlinearity, and self-resonance tuning. The operation mechanisms and recent representative studies of each technique are introduced and the advantages and disadvantages of each method are discussed. In addition, we look into the future research direction for the broadband energy harvester.