• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2007년도 추계학술대회 논문집
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• pp.301-305
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• 2007

This paper is proposed by fuzzy-based MPPT control of photovoltaic to drive induction motor. Design and prototype implement of a fuzzy logic(FL) controller for maxim]m power extraction from a stand-alon photovoltaic Is proposed in this paper. Error and the change of error between maximum power and real power are used by input of fuzzy controller. Moreover, it output changing of voltage from control constant. The validity of this paper is proved by comparing maximum power point tracking and performance of motor drive through comparison fuzzy and PI of tradition method.

• 전기학회논문지
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• 제66권5호
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• pp.757-764
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• 2017

As the reduction of greenhouse gases(GHGs) emission has become a global issue, the microgrid markets are growing rapidly. With the sudden changes in the market, Korean government suggested a new business model called 'Self-Sufficient Energy Islands'. Its main concern is a stand-alone microgrid composed of Distributed Energy Resources(DERs) such as Renewable Energy Sources(RESs), Energy Storage System(ESS) and Fuel Cell, in order to minimize the emission of GHGs. According to these trend, this paper is written to propose an optimal sizing method of DERs in a stand-alone microgrid by using Genetic Algorithm(GA), one of the representative stochastic methods. It is to minimize the net present cost with the variables, size of RESs and ESS. In the process for optimization, the sunless days are considered as additional constraints. Through the case study analysis, the size of DERs installed in a microgrid system has been computed using the proposed method in MATLAB. And the result of MATLAB is compared with that of HOMER(Hybrid Optimization of Multiple Energy Resources), a well-known energy modeling software.

• 한국산림과학회지
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• 제19권1호
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• pp.49-54
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• 1973

면적(面積)이 광대(廣大)하며 지형(地形)은 험준(險峻)한 산림(山林)에서 그의 축적(蓄積)을 조사(調査)하기에는 여러 난점(難點)이 많다. 중량(重量)과 용적(容積)에 비(比)하여 그 가격(價格)이 저렴(低廉)한 임목(林木)의 축적(蓄積)을 조사(調査)하는데 많은 시간(時間)과 노력(勞力)을 소비(消費)함은 산림경영상(山林經營上) 아주 비경제적(非經濟的)이다. 그러므로 항공사진(航空寫眞)만을 가지고 용이(容易)하게 ha 당(當) 임분재적(林分材積)을 추정(推定)할 수 있도록 임분재적표(林分材積表)를 작성(作成)하고 임분재적(林分材積)과 관련(關聯)있는 인자(因子)의 재적추정(材積推定)에의 관여성(關與性)을 구명(究明)하였다. 재료(材料)는 임업시험장(林業試驗場) 광릉시험림내(光陵試驗林內)에 식재(植栽)한 잣나무림(林) 114개소(個所)이며 근래(近來)에 발달(發達)한 통계학(統計學)의 일종(一種)인 다변량해석(多變量解析)과 수량화(數量化)의 이론(理論)을 응용(應用)하였으며 계산(計算)은 한국과학기술연구소(韓國科學技術硏究所)(K.I.S.T.)의 전자계산기연구실(電子計算機硏究室)에서 행(行)하였다. 조제(調製)된 임분재적표(林分材積表)의 중상관계수(重相關係數)는 0.85~0.88 로 상당(相當)히 높은 정확도(正確度)를 갖고 있다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1995년도 하계학술대회 논문집 B
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• pp.603-605
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• 1995

This paper introduces aspects of electrical power system with regard to the application of generator circuit breaker(GCB) in nuclear power generating stations. Technical analyses are performed for the two(2) alternatives, one(1) stand-by auxiliary transformer(SAT) vs two(2) SAT's, on system configuration in case that one(1) GCB is used. The results show that one(1) SAT system may not be justified when larger auxiliary loads are required to increase plant availibility. This paper also presents the feasibility on reliability, operability and maintainability for adopting GCB.

• Journal of Electrical Engineering and Technology
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• 제4권2호
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• pp.211-218
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• 2009

This paper presents a voltage and frequency controller (VFC) for a 4-wire stand-alone wind energy conversion system (WECS) employing an asynchronous generator. The proposed VF con-troller consists of a three leg IGBT (Insulated Gate Bipolar Junction Transistor) based voltage source converter and a battery at its DC bus. The neutral terminal for the consumer loads is created using a T-connected transformer, which consists of only two single phase transformers. The control algorithm of the VF controller is developed for the bidirectional flow capability of the active power and reactive power control by which it controls the WECS voltage and frequency under different dynamic conditions, such as varying consumer loads and varying wind speeds. The WECS is modeled and simulated in MATLAB using Simulink and PSB toolboxes. Extensive results are presented to demonstrate the capability of the VF controller as a harmonic eliminator, a load balancer, a neutral current compensator as well as a voltage and frequency controller.

• 한국전자통신학회논문지
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• 제9권6호
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• pp.641-647
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• 2014

독립형 태양광발전시스템은 배전선로와 계통 연계되지 않고 독립적으로 운영된다는 장점이 있어 시공설비가 간단하고 비용이 적게 드는 장점이 있지만 MPPT를 포함한 컨버터와 생산된 에너지를 배터리에 저장하기 위한 충전회로 및 배터리 매니징 회로가 요구된다. 기존의 대체에너지분야의 이용은 복합발전의 형태보다는 하나의 발전 형태를 주로 채택하고 있으나 태양광/풍력 복합발전시스템을 최적설계하고 배터리능력을 향상시켜 설치가격을 합리화 할 수 있는 통합형 제어시스템이 필요하다.

• Journal of Power Electronics
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• 제16권1호
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• pp.259-267
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• 2016

This paper presents a stand-alone variable speed constant frequency (VSCF) ship shaft generator system based on a brushless doubly-fed machine (BDFM). In this system, the output voltage amplitude and frequency of the BDFM are kept constant under a variable rotor speed and load by utilizing a well-designed current vector controller to regulate the control winding (CW) current. The control scheme is proposed, and the hardware design for the control system is developed. The proposed generator system is tested on a 325 TEU container vessel, and the test results show the good dynamic performance of the CW current vector controller and the whole control system. A harmonic analysis of the output voltage and a fuel consumption analysis of the generator system are also implemented. Finally, the total efficiency of the generator system is presented under different rotor speeds and load conditions.

• ETRI Journal
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• 제29권6호
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• pp.785-793
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• 2007

In this paper, we present an integrated rail-to-rail fully differential operational transconductance amplifier (OTA) working at low-supply voltages (1.5 V) with reduced power consumption and showing high DC gain. An embedded adaptive biasing circuit makes it possible to obtain low stand-by power dissipation (lower than 0.17 mW in the rail-to-rail version), while the high DC gain (over 78 dB) is ensured by positive feedback. The circuit, fabricated in a standard CMOS integrated technology (AMS 0.35 ${\mu}m$), presents a 37 V/${\mu}s$ slew-rate for a capacitive load of 15 pF. Experimental results and high values of two quality factors, or figures of merit, show the validity of the proposed OTA, when compared with other OTA configurations.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 하계학술대회 논문집 D
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• pp.2370-2373
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• 2004

In this paper we describe the design of a Dual-Redundant Power Controller(DRPC) for Control Rod Control System(CRCS). The CRCS also provides information regarding rod motion, rod position, and status of the Rod Control System. It has Hot/Stand-by type, and also has the function of fault detection for controller itself and power modules. We have implemented the various functions with the dual-redundant Power Controller. Due to the developed DRPC, we are assured that the commmecial use by this controller be made before long.

• 한국재료학회지
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• 제27권11호
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• pp.590-596
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• 2017

We demonstrated a CNT synaptic transistor by integrating 6,6-phenyl-C61 butyric acid methyl ester(PCBM) molecules as charge storage molecules in a polyimide(PI) dielectric layer with carbon nanotubes(CNTs) for the transistor channel. Specifically, we fabricated and compared three different kinds of CNT-based synaptic transistors: a control device with $Al_2O_3/PI$, a single PCBM device with $Al_2O_3/PI:PCBM$(0.1 wt%), and a double PCBM device with $Al_2O_3/PI:PCBM$(0.1 wt%)/PI:PCBM(0.05 wt%). Statistically, essential device parameters such as Off and On currents, On/Off ratio, device yield, and long-term retention stability for the three kinds of transistor devices were extracted and compared. Notably, the double PCBM device exhibited the most excellent memory transistor behavior. Pulse response properties with postsynaptic dynamic current were also evaluated. Among all of the testing devices, double PCBM device consumed such low power for stand-by and its peak current ratio was so large that the postsynaptic current was also reliably and repeatedly generated. Postsynaptic hole currents through the CNT channel can be generated by electrons trapped in the PCBM molecules and last for a relatively short time(~ hundreds of msec). Under one certain testing configuration, the electrons trapped in the PCBM can also be preserved in a nonvolatile manner for a long-term period. Its integrated platform with extremely low stand-by power should pave a promising road toward next-generation neuromorphic systems, which would emulate the brain power of 20 W.