• 전기학회논문지
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• 제61권10호
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• pp.1393-1398
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• 2012

Due to environmental regulation and technical improvements, renewable energy sources (RES) are increasingly penetrated and operated in power systems. Clean energy technologies have become cost-competitive with conventional power systems, and in the near future, the generation cost of RES is expected to approach grid parity. In this situation, it should be considered an extraordinarily important issue to be maximized resulting in utilization of RES as well as to develop technologies for efficiency improvement of RES. Therefore, in this paper, the method for determining an optimal installed capacity and interconnected location of RES is proposed in order to minimize the cost of energy not supplied, which can contribute to improve distribution reliability.

• 대한전기학회논문지:시스템및제어부문D
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• 제53권11호
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• pp.753-759
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• 2004

This paper presents a modeling and simulation of a fuzzy controller for maximum power extraction of a grid-connected wind energy conversion system with a link of a rectifier and an inverter. It discusses the maximum power control algorithm for a wind turbine and proposes, in a graphical form, the relationships of wind turbine output, rotor speed, power coefficient, tip-speed ratio with wind speed when the wind turbine is operated under the maximum power control. The control objective is to always extract maximum power from wind and transfer the power to the utility by controlling both the pitch angle of the wind turbine blades and the inverter firing angle. Pitch control method is mechanically complicated, but the control performance is better than that of the stall regulation method. The simulation results performed on MATLAB will show the variation of generator's rotor angle and rotor speed, pitch angle, and generator output.

• Journal of Electrical Engineering and Technology
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• 제3권4호
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• pp.491-498
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• 2008

In this paper a decoupled control of a doubly-fed induction machine(DFIM) feed by a matrix converter is presented. It provides a robust regulation of the stator side active and reactive powers by the direct and quadratic components of the stator current vector, presented in a line-voltage-oriented reference frame. In this case, the stator windings are directly connected to the line grid, while the rotor windings are supplied by this later through a matrix converter controlled by a space vector modulation technique. The proposed solution is suitable for both energy generation and electrical drive applications with restricted speed variation range.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2015년도 제46회 하계학술대회
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• pp.1641-1642
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• 2015

Recently, the interest about Vehicle-to-Grid(V2G) system which can use the electric vehicles as generation sources or storage devices has rapidly increased. However, this technology does not use widely yet, and there is no clear standard or regulation for it. If electric vehicles are connected to the power system indiscreetly, it can cause problem to personnel safety and adverse effect on the power system. Therefore, it is important to analyze the related standards. In this paper, we introduce some international standard related with V2G system.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2015년도 제46회 하계학술대회
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• pp.1639-1640
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• 2015

These days most of countries concern about eco-friendly energy. With this trend, the interests for Electric Vehicles(EVs) have been increased not only for its eco-friendly characteristics but also for the possibility that it can be used as Distributed Generation(DG). However, in terms of using EVs as DG, it requires specific standards. If there is no regulation and many of EVs start to discharge, it could cause severe unstability in power system. As there is no proper standards or regulations of Vehicle-to-Grid(V2G) system, we suggest the development direction of standardization of V2G system in the Republic of Korea by examining other countries' V2G standards.

• Journal of Electrical Engineering and Technology
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• 제3권2호
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• pp.143-151
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• 2008

This paper presents the operation of Fuel Cell Distributed Generation(FCDG) systems in distribution systems. Hence, modeling, controller design, and simulation study of a Solid Oxide Fuel Cell(SOFC) distributed generation(DG) system are investigated. The physical model of the fuel cell stack and dynamic models of power conditioning units are described. Then, suitable control architecture based on fuzzy logic and the neural network for the overall system is presented in order to activate power control and power quality improvement. A MATLAB/Simulink simulation model is developed for the SOFC DG system by combining the individual component models and the controllers designed for the power conditioning units. Simulation results are given to show the overall system performance including active power control and voltage regulation capability of the distribution system.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2019년도 전력전자학술대회
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• pp.416-417
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• 2019

In this paper, an effective power flow control strategy (PFCS) based on the centralized control approach and a DC-link (DCV) restoration algorithm for DC microgrid (DCMG) are presented. By investigating the statuses of system power units, eleven operating modes are given to ensure the system power balance under various conditions. To avoid the system power imbalance caused by the delay of grid fault detection, a reliable DCV restoration algorithm is proposed. In the proposed scheme, when an abnormal variation of the DCV is detected, the battery instantly starts a local emergency control mode to restore the DCV to the nominal value regardless of the control mode from the central controller. The simulations and experiments are carried out to prove the effectiveness of the PFCS and the proposed DCV restoration algorithm.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2019년도 전력전자학술대회
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• pp.41-43
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• 2019

송전망에 장거리 지중선로로 재생 발전원이 연계되는 경우, 지중선로의 커패시턴스 성분으로 인한 계통으로 무효전력 주입이 발생하여 전압상승을 야기시킬 수 있다. 또한 재생 발전원의 발전량 조절의 어려움은 경부하시 전력 생산과 소비의 불균형을 발생시킬 수 있으며 계통의 전압상승을 심화시킬 수 있다. 계통의 전압상승은 계통의 신뢰도를 저하시키고 계통운영에 어려움을 수반한다. 이러한 전압상승은 무효전력보상을 통해 완화가 가능하다. 인버터 기반의 재생 발전원은 무효전력제어 제어 정밀도가 높고 빠르게 제어가 가능하여 계통의 전압상승 완화에 좋은 솔루션이 될 수 있다. 본 논문에서는 송전망 계통에서의 전압상승 완화를 위한 재생 발전원의 무효전력제어기술을 설명한다. 재생 발전원의 무효전력지원에 따른 전압상승 완화 효과를 평가하기 위해 Matlab을 활용하여 송전망 전압상승 및 재생 발전원의 무효전력지원을 모의하였다. 계통 모델에는 영광의 태양광 및 풍력 발전소와 주변 계통의 파라메터를 적용하여 구현하였다.

• 건축역사연구
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• 제12권1호
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• pp.25-41
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• 2003

This paper is a study of Le Corbusier's trace regulateur of the 1920s, particularly its role in the design of the Villas La Roche-Jeanneret and Stein-de Monzie. It proceeds on the basis of the following three themes: first, the relation between the regulating line and the dom-ino frame; second, its status as a proportional device based not on a module system but one that defines relations; third, its function as an essential practical device in the design process. In the Villa La Roche-Jeanneret, the embedded horizontal planes of the dom-ino frame were constant, but the vortical lines of the columns were altered according to the changes in plan. Initially, a left-hand bay window formed a symmetry with the right-hand bay window, the only constant in the design process. With subsequent changes, mullion sections of the horizontal window and roof elements came to provide the reference points for the regulating line. Eventually, a regulating line different from the one that controlled the bay window and the elongated volume came to control the entrance hall of Villa La Roche, resulting in three different kinds of regulating lines in the final version. In contrast to the Villa La Roche-Jeanneret, a singular and consistent regulation line was anticipated in the earliest design stages of the Villa Stein-de Monzie. The repetition of its A:B grid and the standard $2.5m{\times}1.0m$ sliding window determined the proportions of both its plan and elevation, and thus the regulating line became 'automatic,' losing its viability as a practical tool. Though the regulating titles of the La Roche-Jeanneret look as if they were an afterthought, drawn after the design was complete, they were most active, requiring tenacity and discipline in their application. On the other hand, the seemingly 'redundant' regulating line of the Villa Stein-de Monzie gains its raison d'etre from the dom-ino frame. Its cantilevers and uninterrupted horizontal window could be used in decisive fashion because of the guarantee that the correct proportion would always be maintained. Thus we discover that Le Corbusier's discipline of the 1920s had a certain spectrum of flexibility. His 'parti' ranged from the extremely loose and malleable grid of the Villa La Roche-Jeanneret to the fixed grid of the Villa Stein-de Monzie. In different ways, these projects retain the tension between the dom-ino frame and the regulating line. For Le Corbusier, as much as the grid was an object with fixed attributes, it was also an active medium manipulated by the will of the architect.

• 대한의용생체공학회:의공학회지
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• 제32권1호
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• pp.25-31
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• 2011

Blood glucose information is important for self regulation in daily life, but the frequency of self test remains to be only 17%(9 tests/month) in Korea, mainly due to pain during blood sampling. The present study tried to validate the clinical efficacy of the forearm as an alternative sampling site with minimized pain. Capillary blood was sampled both on the index finger($G_F$) and the forearm($G_A$), immediately followed by glucose measurements in 531 subjects, 25 who visited the Health Enhancement Center of C University Hospital, then venous blood($G_V$) was sampled for glucose test. The blood glucose concentration measured on the forearm was closer to the venous glucose than on the finger. The mean difference between $G_V$and $G_F$ was only 10 mg/dL well within the internationally accepted error limit. Error grid analyses of $G_F-G_V$, $G_A-G_V$ and $G_A-G_F$ revealed that the number of data points in regions A and B took 100%, 99.8%, and 97.9%, respectively. These results demonstrate the forearm blood glucose test is not only accurate but also clinically valid. Therefore, the forearm blood glucose test can be a useful way of self managing the chronic diabetes with minimized sampling pain.