• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.1
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• pp.191-196
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• 2014

For the large scale of electricity consumer, since the price for the electricity consumption depends on the peak power, the issue for peak power reduction have been being studied widely. Electric railway systems, which is one of the most representative large scale of loads, also has assignment to reduce the peak power since they have high peak power and low energy consumption load characteristics. In the aspect of the economic operation through reduction of peak power, this paper proposes a novel algorithm for power management system in electric railway systems using energy storage.

• Journal of the Korean Institute of Intelligent Systems
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• v.23 no.1
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• pp.72-79
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• 2013

In the paper, a pattern analysis to decide whether the 1st local peak power point near open circuit voltage is the global peak power point or not, in case that the voltage and current at the 1st local peak power point are in a specific range, for Maximum Power Point Tracking on the photo voltaic power conversion system. When a solar cell panel array is shaded partially, multi-local peak power points can occur. That makes it hard to search the global peak power point. Through Tableau analysis using by piecewise linear solar cell model, V-I characteristic of a solar cell panel array circuit when partial shading problem happens, is simulated. The global peak power and the local peak power points is confirmed by simulations. Voltage and current values and patterns of V-I characteristic are analyzed. The generating efficiency of the solar cell panel array is improved, when the solar cell panel array circuit is operated at the power point estimated by setting up specific range.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.14 no.4
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• pp.305-312
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• 2014

This paper discusses real-time peak shaving algorithms for a large-scale battery energy storage system (BESS). Although several transmission and distribution functions could be implemented for diverse purposes in BESS applications, this paper focuses on a real-time peak shaving algorithm for an energy time shift, considering wind power generation. In a high wind penetration environment, the effective load levels obtained by subtracting the wind generation from the load time series at each long-term cycle time unit are needed for efficient peak shaving. However, errors can exist in the forecast load and wind generation levels, and the real-time peak shaving operation might require a method for wind generation that includes comparatively large forecasting errors. To effectively deal with the errors of wind generation forecasting, this paper proposes a real-time peak shaving algorithm for threshold value-based peak shaving that considers fuzzy wind power generation.

• Korean Journal of Optics and Photonics
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• v.14 no.2
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• pp.189-193
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• 2003

A two-stage erbium-doped fiber amplifier (EDFA) with a band pass filter is used to get optical pulses of high peak value. The pulse signal has a 32 ㏈ extinction ratio, 125 W peak power and 79 ㎽ pulse off power. A nonlinear optical loop mirror (NOLM) is used to lower the pulse off power so as to increase the extinction ratio. The pulse signal after the NOLM has a 50.4 ㏈ extinction ratio, 35 W peak power and 0.3 ㎽ pulse off power.

• Proceedings of the IEEK Conference
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• 2000.06b
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• pp.217-220
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• 2000

In this paper, A low-power MOS monolithic peak detector is presented. Designed for monolithic and low-power characteristics, this MOS peak detector can be integrated easily on the same chip as a module of large communication systems. The simulation results of this peak detector which was composed with four NMOSs and two capacitors show the power dissipation of 0.972㎽ and the good operations for 2㎓ operating pulse frequency. Therefore, it may be used as a functional block for various signal processing systems.

• ETRI Journal
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• v.28 no.2
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• pp.235-238
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• 2006

In this letter, a block code that minimizes the peak-to-average power ratio (PAPR) of orthogonal frequency division multiplexing (OFDM) signals is proposed. It is shown that peak envelope power is invariant to cyclic shift and codeword inversion. The systematic encoding rule for the proposed code is composed of searching for a seed codeword, shifting the register elements, and determining codeword inversion. This eliminates the look-up table for one-to-one correspondence between the source and the coded data. Computer simulation confirms that OFDM systems with the proposed code always have the minimum PAPR.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.6
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• pp.841-849
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• 2014

Urban railway with rectifiers is connected by parallel circuits because substations are joined by the power rail. Thus, if an input voltage of a substation is increased, then the voltage of rectifiers is also increased, and which leads to an increase in the peak power of the substation. To solve this problem, this paper proposes a new method reducing the peak power of substations by adjusting the operation number of rectifiers. Its feasibility is exemplified by some simulations performed for Incheon subway Line 1 and GA(Genetic Algorithm) method has been applied to obtain the optimal input. Simulation results show that peak power can significantly be reduced using the method proposed in this paper.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.63 no.3
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• pp.189-194
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• 2014

Due to the increasing of power consumption, it is difficult to construct accurate prediction model for daily peak power demand. It is very important work to know power demand in next day for manager and control power system. In this research, we develop a daily peak power demand prediction method based on hybrid type composed of AR and Neuro-Fuzzy model. Using data sets between 2006 and 2010 in Korea, the proposed method has been intensively tested. As the prediction results, we confirm that the proposed method makes it possible to effective estimate daily peak power demand than conventional methods.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.63 no.4
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• pp.307-311
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• 2014

Due to the increasing of power consumption, it is difficult to construct accurate prediction model for daily peak power demand. It is very important work to know power demand in next day for manager and control power system. In this research, we develop a daily peak power demand prediction method considering of characteristics of day of week. The proposed method is composed of liner model based on AR model and nonlinear model based on ELM to resolve the limitation of a single model. Using data sets between 2006 and 2010 in Korea, the proposed method has been intensively tested. As the prediction results, we confirm that the proposed method makes it possible to effective estimate daily peak power demand than conventional methods.

• Proceedings of the Optical Society of Korea Conference
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• 1990.02a
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• pp.26-28
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• 1990

Cw arc 램프로 펌핑하는 Alexandrite 레이저의 형광을 optical Spectrum Analyzer를 이용하여 측정하였다. Vibronic 천이에 해당하는 광대역 형광 스펙트럼이 관측되었고, arc 램프 입력에 따른 peak 형광의 세기 및 peak intensity 파장의 입력 power 의존성을 조사하였다. 형광의 세기는 입력 power에 따라 0.16 /kw의 비율로 증가하였고, peak intensity 파장은 입력 power가 5kw 까지는 5 nm/kw 비율로 장파장쪽으로 이동하였다.