• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.3-5
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• 2008

This paper presents a hybrid winding connection method for torque characteristics improving of a traction SRM. In order to get a high torque in wide speed range and torque ripple reduction, series and parallel winding connection are changed according to operating speed. From the analysis of torque character operation mode and efficiency, the proposed control scheme is verified.

• 전기학회논문지
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• 제57권3호
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• pp.409-415
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• 2008

This paper proposed a new optimal design method of the electronic ballast with stable run-up current for Metal Halide lamp during the ignition condition. In order to avoid operation in the acoustic resonance frequency band and to supply the optimal ignition current without demage of inverter switching components during the ignition period, the values of the series inductor Ls, the series capacitor Cs, and the parallel capacitor Cp were determined by analysis of characteristics of inverter transfer function depend on Lamp operating power and resistance of ignition condition and steady state operating condition. For the prototype ballast for a 400W Metal Halide Lamp, experimental results are presented in order to validate the proposed method.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2003년도 춘계전력전자학술대회 논문집(1)
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• pp.106-109
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• 2003

This paper describes an AC voltage regulator using AC chopper and auxiliary transformer which is series connected with main input. It has many advantages such as fast voltage control, high efficiency and low THD. A detail study of step down AC voltage regulator is described and two kinds of novel step-up/down voltage regulator for AVR are proposed. The operation principle and PWM method of the proposed regulator are described. Experimental results show that it can be used as AC voltage regulator for special purpose very efficiently.

• 대한수학교육학회지:학교수학
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• 제4권3호
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• pp.361-373
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• 2002

In this paper, a series of tasks related on polygonal numbers and pyramidal numbers are suggested for using them as teaching unit materials for teaching and learning of sequences in junior high school mathematics. Especially, finding n-th term in those seque-nces, relations among polygonal numbers, and relations among Pyramidal numbers are focused on. A series of tasks related on polygonal numbers and pyramidal numbers have three math-eucational values. First, they have a value as natural materials for teaching and teaming of finding nth term of original sequences using pro-gression of differences. Second, they have a value as materials for teaching and learning of mathematical thinking such as general-ization, analogy, etc. Third, they have a value as materials for teaching and learning of algebraic operation, proof, and connecting mathematical knowledges.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1991년도 하계학술대회 논문집
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• pp.516-520
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• 1991

This paper presents a comparative analysis of two inverter power supply topologies for induction heating and melting applications. The comparison is based on criteria such as resonant condition, component ratings, minimum and maximum operating frequencies, operation under varying load conditions, inverter starting current, and diode reverse recovery time. The voltage source series/parallel resonant inverters are found to offer the best overall performance with respect to converter utilization.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1994년도 하계학술대회 논문집 A
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• pp.422-425
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• 1994

The main objective of this paper is to explore the feasibility and potential benefits of HFLC series compensator as a power flow controller in an ac power system. To accomplish this goal, the detailed 5 [KHz] model for EMTP simulation study is developed. Among the issues considered are analysis, tank circuit design, link frequency selection, harmonics and filter requirement, control and damping effect. The technical evaluation performed in this research can be used in future power network design and operation.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2001년도 추계학술대회 논문집
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• pp.135-138
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• 2001

In order to solve the problem of system efficiency reduced on account of two stage power conversion, we propose a series resonant full bridge inverter circuit for battery-fed microwave oven. This circuit has both a compact size and a light weight. Also, a frequency control adjusts power levels of the microwave oven. Operational principles are explained in detail. A proto-type inverter circuit with 1[kW] power consumption is built and tested for verifying the operation.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2000년도 전력전자학술대회 논문집
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• pp.376-379
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• 2000

This paper presents an improved ZVS partial series resonant DC/DC converter (PSRC) with low conduction losses suitable for high power and high frequency applications. The proposed PSRC have advantages of zero-voltage-swiching (ZVS) of main switches for entire load ranges and low conduction losses of main switches by decreasing current stresses Also the reduction of the effective duty cycle is not occurred during the resonant period of the main circuit because the auxiliary circuit of the proposed converter is placed out of the main power path. An improved ZVS PSRC has a so much characteristics with respect to the reduction of current stress. The operation principles of the proposed converter are explained in detail and the various simulated and experimental results show the validity of the proposed converter.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2001년도 학술대회논문집
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• pp.47-50
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• 2001

In order for effective operation of existing power systems, introduction of the so-called FACTS(Flexible AC Transmission System) such as SVC and UPFC etc, is unavoidable. The UPFC(Unified Power Flow Controller) is composed of STATCOM(Static Compensator) and SSSC(Static Synchronous Series Compensator), and is used to control the magnitude and phase angle of injected sources which are connected bothin series and in parallel with the transmission line to control the power flow and bus voltages. This paper presents a UPFC simulation on RTDS. The voltage and phase angle of a system have been analyzed by regulating the firing angle inside the UPFC.

• 전기학회논문지P
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• 제59권1호
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• pp.112-116
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• 2010

Fuel cell as a renewable energy source is clean and has a lot of advantages. The source can solve energy crisis and environmental problems such as greenhouse effect, air pollution and the ozone layer destruction. This paper introduces hybrid system(hydro-Genius Professional, heliocentris) of solar cell and fuel cell. Also, this paper shows the I-P, V-I characteristics of fuel cells which are connected in parallel and series. From these results, we also found the maximum power was transferred at 0.5[${\Omega}$]. The terminal voltage was also decreased according to the current because of the internal resistance. The power transfer in series was two times than that in parallel.