• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.21 no.3
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• pp.96-106
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• 2007

The terminal voltage of a synchronous generator is maintained by the field current control of excitation system. Generally AC/DC converter which is component of AVR(Automatic Voltage Regulator) system for excitation current control is connected to diode rectifier and DC/DC converter system. In the case of diode rectifier system of phase controlled converter as AC/DC converter have low power factor and harmonics of lower order in the line current. In this paper, two stage three phase PWM AC/DC converter is studied to solve these problems. The characteristics of a proposed converter reduces the harmonics and reactive power of the distribution line and has fast dynamic response in transient period using boost converter and current control mode buck converts. The proposed method is verified by the computer simulation and experimental results in prototype generation system.

• Journal of the Korea Computer Industry Society
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• v.2 no.3
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• pp.357-362
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• 2001

For general laser power supply to control the laser power density, the secondary of the power transformer is connected to the rectifier and filter capacitor. The output of a rectifier is applied to a switching element in the secondary of the transformer. So power supply is complicated and the loss of switching is considerably. In addition, according to increasing pulse repetition rate, charged energy of energy-storage capacitor bank is not transferred sufficiently to flashlamp, and laser output efficiency decreases. In this study, we have proposed the power supply in which the SCR was turned on at the zero point of input AC voltage by the method of zero cross control(ZCC). As a result of that, The new power supply employed ZCC are simple and compact in design. And laser output efficiency increased by the 3.5$\%$ other than conventional power supply (SCADC), when a repetition rate was increased by the 10pps. In 60pps, efficiency was increased by about 20$\%$.

• The Journal of the Korea institute of electronic communication sciences
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• v.19 no.4
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• pp.661-668
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• 2024

Based on the topology of the direct-drive permanent magnet synchronous wind power grid-connected system based on the power electronics full-power converter, the wind turbine model and the grid-side inverter model were studied, and the machine-side rectifier control based on current and speed double closed loops was designed. strategy, as well as a grid-side inverter control strategy based on current and voltage double closed loops, implementing a two-level back-to-back double closed-loop full control strategy. A system simulation model was built using Matlab/Simulink, and the operation of the unit was simulated when the wind speed changed step by step. The grid-connected current with the same phase and good sinusoidal nature of the grid voltage was output. The grid-connected system ran stably and efficiently. The simulation results The validity and rationality of the model, as well as the correctness and feasibility of the control strategy were verified.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.11a
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• pp.248-248
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• 2009

Diagnostic X-ray system has been contributed to wiping out disease to get a good quality images from patients. But, X-ray radiation could be exposed to patient and it is very harmful to the patient. In order to reduce being bombed, the many research and development is now advanced. This research has produced the high voltage occurrence system of full-wave rectification method by using the LC resonance inverter, and evaluated the irradiation reproducibility in order to use it in diagnosis of the patient.

• Proceedings of the KIEE Conference
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• 2007.10c
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• pp.50-52
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• 2007

Throttle Control 장치는 차량의 지능화와 연료 절감의 이유로 기계식에서 전기적 신호의 연결로 구동시키는 시스템으로 발전하고 있다. 전기 전자 시스템을 도입한 ETC(Electronic Throttle Control)의 구성요소 중 필수적인 구동 원으로 DC모터를 많이 사용하고 있지만, DC모터는 정류작용 시 브러시의 스파크를 발생시키는 단점을 가진다. 이에 전기적 및 기계적 Noise가 적고 신뢰성이 높으며 수명이 긴 BLDC 모터의 개발이 필요하다. 이에 BLDC 모터의 기초 설계와 최적 설계를 통해 형상을 설계하고 이를 정자계 유한요소법을 이용하여 해석하고 목표 토크인 0.2[Nm]에 적합한 BLDC 모터를 설계하였다.

• Proceedings of the KIPE Conference
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• 1999.07a
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• pp.41-44
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• 1999

The main purpose of the UPS is to supply independent and stable power to connected equipment. In installing and operating the UPS system, songle module, three phase UPS in more benefit than multi module, songle phase UPS in the point of volume and cost. However, when supplying Rectifier with output power form three phase UPS, by connecting auto-transformer, occurred harmonic and ripple current makes output filter damaged and leads to nonlinear current coasted by unbalance load. Therefor, in this paper the aim of concentring compound-wound transformer and harmonic filter is supplying liner current by reducing harmonic and ripple current and improving unbalance in voltage and distortion in current wave.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.128-128
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• 2010

The high-voltage X-ray generator recently used is very popular, because that can be miniaturized, increased in generating efficiency, elaborated in output control. All these features are available with high-frequency made by using an inverter, the fast switching semiconductor device. In this paper to identify the differences among types of rectification, we compared output ripple with full-wave rectification and dual-voltage rectification methods.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.138-138
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• 2010

X-ray systems for medical treatment use noninvasive procedures. I fabricated a high tension generator of a full-wave rectification type using a LC resonant inviter. It is said that a full-wave rectifying X-ray equipment such as the fabricated system can shorten initiating period and be precision control because of stable output, compared with the X-ray equipment of a half wave rectifying type used in the usual clinical medicine. In order to evaluate the capability of the fabricated high tension generator, I performed exposure dose characteristics experiments.

• Proceedings of the KIEE Conference
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• 1993.11a
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• pp.132-134
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• 1993

A new Zero-Current Switched(ZCS) High Power Factor Rectifier for the. power factor correction is proposed. The proposed single phase rectifier enables a zero-current switching operation of all the power devices allowing the circuit to operate at high switching frequencies and high power levels. A dynamic model and a predictive current control technique for the ZCS-High Power Factor Rectifier(HPFR) are proposed. With the proposed dynamic model, an analysis for the internal operational characteristics is explored. With the proposed control technique, the unity power factor.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.57 no.3
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• pp.231-235
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• 2008

Thyristor rectifiers are still the preferred choice for large magnet power supplies. However, large harmonic voltages, resulting in large current ripple, and slow dynamic response are major drawbacks of these converters. Joos presented a topology and a control technique for a hybrid large-power high-precision magnet power supply in 1996. The system consists of a phase controlled rectifier (PCR) connected in series with a high-frequency PWM converter. This paper improves the power circuit of the PWM converter using interphase transformer. Simulation result proves effect of the proposed system.