• 해양환경안전학회지
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• 제21권6호
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• pp.759-769
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• 2015

본 논문에서는 12펄스 정류기의 커패시터 중앙 DC버스에 개선된 보조전원장치를 설치하는 방법을 제안하였다. 11차 및 13차 고조파가 감소하는 이론적인 배경을 다루었으며 부하전류의 크기, 전원전압의 위상 및 크기, 커패시터 전압에 따라 개선된 보조전원의 파형 및 크기가 어떻게 제어되어야 하는지를 제시하였다. 기존의 구형파 보조전원장치를 적용한 경우는 전 영역에서 고조파 왜형률이 6~60[%]로 큰 편차를 보이지만 본 눈문에서 제안하는 개선된 보조전원장치를 적용한 경우 저 부하에서 고 부하에 이르는 전 영역에서 57~71[%] 라는 안정되고 뛰어난 고조파 왜형율 저감 효과를 보인다. 특히 10[%] 부하상태에서 기존방식은 고조파 왜형율 저감 효과가 6[%]로 효과가 거의 없지만 제안된 방식은 71[%]라는 놀라운 저감성능을 보여주고 있다. 소프트웨어 PSIM을 활용하여 컴퓨터 시뮬레이션을 통해 제안된 방식의 유효성을 입증하였다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2001년도 추계학술대회 논문집
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• pp.129-132
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• 2001

Recently, a ZVT boost converter is embedded in a power factor correction system. The control circuit of the converter assures soft-switching for all the MOSFETs and load regulation. The PFC system contains additional control circuits which assure the input voltage in a sinusoidal form and feed-forward line voltage regulation. In this paper, a soft switching boost converter with zero-voltage transition(ZVT) main switch using zero-current switching(ZCS) auxiliary switch is proposed. Operating intervals of the converter are persented and analyzed. The proposed results show that the main switch maintains UT while auxiliary switch retains ZCS for the complete specified line and load conditions.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1995년도 하계학술대회 논문집 A
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• pp.350-352
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• 1995

The starting characteristics of single phase induction motor(SPIM) is described by control of phase and voltage. Auxiliary winding voltage is controlled by DC amplifier and phase is integrator. These processes enable comparison of torque with slip in each voltage and phase angle variations. Simulation and experimentation results of the motor's torque-slip characteristics using the controlled auxiliary winding voltage and phase angle arc shown and discussed. As a results, starting time is fast and main winding current is small when auxiliary winding voltage is low than rating voltage and starting characteristics is good in phase angle $90^{\circ}$.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2020년도 전력전자학술대회
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• pp.160-162
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• 2020

A control technique for the auxiliary buck/boost converter is proposed herein to improve the load transient response of the buck converter. The proposed technique improves the system efficiency by enabling the soft switching operation of the auxiliary converter. The design guidelines for achieving capacitor charge balance for the output capacitor during the transient are also presented herein. The experimental results revealed that the output voltage undershoot and settling time during the load step-up transient were 40 mV and 14 ㎲, respectively, and the output voltage overshoot and settling time during the load step-down transient were 35 mV and 21 ㎲, respectively. The performance and effectiveness of the proposed technique were experimentally verified using a prototype buck converter with a 15-V input, 3.3-V output, and 200-kHz switching frequency.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2009년도 정기총회 및 추계학술대회 논문집
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• pp.143-145
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• 2009

The method for the current equalization of the rectifier diodes in LLC resonant converter is proposed. The method decreases the current difference between the rectifier diodes using the auxiliary winding of the transformer and asymmetrical pulse width modulation (APWM). The analytical reason of the current unbalance is investigated and the operation principle of the proposed method and APWM control loop are explained. The performance of the proposed method was verified on a 480-W, 400-V/24-V dc/dc converter.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제49권10호
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• pp.683-692
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• 2000

A new primary-side-assisted zero-voltage and zero-current switching full bridge DC-DC converter with transformer isolation is proposed. The auxiliary circuit adopted to assist ZCS for the leading leg is composed of only one small transformer and two diodes. It has a simple and robust structure, and load current control capability even in short circuit conditions. Possibility of magnetic saturation due to asymmetricity of circuits or transient phenomena is greatly reduced, which is a very attractive feature in DC/DC converters with transformer isolation. The power rating of the auxiliary transformer is about 10% of that of the main transformer. Operation of a 12.5KW prototype designed for welding application was verified by experiments.

• 전력전자학회논문지
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• 제11권2호
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• pp.149-158
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• 2006

본 논문에서는 기존에 널리 사용되는 펄스폭 변조 (Pulse width modulation : PWM) 방식의 컨버터와 공진형 컨버터의 장점을 활용하고 단점을 보완할 수 있는 새로운 형태의 영전류 천이형 (Zero current transition : ZCT) 부우스트 컨버터를 제안한다. 제안한 회로는 기존의 PWM 부우스트 컨버터에 보조회로를 추가하여 주 스위치와 출력 다이오드의 스위칭 천이 순간에만 소프트 스위칭 조건을 제공함으로써 전체적인 동작은 기존의 부우스트 컨버터와 크게 차이가 없도록 하였다. 아울러, 보조회로에서의 부가적인 손실 역시 존재하지 않으므로 해서 고효율이 가능하게 된다. 본 논문에서는 제안한 회로의 동작을 분석하고 이를 바탕으로, 보조 회로의 소자값 결정에 도움이 되는 설계방식을 제공한다. 또한, 실험을 통하여 제안한 회로의 동작 원리 및 유용성을 검증하였다.

• Journal of Power Electronics
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• 제7권2호
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• pp.124-131
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• 2007

In this paper, a novel type of auxiliary switched capacitor assisted edge resonant soft switching PWM resonant DC-DC converter with two simple auxiliary commutation lossless inductor snubbers is presented. The operation principle of this converter is described using the switching mode equivalent circuits. This newly developed multi resonant DC-DC converter can regulate its DC output AC power under a principle of constant frequency edge-resonant soft switching commutation by an asymmetrical PWM duty cycle control scheme. The high frequency power regulation and actual power characteristics of the proposed soft switching PWM resonant DC-DC converter are evaluated and discussed. The operating performances of the newly proposed soft switching inverter are represented based on simulation results from an applications point of view.

• 전기학회논문지
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• 제64권2호
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• pp.289-296
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• 2015

In this paper, we propose the nonlinear control based on singular perturbation theory for position tracking and yaw regulation of planar motor. Singular perturbation theory is characterized by the existence of slow and fast transients in the system dynamics. The proposed method consists of auxiliary control to decouple error dynamics. We develop model reduction with control input. Also, we derIve decoupled error dynamics with auxiliary input. The controller is designed in order to guarantee the desired position and yaw regulation without current feedback or estimation. Simulation results validate the effect of proposed method.

• 조명전기설비학회논문지
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• 제29권12호
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• pp.8-14
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• 2015

An effective way to ensure that LEDs produce wanted light output is to use a current driving topology, because the brightness of LEDs is directly related to their current. However, this topology may lead to the lifetime shortening of a illumination system because over-currents may flow through non-damaged LEDs in case some LEDs are damaged. This paper presents an adaptive current control circuits for LEDs, which protect LEDs in a good state by limiting the driving currents according to the number of damaged ones. The proposed control circuits consist of a simple constant-current driver and a micro-controller which monitors the voltage of LED array without any auxiliary current sensors for fault diagnosis. And the driving current is automatically controlled into 6-levels according to the number of failures.