• 전자공학회논문지B
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• 제33B권3호
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• pp.56-61
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• 1996

In this paper, new buck converter of a TV power system is presented. First, we devised a revised driving circuit for an emitter-coupled type buck converter, by which it is possible to reduce the material cost of transformers and voltage stress of power device. Secondly, we adopted a hybrid oscillation technique. When TV system is in off-stage, initial standby power which is necessary for remote controllable TV system is supplied by self-oscillating mode. Main power which is necessry in TV system bing on state is provided by an externally triggered oscillating mode. The switching frequency is synchronized to the oscillating frequency of horizontal deflection in TV, by which we can reduce picture noises and the size of power transformer. Thirdly, a simple error amplifier is inserted to the feed-back loop to keep the output voltage constant which means pulse width modulatio mode is added in driving part of power device. Finally, we showed by experiments that our proposed converter performs well enough to be close to the theoretically predicted values.

• Journal of Electrical Engineering and Technology
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• 제6권4호
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• pp.527-534
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• 2011

In the present paper, the characteristics of Mega-Flux$^{(R)}$, JNEX-Core$^{(R)}$, amorphous and ferrite cores are compared to the inductor of buck-boost converters for Hybrid Electric Vehicles. Core losses are analyzed at the condition of 10 kHz sine wave excitations, and permeability fluctuations vs. temperature and magnetizing force will be analyzed and discussed. Under the specifications of the buck-boost converter for 20 kW THS-II, the power inductor will be designed with Mega-Flux$^{(R)}$ and JNEX-Core$^{(R)}$, and informative simulation results will be provided with respect to dc bias characteristics, core and copper losses.

• Journal of Electrical Engineering and Technology
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• 제6권4호
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• pp.519-526
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• 2011

An investigation of the mechanism of period-doubling bifurcation in a voltage mode controlled buck-boost converter operating in discontinuous conduction mode is conducted from the viewpoint of nonlinear dynamical systems. The discrete iterative model describing the dynamics of the close-loop is derived. Period-doubling bifurcation occurs at certain values of the feedback factor. Results from numerical simulations and experiments are provided to verify the evolution of perioddoubling bifurcation, and the results are consistent with the theoretical analysis. These results show that the buck-boost converters exhibit a wide range of nonlinear behavior, and the system exhibits a typical period-doubling bifurcation route to chaos under particular operating conditions.

• 조명전기설비학회논문지
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• 제29권9호
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• pp.42-50
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• 2015

The Buck-Boost converter consisted of two switches is more expensive than the conventional Buck converter, because of the increase of the components. However, it can control the DC voltage depending on the requested load voltage without additional circuits, because it can control the voltage under the relatively wide range of the load. Additionally, it can control the output voltage constantly under the variation of the input voltage. In the paper two control loops consisted of current and voltage control are designed. When two controllers are operated at the same time the problem of the output voltage is occurred. Therefore, the solution of the output voltage problem is proposed. Finally, the validity of the proposed scheme is investigated with simulated and experimental results for a prototype system rated at 1kVA.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2007년도 추계학술대회 논문집
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• pp.31-33
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• 2007

In this paper, a simple digital control scheme for the single/parallel module buck converters is proposed using a digital state feedback control method. The discrete state feedback controller structure for the robust tracking control is derived by using the error state. The proposed control system can precisely achieve the interleaved current sharing and the output regulation, and can achieve the systematical controller design for a given converter specification using the pole placement technique. For a design example, the single module buck converter is simulated using the MATLAB Simulink software and two 100W parallel module buck converters with a TMS320F2812 DSP is implemented.

• Journal of Power Electronics
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• 제14권2호
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• pp.217-225
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• 2014

This paper deals with the optimization of the driving techniques for the ZVT synchronous buck converter proposed in [1]. Two new gate drive circuits are proposed to allow this converter to operate by only one control signal as a 12V voltage regulator module (VRM). Voltage-driven method is applied for the synchronous rectifier. In addition, the control signal drives the main and auxiliary switches by one driving circuit. Both of the circuits are supplied by the input voltage. As a result, no supply voltage is required. This approach decreases both the complexity and cost in converter hardware implementation and is suitable for practical applications. In addition, the proposed SR driving scheme can also be used for many high frequency resonant converters and some high frequency discontinuous current mode PWM circuits. The ZVT synchronous buck converter with new gate drive circuits is analyzed and the presented experimental results confirm the theoretical analysis.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2011년도 전력전자학술대회
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• pp.169-170
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• 2011

본 논문은 양방향 Buck 컨버터 DCM 구동 시 사용되는 스위치의 전류링잉현상을 상세히 분석하고 이에 따른 스위치 효율과 시스템 전력 효율 차이를 실험을 통해 검증한다. 분석을 통해 얻은 결과를 바탕으로 양방향 Buck 컨버터 설계 시 전력 효율을 높이는 스위치 및 다이오드를 선정하였다.

• Journal of Electrical Engineering and Technology
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• 제11권1호
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• pp.125-134
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• 2016

We propose an efficient high voltage level shifter for a high side Buck converter driving a light-emitting diode (LED) lamp. The proposed circuit is comprised of a low voltage pulse width modulation (PWM) signal driver, a coupling capacitor, a resistor, and a diode. The proposed method uses a property of a PWM signal. The property is that the signal repeatedly transits between a low and high level at a certain frequency. A low voltage PWM signal is boosted to a high voltage PWM signal through a coupling capacitor using the property of the PWM signal, and the boosted high voltage PWM signal drives a p-channel metal oxide semiconductor (PMOS) transistor on the high side Buck converter. Experimental results show that the proposed level shifter boosts a low voltage (0 to 20 V) PWM signal at 125 kHz to a high voltage (370 to 380 V) PWM signal with a duty ratio of up to 0.9941.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.151-153
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• 2007

In this paper, the control method of extracting maximum power from the seaflow energy is proposed. This system consists of buck-boost converter, bridge diode. The control is performed by using the variable duty ratio control of buck-boost converter. For extracting maximum power, it is necessary to know the seaflow turbine's maximum power curve and the seaflow speed measurement. But this makes the system difficult and expensive to implement. So this paper proposes the MPPT control method where the seaflow speed and the maximum power curve of the seaflow turbine are not required. The effectiveness of algorithm is simulated based on Matlab $Simulink^{(R)}$.

• 한국조명전기설비학회지:조명전기설비
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• 제10권6호
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• pp.54-61
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• 1996

본 논문에서는 기존에 제시된 영전압 준공진 buck dc-dc 컨버터를 시뮬레이션을 이용하여 분석하고, 이에서 발생하는 문제점을 분석하였다. 그리고 부하저항을 낮게 가변함에 따라 소자의 스트레스가 증가함을 확인하였다. 그 원인이 freewheeling다이오드의 기생 커채시턴스에 의한 전압상승에 의하여 발생함을 확인하고, 이를 개선할수 있는 영전압 스위칭 컨버터를 제시한다.