• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 F
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• pp.2076-2078
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• 1998

This paper presents STATCON(Static Condenser) control schemes for voltage regulation, power factor correction and harmonics mitigation. Each control scheme can be applied in the system depending on the system requirements. The 20KVA STATCON is developed and tested in the reduced system model for the verification of three different control algorithms. The results of proposed controls are compared for power factor correction and voltage regulation algorithms. For each algorithm, harmonic mitigation scheme is adopted as a part of control. Finally verification of STATCON for the transient response is implemented by voltage flicker test.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2018년도 전력전자학술대회
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• pp.207-209
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• 2018

본 논문은 고효율 및 고전력밀도 3-레벨 PFC(Power Factor Correction) 컨버터를 제안한다. 기존 PFC의 고 전력밀도를 위한 스위칭 주파수 상승은 스위칭 특성이 우수한 소자를 적용하거나, 별도의 스너버 회로가 요구되므로 설계가 복잡하며 고전력밀도 달성에 한계가 있다. 제안 PFC 컨버터는 3-레벨 방식을 적용하여 각 스위칭 소자의 전압 스트레스를 절반으로 감소시켰으며, 스위치 손실 저감을 통한 고속 스위칭 동작으로 리액티브 소자의 고밀도화를 달성하였다. 또한, 기존의 3-레벨방식은 디지털 제어를 통해 스위칭 소자의 전압 평형이 이루어졌지만, 본 논문에서는 아날로그 IC에 전압 평형을 위한 RC Delay 회로와 소수의 SMD(Surface-mount devices) 소자만을 이용하여 별도의 제어회로 없이 전압 평형이 가능하므로 고 전력밀도 달성에 유리하다. 제안회로의 타당성을 검증하기 위해 CRM(Critical conduction mode) PFC 컨버터를 기반으로 250W급 시작품 제작을 통한 실험 결과를 제시한다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2019년도 추계학술대회
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• pp.61-63
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• 2019

본 논문은 3.3 kW 전기자동차용 탑재형 충전기의 전력 밀도 향상을 위해 디커플링 기법이 적용된 PFC (Power factor correction) 회로의 초치적 설계 방안을 제안한다. 최적 설계를 위하여 buck-boost 컨버터 형태의 디커플링 회로 동작 원리를 기반으로 스위칭 주파수에 따른 PFC 회로의 손실과 부피를 분석하고 최적 설계점을 도출한다.

• Journal of Power Electronics
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• 제11권3호
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• pp.327-334
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• 2011

Single-phase power factor correction (PFC) converter circuits are non-linear systems due to the contribution of their multiplier. This non-linearity causes difficulties in analysis and design. Models that reduce the system to a linear system involve considerable approximation, and produce results that are susceptible to instability problems. In this paper a piecewise affine (PWA) system is introduced for describing the nonlinear averaged model. Then robust output feedback controllers are established in terms of the linear matrix inequality (LMI). Simulation and experiments results show the effectiveness of the proposed control method.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2008년도 추계학술대회 논문집
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• pp.150-153
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• 2008

This paper presents soft-switching boost converter adding to auxiliary switch and resonant circuit in conventional boost converter. This approach features a two power stage which implements both conventional BLDC motor speed control and input power factor correction. This converter is especially useful in application such as home appliance. Theoretical analysis and simulation results are presented.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2012년도 전력전자학술대회 논문집
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• pp.195-196
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• 2012

In recent years, in an effort to improve the efficiency and the power density of the front-end power factor correction(PFC), the interleaving of multiple converter is employed. The conventional interleaved continuous conduction mode(CCM) boost PFC converter requires input and output voltage sensing and three current sensing to obtain current balancing between modules. In this paper, the interleaved CCM PFC converter based on modulated carrier control is proposed. With the proposed method, two phase interleaved PFC can be realized simply without line voltage sensing resistor and can achieve current balancing without additional current sensing resistor on common return path. The simulation studies are carried out to verify the effectiveness of the proposed control scheme.

• 전력전자학회논문지
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• 제24권3호
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• pp.207-214
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• 2019

In this study, discrete-time domain analysis is proposed to investigate the input current of a buck AC/DC light-emitting diode (LED) driver. The buck power factor correction converter can operate in both discontinuous conduction mode (DCM) and continuous conduction mode (CCM). Two discontinuous and two continuous conduction operating modes are possible depending on which event terminates the conduction of the main switch in a switching cycle. All four operating modes are considered in the discrete-time domain analysis. The peak current-mode control with slope compensation is used to design a low-cost AC/DC LED driver. A slope compensation design of the buck AC/DC LED driver is described on the basis of a discrete-time domain analysis. Experimental results are presented to confirm the usefulness of the proposed analysis.

• 대한기계학회논문집A
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• 제33권10호
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• pp.1151-1157
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• 2009

Nuclear power plants applying for the continued operation over design life are required to address the effects of reactor water environment in fatigue design requirement of the ASME Code. Reactor water environmental effects are generally evaluated by calculating fatigue correction factors on fatigue usage. This paper describes the application for pressurizer surge line of environmental fatigue correction factors and the strain rate impact in the application. From this paper, the environmental fatigue correction factors resulted from the assumption of a step change in temperature are especially compared with those calculated from the data measured during plant startup. As a conclusion of this paper, the design transient conditions applied to the fatigue design may be conservative in case of the environmental fatigue evaluation.

• Journal of Power Electronics
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• 제15권3호
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• pp.577-586
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• 2015

The combination of voltage feedforward and feedback control is a conventional approach for correcting the power factor in single-phase ac-dc boost converters. The feedback duty ratio increases significantly with an increase of the line frequency and input inductance. Therefore, the performance of the conventional approach is highly dependent on the bandwidth of the feedback controller. As a result, the input power quality can be significantly exacerbated due to uncompensated duty ratios if the feedback controller is limited. This paper proposes an input impedance and current feedforward control method to reduce the control portion of the feedback controller. The findings in this paper are 1) the theoretical derivation and analysis of variations of line frequency and input inductance on a power factor correction approach, 2) guaranteed consistent performance in a wide range of conditions, and 3) that a low switching frequency can be utilized by the proposed method. A MATLAB/Simulink model and a 1.2kW dual boost converter are built to demonstrate the effectiveness of the proposed method.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 제39회 하계학술대회
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• pp.942-943
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• 2008

The boost converter is usually used in power factor correction. The dynamic losses of its output diode are produced during the reverse recovery time. The power efficiency is decreased due to the losses and also it generates the noise. These disadvantages have been remarkably improved by ZCS and ZVS techniques of power factor improvement circuit. Some benefits lead to the achievement of higher power density and the development cost can be decreased. In this paper work, the reverse recovery suppression(RS) PFC method is used. A inductor and a diode are added into the conventional circuit. The switching device, MOSFET is turned off after the reverse recovery current has come to the zero level. The Zero Current Switching(ZCS) is implemented at that time. This power conversion technique improves the efficiency to about 1% and reduces the noise obviously. And the additional inductor can be designed using an original filter core in the circuit. The converter size is reduced effectively.