• Proceedings of the KIEE Conference
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• 2000.07b
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• pp.1306-1308
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• 2000

A new ZVT PFC for using 3[KW] power amplifier is proposed. Generally, the single phase diode rectifier has been widely used in the SMPS of the conventional power amplifier. But this rectifier has occurred some problems which are the input power factor and current harmonics. To solve the above problems, in this paper, two topology is adopted. The one is the boost type PFC for improving the input power factor. The other is the ZVT resonant circuit for reducing the switching loss and stress. In this paper, the proposed topology is analyze designed to built the ZVT PFC for using 3[KW] power amplifier. In order to verify the circuit va finally, the PSPICE simulation and experiment results are presented.

• Electronics and Telecommunications Trends
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• v.33 no.2
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• pp.48-55
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• 2018

Immersive media, which maximizes the viewer's sense of presence and immersion, has been developed in the form of 3D stereoscopic media and UHD media. Going one step further, VR media, which can provide immersive experiences within an artificially created environment, have recently been considered a type of next-generation media. Within this trend, numerous IT and broadcasting companies around the world are actively investing their time and resources to boost the emerging VR industry. In this paper, we introduce the representative VR media acquisition and broadcasting service technologies that are leading the current VR industry.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2004.05a
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• pp.492-496
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• 2004

When using a conventional power factor correction circuit, a comparatively huge capacitor is used to boost-up output voltage. It has a large amount of harmonic distortion in the input current waveform. To improve the input current waveform of diode rectifiers, we propose a new operating principle for the power factor correction circuit. Due to the fact that the proposed circuit uses smaller ones and a smaller reactor, the output voltage increases and obtains higher input current waveforms. These are suitable for the harmonics guidelines. The proposed circuit is able to obtain higher power factor and efficiency. Also, it has reduced switching loss and held over-shooting by using an inverter of eliminated dead-time HPWM that has non-linear impedance circuits to make up diodes, capacitance and a reactor. We compared the conventional PWM inverter and proposed HPWM inverters and found that a high input power factor of 97[%] and an efficiency of 98[%] were also obtained.

• Proceedings of the KIEE Conference
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• 2002.06a
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• pp.6-8
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• 2002

Generally in solar air conditioning system, the diode rectifier is used to build up DC link voltage from AC source. The diode rectifier is simple and cheap but it brings out the problems of low power factor and plentiful harmonics at the AC source. Also It can degrade the utilization rate of solar energy because the reverse of power flow cannot be made. Hence, in this paper to overcome the peak power problems in summer and to endure good AC input characteristics, solar air conditioning system using the PWM converter is proposed. A high input power factor of 97[%] and an efficiency of 98[%] are also obtained. The harmonic guide lines of proposed rectifier is no interfered with inverter switching, resulting in a simple, reliable and low cost ac to dc converters in comparison with the boost type current improving circuits.

• Proceedings of the KIPE Conference
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• 2017.07a
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• pp.246-247
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• 2017

단상 ac/dc, dc/ac 시스템의 경우, ac와 dc사이의 전력 불균형으로 인해 double line frequency ripple power가 발생한다. 이는 harmonic disturbance을 야기시킨다. 일반적으로 전력 리플을 줄이기 위하여 dc-link에 용량이 큰 전해 커패시터를 사용하는데, 용량이 큰 전해 커패시터는 높은 equivalent series resistance(ESR)을 가지며, 상대적으로 짧은 수명을 갖는 한계를 갖는다. 본 논문은 active power decoupling을 추가함으로써 전해 커패시터를 용량이 작은 필름 커패시터로 대체한 회로 구조를 제시한다. 그리고 dc-link 커패시터 선정방법, 설계한 제어기의 성능과 부하 변동에 따른 실험을 PSIM 시뮬레이션으로 확인하고 실험을 통해 검증한다.

• Proceedings of the KIPE Conference
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• 2001.07a
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• pp.219-222
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• 2001

In this paper, we firstly proposed to the boost type PFC circuit for a power factor improving and a harmonic decreasing. The predict current control method is used to control these PFC circuit. This current control method has a merit that is possible to improve power factor and harmonics. In addition, we suggested to the active DC filter, which is connected with the DC output terminal, in order to compensate the DC ripple components. Consequently, these results are proved by the simulation tool, PSIM, which is an exclusive simulator of power electronics.

• Journal of Electrical Engineering and Technology
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• v.9 no.5
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• pp.1537-1543
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• 2014

This paper presents a new DC/AC multilevel converter. This configuration uses single DC sources. The proposed converter has two stages. The first stage is a DC/DC converter that can produce several DC-links in the output. The DC/DC converter is one type of boost converter and uses single inductor. The second stage is a multilevel inverter with several capacitor links. In this paper, one single input multi output DC-DC converter is used in order to voltage balancing on multilevel converter. In addition, as compare to traditional multilevel inverter, presented DC/AC multilevel converter has less on-state voltage drop and conduction losses. Finally, in order to verify the theoretical issues, simulation and experimental results are presented.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.2
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• pp.354-356
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• 2017

We focused on light management technology in amorphous silicon solar cells to suppress increase in absorber thickness for improving power conversion efficiency (PCE). $MgF_2$ and $TiO_2$ anti-reflection layers were coated on both sides of Asahi VU ($glass/SnO_2:F$) substrates, which contributed to increase in PCE from 9.16% to 9.81% at absorber thickness of only 150 nm. Also, we applied very thin $MgF_2$ as a rear reflector at n-type nanocrystalline silicon oxide/Ag interface to boost photocurrent. By reinforcing rear reflection, we could find the PCE increase from 10.08% up to 10.34% based on thin absorber about 200 nm.

• Proceedings of the KIPE Conference
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• 2014.07a
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• pp.23-24
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• 2014

본 논문은 절연형 양방향 DC-DC 컨버터의 방전모드와 변압기 권선비에 따른 손실 분석에 대해 다루었다. Phase-Shift방전모드와 Boost방전모드에서 변압기 권선비에 따른 스위치손실을 분석하여 손실을 최소로 하는 변압기 권선비와 최적의 방전모드를 결정하고자 한다.

• Proceedings of the KIPE Conference
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• 2014.07a
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• pp.417-418
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• 2014

본 논문은 PFC (Power Factor Correction)와 절연형 DC-DC 컨버터의 2단 구조를 갖는 가전제품용 저전압 시스템의 효율을 분석하며, 이에 따른 Buck 및 Boost PFC 토폴로지와 절연형 DC-DC 컨버터 효율 및 설계 차이점을 비교한다. PFC 구조에 따른 각 시스템의 역률 규제 만족 여부와 시스템 효율을 이론적 해석 및 시뮬레이션을 통해 검증한다.