• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1482-1483
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• 2007

SI-Thyristor는 스위칭 특성상, turn on시에는 전압구동 특성을 지니며, turn off시에는 전류구동 특성과 전압구동 특성을 지니고 있기 때문에, 그 두가지 특성을 명확히 하여 스위칭 특성을 구분 짓는 것이 어렵다. 본 논문은 SI-Thristor-정전유도용량 사이리스터-의 펄스파워 어플리케이션으로 고안된 게이트 드라이버를 이용하여 직렬연결 특성을 측정했으며, 펄스파워 어플리케이션으로서의 SI-Thrysitor의 스위칭 특성과 그에 적합한 게이트 드라이버의 개선점과 특성에 대하여 기술되어 있다.

• Proceedings of the KIPE Conference
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• 2007.11a
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• pp.34-36
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• 2007

A new soft switching boost converter is proposed in this paper. The conventional boost converter generates switching losses at turn on and off. Because of that, the whole system efficiency is reduced. The proposed converter utilizes soft switching method using an auxiliary switch and resonant circuit. Thus, the converter reduces switching losses lower than ones of hard switching method. The proposed soft switching boost converter can be applied to photovoltaic system, power factor correction circuit and so on.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.34S no.6
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• pp.77-84
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• 1997

buck type converter doesn't appear when an input voltag eis lower than an output voltage. This is the main reason the buck converter has not been used for high power factor converters. In this paper, soft switching high power factor buck converter is proposed. This converter is composed of diode rectifier, input capacitor can be small enough to filter input current, buck converter with loss less snubber circuit. Converter is operated in discontinous conduction mode, turn on of the switching device is a zero current switching (ZCS) and high powr factor input is obtianed. In addition, zero voltage switching (ZVS) at trun off is achieved and switching loss is reduced using loss less snubber circuit. The capacitor used in the snubber circuit raised output voltage. Therefore, proposed converter has higher output voltage and higher efficiency than conventional buck type converter at same duty factor in discontinous conduction mode operation. High power factro, efficiency, soft switching operation of proposed converter is veified by simulation using Pspice and experimental results.

• Proceedings of the KIPE Conference
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• 1998.10a
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• pp.1051-1055
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• 1998

To achieve high efficiency in high power and high frequency applications, reduction of switching losses and noise is very important. In this paper, an improved zero voltage switching forward dc/dc converter is proposed. The proposed converter is constructed by using energy recovery snubbers in parallel with the main switches and output diodes of the conventional forward dc/dc converter. Due to the use of the energy recovery snubbers in the primary and secondary side, the proposed converter achieves zero-voltage-switching turn-off without switching losses for switching devices and output rectification diodes. The complete operating principles and experimental results will be presented.

• Proceedings of the KIPE Conference
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• 2008.10a
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• pp.121-123
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• 2008

A high efficiency soft switching boost converter is proposed in this paper. The conventional boost converter generates switching losses at turn on and off. Because of those, the whole system efficiency is reduced. The proposed converter utilizes soft switching method using resonant circuit with an auxiliary switch. Therefore, the proposed converter reduces switching losses lower than the hard switching. The proposed soft switching boost converter can be applied to photovoltaic system, power factor correction circuit and etc.

• Proceedings of the KIPE Conference
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• 1999.07a
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• pp.443-447
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• 1999

The AC drive systems of a voltage source inverter and an induction motor. The inverter non linearity caused by the turn on/off time dependency of the current level in the switching IGBT is described in the first part of this paper. To improve the low-speed drive characteristics, accurate applied voltage calculation is proposed under considerations of the compensations for the quantization error in the digital controller, the forward voltage drop of switching drives and the dead time of the inverter. The experimental studies show the improved drive characteristics.

• Journal of IKEEE
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• v.12 no.2
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• pp.110-117
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• 2008

This paper presents a new Insulated Gate Bipolar Transistor(IGBT) based on Non Punch Through(NPT) IGBT structure for power switching device. The proposed structure has adding N+ beside the P-base region of the conventional IGBT structure. The added n+ diffusion of the proposed device ensure device has faster turn-off time and lower forward conduction loss than the conventional IGBT structure. But, added n+ region can reduce th breakdown voltage and latching current density of the proposed device due to its high doping concentration. This problems can be overcome by using diverter on the right side of the device. In the simulation results, turn-off time of the proposed device is 0.3us and the on-state voltage drop is 3V. The results show that the proposed device has superior characteristic than conventional structure.

• Journal of international Conference on Electrical Machines and Systems
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• v.3 no.4
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• pp.465-471
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• 2014

This paper proposes a new switching algorithm for an active clamp snubber to improve the efficiency of a module integrated converter system. This system uses an active clamp method for the snubber circuit for the efficiency and reliability of the system. However, the active clamp snubber circuit has the disadvantage that system efficiency is decreased by switch operating time because of heat loss in resonance between the snubber capacitor and leakage inductance. To address this, this paper proposes a new switching algorithm. The proposed algorithm is a technique to reduce power consumption by reducing the resonance of the snubber switch operation time. Also, the snubber switch is operated at zero voltage switching by turning on the snubber switch before main switch turn-off. Simulation and experimental results are presented to show the validity of the proposed new active clamp control algorithm.

• Proceedings of the KIPE Conference
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• 2017.11a
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• pp.101-102
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• 2017

This paper presents analysis of losses of switching device for full bridge inverter connected to grid. The losses are a dominant factor that judges efficiency of the system. The losses of switching device are divided to switching loss and conduction loss. They are can be estimated by analyzing periodic switching waveforms. The switching loss is generated at the point that turn-on and off. And the conduction loss is generated while the switch is on condition. The estimated losses of switch are compared to simulation result in this paper.

• Proceedings of the KIPE Conference
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• 1999.07a
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• pp.614-617
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• 1999

To achieve high efficiency in high power and high frequency applications, reduction of switching losses and noise is very important. In this paper, an improved zero voltage switching forward dc/dc converter is proposed. The proposed converter is constructed by using energy recovery snubbers in parallel with the main switches and output diodes of the conventional forward dc/dc converter. Due to the use of the energy recovery snubbers in the primary and secondary side, the proposed converter achieves zero-voltage-switching turn-off without switching losses for switching devices and output rectification diodes. The complete operating principles and experimental results will be presented.