• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 B
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• pp.1010-1011
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• 2006

A new soft switched active snubber circuit is proposed to achieve zero voltage and zero current switching for all the switching devices in PWM DC-DC converters. The unique location of the snubber capacitor and inductor ensures low current/voltage stresses and commutation losses. With a saturable reactor, the conduction loss of the auxiliary switch could be further minimized. A boost converter adopting this technique is presented as an example, to illuminate its operation principles and derive the design procedures. Simulation and hardware implementation have been made to validate its performance. Some other basic PWM DC-DC topologies using the proposed snubber have also been given.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2008년도 하계학술발표대회 논문집
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• pp.1358-1365
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• 2008

By Computational Fluid Dynamics simulation, general information about an internal gas flow can be achieved. This will be very useful to improve flow inside the pipes and snubber system. Relating with hydrogen compressing system, which plays an important role in hydrogen energy utilization, this method should be a powerful tool to observe the flow quickly and clearly. Flow pressure characteristic analysis of hydrogen gas flowing through the snubber of a reciprocating compressor is presented in this paper. The CFD calculation of pressure pulsation and pressure loss are very close to the experiment. Therefore, consequently development of the better hydrogen compressing system will be observed with better understanding by CFD.

• 전기학회논문지P
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• 제66권2호
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• pp.58-62
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• 2017

This paper presents a novel prototype of the resonant AC link snubber circuit for the three-phase sinwave soft-switching PWM inverter. In principle, its operating principle is described, and the performance evaluations of the specific instantaneous space voltage modulated three-phase sinewave soft switching PWM inverter incorporating a resonant AC link snubber is illustrated, and evaluated, introducing the specific space voltage vector modulation implementation. It is conferred that the validity of three-phase soft-switching inverter treated here in setup experiment.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2018년도 전력전자학술대회
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• pp.18-20
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• 2018

This paper proposes a new pair of Active Snubber Cells (ASCs) which can fully provide soft switching for a Floating-output Double Boost Converter (FDBC). Besides that, the introduced ASCs are applicable for all basic DC-DC converters. Main switches of the FDBC turn on and off with ZVS. However, the main diodes are ZCS turned off. Furthermore Snubber switches are turned on and off with ZCS and ZVS respectively. It worthy to mention also that the soft switching for snubber diodes of the presented cells is achieved. A 1.5kW, 100kHz prototype of the FDBC with the proposed ASCs was built and evaluated; and the maximum attained efficiency is 97.3%.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2002년도 추계학술대회 논문집
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• pp.133-136
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• 2002

This paper presents m improved soft switching Buck converter using an energy recovery snubber which is composed of a tapped inductor, two snubber capacitors and three snubber diodes. The proposed Buck converter achieves zero voltage turn-of in the main power switch md freewheeling diode. The operating Principle of the Proposed Buck converter is described through the simulation, relevant equation and analysis.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2002년도 추계학술대회 논문집
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• pp.227-230
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• 2002

The switching device in an inductive circuit is stressed by the over-voltage at the turn-off time. Thus if the peak value of the over-voltage is not properly limited, the switching device may be broken. Therefore, the snubber circuit should be added to protect the switching device from the over-voltage. The circuit designer must be familiar with the design of the snubber This paper tests the possibility that TVS instead of the conventional snubber can be applied to the protection circuit of the switching device without using the complicated design equations, and shows that the rating of TVS can be easily selected by considering only several parameters of TVS. The experimental results show the reduced switching voltage of the switching device at the turn-off time.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1993년도 하계학술대회 논문집 B
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• pp.773-776
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• 1993

The thyristor turn-off model plays an important part in the design of thyristor snubber circuit. However, it is difficult to determine the thyristor turn-off characteristics. In this paper two methods to establish the simple thyristor turn-off model are proposed based on the reverse recovery characteristics given in the data sheets. Using the simple thyristor turn-off model, the optimum thyristor snubber circuit design procedures are presented considering maximum voltage spike, maximum reverse dv/dt, and turn-off loss.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• 제2B권3호
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• pp.115-124
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• 2002

This paper presents an active auxiliary edge-resonant DC link snubber with a ringing surge damper and a three-phase voltage source type zero voltage soft-switching inverter with the resonat snubber treated here for the AC servo motor driver applications. The operation of the active auxiliary edge-resonant DC link snubber circuit with PWM voltage is described, together with the practical design method to select its circuit parameters. The three-phase voltage source type soft-switching inverter with a single edge-resonant DC link snubber treated here is evaluated and discussed for the small-scale permanent magnet (PM) type-AC servo motor driver from an experimental point of view. In addition to these, the AC motor stator current and its motor speed response for the proposed three-phase soft-switching inverter employing Intelligent Power Module(IPM) based on IGBTS are compared with those of the conventional three-phase hard-switching inverter using IPM. The practical effectiveness of the three-phase soft-switching inverter-fed permanent magnet type AC motor speed tracking servo driver is proven on the basis of the common mode current in a novel type three-phase soft-switching inverter-fed AC motor side and the conductive noise on the mains terminal interface voltage as compared with those of the conventional three-phase hard-switching inverter-fed permanent magnet type AC servo motor driver for the speed tracking applications.

• Journal of Power Electronics
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• 제3권4호
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• pp.249-258
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• 2003

This paper presents a high-efficient and cost effective three-phase AC/DC-DC/AC power conversion system with a single two-switch type active Auxiliary Resonant DC Link (ARDCL) snubber circuit, which can minimize the total power dissipation. The active ARDCL snubber circuit is proposed in this paper and its unique features are described. Its operation principle in steady-state is discussed for the three phase AC/DC-DC/AC converter, which is composed of PWM rectifier as power factor correction (PFC) converter, sinewave PWM inverter. In the presented power converter system not only three-phase AC/DC PWM rectifier but also three-phase DC/AC inverter can achieve the stable ZVS commutation for all the power semiconductor devices. It is proved that the proposed three-phase AC/DC-DC/AC converter system is more effective and acceptable than the previous from the cost viewpoint and high efficient consideration. In addition, the proposed two-switch type active auxiliary ARDCL snubber circuit can reduce the peak value of the resonant inductor injection current in order to maximize total system actual efficiency by using the improved DSP based control scheme. Moreover the proposed active auxiliary two-switch ARDCL snubber circuit has the merit so that there is no need to use any sensing devices to detect the voltage and current in the ARDCL sunbber circuit for realizing soft-switching operation. This three-phase AC/DC-DC/AC converter system developed for UPS can achieve the 1.8% higher efficiency and 20dB lower conduction noise than those of the conventional three-phase hard-switching PWM AC/DC-DC/AC converter system. It is proved that actual efficiency of the proposed three-phase AC/DC-DC/AC converter system operating under a condition of soft switching is 88.7% under 10kw output power.

• 전기전자학회논문지
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• 제26권4호
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• pp.553-559
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• 2022

본 논문에서는 cascode GaN FET의 하프 브릿지 구성에서 오실레이션 억제를 위한 RC 스너버 회로 설계 기술을 분석한다. 대표적인 WBG 소자인 cascode GaN FET는 우수한 고속 스위칭 특성이 우수하다. 다만, 이러한 고속 스위칭 특성으로 인하여 false turn-off 문제가 야기되며, 이를 억제하기 위해 RC 스너버 회로가 필수적이다. 따라서, 일반적으로 많이 사용되는 실험 기반의 선정 기법과 근궤적법을 이용한 분석 기법을 비교한다. 일반적인 방법의 경우 실험적 경험을 바탕으로 오실레이션 억제 성능이 만족될 때까지 지속적인 회로 변경이 필요하다. 하지만, 근궤적 기법의 경우 비진동 R-C 맵을 기반으로 초기값을 설정 할 수 있다. 이러한 설계 기술에 따른 성능을 비교하기 위해 모의실험과 실제 더블 펄스 회로 구성을 통한 실험을 진행하였다.