• 수산해양교육연구
• /
• 제9권2호
• /
• pp.209-221
• /
• 1997

This paper presents a soft switching unity power factor PWM rectifier, which features reduced conduction losses and soft switching with no auxiliary switches. The soft switching are achieved by using a simple commutation circuit with no auxiliary switches, and reduced conduction loses are achieved by employing a single converter, instead of a typical front end diode rectifier followed by a boost rectifier. Furthermore, thanks to good features such as simple PWM control at constant frequency, low switch stress and low VAR rating of commutation circuits, it is suitable for high power applications. The principle of operation is explained in detail, and major characteristics analysis and experimental results of the new converter also included.

• International journal of advanced smart convergence
• /
• 제9권2호
• /
• pp.105-113
• /
• 2020

In this paper, we proposed a soft switched synchronous boost converter, which can perform discharging the battery, is proposed. The proposed converter has low switching loss even at high frequency operation due to its soft switching characteristics. The converter operates in synchronous mode to minimize conduction loss because of changing the rectified diode to MOSFET with a low on resistance. In this reason, the efficiency of the converter can be greatly improved in high frequency. In this paper, the battery discharger with a switching frequency of 100 kHz, has been designed. The designed converter also simulated to prove the converter's characteristics of synchronous operation as well as soft switching operation. The simulation shows that the proposed converter always meets the soft switching conditions of turning on and off switching in the zero voltage and zero current states. Therefore, simulation results have confirmed that the proposed battery discharge had soft switching characteristics. The simulation results have confirmed that the proposed battery discharger had soft switching and synchronous operation characteristics.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1999년도 하계학술대회 논문집 F
• /
• pp.2665-2667
• /
• 1999

This Paper proposes a new toplogy snubber circuit of Full-Bridge DC-DC Converter for reducing conduction losses and snubber circuit heating loss. Using Partial Resonent Soft Switching Method and Clamping, studying on a new snubber circuit for reducing losses that a snubber circuit heating loss in the secondly diode rectification side, a switching losses in the primary side of IGBT inverter and conduction losses in the high frequency insulation transformer. In this paper, we present FB DC-DC converter included a new lossless snubber circuit, and then be analyzed and simulated.

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 2005년도 전력전자학술대회 논문집
• /
• pp.140-142
• /
• 2005

SMPS의 손실에는 switching loss, conduction loss, core loss가 있다. 최근 SMPS에서는 switching loss를 줄여 효율을 높이고자 반도체 스위치 2개를 사용하는 공진형 구조가 증가하고 있다하지만 공진형 구조는 반도체 스위치에서 소비되는 conduction loss로 의해 기존의 컨버터에 비해 무부하시 전력 소모가 크다. 그러나 최근 시장은 무부하시 소비되는 대기전력의 규제가 이슈가 되고 있다. 본 논문에서는 active clamped flyback converter에서 무부하시 반도체 스위치의 conduction loss의 감소를 위해 Clamp 회로의 보조 스위치는 동작시키지 않고, flyback converter로만 동작하도록 설계하여 무부하시에는 기존의 flyback converter의 동작과 같이 도통 손실이 급속히 줄도록 하였다. 또한 스위칭 손실을 줄이기 위해 주 스위치의 동작 주파수를 감소시켜 SMPS의 무부하시의 소모를 감소시켰다. 70W급 SMPS의 제작과 실험을 통해 위의 방법을 증명하고자 한다.

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 2017년도 전력전자학술대회
• /
• pp.577-595
• /
• 2017

${\bullet}$ Silicon Carbide (SiC) had excellent material properties as the base material for next generation of power semiconductor. In developing SiC MOSFET, gate oxide reliability issues had to be first overcome before commercial application. Besides, a high and stable gate-source voltage threshold $V_{GS(th)}$ is also an important parameter for operation robustness. SiC MOSFET with such characteristics can directly use existing high-speed IGBT gate driver IC's. ${\bullet}$ The linear voltage drop characteristics of SiC MOSFET will bring lower conduction loss averaged over full AC cycle compared to similarly rate IGBT. Lower switching loss enable higher switching frequency. Using package with auxiliary source terminal for gate driving will further reduce switching losses. Dynamic characteristics can fully controlled by simple gate resistors. ${\bullet}$ The low switching losses characteristics of SiC MOSFET can substantially reduce power losses in high switching frequency operation. Significant power loss reduction is also possible even at low switching frequency and low switching speed. in T-type 3-level topology, SiC MOSFET solution enable three times higher switching freqeuncy at same efficiency.

• Journal of Power Electronics
• /
• 제16권1호
• /
• pp.121-132
• /
• 2016

In this paper, high-efficiency design methodology of a zero-voltage-switching full-bridge (ZVS-FB) pulse width modulation (PWM) converter for server-computer power supply is discussed based on self-driven synchronous rectifier (SR) performance. The design approach focuses on rectifier conduction loss on the secondary side because of high output current application. Various-number parallel-connected SRs are evaluated to reduce high conduction loss. For this approach, the reliability of gate control signals produced from a self-driver is analyzed in detail to determine whether the converter achieves high efficiency. A laboratory prototype that operates at 80 kHz and rated 1 kW/12 V is built for various-number parallel combination of SRs to verify the proposed theoretical analysis and evaluations. Measurement results show that the best efficiency of the converter is 95.16%.

• 전력전자학회논문지
• /
• 제6권5호
• /
• pp.453-459
• /
• 2001

본 논문에서는 Two-transistor 포워드 컨버터에서 사용 가능한 기존의 소프트 스위칭 기법과 새로운 소프트 스위칭 기법의 손실 분석을 수행한다. 두 트랜지스터에서 발생하는 스너버 전류에 의한 트랜지스터 손실과 내부 커패시터에 의한 턴-온 손실을 유도하고, 각각의 트랜지스터에서 발생하는 전체 손실을 계산한다. 손실 계산을 통해 기존의 소프트 스위칭 기법에서는 두 트랜지스터에서 발생하는 손실이 상이함을 보이고, 새로운 소프트 스위칭 기법에서는 손실이 적으면서도 두 트랜지스터에서의 손실이 고르게 발생함을 알 수 있다. 그리하여 제안된 소프트 스위칭 스너버를 사용하여 고른 열분포와 향상된 신뢰도를 얻을 수 있음을 보인다.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2008년도 제39회 하계학술대회
• /
• pp.920-921
• /
• 2008

This paper presents the efficiency analysis of CCM(Continuous Current Mode) boost converter. A thorough efficiency analysis of a boost converter taking into account the conduction losses, the diode power loss, the switching losses, the gate-drive loss and the capacitive switching loss, for both continuous conduction mode is presented.

• Journal of Power Electronics
• /
• 제9권2호
• /
• pp.275-287
• /
• 2009

This paper investigates analytical models of Conduction and Switching Losses (CASLs) of a matrix-Z-source converter (MZC). Two analytical models of the CASLs are obtained through the examination of operating principles for a Z-source inverter and ac-dc matrix converter respectively. Based on the two models, the analytical model of CASLs for a MZC is constructed and visualized over a range of exemplified operating- points, each of which is defined by the combination of power factor (pt) and modulation index (M). The model provides a measurable way to approximate the total losses of the MZC.

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 2012년도 추계학술대회 논문집
• /
• pp.75-76
• /
• 2012

This paper presents an analysis of power losses in three-level T-Type Inverters. The switching loss in different switching frequencies and the conduction loss at different modulation indices and power factors are investigated. Finally, it is shown that the results of analysis coincide with those which resulted from CASPOC software simulation.