• Journal of international Conference on Electrical Machines and Systems
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• 제3권4호
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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.

• 전기학회논문지
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• 제60권4호
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• pp.781-788
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• 2011

This paper proposes a boost-input self-driven active clamp ZVS converter eliminating the extra dirve circuit for the active clamp switch. The converter used the auxiliary winding of the transformer to drive the active clamp switch and to achieve asymmetrical duty control. This paper presents the operation principle and the analyzed results of dynamic characteristics including steady state characteristics of the converter proposed. The experimental results were used to verify the theoretical predictions. A 300W (15V/20A) prototype converter that only exhibited 2-turn winding number in the auxiliary winding was sufficient to drive the active clamp switch on the input voltage of 80V. Finally, the maximum efficiency of 91.2% was achieved for the prototype converter and the proposed converter had stable closed loop characteristic with phase margin $55^{\circ}$.

• 전자공학회논문지SC
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• 제40권5호
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• pp.350-354
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• 2003

본 논문에서는 능동 클램프 스위치를 위한 별도의 구동 회로가 생략된 새로운 자기 구동 능동 클램프 포워드 컨버터를 제안하였다. 능동 클램프 스위치의 구동에는 컨버터 자체의 변압기의 보조 권선을 이용하였고, 두 스위치 구동 신호 사이의 데드 타임을 설정하기 위하여 간단한 R-C지연 회로를 추가하였다. 제안된 컨버터의 동작 원리를 제시하였고 실험 결과를 가지고 이론적인 결과를 입증하였다. 출력 100W(5V/20A)의 컨버터를 제작하였으며 입력이 50V일 때 능동 클램프 스위치의 구동에 단지 1.5T의 보조 권선의 권선수로 충분하다는 점을 보였다. 끝으로 제안된 컨버터의 측정 효율을 제시하였고 91%의 최대 효율을 달성하였다.

• 전력전자학회논문지
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• 제18권5호
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• pp.477-484
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• 2013

This paper proposes a novel switching method of active clamp snubber for efficiency improvement of PV module integrated converter(MIC) system. Recently, MIC solar system is researched about the efficiency and safety. PV MIC system is used active clamp method of snubber circuit for the price and reliability of the system. But active clamp snubber circuit has the disadvantage that system efficiency is decreased for switch operating time because of heat loss of resonant between snubber capacitor and leakage inductance. To solve this problem, this paper proposes a novel switching method of the active clamp. The proposed method is a technique to reduce power consumption by reducing the resonance of the snubber switch operation time and through simulations and experiments proved the validity.

• Journal of Power Electronics
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• 제9권1호
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• pp.26-35
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• 2009

A high efficiency active clamp sepic-flyback converter is presented for fuel cell generation systems. The proposed converter is a superposition of a sepic converter mode and. flyback converter mode. The output voltages of the sepic converter mode and flyback converter mode can be regulated by the same PWM technique with constant frequency. By merging the sepic and flyback topologies, they can share the transformer, power MOSFET and active clamp circuit. The result has outstanding advantages over conventional active clamp DC-DC converters: high efficiency, high power density, and component utilization. Simulation results and experimental results are presented to verify the principles of operation for the proposed converter.

• 반도체디스플레이기술학회지
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• 제17권3호
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• pp.21-26
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• 2018

In this paper, the switching characteristics of the active clamp type flyback converter, which is deemed suitable for the miniaturization of the external power supply for home appliance, were analyzed and the process of reducing the switching loss was explained. The active clamp type flyback converter operating in the DCM has confirmed that the surge voltage of the main switch does not occur and the turn-off / on loss of the switch do not occur in principle. Also, in the case of the switch for synchronous rectifier, it was showed that the switch current showed half-wave rectified sinusoidal characteristic, and the switching loss was reduced. The switching characteristics of the experimental results gathered from 120 W class prototype were compared with the theoretical waveform in the steady-state and it was confirmed that the power conversion efficiency of the active clamp type flyback converter was maintained high due to the reduction of the switching loss.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 B
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• pp.1193-1195
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• 2002

This paper presents Active-clamp Class-E high frequency resonant inverter with single-stage. The proposed circuit is integrated Active-c class-E circuit to boost converter with the funct power factor correction. Boost converter is opera positive and negative half cycle respectively at frequency(60Hz), operating in Discontinuous Con Mode(DCM) of boost converter performs high p factor. By adding active-clamp circuit in Cl inverter, main switch of inverter part is operat only ZVS(Zero Voltage Switch), but also reduce switching voltage stress of main switch. Simulation result using Psim4.1 show that the p prove the validity of theoretical analysis. This proposed inverter will be able to be pract used as a power supply in various fields are ind heating applications, DC-DC converter etc.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제53권8호
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• pp.517-524
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• 2004

In this paper, a novel zero-voltage-switching(ZVS) resonant DC-DC converter is proposed. It is composed of two symmetrical active-clamped circuits, the converter can be achieve ZVS in each switches. Also, active clamp capacitor ratios($\alpha$) of proposed circuit can be reduce a peak stress of switching voltage for each main switch. Simulation results using Pspice 9.2 ver and $C^{++}$ characteristic analysis show a provement for the validity of theoretical analysis. The analysis of the proposed Current-Fed Push Pull type DC-DC converter is generally described by using normalized parameter, and achieved an evaluated characteristic values which is needed to design a circuit. We confirm a rightfulness theoretical analysis by comparing a theoretical values and experimental values obtained from experiment using MOSFET as switching devices.

• 반도체디스플레이기술학회지
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• 제17권4호
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• pp.56-61
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• 2018

In this paper, a new type of active snubber was proposed to lower the excessive rated voltage of the clamp capacitor which was a problem in the conventional circuit by applying auxiliary winding into the active snubber. A simplified equivalent circuit of the proposed snubber was derived by applying it to QR flyback converter, and the equivalent circuits for each switch state was shown under the steady-state condition. In addition, the maximum voltage of the clamp capacitor as well as the main switch was found by using the steady-state equations. In particular, it was found that the clamp capacitor voltage could be controlled by the auxiliary winding ratio. In order to verify the utility and practicality of the proposed converter with auxiliary winding type active snubber circuit, a prototype with an output voltage of 19V and a maximum load current of 6A was produced and the results were reported.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제53권2호
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• pp.114-122
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• 2004

This paper presents a novel single-stage active-clamp type high frequency resonant inverter. The proposed topology is integrated full-bridge boost rectifier as power factor corrector and active-clamp type high frequency resonant inverter into a single-stage. The input stage of the full-bridge boost rectifier works in discontinuous conduction mode(DCM) with constant duty cycle and variable switching frequency. So that a boost converter makes the line current follow naturally the sinusoidal line voltage waveform. By adding additional active-clamp circuit to conventional class-E high frequency resonant inverter, main switch of inverter part operates not only at Zero-Voltage-Switching mode but also reduces the switching voltage stress of main switch. Simulation results have demonstrated the feasibility of the proposed high frequency resonant inverter. Characteristics values based on characteristics estimation through circuit analysis is given as basis data in design procedure. Also, experimental results are presented to verify theoretical discussion. This proposed inverter will be able to be practically used as a power supply in the fields of induction heating applications, fluorescent lamp and DC-DC converter etc.