• 제목/요약/키워드: Switching losses

검색결과 533건 처리시간 0.022초

An Improved Asymmetric Half-Bridge Converter for Switched Reluctance Motor in Low-Speed Operation with Current Regulated Mode

  • Woothipatanapan, Sakhon;Chancharoensook, Phop;Jangwanitlert, Anuwat
    • Journal of Power Electronics
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    • 제15권6호
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    • pp.1533-1546
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    • 2015
  • This study presents a novel method for reducing the switching losses of an asymmetric half-bridge converter for a three-phase, 12/8 switched reluctance motor operated in low speed. In particular, this study aims to reduce the switching-off losses of chopping switches in the converter when operated in the current regulated mode (chopping mode). The proposed method uses the mixed parallel operation of IGBT (chopping switch) and MOSFET (auxiliary switch). MOSFET is precisely controlled to momentarily conduct prior to the turn-off interval of the IGBT. Consequently, the voltage across the switches is clamped to approximately zero, substantially decreasing the turn-off switching losses. The analytical expressions of power losses are extensively elaborated. Compared with the conventional asymmetric half-bridge converter, the modified converter can effectively minimize the switching losses. Therefore, the efficiency of the converter is eventually improved. Computer simulation and experimental results confirm the effectiveness of the proposed technique.

동기 정류기를 이용한 고효율 역률보상형 AC/DC 컨버터 (High Efficiency PFC AC/DC Converter with Synchronous Rectifier)

  • 박한웅
    • 전력전자학회:학술대회논문집
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    • 전력전자학회 2000년도 전력전자학술대회 논문집
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    • pp.266-269
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    • 2000
  • This paper presents a novel single-stage unity power factor converter which features the reduced switching losses by zero-voltage switching and zero-current switching (ZVZCS). Hence the turn-on and turn-off losses of switches are sufficiently reduced. And the reduced conduction losses are achieved by the elimination of one leg of front-end rectifier. And low on-resistance MOSFETs (Synchronous Rectifier) are used in the rectifier at the secondary side of high frequency transformer instead of diodes. Theoretical analysis simulated results of a AC to DC 150W(5V, 30A) converter are presented.

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AC 모듈형 태양광 모듈 집적형 컨버터를 위한 소프트 스위칭 DC-DC 컨버터 (Soft Switching DC-DC Converter for AC Module Type PV Module Integrated Converter)

  • 윤선재;김영호;정용채;원충연
    • 전력전자학회논문지
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    • 제18권3호
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    • pp.247-255
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    • 2013
  • In this paper, a soft switching DC-DC converter for AC module type photovoltaic (PV) module integrated converter is proposed. A push-pull converter is suitable for a low voltage PV AC module system because the step-up ratio of a high frequency transformer is high and the number of primary side switches is relatively small. However, the conventional push-pull converters do not have high efficiency because of high switching losses by hard switching and transformer losses (copper and iron losses) by high turns-ratio of the transformer. In the proposed converter, primary side switches are turned on at zero voltage switching (ZCS) condition and turned off at zero current switching (ZVS) condition through parallel resonance between secondary leakage inductance of the transformer and a resonant capacitor. Therefore the proposed push-pull converter decreases the switching loss using soft switching of the primary switches. Also, the turns-ratio of the transformer can be reduced by half using a voltage-doubler of secondary side. The theoretical analysis of the proposed converter is verified by simulation and experimental results.

Self-Feeder Driver for Voltage Balance in Series-Connected IGBT Associations

  • Guerrero-Guerrero, A.F.;Ustariz-Farfan, A.J.;Tacca, H.E.;Cano-Plata, E.A.
    • Journal of Power Electronics
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    • 제19권1호
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    • pp.68-78
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    • 2019
  • The emergence of high voltage conversion applications has resulted in a trend of using semiconductor device series associations. Series associations allow for operation at blocking voltages, which are higher than the nominal voltage for each of the semiconductor devices. The main challenge with these topologies is finding a way to guarantee the voltage balance between devices in both blocking and switching transients. Most of the methods that have been proposed to mitigate static and dynamic voltage unbalances result in increased losses within the device. This paper introduces a new series stack topology, where the voltage unbalances are reduced. This in turn, mitigates the switching losses. The proposed topology consists of a circuit that ensures the soft switching of each device, and one auxiliary circuit that allows for switching energy recovery. The principle for the topology operation is presented and experimental tests are performed for two modules. The topology performs excellently for switching transients on each of the devices. The voltage static unbalances were limited to 10%, while the activation/deactivation delay introduced by the lower module IGBT driver takes place in the dynamic unbalances. Thus, the switching losses are reduced by 40%, when compared to hard switching configurations.

직력 캐패시터를 가진 E급 공진형 정류기 설계에 관한 연구 (A Study on the Design of the Class E Resonant Rectifier with a Series Capacitor)

  • 김남호
    • Journal of Advanced Marine Engineering and Technology
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    • 제22권3호
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    • pp.343-352
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    • 1998
  • Higher frequency of energy transfer or at least energy conversion has to be used in order to reduce the size of inductors and capacitors required in the power supplies. Conventional PWM switching-mode power supplies have a limitation of operating frequency due to switching losses in the switching transistors and rectifier diodes. Means of reducing switching losses have been developed for high-frequency resonant amplifiers or more exactly dc/ac inverters. Because of smooth current and voltage waveforms resonant convertesrs havelower device switching losses and stresses lower electromagnetic interference(EMI) and lower noise than PWM converters. Therefore in this paper design equations of Classs E resonant low dv/dt rectifier with a series resonant capacitor drived using Fourier series techniques. The theory is compared with simulation results obtained for the rectifier operating at 10[MHz] ac input and 5[V] coutput.

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Zero-Voltage-Transition Pulse-Width-Modulation Boost 컨버터의 전달 특성 (Transfer Characteristics of the Zero- VoltageTransition Pulse-Width - Modulation Boost Converter)

  • 김진성;박석하;김양모
    • 전자공학회논문지B
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    • 제33B권10호
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    • pp.148-156
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    • 1996
  • Increasing the switching frquency is essential to achieve the high density of switched mode power supplies, but this leads to the increase of switching losses. A number of new soft switching converters have been presented ot reduce switching losses, but most of them may have some demerits, such as the increase of voltage/current stresses and high conduction losses. To overcome these problems, the ZVT-PWM converter has recently been presented. in this paper, the operation characteristics of the ZVT-PWM boost converter is analyzed, and the steady-states (DC) and small-signal model of this converter are derived and analyzed, and then the transfer functions of this converter are derived. The transfer functions of ZVT-PWM boost converter are similar to those of the conventional PWM boost converter, but the transfer characteristics are affecsted by te duty ratio and the switching frequency.

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Two-transistor 포워드 컨버터에서 소프트 스위칭 기법의 손실 분석 (Loss Analyses of Soft Switching Techniques for Two-transistor Forward Converter)

  • 김만고
    • 전력전자학회논문지
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    • 제6권5호
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    • pp.453-459
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    • 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.

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Power Loss and Junction Temperature Analysis in the Modular Multilevel Converters for HVDC Transmission Systems

  • Wang, Haitian;Tang, Guangfu;He, Zhiyuan;Cao, Junzheng
    • Journal of Power Electronics
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    • 제15권3호
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    • pp.685-694
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    • 2015
  • The power loss of the controllable switches in modular multilevel converter (MMC) HVDC transmission systems is an important factor, which can determine the design of the operating junction temperatures. Due to the dc current component, the approximate calculation tool provided by the manufacturer of the switches cannot be used for the losses of the switches in the MMC. Based on the enabled probabilities of each SM in an arm, the current analytical models of the switches can be determined. The average and RMS currents can be obtained from the corresponding current analytical model. Then, the conduction losses can be calculated, and the switching losses of the switches can be estimated according to the upper limit of the switching frequency. Finally, the thermal resistance model of the switches can be utilized, and the junction temperatures can be estimated. A comparison between the calculation and PSCAD simulation results shows that the proposed method is effective for estimating the junction temperatures of the switches in the MMC.

대전력 교류전동기 구동용 소프트 스위칭 인버터의 EMI 해석 (EMI Analysis of Soft Switching Inverter on High Power AC Motor Drive)

  • 권순걸
    • 융합신호처리학회논문지
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    • 제3권3호
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    • pp.76-81
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    • 2002
  • 대전력 전동기 구동장시스템에서 하드 스위칭 토폴로지는 심각한 스위칭 손실과 EMI잡음문제를 일으키며, 인버터 스위칭 주파수는 과도한 손실과 열적문제 때문에 제한되게 된다. 본 연구의 목적은 개선된 소프트 스위칭 토폴로지에 의해 스위칭손실과 EMI를 저감할 수 있는 대용량 교류전동기의 구동에 적합한 시스템을 개발하고자하며, 시뮬레이션과 실험을 통하여 그 타당성을 입증하였다.

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Analytical Model of Conduction and Switching Losses of Matrix-Z-Source Converter

  • You, Keping;Rahman, M.F.
    • Journal of Power Electronics
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    • 제9권2호
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    • pp.275-287
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    • 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.