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Dual 컨버터로 동작하는 새로운 ZCS PWM Boost Converter
김태우(Tea-Woo Kim),진기호(Gi-Ho Chin),김학성(Hack-Sung Kim) 전력전자학회 2002 전력전자학술대회 논문집 Vol.- No.-
A Novel Zero Current 5witcing(ZC5) Pulse Width Modulation(PWM) boost converter for reducing two rectifiers reverse recovery related losses is proposed<br/> The switches of the proposed converter are operating to work alternatively turn-on and turn-off with soft switching(ZV5, ZC5) condition. The reverse recovery related switching losses and EMI problems of the proposed converter eliminates the reverse recovery current of the freewheeling diode (D, D1) by adding the resonant inductor Lr, in series with the switch 52<br/> The voltage and current stresses of the components are similar to those in its conventional hard switching counterpats. As mentioned above, the characteristics are verified through experimental results.
김태우(Tea-Woo Kim),정효근(Hyo-Geun Jung),안희욱(Hee-Wook Ahn),김학성(Hack-Sung Kim) 전력전자학회 2001 전력전자학술대회 논문집 Vol.2001 No.7
This paper introduces a ZC-ZVS PWM(Pulse-Width -Modulation) boost converter. The IGBT(main switch) of the proposed converter is always switched at ZCS and soft switching of MOSFET(auxiliary switch) as well. Therefore, the proposed converter minimized the turn on/turn off switching losses of switches and reduced conduction losses by using IGBT switch. Moreover, using paralleled IGBT-MOSFET switch overcame the switching frequency limitation. Therefore high power density system can be realized As mentioned above, the characteristics are verified through experimental results.
김태우(Tea-Woo Kim),안희욱(Hee-Wook Ahn),김학성(Hack-sung Kim) 전력전자학회 2000 전력전자학술대회 논문집 Vol.2000 No.11
This paper introduces a boost converter using ZVT-PWM method. The main switch of the proposed converter is always switched at zero voltage and soft switching of auxiliary switches as well. Therefore, the proposed converter is reduced the turn off switching losses of the auxiliary switch and resonant transition period, resonant transition energy by using additional active switch compared with conventional ZVT-PWM converter, As mentioned above, the characteristics are verified through experimental results
병렬 MOSFET 스위치를 이용한 ZCT PWM Boost Converter
김태우(Tea-Woo Kim),허도길(Do-Gil Hur),김학성(Hack-Sung Kim) 전력전자학회 2002 전력전자학술대회 논문집 Vol.- No.-
A ZCT(Zero Current Transition) PWM(Pulse-width -Modulation) boost converter Using parallel MOSFET switch is proposed m this paper. The IGBT(main switch) of the proposed converter is always turned on with zero current switching and turned off with zero current/zero voltage switching The MOSFET(auxiliary switch) is also operates with soft switching condition<br/> In addtion to, the proposed converter eliminates the reverse recovery current of the freewheeling diode by adding the resonant inductor, Lr, in series with the main switch. Therefore, the turn on/turn off switching losses of switches are minimized and the conduction losses by using IGBT switch are reduced. In addition to, using parallel MOSFET switch overcomes the switching frequency limitation occurred by current tail<br/> As mentioned above, the characteristics are verified through experimental results.
Tea Woo Kim(김태우),Nam Sub Woo(우남섭),Sang Mok Han(한상목),Young Ju Kim(김영주) 대한기계학회 2019 대한기계학회 춘추학술대회 Vol.2019 No.11
The accelerational pressure gradient of air and highly viscous liquid slug flow in horizontal and low mixture Reynolds number condition was estimated by utilizing the results from Particle Image Velocimetry (PIV) and Computational Fluid Dynamics (CFD). A total of 27 and 3 data points from PIV and CFD obtained by previous studies were used for the calculations of the convective component of pressure gradient in the momentum equations, respectively. The ratio of accelerational pressure gradient and the total pressure gradient presented between -3 % and +6 %. This indicates that the accelerational component is negligible in the prediction of total pressure gradient with air and highly viscous liquid slug flow in horizontal pipe.