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새로운 유도가열용 ZCS PWM SEEP 고주파 인버터의 특성
김칠용(C. Y. Kim),문상필(S. P. Mun),김영문(M. Y. Kim),김해재(H. J. Kim) 대한전기학회 2009 대한전기학회 학술대회 논문집 Vol.2009 No.11
This research presented the new zero-current switching pulse width modulation SEPP(Single Ended Push-Pull)high frequency inverter for solving the problem of the zero-current SEPP high frequency inverter circuit which is using widely in the practical application of an induction heating apparatus, the soft switching operation and power control are impossible when the lowest power supply in the zero-current switching pulse width modulation SEPP high frequency inverter. The inverter circuit which is attempted by on-off operation of a switch has the reduction effect of the power loss due to a soft switching and a high frequency switching. And it confirmed that the power regulation is possible continuously from 0.25[㎾] until 2.84[㎾] in the case the duty rate(D) changes from 0.08 to 0.3 under zero-current switching operating by a dissymmetry pulse width modulating control and the power conversion efficiency comes true the efficiency of 95[%]. Due to the result above, the ZCS PWM SEPP high frequency inverter will be effective as sources of an induction heating apparatus.
새로운 능동 클램핑방식을 이용한 연료전지용 DC-AC 인버터의 특성
김칠용(C.Y. Kim),조만철(M.C Cho),문상필(S.P. Mun),김영준(Y.J. Kim),Mutsuo Nakaoka,김홍삼(H.S. Kim) 한국조명·전기설비학회 2007 한국조명·전기설비학회 학술대회논문집 Vol.2007 No.11월
In the dissertation, a power conversion system for fuel cell is composed of a PWM inverter with LC filter in order to convert fuel cell voltage to a single phase 220[V]. In addition, new insulated DC-DC converters are proposed in order that fuel cell voltage is boosted to 300[V]. In this paper, it requires smaller components than existing converters, which makes easy control. The proposed DC-DC converter controls output power by the adjustment of phase-shift width using switch S5 and S6 in the secondary switch, which provides 93-97[%] efficiency in the wide range of output voltage. Fuel cell simulator is implemented to show similar output characteristics to actual fuel cell. Appropriate dead time td enables soft switching to the range where the peak value of excitation current in a high frequency transformer is in accordance with current in the primary circuit. Moreover, appropriate setting to serial inductance La reduces communication loss arisen at light-load generator and serge voltage arisen at a secondary switch and serial diode. Finally, TMS320C31 board and EPLD using PWM switching technique to act a single phase full-bridge inverter which is planed to make alternating current suitable for household.
김칠용(C. Y. Kim),문상필(S. P. Mun),김영문(M. Y. Kim),김해재(H. J. Kim),류재엽(J. Y. Lyu),김수욱(S. W. Kim) 대한전기학회 2007 대한전기학회 학술대회 논문집 Vol.2007 No.11
This research presented the new zero-current switching pulse width modulation SEPP(Single Ended Push-Pull)high frequency inverter for solving the problem of the zero-current SEPP high frequency inverter circuit which is using widely in the practical application of an induction heating apparatus, the soft switching operation and power control are impossible when the lowest power supply in the zero-current switching pulse width modulation SEPP high frequency inverter. The inverter circuit which is attempted by on-off operation of a switch has the reduction effect of the power loss due to a soft switching and a high frequency switching. And it confirmed that the power regulation is possible continuously from 025[㎾] until 2.84[㎾] in the case the duty rate(D) changes from 0.08 to 0.3 under zero-current switching operating by a dissymmetry pulse width modulating control and the power conversion efficiency comes true the efficiency of 95[%]. Doe to the result above, the ZCS PWM SEPP high frequency inverter will be effective as sources of an induction heating apparatus.
H. C. Choi(崔海椿),G. S. Chung(鄭根植),S. Y. Cho(趙守衍),B. S. Choi(崔富述),C. Y. Kim(金七龍),T. S. Kwark(郭泰淳),D. C. Lee(李東昌),N. K. Park(朴南圭) 한국육종학회 1984 한국육종학회지 Vol.16 No.2
To evaluate stability for grain yield of rice breeding lines and to identify the environmental status of some rice breeding sites, twenty one breeding lines (japonica; 13, indica; 8) and four check cultivars were grown at seven locations(Suwon, Cholwon, Chinbu, Yonkok, Unbong, Yongdok, Hwaso) in 1983 and the data for grain yield and other agronomic characters was analyzed by the method of stability analyses3,4) and principal component analysis.8) The results are summarized as follows; 1. Yongdok showed similar growth duration with Suwon, but other sites showed about 5-14 days longer duration than Suwon in the order of Hwaso < Unbong < Cholwon < Chin bu < Yonkok. Un bong pointed out the highest mean grain yield, 698 kg/10a and it was followed by the order of Suwon > Chol won> Hwaso > Yongdok > Chinbu > Yonkok. Yonkok might be a desirable site for selecting tolerant materials to so-called delaying-type cold, since it showed the most delayed heading time, the widest intervarietal variation of heading, the lowest level and smallest intervarietal variation in grain yield. 2. Among seven locations Cholwon, Unbong and Hwaso revealed similar ecological reaction by principal component analysis using mean value and standard deviation of some agronomic characters, but Unbong, Hwaso and Yongdok were similarly characterized by meteorological factors during the rice growing period. Yonkok and Chinbu showed nearly similar ecological response but were diff erently characterized by meteorological factors. Seven locations were classified largely into two regions by clustering based on correlation coefficients between genotype×environment (G×E) interaction term for grain yield at each location. 3. The yield stability of rice breeding lines can be evaluated by any parameters such as regression coefficients, residual mean squares deviated from the regression3), and 1st principal component extracted from G × E interaction term 8). Most indica lines revealed higher yield potential but lower stability than japonica strains. 4. The 1st principal component extracted from G×E interaction term for grain yield indicated close correlationship with the regression coefficients, deviations from the regression, average grain yield and coefficients of variation for yield. Also the regression coefficients showed significant positive correlation with deviations from the regression and average grain yield. 5. Contributions of the components to grain yield were largely different between locations; that is, number of panicles per hill acted decisive role on grain harvest at Yonkok and Yongkok, while number of spikelets per panicle mainly contributed to yield at Suwon, Unbong and Hwaso. 6. Average grain yield at each location were closely correlated with mean air temperature and average daily sunshine hours during the grain filling period.
조만철(M.C Cho),윤영변(Y.B Youn),김홍삼(H.S Kim),박도형(D.H. Pank),김칠용(C.Y. Kim) 대한전자공학회 2007 대한전자공학회 학술대회 Vol.2007 No.7
In the dissertation, a power conversion system for fuel cell is composed of a PWM inverter with LC filter in order to convert fuel cell voltage to a single phase 220[V]. In addition, new insulated DC-DC converters are proposed in order that fuel cell voltage is boosted to 380[V]. In this paper, it requires smaller components than existing converters, which makes easy control. The proposed DC-DC converter controls output power by the adjustment of phase-shift width using switch S5 and S6 in the secondary switch, which provides 93-97[%] efficiency in the wide range of output voltage. Fuel cell simulator is implemented to show similar output characteristics to actual fuel cell. Appropriate dead time td enables soft switching to the range where the peak value of excitation current in a high frequency transformer is in accordance with current in the primary circuit. Moreover, appropriate setting to serial inductance La reduces communication loss arisen at light-load generator and serge voltage arisen at a secondary switch and serial diode.
전도손실 저감 및 효율 상승을 위한 PWM DC-DC 컨버터의 특성
김영문(M. Y. Kim),김해재(H. J. Kim),김칠용(C. Y. Kim),류재엽(J. Y. Lyu),김수욱(S. W. Kim) 대한전기학회 2007 대한전기학회 학술대회 논문집 Vol.2007 No.11
Presented increase and so on of switch stress and switching dissipation and EMI that is happened in general PWM converter and in this study to solve problem the resonance energy return to life rate and new active snubber PWM converter because do maximization. Active snubber PWM converter that try adds auxiliary switch and resonance capacitor, diode to existing converter under all switching conditions turn on/off Minimised switching dissipation that occur. Reduced harmonic components absorbing station recovery electric current that happen to snubber diode inserting diode and resistance. And decreased peak current that is happened in auxiliary switch arranging resonance capacitor and inductor properly. Certified effect that efficiency rises about 2.5 [%] more than existent PWM converter in rated load through an experiment.
새로운 액티브 스너버를 이용한 고주파 PWM DC-DC 컨버터의 토플로지
조만철(M.C. Cho),김칠용(C.Y. Kim),서기영(K.Y. Suh),이현우(H.W. Lee),권순걸(S.K. Kwon) 대한전기학회 2006 대한전기학회 학술대회 논문집 Vol.2006 No.7
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 creation 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.