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원화영(Hwa-Young Won),채수용(Soo-Yong Chae),이형주(Hyoung-Ju Lee),김희선(Hee-Sun Kim),홍순찬(Soon-Chan Hong) 전력전자학회 2008 전력전자학술대회 논문집 Vol.- No.-
Charging or discharging secondary batteries such as a lithium-ion battery is essential in the stage of production and takes long time over two hours. And the charge/discharge system is operated with high switching frequency over several tens ㎑. Therefore, to simulate such a system in the conventional way takes very long time and huge files are produced. Finally, the simulation would be unable with general PC class. In this paper, the lithium-ion battery charge/discharge system is analyzed by using state space averaging method. As a result, the simulation time is reduced dramatically and the charge/-discharge characteristics of the lithium-ion battery can be observed.
에너지 회수가 가능한 2차전지 충방전시스템용 3상 양방향 AC-DC 컨버터
임승범(Seung-Beom Lim),원화영(Hwa-Young Won),채수용(Soo-Yong Chae),서영민(Young-Min Seo),이준영(Jun-Young Lee),고종선(Jong-Sun Ko),홍순찬(Soon-Chan Hong) 전력전자학회 2008 전력전자학술대회 논문집 Vol.- No.-
The electronic products such as laptop PC, cellular phone, robots and etc. need the DC power source. Recently, the secondary battery is frequently used as the portable DC power source and it needs forming process. In this paper, we proposed the bidirectional converter that the battery can be charged with high power factor and the discharged energy is regenerated into AC power source. In the charging mode, the converter acts as the boost rectifier. And the AC input current is controlled in phase with the AC input voltage. As a result, the power factor is improved nearly to unity. In the discharging mode, the DC power of battery wasted in resistor is regenerated to the AC bus line. Finally, the validity of the proposed bidirectional converter is verified by computer simulations and experimentation.
이형주(Hyoung-Ju Lee),원화영(Hwa-Young Won),임승범(Seung-Beom Lim),홍순찬(Soon-Chan Hong) 한국조명·전기설비학회 2010 조명·전기설비학회논문지 Vol.24 No.5
본 논문에서는 새로운 변조방식을 사용한 단상 인버터 시스템을 제안한다. 제안한 시스템은 buck-boost 변환기와 인버터로 구성되며 새로운 변조방식인 PWAM(Pulse Width/Amplitude Modulation)방식을 사용하여 제어한다. PWAM방식은 PWM(Pulse Width Modulation)방식과 PAM(Pulse Amplitude Modulation) 방식이 혼합된 새로운 변조방식이며 인버터의 입력단에 위치한 buck-boost 변환기는 일정한 직류전압을 입력으로 받아 가변 직류전압으로 변환한다. 인버터는 buck-boost 변환기에서 출력된 가변 직류전압을 입력으로 하며, PWM 구간에서는 PWM 스위칭을 하고 PAM 구간에서는 인버터가 스위칭을 하지 않음으로써 정현 교류전압으로 변환한다. 제안한 PWAM방식을 사용한 단상 인버터 시스템은 PAM 구간에서 스위칭 동작을 하지 않으므로 기존의 방식에 비해 스위칭 횟수가 감소하여 스위칭 손실을 줄일 수 있다. In this paper, we propose a single-phase inverter system using new modulation method. The proposed system is composed of a buck-boost converter and an inverter and controlled by PWAM scheme. PWAM method is a new modulation method which is the incorporation of PWM(Pulse Width Modulation) and PAM(Pulse Amplitude Modulation) methods. The DC voltage which is the input voltage of buck-boost converter is converted into a variable DC voltage by buck-boost converter. Also, the variable DC voltage which is the output voltage of buck-boost converter is converted into a sinusoidal AC voltage by inverter. The input voltage of inverter is processed by PWM switching in PWM section and bypassed in PAM section. By using PWAM method, switching action is not existed in PAM section and thus the times of switching is reduced. As a result, the switching loss can be reduced.
이형주(Hyoung-Ju Lee),김희선(Hee-Sun Kim),원화영(Hwa-Young Won),임승범(Seung-Beom Lim),서영민(Young-Min Seo),홍순찬(Soon-Chan Hong) 전력전자학회 2009 전력전자학술대회 논문집 Vol.2009 No.1
This paper proposes a new modulation method for single-phase inverter system. The proposed modulation method is an incorporation of PWM(Pulse Width Modulation) and PAM(Pulse Amplitude Modulation) methods. Inverter system is operated with PWM method at the predetermined reference voltage or below and with PAM method over the reference voltage. The applied DC voltage to the inverter is adjusted by the buck-boost converter furnished at the input terminals of inverters. We call the new method as a PWAM(Pulse Width/Amplitude Modulation) method. If the PWAM method is used, the times of switching are reduced. As a result, the switching loss and the size of heat sink for switching elements are reduced. To verify the validity, simulations are carried out.
김희선(Hee-Sun Kim),정대택(Dae-Taek Chung),원화영(Hwa-Young Won),이형주(Hyoung-Ju Lee),홍순찬(Soon-Chan Hong) 전력전자학회 2009 전력전자학술대회 논문집 Vol.2009 No.2
Isolated boost converter is desirable in the dc/dc converter applications where isolation is required and a large step up is needed. In this paper, it is proposed and analyzed the isolated boost converter which can step up low input voltage to high output voltage using transformer. Instead of using a conventional scheme, the proposed converter has the reset winding for volt-sec balance of transformer. Finally, the validity of the proposed isolated boost converter is verified by simulation.