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      • PWM 전압제어로 생체에 필요한 알칼리 이온수의 농도(ph)변화에 관한 연구

        권윤중,이성창 대한전자공학회 2004 電子工學會論文誌-SC (System and control) Vol.41 No.6

        사람의 체질이 산성화로 변화되는 것을 막고 생체 밸런스를 유지하기위해 알칼리수를 인간의 인체에 공급할 필요가 있다. 알칼리수는 인체에 유익한 칼슘(Ca/sup +/), 칼륨(K/sup +/), 마그네슘(Mg/sup +/), 나트륨(Na/sup +/)등을 포함한 물로 되어있다. 이러한 알칼리수를 생성하기 위해서는 물을 전기분해하여 격막(격리된 특수막)을 통해 - 전극 쪽으로 미네랄들을 모아 생성한다. 물론 반대로 + 전극쪽으로는 염소(Cl), 인(P), 유황(S) 등의 - 이온을 띈 유기물들이 모여 산성수도 발생되어 다른 용도의 물로 사용할 수 있다. 이 전기분해 과정에서 - 극판과 + 극판에 PWM(pulse width modulation)전압을 Microprocessor를 이용하여 4종류의 PWM 전압을 구현하고, 전압별 ph농도 변화를 고찰해 보았다. 이와 같이 PWM제어를 이용하면 필요한 ph농도 값의 알칼리 이온수를 설정 값으로 하면 정확하게 얻을 것으로 예상된다. It is necessary for what just keep a living body balance be devoted to it being varied with acidity serious trouble, and constitution of a study person about the density (ph) change that an alkaline ion necessary for a living body is numerical to supply a human body with number alkali by PWM voltage control. Works in the water which included the calcium (Ca), kalium (K), magnesium (Mg), natrium (Na) back who is helpful for a human body, and there is Alkaline. It is done this alkaline electrolysis to ask in order to create a number, and minerals are gathered through isolated layer (isolated special layer) to a - electrode direction, and is created. of course, prominent derelicts gather, and the acidity capital is happened, and -ion of a chlorine (Cl), phosphorus(P), sulfur (S) back is usable unfavorably in water of different use to a + electrode direction. Microprocessor was used with a - pole and a + pole with a PWM(pulse width modulation) voltage in this electrolysis process, and four kinds of PWM voltages were implemented, and a voltage every ph density change tried to be considered. It is expected by getting exactly if number alkaline ion of ph density value necessary is done with setting value if PWM control is used thus.

      • KCI등재

        3레벨 4레그 PWM 컨버터의 커먼 모드 전압 저감

        지승준(Seung-Jun Chee),고상기(Sanggi Ko),김현식(Hyeon-Sik Kim),설승기(Seung-Ki Sul) 전력전자학회 2014 전력전자학회 논문지 Vol.19 No.6

        This paper presents a carrier-based pulse-width modulation(PWM) method for reducing the common-mode voltage of a three-level four-leg converter. The idea of the proposed PWM method is intuitive and easy to be implemented in digital signal processor-based converter control systems. On the basis of the analysis of space-vector PWM(SVPWM) and sinusoidal PWM(SPWM) switching patterns, the fourth leg pole voltage of the three-phase converter called “f leg pole voltage” is manipulated to reduce the common-mode voltage. To synthesize f leg pole voltage for the suppression of the common-mode voltage, positive and negative pole voltage references of f leg are calculated. An offset voltage is also deduced to prevent the distortion of a, b, and c phase voltages. The feasibility of the proposed PWM method is verified by simulation and experimental results. The common-mode voltage of the proposed PWM method in peak-to-peak value is 33% in comparison with that of the conventional SVPWM method. The transition number of the common-mode voltage is also reduced to 25%.

      • KCI등재

        Pulse-Width Modulation Strategy for Common Mode Voltage Elimination with Reduced Common Mode Voltage Spikes in Multilevel Inverters with Extension to Over-Modulation Mode

        Khoa-Dang Pham,Nho-Van Nguyen 전력전자학회 2019 JOURNAL OF POWER ELECTRONICS Vol.19 No.3

        This paper presents a pulse-width modulation strategy to eliminate the common mode voltage (CMV) with reduced CMV spikes in multilevel inverters since a high CMV magnitude and its fast variations dv/dt result in bearing failure of motors, overvoltage at motor terminals, and electromagnetic interference (EMI). The proposed method only utilizes the zero CMV states in a space vector diagram and it is implemented by a carrier-based pulse-width modulation (CBPWM) method. This method is generalized for odd number levels of inverters including neutral-point-clamped (NPC) and cascaded H-bridge inverters. Then it is extended to the over-modulation mode. The over-modulation mode is implemented by using the two-limit trajectory principle to maintain linear control and to avoid look-up tables. Even though the CMV is eliminated, CMV spikes that can cause EMI and bearing current problems still exist due to the deadtime effect. As a result, the deadtime effect is analyzed. By taking the deadtime effect into consideration, the proposed method is capable of reducing CMV spikes. Simulation and experimental results verify the effectiveness of the proposed strategy.

      • SCIESCOPUSKCI등재

        Pulse-Width Modulation Strategy for Common Mode Voltage Elimination with Reduced Common Mode Voltage Spikes in Multilevel Inverters with Extension to Over-Modulation Mode

        Pham, Khoa-Dang,Nguyen, Nho-Van The Korean Institute of Power Electronics 2019 JOURNAL OF POWER ELECTRONICS Vol.19 No.3

        This paper presents a pulse-width modulation strategy to eliminate the common mode voltage (CMV) with reduced CMV spikes in multilevel inverters since a high CMV magnitude and its fast variations dv/dt result in bearing failure of motors, overvoltage at motor terminals, and electromagnetic interference (EMI). The proposed method only utilizes the zero CMV states in a space vector diagram and it is implemented by a carrier-based pulse-width modulation (CBPWM) method. This method is generalized for odd number levels of inverters including neutral-point-clamped (NPC) and cascaded H-bridge inverters. Then it is extended to the over-modulation mode. The over-modulation mode is implemented by using the two-limit trajectory principle to maintain linear control and to avoid look-up tables. Even though the CMV is eliminated, CMV spikes that can cause EMI and bearing current problems still exist due to the deadtime effect. As a result, the deadtime effect is analyzed. By taking the deadtime effect into consideration, the proposed method is capable of reducing CMV spikes. Simulation and experimental results verify the effectiveness of the proposed strategy.

      • SCIESCOPUSKCI등재

        New Generalized PWM Schemes for Multilevel Inverters Providing Zero Common-Mode Voltage and Low Current Distortion

        Nguyen, Nho-Van,Nguyen, Tam-Khanh Tu The Korean Institute of Power Electronics 2019 JOURNAL OF POWER ELECTRONICS Vol.19 No.4

        This paper presents two advanced hybrid pulse-width modulation (PWM) strategies for multilevel inverters (MLIs) that provide both common-mode voltage (CMV) elimination and current ripple reduction. The first PWM utilizes sequences that apply one switching state at the double ends of a half-carrier cycle. The second PWM combines the advantages of the former and an existing four-state PWM. Analyses of the harmonic characteristics of the two groups of switching sequences based on a general switching voltage model are carried out, and algorithms to optimize the current ripple are proposed. These methods are simple and can be implemented online for general n-level inverters. Using a three-level NPC inverter and a five-level CHB inverter, good performances in terms of the root mean square current ripple are obtained with the proposed PWM schemes as indicated through improved harmonic distortion factors when compared to existing schemes in almost the entire region of the modulation index. This also leads to a significant reduction in the current total harmonic distortion. Simulation and experimental results are provided to verify the effectiveness of the proposed PWM methods.

      • KCI등재

        New Generalized PWM Schemes for Multilevel Inverters Providing Zero Common-Mode Voltage and Low Current Distortion

        Nho-Van Nguyen,Tam-Khanh Tu Nguyen 전력전자학회 2019 JOURNAL OF POWER ELECTRONICS Vol.19 No.4

        This paper presents two advanced hybrid pulse-width modulation (PWM) strategies for multilevel inverters (MLIs) thatprovide both common-mode voltage (CMV) elimination and current ripple reduction. The first PWM utilizes sequences thatapply one switching state at the double ends of a half-carrier cycle. The second PWM combines the advantages of the former andan existing four-state PWM. Analyses of the harmonic characteristics of the two groups of switching sequences based on ageneral switching voltage model are carried out, and algorithms to optimize the current ripple are proposed. These methods aresimple and can be implemented online for general n-level inverters. Using a three-level NPC inverter and a five-level CHBinverter, good performances in terms of the root mean square current ripple are obtained with the proposed PWM schemes asindicated through improved harmonic distortion factors when compared to existing schemes in almost the entire region of themodulation index. This also leads to a significant reduction in the current total harmonic distortion. Simulation and experimentalresults are provided to verify the effectiveness of the proposed PWM methods.

      • KCI등재

        계통 연계형 태양광 발전시스템의 전력변환기 제어에 관한 연구

        나승권(Seung-Kwon Na),구기준(Gi-Jun Ku),김계국(Gye-Kuk Kim) 한국컴퓨터정보학회 2009 韓國컴퓨터情報學會論文誌 Vol.14 No.2

        본 논문에서는 태양광 발전시스템을 이용한 승압 초퍼와 전압형 PWM(Pulse Width Modulation) 인버터인 전력변환기로 구성하였고, 안정된 변조를 위해서 동기신호와 제어신호를 원칩 마이크로프로세서에 의해서 처리하였다. 전력비교에 따라 시간 비율을 변화시키지만 태양전지는 전형적인 수하특성을 갖고 있어, 일사량과 온도변화에 관계없이 항상 최대 출력점을 추적하도록 승압초퍼를 제어하였다. 또한 PWM 전압형 인버터는 태양전지가 연속 발전할 수 없는 단점을 보완하기 위해 일반 상용전원과 연계함으로써 약 10∼20[%] 전력절감효과를 얻을 수 있는 에너지절약 전원 복합형 전력변환장치로 구성하였다. 그리고 태양광 발전의 효율을 높이기 위하여 센서와 마이크로프로세서를 이용한 태양광위치추적 장치를 설계하여 고정방식의 태양광 발전에 대하여 비교해 보았다. 그 결과, 태양광 위치추적장치는 고정방식의 태양광 발전에 비해 5% 정도 개선됨을 알 수 있었다. 또한, PWM 전압형 인버터와 위상동기를 위해서 계통전압을 검출하여 계통전압과 인버터 출력을 동상 운전하므로 잉여전력을 계통과 연계할 수 있게 하였다. 그리고 고역율과 저고조파 출력을 유지함으로서 부하와 계통에 전력이 안정하게 공급될 수 있도록 제어하였다. In this paper, a photovoltaic system is designed with a step up chopper and single phase PWM(Pulse Width Modulation) voltage source inverter. Where proposed Synchronous signal and control signal was processed by one-chip microprocessor for stable modulation. The step up chopper operates in continuous mode by adjusting the duty ratio so that the photovoltaic system tracks the maximum power point of solar cell without any influence on the variation of insolation and temperature because solar cell has typical voltage and current dropping character. The single phase PWM voltage source the inverter using inverter consists of complex type of electric power converter to compensate for the defect, that is, solar cell cannot be developed continuously by connecting with the source of electric power for ordinary use. It can cause the effect of saving electric power. from 10 to 20[%]. The single phase PWM voltage source inverter operates in situation that its output voltage is in same phase with the utility voltage. In order to enhance the efficiency of photovoltaic cells, photovoltaic positioning system using sensor and microprocessor was design so that the fixed type of photovoltaic cells and photovoltaic positioning system were compared. In result, photovoltaic positioning system can improved 5% than fixed type of photovoltaic cells. In addition, I connected extra power to the system through operating the system voltage and inverter power in a synchronized way by extracting the system voltage so that the phase of the system and the phase of single-phase inverter of PWM voltage type can be synchronized. And, It controlled in order to provide stable pier to the load and the system through maintaining high lurer factor and low output power of harmonics.

      • KCI등재

        산성이온수 농도제어를 위한 Microprocessor를 이용한 PWM 제어

        권윤중(Yunjung Kwon),남상엽(Sangyep Nam) 대한전자공학회 2013 전자공학회논문지 Vol.50 No.7

        전해 산성이온수는 알칼리성 이온수에 비해 응용분야가 음용을 목적으로 하는 알칼리이온수와 많이 다르게 이용되고 있으며 ph 농도에 따라 강산성인 경우 잔류염소에 의한 살균 목적의 소독제로 사용되고, 중산성인 경우 세척과 세안으로 사용하고, 약산성인 경우 식재료와 혼합하여 요리에 널리 사용할 수 있다. 이런 산성이온수를 생성하기 위해서는 물을 전기분해 하여 사용하는데 전기분해 하는 과정에서 염소가스와 수산화나트륨 등의 물질로 살균력을 가지며, 전기분해시 +전극 쪽으로 -이온을 띤 염소, 인, 유황 등의 유기물이 모여져 산성이온수를 만든다. 또한 산성수와 알칼리수를 분리하기 위해서 격막을 사용했다. ph 농도변화의 구현방법은 Microprocessor를 이용하여 강산성에서 약산성 사이의 ph 농도를 PWM(pulse width modulation) 제어로 3종류의 PWM 전압을 전해조 전극에 인가하여 PWM제어에 의한 연속적으로 농도가 조절된 산성수가 생성되게 구현하였다. We are used with the alkaline ion water which an application field does to object for drinking water compare with the alkaline ion water which asked ion acid electrolysis so as to be very different. This is used with sterilization disinfection use by residual chlorine in case of strong acidity according to ph intensity, and in case of middle acidity use by washing and face washing, and mix with meal materials in case of weak acidity widely usable in cooking. Acid ion water generates as we electrolyze water. Chlorine gas and sodium hydroxide etc. was generated at electrolysis process, and we have toward sterilizing power. Derelicts such as chlorine, phosphorus, sulfur etc. are gathered from a negative ion, and we make acid ion water to + electrode direction in electrolysis. We used a diaphragm in order to disconnect too acid water and alkaline water. We implemented so that the acid water which it came down to three kinds of PWM voltage to PWM (pulse width modulation) control, and implementation method of ph intensity change authorized ph intensity between weak acidity to electrode in strong acidity as we used Microprocessor, and intensity was adjusted successively by PWM control was generated.

      • A Buck DC-DC converter with maximum efficiency of 94.58% using dualmodes PWM/PFM implemented in 0.18 μm CMOS process

        Zaffar Hayat Nawaz Khan,Hamed Abbasizadeh,Young Jun Park,Danial Khan,Deeksha Verma,Kang-Yoon Lee 대한전자공학회 2017 대한전자공학회 학술대회 Vol.2017 No.1

        A high-efficiency DC-DC buck converter with pulse-width modulation (PWM) and pulse-frequency modulation (PFM) is proposed. This converter works in PWM mode when load current is greater than 300mA. In order to improve efficiency, it switches to PFM mode when load current is less than 300mA. With suitable control and mode switch method, simulation result indicates that the converter performs continuous switching between PWM and PFM modes. The total load current is 1.67A; the maximum efficiency reaches up to 94.58%. Simulated and implemented in 0.18 μm CMOS process.

      • Stability Analysis for Fuzzy Pulse-Width-Modulated Systems

        Hwa Chang Sung,Jin Bae Park,Young Hoon Joo 제어로봇시스템학회 2008 제어로봇시스템학회 국제학술대회 논문집 Vol.2008 No.10

        This paper proposes the stability analysis for the fuzzy pulse-width-modulation (PWM) system which based on intelligent digital redesign (IDR) method. The term IDR is to convert an existing analog control into an equivalent digital one in the sense of state-matching. The IDR problem can be reduced to find the digital gains minimizing the norm distance between the closed-loop states of the analog and digital control. The redesigned digital controller is again converted into PWM controller for stabilizing the fuzzy PWM system.

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