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CAN통신을 이용한 H-브릿지 멀티레벨 인버터의 PWM 동기화 및 위상전이 방법
박영민(Y.M.Park),유한승(H.S.Yoo),장성영(S.Y.Jang),이현원(H.W.Lee),이세현(S.H.Lee),서광덕(K.D.Seo) 전력전자학회 2004 전력전자학술대회 논문집 Vol.- No.-
H-브릿지 멀티레벨 인버터는 여러 개의 단상 Power Cell을 직렬로 연결함으로써 저전압 전력용 반도체를 사용하여 고전압을 얻을 수 있고, 정현파에 가까운 출력전압 파형을 얻을 수 있는 멀티레벨 인버터 토폴로지이다. 본 토폴로지는 출력전압 레벨에 비례하여 Power Cell의 수가 증가하므로, 주제어기의 연산능력에 대한 부담증가와 신호선의 많아지는 단점이 있다. 따라서 Power Cell제어를 직접적인 PWM 신호가 아닌 통신을 사용함으로써 이러한 단점을 극복할수 있으며, 신뢰성 측면이나 보수/유지 측면에서도 유리하다. 본 논문은 산업현장에서 신뢰성을 인정받아 많이 사용되고 있는 직렬통신 방식의 일종인 CAN통신 인터럽터를 이용한 H-브릿지 멀티레벨 인버터 Power Cell의 PWM 동기화 및 위상전이 방법에 관한 것이다. 제안된 방법의 주요 장점은 주제어기와 셀 제어기 사이에 직렬통신(CAN)을 사용함으로써 주제어기와 셀 제어기의 신호선의 단순화, 주제어기의 부담 감소, Power Cell의 모듈화, 셀 단위의 보호동작 용이, 확장성 향상 그리고 제어 신호 및 Power Cell의 신뢰성을 향상에 있다. 13레벨로 구성된 H-브릿지 멀티레벨 인버터 시험을 통해 제안된 방법의 타당성과 신뢰성을 입증하였다.
Study on 3D Curved Humidity Sensor Process Using Double Blanket Reverse Offset Printing
H. A. Lee(이현아),D. S. Kim(김동수) Korean Society for Precision Engineering 2021 한국정밀공학회 학술발표대회 논문집 Vol.2021 No.11월
There is a lot of demand for a technology that can be directly printed on the 3D structure. Instead of attaching electronic devices, research was conducted on a method that can be directly transferred onto various substrates. In this paper, the blanket part was developed softly in reverse offset equipment capable of fine line width during the printing process. It was developed to enable printing on various substrates. The fine line width was printed on the curved surface using double blanket reverse offset printing equipment. A sensor having a line width of about 30 μm and a line spacing of Ag IDE was fabricated, and a cellulose nanofiber sensing layer was coated thereon to measure the humidity sensor. Characteristics such as sensitivity and hysteresis of the humidity sensor were analyzed. The results of a humidity-sensing investigation and mechanical testing showed that the fabricated miniaturized sensors have excellent mechanical stability, sensing characteristics, good repeatability, and relatively fast response/recovery times operating at room temperature.
이현원(H.W.Lee),최세경(S.K.CHOI),김명찬(M.C.KIM),이선재(S.J.LEE),이상동(S.D.LEE) 전력전자학회 1999 전력전자학술대회 논문집 Vol.- No.-
The three level circuit systems are able to reduce harmonic currents without requiring high frequency switching to the devices, and are suitable for high voltage, large capacity systems. However the three level circuit system has a problem that the mid point potential varies when the current flows into or out of the mid point. the variation causes voltage deviation in the DC waveforms as well as unbalanced voltage stress to the switching devices therefore the variation should be suppressed.<br/> In this paper we have proposed a new kind of PWM method for three level circuit system based on the change of phase PWM reference value with the ability to suppress the mid point voltage variation. The new method is easily implemented without complicated calculation and it's performance is similar to space vector modulation. The validity of the proposed method is verified by computer simulation
이현관(H.K Lee),이기식(G.S Lee),정봉근(B.G Chung),공영수(Y.S Chung),김은수(E.S Kim),차인수(I.S Cha),윤정필(J.P Yoon) 대한전기학회 2006 대한전기학회 학술대회 논문집 Vol.2006 No.4
Recently, the high frequency boost DC-DC converter has been widely used for the PCS system because of its small size and low cost. In this paper, the experimental results of the boost DC/DC converter using LLC series resonant converter are verified on the simulation based on the theoretical analysis and the 1㎾ experimental prototype.
이현관(H.K. Lee),공영수(Y.S. Kong),김은수(E.S. Kim),조정구(J.G. Cho) 전력전자학회 2005 전력전자학술대회 논문집 Vol.- No.-
For transferring the primary power to the secondary one, the high frequency series resonant converter has been widely used for the contactless power supply system. However, the high frequency series resonant converter has the disadvantages such as the low efficiency, the high voltage gain characteristics and deviation of the phase angle in the overall load range. To improve this disadvantage, In this paper, the characteristics of the high efficiency and unit voltage gain as well as inphase are revealed in the proposed three-level LCLC ( Inductor - Capacitor - Inductor - Capacitor)resonant converter. The results are verified on the simulation based on the theoretical analysis and the 4kW experimental prototype.