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카본 브러쉬 타입 코로나 방전기의 방전 특성에 관한 실험 및 수치적 연구
김세현(Se Hyun Kim),박기웅(Gi Woong Park),최호연(Ho Yeon Choi),최창영(Chang Yong Choi),박성현(Seong Hyun Park),박용갑(Yong Gap Park),이동근(Dong Geun Lee),하만영(Man Yeong Ha) 대한기계학회 2021 大韓機械學會論文集B Vol.45 No.12
본 연구에서는 카본 브러쉬 타입 코로나 방전기의 방전 특성을 실험 및 수치적으로 연구하였다. 카본 브러쉬 방전으로 발생하는 이온에 의한 전류 변화를 채널 바닥에서 유속 유무에 따라 실험하여 측정하였다. 실험 결과는 수치 해석 결과와 비교되고 수치 해석 결과는 실험 결과와 경향 및 크기가 유사하게 나타났다. 방전기 방향에 따른 전류 밀도 분포의 변화를 조사하기 위해 방전기 방향 및 유속 유무에 따른 수치 해석을 수행하고, 그 결과를 비교 분석하였다. 유속 유무에 따라 전류 밀도 분포가 변화하는 것으로 나타났고, 유속이 존재할 때 이온이 유동을 따라 이동하는 것으로 나타났다. 또한 방전기 방향에 따라 바닥에서의 전류 밀도 분포에 차이가 나타났다. In this paper, the discharge characteristics of a carbon brush-type corona discharger were studied experimentally and numerically. The current change due to ions generated by carbon brush discharge was measured experimentally at the bottom of the channel. The experimental results were compared with the numerical results and were found to be similar in trend and magnitude. To investigate the change in the ion charge density distribution, according to the direction of the discharger, numerical analysis was performed with respect to the direction of the discharger, and flow velocity. The charge density distribution was found to change with the velocity, and the ions were found to move downstream of the flow when the flow velocity was present. Furthermore, there was a difference in the distribution of charge density at the bottom, according to the direction of the discharger.
3상 PM-BLDCM 구동용 NPC형 3레벨 인버터의 제어기법
최창영(Chang-Young Choi),모동영(Dong-Yeong Mo),이상철(Sang-Cheol Lee),김태웅(Tae-Woong Kim) 전력전자학회 2009 전력전자학술대회 논문집 Vol.2009 No.1
In order to reduce torque ripple and voltage stress of stator windings, NPC 3 level inverter topology for PM-BLDCM drive and its suitable rectangular SVPWM control scheme are proposed in this paper. Torque ripple of PM-BLDCM driven by both two inverter topologies are respectively investigated, and its effectiveness is verified through simulations using PSIM.
2 차원 채널 내부에서 자유 낙하하는 정사각형 입자의 운동에 관한 수치적 연구
최창영(Chang Young Choi),윤현식(Hyun Sik Yoon),하만영(Man Yeong Ha) 대한기계학회 2009 대한기계학회 춘추학술대회 Vol.2009 No.11
This paper presents a numerical investigation of the characteristics of flow around a square particle freely falling in a two-dimensional channel. The FSI (fluid-solid interaction) has been realized by using the directforcing fictitious domain (DF/FD) method. In order to identify the effect of fluid properties on the flow characteristics and solid motion by FSI, two different densities and especially, a various range of the fluid viscosity have been considered. In addition, the off-centered distance as the initial position of the square particle has been imposed to research the effect of the gap between the channel wall and the square particle. Quantitative information about the drag coefficient on the square particle is highlighted.
3상 영구자석형 브러시리스 전동기 구동에 적합한 구형파 SVPWM 제어기법의 제안
이상철(Sang-Cheol Lee),최창영(Chang-Young Choi),모동영(Dong-Yeong Mo),조춘호(Choon-Ho Cho),김동민(Dong-Min Kim),김태웅(Tae-Woong Kim) 전력전자학회 2009 전력전자학술대회 논문집 Vol.2009 No.1
In this paper, the rectangular space vector PWM control algorithm suitable for 3 phase PM-BLDCM drive is proposed on the based of conventional sinusoidal SVPWM for IM or PMSM drives. Compared to a conventional rectangular PWM control scheme by triangular comparison, the proposed rectangular SVPWM control scheme is simpler and can be easier embedded in the digital control system. And this scheme has advantages to reduce torque ripple of PM-BLDCM. These effectiveness will be verified through analyzed simulation results using PSIM.
조춘호(Choon-Ho Cho),모동영(Dong-Yeong Mo),이상철(Sang-Chul Lee),최창영(Chang-Young Choi),이건식(Gun-Sik Lee),김태웅(Tae-Woong Kim),박귀근(Gwi-Geun Park) 전력전자학회 2010 전력전자학술대회 논문집 Vol.2010 No.7
Matrix converter is direct power conversion system. Matrix converter has many merits that possible bidirectional power flow, input power factor own control and system without DC-link. But matrix converter has some demerits that need many switching devices and switching loss. This paper suggest optimal matrix converter control scheme for improvement for switching loss part. Proposed control scheme verified that 10% improvement in efficiency, input current's harmonic loss and output voltage's EMI improvement.
이건식(Geon-Sik Lee),모동영(Dong-Yeong Mo),이상철(Sang-Cheol Lee),최창영(Chang-Young Choi),조춘호(Chun-Ho Cho),김태웅(Tae-Woong Kim),박귀근(Gwi-Geun Park) 전력전자학회 2010 전력전자학술대회 논문집 Vol.2010 No.7
매트릭스컨버터의 제어기법은 입력측의 전류형과 출력측의 전압형의 조합에 의해 구성된 미래지향형 AC/AC 전력변환시스템이다. 이를 제어하기위해서 기존 SVPWM을 적용하면 섹터정보 및 인가시간의 계산과정이 복잡해지고 계산량이 많아지는 단점이 있다. 본 논문에서는 상기의 문제점을 해결하기 위해 전압형 인버터에 사용하고 있는 기존 간략형 SVPWM과 함께 입력측 전류형에도 이를 변형하여 적합한 간략형 SVPWM를 동시에 적용하여 전체의 PWM에 관련된 계산과정을 단순화시키고 계산량을 저감시킬 수 있는 제어기법을 제안한다.
조춘호(Choon-Ho Cho),모동영(Dong-Yeong Mo),이상철(Sang-Chul Lee),최창영(Chang-Young Choi),이건식(Gun-Sik Lee),김태웅(Tae-Woong Kim),박귀근(Gwi-Geun Park) 전력전자학회 2010 전력전자학술대회 논문집 Vol.2010 No.7
Two-Stage Direct Power Converter(TSDPC) has many merits that possible bidirectional power flow, input power factor own control and system using imaginary DC-link. But TSDPC has some demerits that need many switching devices and switching loss. This paper suggest optimal TSDPC control scheme for improvement for switching loss part by changing the space vector approval times. This paper is verified that 9% improvement in switching efficiency and proposed system has lower harmonic of input currents and output voltage.
매트릭스 컨버터에 의한 AC 서보 영구자석형 동기전동기의 제어기 설계에 대한 고찰 : 속도제어기
정충일(Chung-Il Jeong),이상철(Sang-Cheol Lee),모동영(Dong-Yeong Mo),최창영(Chang-Young Choi),김태웅(Tae-Woong Kim),박귀근(Gwi-Geun Park) 전력전자학회 2008 전력전자학술대회 논문집 Vol.- No.-
This paper deals with the design for speed controller to drive PMSM by matrix converter without DC-link circuit as the power conversion system of AC servo motor drive. To design the speed controller of PMSM drive, the closed-loop transfer function of speed controller is calculated and then the frequency-domain response characteristics are analyzed by bode plot using Matlab. Based on the results by bode plot, the speed control gains are determined. As the real effects of controller designed in the frequency-domain display in the time-domain, the performance of speed controller is confirmed by the step response of speed controller. The design examples are shown and its validity of the design method mentioned in the paper is verified through PSIM simulation.