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독립제어구조를 갖는 N+1 모듈형 UPS 시스템의 병렬운전
조준석,한재원,최규하 전력전자학회 2002 전력전자학회 논문지 Vol.7 No.5
In this paper, a novel wireless parallel operation algorithm of N+1 redundant UPS system with no control interconnections for load-sharing is presented. The proposed control system eliminates the sensing noise and interconnection interference of conventional parallel operation system. To reduce a reactive power deviation in wireless control method, this technique automatically compensates for inverter parameter variation and line impedance imbalances with wireless auto-tuning method. In addition, to increase reliability on transient characteristics of parallel operation, a virtual injected impedance is adopted to eliminate a circulation current among inverter modules. Simulation results are provided in this paper to prove the proposed novel wireless algorithm. 본 논문에서는 N+1 모듈형 UPS 시스템의 병렬운전을 위해 기존에 사용된 부하분담용 신호선을 제거하고 독립적인 운전을 수행하는 새로운 형태의 wirelss 병렬제어 알고리즘을 제안하고자 한다. 제안된 제어시스템은 기존 방식이 갖는 센싱 노이즈나 상호간섭에 의한 문제를 제거할 수 있다. 또한 wireless방식의 단점을 보완하기 위해 인버터간 불평형요소 제거 알고리즘을 적용하여 무효전력편차의 발생을 최소화하는 구조를 가지며, 시스템의 불안정한 과도특성을 완충하는 가상의 임피던스를 삽입하여 과도순환전류를 저감하는 방식이 적용되었다. 제안된 알고리즘의 타당성을 검증하기 위해 시뮬레이션 결과를 제시하였다.
方向의 變化에 따른 Compton Scattering 分布에 關한 硏究
趙準錫 대구보건대학 1984 대구보건대학 論文集 Vol.8 No.-
The Compton scattering of x-rays can be interpreted as the result of elastic collisions between x-ray photons and free electrons. According to quantum theory, a photon of wavelength λ has a kinetic energy hc/λ, and a linear momentum of magnitude h/λ where h is Planck's constant and c is the speed of light. In the Compton effect, An incident beam of x-rays of known wavelength λ in a known is scattered in passing through matter, and the scattered radiation at an angle θ to the incident beam is found to have a longer wavelength λ' which is a function of the angle. Assuming anelastic collision between an incident photon and an electron of mass at rest, set up the equations expressing conservation of energy and momentum. Use the relativitic expressions fer the energy and momentum of the electron. Show that the change in x-ray wavelength is λ'-λ =1/m_(0)C(1-cosθ) and that the ejected electrom appears at an angle given by ◁수식원문참조▷
조준석(Jun-Seok Cho),배병덕(Bae-Byung Duk),정태욱(Tae-Uk Jung) 대한전기학회 2010 대한전기학회 학술대회 논문집 Vol.2010 No.7
Small wind turbine system required a cost effective and mechanically simple structures in order to be a reliable energy source. A small wind turbine system mainly required a boost converter, AFPM generator with non-slotted stator can't generate high voltage at low wind speed due to long air-gap. It is the reason of output efficiency drop. Therefore, in this paper, the Axial Field Permanent Magnet synchronous generator with internal rotor and dual slotted stators for the small wind turbine is studied, and deal with a cogging torque minimization since the use of iron slotted stator causes to increase the cogging torque. For this study, structural modeling and characteristics analysis are accomplished by 3D finite element analysis
조준석(J.S.Cho),최규하(G.H.Choe) 전력전자학회 2003 전력전자학술대회 논문집 Vol.2003 No.7(1)
This paper presents a non-electrical isolated prototype of N+X redundant UPS with two-quadrant converter. Proposed topology has multl-functions of battery charge and discharge regulation, operates with a near unity input power factor, compensates unbalanced voltage on DC bus capacitors, and regenerates the circulating active power among the inverters into battery or grid And furthermore, this system adopts a novel wireless parallel operation algorithm of N+X redundant UPS system with no control interconnections Simulation and experiment results are provided in this paper to prove the validity of proposed topology and wireless control algorithm
도시형 풍력발전기용 AFPM 발전기의 전자기적 구조설계에 관한 연구
조준석(Jun-Seok Cho),최세권(Se-kwon Choi),김주용(Ju-yong Kim),정태욱(Tae-Uk Jung) 대한전기학회 2009 대한전기학회 학술대회 논문집 Vol.2009 No.7
Wind power system attracts most interest because of high-energy efficiency with environment-friendly. Small scale wind power applications requires a cost effective and mechanically simple generator in order to be a reliable energy source. The use of direct driven generators, instead of geared machines, reduces the number of drive components, which offers the opportunity to reduce costs and increases system reliability and efficiency. This paper presents the development of a coreless axial-flux permanent magnet(AFPM) generator for a urban wind power system. It is analyzed by electromagnetic simulation program Maxwell 3D
독립제어구조를 갖는 N+1 모듈형 UPS 시스템의 병렬운전
조준석(Cho Jun-Seok),한재원(Han Jae-Won),최규하(Choe Gyu-Ha) 전력전자학회 2002 전력전자학술대회 논문집 Vol.- No.-
In this paper, a navel wireless parallel operation algorithm of N+1 redundant UPS system with no control interconnections is presented The load sharing of multiple UPS modules are controlled by Q-V droop and P-δ droop algorithm This algorithm compensates for inverter parameter variation and line impedance imbalances with wireless auto-tuning method And to increase the reliability of transient characteristic under parallel operation, a virtual injected impedance is proposed to decrease a circulation current between inverter modules Simulation results are provided to prove the novel wireless algorithm.
UPS용 인버터의 LC필터 출력 전압제어를 위한 디지털 제어기 설계
조준석(Jun-Seok Cho),이승요(Seung-Yo Lee),최규하(Gyu-Ha Choe),목형수(Hyung-Soo Mok),신우석(Woo-Seok Shin),한석우(Seok-Woo Han) 전력전자학회 1998 전력전자학술대회 논문집 Vol.- No.-
This paper presents an observer filter algorithm to estimate the load currents in the output voltage control of 3-phase uninterruptible power supply with deadbeat controller As the result of the proposed algorithm, the sensors to measure the<br/> load currents is not required The comparison of output voltage controls according to the methods of measuring the load currents is also presented in this paper The results of comparison are shown by the simulation.<br/> <br/>
Microwave Oven 용 커패시터 내장형 고주파변압기의 해석 및 설계에 관한 연구
조준석(J.S. Cho),박강희(K.H. Park),목형수(H.S. Mok),최규하(G.H. Choe) 전력전자학회 2000 전력전자학술대회 논문집 Vol.2000 No.11
A conventional power supply to drive a microwave oven has ferro-resonant transformer and high voltage capacitor (INC). Though it is simple, transformer is bulky, heavy and has low-efficiency. To improve this defect, a high frequency switching inverter-type power supply has been investigated and developed in recent years^[1][2] But, because of It's additional circuit and devices ,inverter-type power supply IS more expensive than conventional one. In this paper, The design procedure of a novel HVC embedded high frequency transformer is proposed for down-sizing and cost reduction. Also, transformer equivalent circuit model is derived by FEM analysis and parameter measurements. And the operation of proposed HVC embedded transformer is verified by simulations and experimental results.