PFC2D를 이용한 절리암반의 역학적 물성 평가연구

박의섭(Eui-Seob Park),류창하(Chang-Ha Ryu) 한국암반공학회 2005 터널과지하공간 Vol.15 No.2

절리 암반의 역학적 물성 및 거동 평가가 터널 및 지하구조물의 설계에 매우 중요하다 할지라도, 그것은 항상 매우 어려운 문제로 간주되어 왔다. 암반 거동을 모사하는데 있어서 어려움중의 하나는 적절한 구성 모델을 선정하는 것이다. 이러한 한계점은 PFC와 같이 사용자로 하여금 암반의 구성 모델을 요구하지 않는 개별요소 프로그램의 개발과 함께 극복되어질 것이다. 본 연구에서는 도로터널 현장의 30 m × 30 m × 30 m 절리 암반블록을 대상으로, 시추 및 지표 지질조사를 통해 얻어진 절리의 기하학적 형태자료를 근거로 개별균열망이 작성되었다. 개별균열망 모델의 절리 형상을 근거로 절리가 없는 상태에서 점차적으로 절리군을 추가해가면서 2차원 PFC 모델이 만들어졌다 또한 각각의 PFC 모델에 대한 수치모사를 통하여 각 모델의 응력-변형율 곡선이 얻어졌다 응력-변형율 곡선으로부터 절리 암반의 역학적 물성이 결정되었다. 절리의 존재는 암반의 역학적 물성에 상당한 영향을 미쳤으며, 더욱 중요한 것은 PFC 모델의 역학적 거동은 기존의 수치모델에서 요구되는 구성 모델에 의하여 결정되지 않는다는 것이다. Although the evaluation of the mechanical properties and behavior of jointed rock masses is very important for the design of tunnel and underground openings, it has always been considered the most difficult problem. One of the difficulties in describing the rock mass behavior is the selection of the appropriate constitutive model. This limitation may be overcome with the progress in discrete element software such as PFC, which does not need the user to prescribe a constitutive model for rock mass. In this paper, a 30 m × 30 m × 30 m jointed rock mass of road tunnel site was analyzed. A discrete fracture network was developed from the joint geometry obtained from core logging and surface survey. Using the discontinuities geometry from the DFN model, PFC simulations were carried out, starting with the intact rock and systematically adding the joints and the stress-strain response was recorded for each case. With the stress-strain response curves, the mechanical properties of jointed rock masses were determined. As expected, the presence of joints had a pronounced effect on mechanical properties of the rock mass. More importantly, getting the mechanical response of the PFC model doesn't require a user specified constitutive model.

3상 모듈형 UPS용 Interleaved PFC의 디지털 제어

김상훈(Kim, Sang-Hoon),박내춘(Park, Nae-Chun) 강원대학교 산업기술연구소 2012 産業技術硏究 Vol.32 No.1

In this paper the digital control scheme of interleaved PFC for 3-phase modular UPS is presented. The interleaved PFC is composed of two identical PFC connected in parallel and each PFC is controlled by the interleaved switching signals which have the same switching frequency and the 180° phase difference. As a consequence of the interleaving operation, the Interleaved PFC exhibits both lower current ripple at the input side and lower voltage ripple at the outside. Therefore, the switching and conduction losses as well as EMI levels can be significantly decreased. Simulation and experimental results verify the usefulness of the interleaved PFC.

Membrane Characteristics for Removing Particulates in PFC Wastes

Gye-Nam Kim,Sung-Yeol Lee,Hui-Jun Won,Chong-Hun Jung,Won Jin Oh,Jin-Ho Park 한국방사성폐기물학회 2005 방사성폐기물학회지 Vol.3 No.2

원자력연구시설의 핫셀 내 바닥이나 장치표면에 부착된 고방사능분진의 제거를 위해서 PFC제염기술을 적용한다. 고가인 PFC 용액의 재사용을 위해서는 여과장치의 개발이 필요하고 제염종료 후 이차폐기물의 양을 최소화할 필요가 있다. PFC 제염폐액 내 방사성 입자를 제거하기 위해 핫셀 내의 고방사능분진의 오염 특성을 조사했다. 여과 막을 이용한 입자의 제거효율 측면에서 보면 세라믹 , PVDF, PP 막 모두가 95 이상의 높은 여과 성능을 보였다. 기공 크기가 같은 동일 여과 막에서는 입자가 크거나 가하는 압력이 높을수록 좀더 높은 제거효율을 나타내었고, 3psi이하에서는 PVDF의 제거효율이 다른 막에 비해 작게 나타났다. 플럭스 성능은 PVDF 막이 가장 높은 수준을 나타냈고 세라믹과 PP 막에서는 다소 낮은 성능을 보였다. PVDF 막은 낮은 압력과 짧은 여과시간으로 최대(한계)플럭스에 도달함을 확인하였다. 세라믹 막은 모의입자의 제거 효율은 높지만 다소 낮은 Flux 성능을 나타냈다. 또한, 막 자체의 비싼 가격과 쉽게 부서지는 성질의 단점을 지니고 있지만 무기화합물의 재질로 되어있기 때문에 알파방사능 환경에서 H, 가스를 발생하는 고분자 막인 PVDF, PP 막과 비교하여 훨씬 안정적이었다. 그리고 이들 소수성 여과막들의 특성 비교를 바탕으로 세라믹 막을 적용한 PFC 실증 여과장치의 공정도를 살펴보았다. PFC(Perfluorocarbon) decontamination process is one of best methods to remove hot particulate adhered at inside surface of hot cell and surface of equipment in hot cell. It was necessary to develop a particulate filtration equipment to reuse PFC solution used on PFC decontamination due to its high cost and to minimize the volume of second wastewater. Contamination characteristics of hot particulate were investigated and then a filtration process was presented to remove hot particulate in PFC solution generated through PFC decontamination process. The removal efficiency of PVDF(Poly vinylidene fluoride), PP(Polypropylene), Ceramic(AlO filter showed more than 95. The removal efficiency of PVDF filter was a little lower than those of other kiters at same pressure(3psi). A ceramic filter showed a higher removal efficiency with other filters, while a little lower flux rate than other filters. Due to inorganic composition, a ceramic filter was highly stable against radio nuclides in comparison with PVDF and PP membrane, which generate H gas in e-radioactivity atmosphere. Therefore, the adoption of ceramic filter is estimated to be suitable for the real nitration process.

Semi-boost PFC에 의한 형광등용 전자식 안정기 해석

한재현(Han Jae Hyun),조계현(Jo Gye Hyun),박종연(Park Chong Yeun) 강원대학교 산업기술연구소 2003 産業技術硏究 Vol.23 No.1

There are many kinds of electronic ballast for various kinks of fluorescent lamps. The PFC(Power Factor Correction) circuit in electronic ballast is classified in two types. One is the active PFC and the other is the passive PFC circuit. The active type PFC is higher than the passive type, but the cost of the passive type is cheaper than the active type. In this study, we introduced the modified passive PFC method which is called semi-boost PFC, and then we analyzed and experimented the electronic ballast which is composed of the semi-boost PFC, half-bridge, and LCC resonant tank. Experimental results showed that the PF≥0.98, CF≤1.4 and input current THD○ 15%.

Semi-boost PFC에 의한 형광등용 전자식 안정기 해석

한재현,조계현,박종연 강원대학교 산업기술연구소 2003 産業技術硏究 Vol.23 No.A

There are many kinds of electronic ballast for various kinks of fluorescent lamps The PFC(Power Factor Correction) circuit in electronic ballast is classified in two types One is the active PFC and the other is the passive PFC circuit. The active type PFC is higher than the passive type. but the cost of the passive type is cheaper than the active type. In this study, we introduced the modified passive PFC method which is called semi-boost PFC. and then we analyzed and experimented the electronic ballast which is composed of the semi-boost PFC, half-bridge. and LCC resonant tank Experimental results showed that the PF 0.98, CF 1.4 and input current THD??15%

An Improved Predictive Functional Control with Minimum-Order Observer for Speed Control of Permanent Magnet Synchronous Motor

Shuang Wang,Junyong Fu,Ying Yang,Jian Shi 대한전기학회 2017 Journal of Electrical Engineering & Technology Vol.12 No.1

In this paper, an improved predictive functional control (PFC) scheme for permanent magnet synchronous motor (PMSM) control system is proposed, on account of the standard PFC method cannot provides a satisfying disturbance rejection performance in the case of strong disturbances. The PFC-based method is first introduced in the control design of speed loop, since the good tracking and robustness properties of the PFC heavily depend on the accuracy of the internal model of the plant. However, in orthodox design of prediction model based control method, disturbances are not considered in the prediction model as well as the control design. A minimumorder observer (MOO) is introduced to estimate the disturbances, which structure is simple and can be realized at a low computational load. This paper adopted the MOO to observe the load torque, and the observations are then fed back into PFC model to rebuild it when considering the influence of perturbation. Therefore, an improved PFC strategy with torque compensation, called the PFC+MOO method, is presented. The validity of the proposed method was tested via simulation and experiments. Excellent results were obtained with respect to the speed trajectory tracking, stability, and disturbance rejection.

정전압형 전자식 안정기 회로의 고조파 저감을 위한 PFC회로의 설계

이현우,이현무,고강훈,고희석 한국조명전기설비학회 2004 조명·전기설비학회논문지 Vol.18 No.4

이 논문에서 정 전압형 PFC 전자식 안정기에 대하여 제안하였다. 제안하는 PFC 전자식 안정기는 고효율 승압형 컨버터와 기존의 하프브리지 인버터를 조합한 것이다. 제안된 PFC 전자식 안정기는 전압 분압기와 소프트 스위칭기술을 사용하여 입력전류의 왜형과 입력전류의 고조파가 감소됨을 증명하였다. 형광램프에 대한 시뮬레이션결과는 이론적인 분석과 일치함을 나타내었다. In this paper, a PFC(Power Factor Correction) electronic ballast with constant voltage-fed is proposed. The proposed PFC electronic ballast is combined of a high-efficiency boost converter and a conventional half bridge inverter. It is proved that the ripple of input-current and the input-current's harmonic of the proposed PFC electronic ballast are reduced using the voltage divider and soft-switching technique. It is demonstrated that simulation results for fluorescent lamp correspond with theoretical analysis.

ZVT 스위칭 기법을 적용한 PFC-인버터

이성룡,전칠환,권순신 전력전자학회 2000 전력전자학회 논문지 Vol.5 No.6

최근 들어 인버터 에어컨과 같은 유도전동기 구동 분야에서 인버터에 역달제어회로를 부가한 PFC 인버터에 대한 논의가 활발하게 진행되고 있다. 본 연구에서는 이러한 PFC 인버터의 효율을 개선하기 위하여 ZVT 스위칭 기법을 적용하는 방법에 대하여 논하고, 이ㅡㄹㄹ 동작 모드에 따른 해석과 함께 최적의 회로를 설계하였으며, 제안된 회로를 시뮬레이션 및 실험을 통하여 그 유용성을 입증하였다. A soft-switching PFC-Inverter for using AC motor drive such as the inverter air-conditioner with single phase medium size is proposed. In order to improve the power factor and the efficiency, in this paper, the ZVT topoloty in the conventional PFC-Inverter is adopted. So, the operation mode of the proposed ZVT PFC-Inverter is analyzed and the optimum circuit is designed. At last, the PSPICE, PSIM simulation and experiment results are presented in order to verify the validity of the proposed circuit.

1단구조방식의 PFC회로를 갖는 단상 SRM 구동시스템의 특성해석

안진우,이동희,이진국,안영주 전력전자학회 2006 전력전자학회 논문지 Vol.11 No.4

In this paper the characteristic analysis of a single-phase switched reluctance motor (SRM) drive system with power factor correction (PFC) circuit is presented. The SRM is a low cost, simple and has a good high speed performance. The SRM drive with diode rectifier and filter capacitor has a low power factor because of short switch on time of capacitor. A novel switching topologic is presented to improve power factor and reduce torque ripple based on analysis of PFC circuit. Accordingly the SRM drive system with PFC circuit is also presented. Through the numerical analysis of the system, the toque ripple, power factor and efficiency with the change of rotary speed, load torque and capacity of the capacitor are achieved and compared with actual measured value. 본 논문에서는 1단구조방식의 PFC회로를 갖는 단상 SRM 구동시스템의 특성해석에 대해 다룬다. 단상 SRM은 기계적 및 전기적 구조가 단순하고, 견고하며, 고속운전특성이 우수하다. 다이오드 브릿지 정류기와 직류링크회로의 커패시터로 구성된 종래의 단상 SRM 구동방식은 커패시터의 짧은 시간의 충·방전 전류에 의해 역률이 크게 저하되는 문제가 발생한다. 따라서, 본 논문에서는 우선 부가적인 능동회로가 없는 1단방식의 PFC회로에 대한 분석을 통하여 역률개선 및 토크리플 억제를 위한 스위칭 토플로지를 새로 제안한다. 제안한 스위칭 토플로지로 작동하는 PFC회로를 갖는 단상 SRM 구동시스템을 구축하고 시스템에 대한 수치해석을 통해 운전속도, 부하토크 및 커패시터 용량에 따른 토크리플, 역률 및 효율 등 시스템의 특성을 얻으며, 이를 실제 실험결과와 비교한다.

Hardware-Based Implementation of a PIDR Controller for Single-Phase Power Factor Correction

Le Dinh Vuong(레딘브엉),Sang-Min Park(박상민),In-Keun Yu(유인근),Minwon Park(박민원) 한국산업정보학회 2016 한국산업정보학회논문지 Vol.21 No.4

In a single-phase power factor correction (PFC), the standard cascaded control algorithm using a proportional-integral-derivative (PID) controller has two main drawbacks: an inability to track sinusoidal current reference and low harmonic compensation capability. These drawbacks cause poor power factor and high harmonics in grid current. To improve these drawbacks, this paper uses a proportional-integral-derivative-resonant (PIDR) controller which combines a type-III PID with proportional-resonant (PR) controllers in the PFC. Based on a small signal model of the PFC, the type-III PID controller was implemented taking into account the bandwidth and phase margin of the PFC system. To adopt the PR controllers, the spectrum of inductor current of the PFC was analyzed in frequency domain. The hybrid PIDR controller were simulated using PSCAD/EMTDC and implemented on a 3kW PFC prototype hardware. The performance results of the hybrid PIDR controller were compared with those of an individual type-III PID controller. Both controllers were implemented successfully in the single-phase PFC. The total harmonic distortion of the proposed controller were much better than those of the individual type-III PID controller.