• Proceedings of the KIPE Conference
• /
• 2000.07a
• /
• pp.596-599
• /
• 2000

벡터 제어이론은 교류전동기의 토오크와 자속을 독립적으로 제어할 수 있는 특징이 있으므로 토오크 제어를 주로 하는 견인용 전동기의 제어에 적용하기 위한 연구가 활발히 수행되어 왔다 그러나 선형 유도전동기 구동에는 아직 널리 사용되지 않은 실정이다 벡터 제어이론은 일반적으로 회전자자속 기준제어(Rotor flux oriented control)을 의미하며 이를 구현하기 위한 방법은 자속을 직접 측정 혹은 연산하는 직접제어 방식과 속도를 측정하여 슬립주파수 명령을 제어하는 간접방식으로 분류된다. 최근에는 기존의 회전자자속 기준방식뿐만 아니라 고정자자속(Stator flux oriented) 공극자속(Air gap flux oriented) 기준 방식등이 제안되고 있다. 본연구에서는 자기부상열차의 추진용 선형 유도 전동기의 추진에 가장 적합하다고 생각되는 고정자자속 기준벡터제어 방식과 이를 구현하기 위한 고정자 자속을 추정하는 방법에 대하여 설명한다. 또한 속도제어를 위한 속도 추정방식도 안내코일 등 부장치 없이 전동기 파라미터로 추정할 수 있는 기법에 대하여 논한다.

• Proceedings of the KIEE Conference
• /
• 2006.07b
• /
• pp.703-704
• /
• 2006

본 논문은 슬립 주파수형 벡터제어에 기초하여 인버터 구동 교류 서보전동기 속도제어 시스템을 구성하고 광범위한 속도제어 방법에 대하여 나타내었다. 구동 시스템은 16비트 CPU(V50)을 이용한 디지털 제어기와 전동기 구동 전원으로 순시전류 추종방식 인버터(Current Source Inverter)로 구성된다. 실제 300[W] 유도전동기의 저속에서 속도 변동(진동)이 발생하는 원인을 해석하기 위해서 회로 동작을 소프트웨어와 하드웨어적으로 조사한다. 시뮬레이션을 하여 저속에서 속도변동 원인을 구명하고 그 대책에 대하여 나타내었다.

• Korean Journal of Materials Research
• /
• v.10 no.8
• /
• pp.545-550
• /
• 2000

3Y-TZP, 12Ce-TZP 및 3Y-TZP, 12Ce-TZP 현탁액의 제타포텐셜과 겉보기점도의 측정으로부터 슬립주입공정에 의한 다층복합체의 제조조건을 조사하였다. 아울러 다층복합체의 소결밀도, 미세구조, 결정상에 미치는 열처리의 영향을 검토하였다. 3Y-TZP와 12Ce-TZP 현탁액의 등전점을 pH 8부근이었으나 3Y-TZP/12Ce-TZP의 등전점은 pH8.6이었다. 현탁액은 전단속도의 증가와 더불어 점도가 감소하는 의가소성유동을 나타내었다. 15 및 20vol% 고체함량을 갖는 3Y-TZP와 3Y-TZP/12Ce-TZP 현탁액은 소량(0.3wt%)의 유기해교제의 첨가만으로 슬립주입에 적당한 유동성을 보유하였으나, 12Ce-TZP의 경우는 점도를 감소시키기 위하여 부가적인 전해질이 필요하였다. 이론밀도의 98% 이상을 보유하고 0.3~$2.2\mu\textrm{m}$의 입경을 갖는 치밀한 다층복합체가$ 1500^{\circ}C$ 소결로 얻어졌다.

• Tunnel and Underground Space
• /
• v.32 no.6
• /
• pp.598-610
• /
• 2022

Avoiding a fault zone would be a best practice for safety in underground construction, which is only sometimes possible because of many restrictions and other field conditions. For instance, there is an ongoing conception of Korea-Japan subsea tunnels that inevitably cross a massive fault system in the Korea Strait. Therefore it was deemed necessary to find an efficient way of predicting the likely behaviour of underground structures under fault slip. This paper presents the findings from simple numerical analysis for investigating the stress induced at a normal fault with a dip of 45 degrees. We used a boundary element software that assumed constant displacement discontinuity, which allowed the displacement to be estimated separately at both the fault's hangingwall and footwall sides. The results suggested that a principal stress rotation of 45 degrees occurred at the edges of the fault during the slip, which was in agreement with the phenomenon for fault plane suggested in the body of literature. A simple numerical procedure presented in this paper could be adopted to investigate other fault-related issues associated with underground structure construction.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.4 no.1
• /
• pp.73-81
• /
• 1999

A new slip power recovery system applying a switch mode converter to the rotor circuit of the wound rotor induction machine is proposed and investigated in this paper. With the analysis of the steady-state performances of the proposed system, it can be shown that the speed can be controlled by the duty ratio of the converter switch and the several characteristics of a conventional system can be also improved. In particular, the low power factor and the harmonic components in the line current, which are the main disadvantages of the conventional system, is significantly improved, and linear speed regulation can be obtained. Theoretical and experimental results are presented and illustrated to demonstrate the satisfactory working of the proposed system.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.17 no.3
• /
• pp.74-80
• /
• 2009

The objective of this paper was to investigate the slip rate and the slip frequency number of damper clutch of torque converter in 2.4L passenger vehicle with 5-speed A/T and analyze the effect of slip control and control strategy on driving characteristics and the fuel economy. The newly developed torque converter with the more durable wet friction material and the slip-controlled damper clutch system, the DCC system, was installed, which was easily compatible and amendable of the lock-up clutch of the base system. The vehicle has been tested on the fuel economy modes such as FTP-75, HWFET and NEDC (ECE15+EUDC) driving cycle at chassis dynamometer. The DCC mode (II), of which the control strategy had both the lock-up and the slip-controlled clutch, and the DCC mode (I) with full slip-controlled clutch were compared with the base system with only the lock-up clutch. As the research result, comparison to base system, the fuel consumption of the vehicle with the DCC control (II) was effectively improved by 6.6% and 7.7% on FTP-75 and NEDC mode.

• Journal of the Korean Society for Railway
• /
• v.11 no.2
• /
• pp.176-181
• /
• 2008

This paper presents results from experimental analysis of a friction-driven wheel responsible for generating wheel squeal noise. Squeal noise generating mechanism has been examined under the laboratory condition by the model rig on a small scale. Creep characteristics and squeal noise were observed by changing the possible variables, such as relative velocities and friction coefficients in time- and frequency-domain.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2010.05a
• /
• pp.459-460
• /
• 2010

For the application of slip form method to the pylon of Yi Sun-shin bridge which has much variation in its cross section, the change of setting properties of concrete due to changing weather and long pumping distance has to be taken into consideration. Different setting properties of several types of cement according to the amount of compound and ambient temperature were observed in this paper.

• Proceedings of the KIEE Conference
• /
• 2007.07a
• /
• pp.1199-1200
• /
• 2007

고속철도차량의 국내기술확보를 위해 최고운행속도 350km/h의 한국형 고속전철시스템을 개발하여 단품시험, 완성차시험, 공장시험 등을 통해 기본적인 성능을 확인한 후 현재는 본선시운전 시험이 진행중이다. 본 논문에서는 국내기술로 개발된 한국형 고속열차의 슬립검지를 위한 계측시스템 구성과 검지 내용에 대해 서술하고 있다.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.47 no.1
• /
• pp.9-16
• /
• 2019

In the present study, to investigate flows around space launch vehicles at mid-high altitudes efficiently, a three-dimensional unstructured mesh Navier-Stokes solver employing a Maxwell slip boundary condition was developed. Validation of the present flow solver was made for a blunted cone-tip configuration by comparing the results with those of the DSMC simulation and experiment. It was found that the present flow solver works well by capturing the velocity slip and the temperature jump on the solid surface more efficiently than the DSMC simulation. Flow simulations of space launch vehicles were conducted by using the flow solver. Mach number of 6 at the mid-high altitude around 86km was considered, and the flow phenomena at the mid-high altitude was discussed.