• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2002년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
• /
• pp.79-81
• /
• 2002

This paper develops a adaptive fuzzy controller based fuzzy logic control for high performance speed controller in permanent magnet synchronous motor(PMSM) drives. In the proposed system, fuzzy control is used to implement the direct controller as well as the adaptation mechanism. The operation of the direct fuzzy controller and the fuzzy logic based adaptation mechanism is studied. A model reference adaptive scheme is proposed in which the adaptation mechanism is executed by fuzzy logic based on the error and change of error measured between the motor speed and output of a reference model. The control performance of the adaptive fuzzy controller is evaluated by simulation for various operating conditions. The validity of the proposed adaptive fuzzy controller is confirmed by performance results for PMSM drive system.

• International Journal of Precision Engineering and Manufacturing
• /
• 제5권4호
• /
• pp.43-49
• /
• 2004

A spring-actuated linkage system is used to satisfy the desired opening and closing characteristics of the electric contacts of a vacuum circuit breaker. If the type of a circuit breaker and the structure of the linkage system are predetermined, then design parameters such as stiffness, free length and attachment points of the spring become the important issues. In this paper, based on the energy conservation, the total system energy is constant throughout the operating range of the mechanism; a systematic procedure to optimize the spring design parameters is developed and applied to a simplified mechanism of a circuit breaker. The developed procedure is converted to the environment of the multi-body dynamics program, ADAMS for an in-depth consideration of the complex dynamics of a circuit breaker mechanism.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2000년도 하계학술대회 논문집 B
• /
• pp.714-716
• /
• 2000

In the System-integrated modular advanced reactor(SMART), the motor for Control element drive mechanism(CEDM) requires high density power and simple drive mechanism to reduce volume because of restriction by install-space and must satisfy the reactor operating circumstances with high pressure and temperature. In this paper, we perform the basic design of the two kinds (Variable reluctance type and Hibrid-reluctance type) of the transverse flux motor to develop the prototype motor for the control element drive mechanism of SMART. Analyzed these motors by the FEM in the 2-dimension, we show the characteristics for each of the analysis model.

• 미생물학회지
• /
• 제28권3호
• /
• pp.249-257
• /
• 1990

In the course of operating the accommodative and detoxifying mechanism against cadmium, its physio-biochemical changes were observed in Klebsiella aerogenes ATCC 10031. Changes of enzyme activity concerned phosphate metabolism, changes of phospholipid composition and in view of energy metabolism the changes of the nucleotide pool were examined. Activities of both alkaline and acid phosphatase were derepressed 4-10 folds under cadmium added cultures. Moreover, production of phospholipid such as lysophosphatidyl choline (LPC), phosphatidyl serine (PS) and phosphatidyl ethanolamone (PE) was increased and uridylate nucleotide pool was increased under Cd-surplus culture. These results i.e. overproduction of phosphatase catalyzing phosphate residue, increase of the production of PE and PS which have a close affinity with cadmium, and indrease of uridylate nucleotide pool used as a carrier of polysaccharide synthesis like bacterial capsule exhibited cellular responses for active defence against Cd-pressure. It was postulated that these phenomena should play another assistant roles in Cd-detoxifing mechanism.

• Journal of electromagnetic engineering and science
• /
• 제18권2호
• /
• pp.129-135
• /
• 2018

This paper proposes a design of small controlled reception pattern antenna (CRPA) arrays using circular microstrip loops with frequency-insensitive characteristics. The proposed array consists of seven identical upper and lower circular loops that are electromagnetically coupled, which results in a frequency-insensitive behavior. To demonstrate the feasibility of the proposed feeding mechanism, the proposed array is fabricated, and its antenna characteristics are measured in a full-anechoic chamber. The operating principle of the proposed feeding mechanism is then interpreted using an equivalent circuit model, and the effectiveness of the circular loop shape is demonstrated by calculating near electromagnetic fields in proximity to the radiator. The results confirm that the proposed feeding mechanism is suitable to have frequency-insensitive behavior and induces strong electric and magnetic field strengths for higher radiation gain in extremely small antenna arrays.

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 2007년도 하계학술대회 논문집
• /
• pp.114-116
• /
• 2007

Mechanical spring and hydraulic pressure operated mechanisms are applied in most of today's High Voltage Gas Insulated Switchgear(GIS)s. This paper proposes a new type of operation mechanism for GIS circuit breakers rated at 245kV and 40kA. The Motor-Direct-Drive-Mechanism (MDDM) has many advantages compared to conventional operating mechanisms. It has a very simple structure with only one moving part, low mechanical stress and audible noise. It also allows monitoring, operation speed control and self-diagnosis functions.

• Bulletin of the Korean Chemical Society
• /
• 제6권2호
• /
• pp.99-102
• /
• 1985

Substituent effects of substrate and nucleophile for the reaction of substituted phenacyl tosylates with pyridines were determined conductometrically in acetonitrile. Activation parameters for these reactions were also calculated. The substituent effects in nucleophile were increased with electron-donating power of pyridines and Br${\o}$nsted linear relationship was shown. Rate constant was increased by both electron-donating and electron-attracting groups in the substrate. It seems that dissociative S$_{N}$2 ("loose" transition state) mechanism is operating in the case of electron-donating substituents while associative S$_{N}$2 ("tight" transition state) mechanism is operative in the case of electron-attracting substituents.

• 한국윤활학회:학술대회논문집
• /
• 한국윤활학회 2002년도 proceedings of the second asia international conference on tribology
• /
• pp.289-290
• /
• 2002

Stainless steel ball bearings are used in the control element drive mechanism and driving mechanisms such as step motor and gear boxes for the integral nuclear reactor, SMART. The bearings operate in pressurized pure water (primary coolant) at high temperature and should be lubricated with only this water because it is impossible to supply greases or any additional lubricant since the whole nuclear rector system should be perfectly sealed and the coolant cannot contain ingredients for bearing lubrication. Temperature of water changes from room temperature to about 120 degree Celsius and pressure rises up to 15MPa in the nuclear reactor. It can be anticipated that the frictional characteristics of the ball bearings changes according to the operating conditions, however little data are available in the literature. It is found that friction coefficient of 440C stainless steel itself does not change sharply according to temperature variation from the former research, and the friction coefficient is about 0.45 at low speed range. In this research frictional characteristics of the assembled ball bearings are investigated. A special tribometer is used to simulate the axial loading and the bearing operating conditions, temperature and pressure in the driving mechanism in the nuclear reactor. Highly purified water is used as lubricant ‘ and the water is heated up to 120 degree Celsius and pressurized to 15MPa. Friction force is monitored by the torque transducer.

• 한국분무공학회지
• /
• 제20권2호
• /
• pp.88-94
• /
• 2015

Recently, exhaust gas regulation has been gradually strengthened due to depletion of fossil fuels and environmental problem like a global warming. Due to this global problem, the demand for eco-friendly vehicle development is rapidly increasing. A clean diesel vehicle is considered as a realistic alternative. The common-rail fuel injection system, which is the key technology of the clean diesel vehicle, has adopted injection strategies such as high pressure injection, multiple injection for better atomization of the fuel. In addition, the emission regulations in the future is expected to be more stringent, which a conventional engine is difficult to deal with. One of the way for actively proceeding is the study of alternative fuels. Among them, the bio-diesel has been attracted as an alternative of diesel. So, in this study, spray characteristics of bio-diesel was analyzed in the common-rail fuel injection system with three injectors driven by different operating mechanism.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2008년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
• /
• pp.119-121
• /
• 2008

This paper is proposed a high Performance speed control of the synchronous reluctance motor through the SV-PWM(Space Vector Pulse Width Modulation) of FAM-PI(Fuzzy Adaptive Mechanism-PI). SV-PWM is controlled using FAM-PI control. SV-PWM can be maximum used maximum do link voltage and is excellent control method due to characteristic to reducing harmonic more than others. Fuzzy control has a advantage which can be robustly controlled. FAM-PI controller is changed fixed gain of PI controller using fuzzy adaptive mechanism(FAM) to match operating condition. The results on a speed controller of IPMSM are presented to show the effectiveness of the proposed gain tuner. And this controller is better than the fixed gains one in terms of robustness, even under great variations of operating conditions and load disturbance.