• Journal of the Korean Data and Information Science Society
• /
• v.8 no.1
• /
• pp.31-39
• /
• 1997

we shall propose some Bayes estimators and some generalized maximum likelihood estimators for reliability of a two-unit hot standby system with perfect switch based upon a complete sample of failure times observed from the exponential model and compare the peformances of the proposed estimators in terms of mean squared error.

• 제어로봇시스템학회:학술대회논문집
• /
• 1992.10a
• /
• pp.71-74
• /
• 1992

This paper describes the automation of the surface grinder for a grinding wheel by application of programmable logic controller(PLC) with a position sensor, and a limit switch. The control system is designed to provide feeding a workpiece on the turn table and pressing it by the upper disk automatically. In this development the automation of checking the thickness of a grinding wheel is most important. In order to measure the relative displacement, the proximity sensors were employed and the sensitivities of the sensors were investicated and discussed the superiority. It has been shown by model experiment that the automation system of the surface grinder is performed satisfactory.

• Proceedings of the KIEE Conference
• /
• 1998.07b
• /
• pp.807-809
• /
• 1998

Plant Protection Systems(PPS) are those systems that initiate safety actions to mitigate the consequences of design basis events by sending signals to Reactor Trip Switch Gear System(RTSS) and Engineered Safety Features-Component Control Systems(ESF-CCS). This paper illustrates distinctive features and improved design concepts of Korea Next Generation Reactor(KNGR) based on the experience obtained through prototyping of PPS.

• 전기의세계
• /
• v.25 no.2
• /
• pp.65-71
• /
• 1976

Thyristor 등의 Power Semiconductor에 의한 전자장치를 사용하여 전력의 Conversion, Control 그리고 Switch 등의 기술분야를 Solid State Powerelectronics라고 H.F.Storm는 말하였다. 또 필자는 Thyristor와 전동기제어, System화된 전동기 등에서 Power elecrronics를 언급하고 그 말미를 밝힌 바 있다. Powerelectronics란 전력, 산업용의 Electronics라고 말할 수 있고 광의의 해석에서는 (1)Solid State Power Device에 의한 전력변환, 제어, (2)Computor 및 이에 관련된 응용기술로서의 정보처리의 전력계의 이용, (3)Plasma, Super-Conductor, Laser의 3가지 분야를 말하나 현재로서는 (1)의 분야가 제일 적합하다. 본문에서는 Powerelectronics의 구성요소가 비록 Power에서 Power로 끝나지만 Electronics, Power 및 Control의 3분야의 유기적 형성에서 이루어진다는 것과 이것이 이루어 놓은 업적은 많으나 학문적 체계에는 이 분야의 전문가들의 힘이 커야 한다는 것을 강조하면서 Powerelectronics의 배경에 관해 기술하고자 한다.

• Proceedings of the KIEE Conference
• /
• 1994.11a
• /
• pp.169-171
• /
• 1994

This paper suggests a SRM control scheme driven by a variable voltage source. This scheme shows that it is unnecessary to introduce a switch to control dc-link voltage and to limit a phase current. And its vary easy to build-up flat-topped phase current which is advantageous to the high torque and efficiency drive of a SRM. Experimental tests are shown to verify this suggestion.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.11 no.4
• /
• pp.1233-1238
• /
• 2010

The lighting industry has become the bigger and more systemized using the semiconductor LED with each control R(Red), G(Green), B(Blue). The communication standard DMX512(ANSI E1.11) protocol of it basically needs the address which can be distinguished between the lighting terminals. The conventional method has to give the address of the lighting any methods like dip switch, EEROM and PROM. Then the lighting terminal can receive RGB data from DMX512 communication. According to electrical characteristics DMX512 protocol has to the splitter every 32 lighting terminals. If 512 lightings is all connected, maximum 16 splitters are needed. This paper is solved above weakness in DMX512 protocol using serial connection all lighting terminals. Also I developed the intelligent lighting terminal with auto-addressing. This was solved the inconvenience of the address assignment and the usage of the splitter. The developed products is applied and selled the semiconductor lighting terminals using ON-OFF control, dimming control, sequential control and rainbow control.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.7 no.5
• /
• pp.1026-1031
• /
• 2003

Automatic feed pumps are operated and stopped by a pressure switch. Thus, because of repeated operations and stops of the pumps according to fluctuations of water volume, operation with constant rate and pressure is impossible. Moreover, because of repeated running of the pump, keeping up of constant pressure is impossible and damage and energy loss are weak points of the pimps. To make up for defects of an automatic feed pump, this paper designed and made a static pressure feed system which was composed of a feed water control valve, a flow sensor and a control system. The valve device plays an important part in reducing load of pumps by constant water supply regardless of outflow of water. Outflow of water is determined by infrared diode of the flow sensor. The control system is made of a 8 bit micro-processor and the pump was controled by a specific control algorithm. With the constant pressure feed system, discharge pressure was kept at fixed pressure, accurate operations and stops were smoothly accomplished and the pump was operated with constant pressure. Thus, the constant pressure feed system can be considered as an advanced system which made up for the weak points in the current automatic feed systems.

• The Transactions of the Korean Institute of Electrical Engineers D
• /
• v.55 no.12
• /
• pp.511-517
• /
• 2006

The key issues in high power, high energy applications such as electromagnetic launchers include safety, reliability, flexibility, efficiency, compactness, and cost. To explore some of the issues, a control scheme for a large current wave-forming was designed, built and experimentally verified using a 2.4MJ pulse power system (PPS). The PPS was made up of eight capacitors bank unit, each containing six capacitors connected in parallel. Therefore there were 48 capacitors in total, with ratings of 22kV and 50kJ each. Each unit is charged through a charging switch that is operated by air pressure. For discharging each unit has a triggered vacuum switch (TVS) with ratings of 200kA and 250kV. Hence, flexibility of a large current wave-forming can be obtained by controlling the charging voltage and the discharging times. The whole control system includes a personal computer(PC), RS232 and RS485 pseudo converter, electric/optical signal converters and eight 80C196KC micro-controller based capacitor-bank module(CBM) controllers. Hence, the PC based controller can set the capacitor charging voltages and the TVS trigger timings of each CBM controller for the current wave-forming. It also monitors and records the system status data. We illustrated that our control scheme was able to generate the large current pulse flexibly and safely by experiments. The our control scheme minimize the use of optical cables without reducing EMI noise immunity and reliability, this is resulting in cost reduction. Also, the reliability was increased by isolating ground doubly, it reduced drastically the interference of the large voltage pulse induced by the large current pulse. This paper contains the complete control scheme and details of each subsystem unit.

• Journal of the Institute of Electronics Engineers of Korea SC
• /
• v.44 no.5
• /
• pp.18-29
• /
• 2007

The main objective of this paper is to propose a new stability analysis method for a networked control system with multiple packet transmission. The new scheduling method that can guarantee the maximum time delay and discrete switch state equation model which represent a network data loss is proposed. The equivalent model of a MIMO(multi-input multi-output) networked control system is derived from a state space model of linear time invariant interconnected systems in the form of asynchronous dynamical system. Using this model, this paper presents new stability theorems that can determine stability of the networked control system with regard to time delay, data loss, and the number of transmission packets. Simulation results verify the effectiveness of proposed stability analysis method.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.19 no.3
• /
• pp.35-43
• /
• 2005

Matrix converters have been studied for eliminating dc link of conventional converter-inverter system, and various undulation strategy have been proposed. Therefore, matrix converter have no energy storage component except for small ac later for the elimination of switching ripple, and can be made compact and highly reliable compare with the do link inverter system. Matrix converter, however, directly connected the input and the output terminals by bidirectional static switch. As a result if the input voltage are asymmetrical, and contain harmonics, the influence of the distortions directly appear on the output terminal. This problem is a major obstacle to the matrix converter. A new control method using average comparison strategy have been proposed in this paper. This control method realizes sinusoidal input and output current unity input displacement factor regardless of load power factor. Moreover, compensation of the asymmetrical and/or harmonic containing input voltage is automatically realized, and calculation time of control function is reduced.