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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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The Transactions of The Korean Institute of Electrical Engineers
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The Korean Institute of Electrical Engineers
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Volume & Issues
Volume 57, Issue 12 - Dec 2008
Volume 57, Issue 11 - Nov 2008
Volume 57, Issue 10 - Oct 2008
Volume 57, Issue 9 - Sep 2008
Volume 57, Issue 8 - Aug 2008
Volume 57, Issue 7 - Jul 2008
Volume 57, Issue 6 - Jun 2008
Volume 57, Issue 5 - May 2008
Volume 57, Issue 4 - Apr 2008
Volume 57, Issue 3 - Mar 2008
Volume 57, Issue 2 - Feb 2008
Volume 57, Issue 1 - Jan 2008
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Application Optimal Reconfiguration Algorithm for Distribution Power System to KEPCO System
Seo, Gyu-Seok ; Baek, Yaung-Sik ; Chae, Woo-Gyu ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 10, 2008, Pages 1681~1687
This paper shows application of optimal reconfiguration algorithm for distributing power system to KEPCO system for loss minimization and load balancing. That is, it suggests additional algorithm to check potential problems caused in case of theoretical algorithm being applied to real system and recover from them. Also, comparing the results of reconfiguration algorithm Tabu-Search Algorithm applied to current KEPCO distribution power system and those of Branch Exchange Algorithm using initial operation point suggested in this paper, it shows how much the results are improved in aspects of load balancing, loss reduction and calculating time.
Calculation of an Induced Voltage on Telecommunication Lines in Parallel Distribution Lines
Kim, Hyun-Soo ; Rhee, Sang-Bong ; Yeo, Sang-Min ; Kim, Chul-Hwan ; Lyu, Seong-Heon ; Kim, Seong-Arm ; Weon, Bong-Ju ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 10, 2008, Pages 1688~1695
Recently, it is common in a distribution system of Korea Electric Power Corporation (KEPCO) to find instances where distribution lines are parallel. A traditional method of an induced voltage calculation is not suitable for parallel distribution lines. For more actual analysis of induced voltage on telecommunication lines in parallel distribution lines, a new calculation method is needed. This paper presents a new calculation method of an induced voltage on telecommunication line using equivalent
circuits matrix in parallel distribution lines. The advantages of the calculation method are using actual neutral current value and not using screening factor for considering the overhead ground wire and the neutral wire. To verify the effectiveness and the accuracy of the method, various case studies are performed with EMTP(Electro-Magnetic Transients Program).
The Voltage Compensation Strategy of Distribution System Using the Ubiquitous-based Distributed Voltage Control Method
Ko, Yun-Seok ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 10, 2008, Pages 1696~1702
This paper proposes a voltage compensation device direct control strategy to realize the distributed, autonomous voltage control of the distribution system, which based on voltage data collected from customers of the remote site under the ubiquitous-based distribution system. In the proposed method, The ULTC and the SVR(Step Voltage Regulator)s compensate autonomously the voltage for self-compensation area based on the voltage data furnished from the ubiquitous device of customers. Also, the SVRs overcome the limit of single-operation of ULTC by the interlocking operation with the ULTC and enhance the voltage compensation capability for the customer. In particular, an optimization design method and a fuzzy design method are compared to determine the effective control method of the voltage compensator under the ubiquitous-based on-line operation environments. In fuzzy method, the tap of voltage compensator is defined as output member. Finally, the proposed two methods are implemented in Visual C++ MFC, the effectiveness is proved by simulation based on the worst virtual voltage data. Also, an optimal voltage compensation strategy is determined under on-line environments based on analyzed results.
Effect Analysis of the Low Frequency Oscillation Mode of Inter-area System According to Load Characteristics
Kim, Hak-Man ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 10, 2008, Pages 1703~1707
Low frequency oscillation of inter-area system is important problem in power system areas because the operation conditions of power system depend on it. Generally, the analysis of the problem is used by small signal stability. Especially, the analysis results are affected by decision of load models. In this paper, the effect of the analysis results was studied according to load component characteristics. ZIP model, popular in large-scaled power system analysis, was used as the load model. Many cases were studied according to the combination of ZIP model in inter-area system.
Design of a Low-order Pole Placement Power System Stabilizer Using Simultaneous Stabilization
Kim, Seog-Joo ; Lee, Jong-Moo ; Kwon, Soon-Man ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 10, 2008, Pages 1708~1712
This paper describes a linear matrix inequality (LMI) approach to the design of robust low-order power system stabilizers (PSSs), which are used to damp out local-mode oscillations of synchronous generators. The performance of a PSS is expressed as the location of the closed-loop poles, and a single fixed-gain pole-placement controller is synthesized for a wide range of operating conditions. The synthesis results in simultaneous regional pole-placement stabilization. and is formulated as an LMI feasibility problem with a rank condition. A penalty method is applied to solve the rank-constrained LMI problem. Numerical experiments with a single-machine connected to an infinite bus system were performed to demonstrate the proposed method.
A Operated Characteristic Analysis of HTS Cable in Unbalanced Load Using PSCAD/EMTDC
Lee, Hyun-Chul ; Hwang, Si-Dol ; Lee, Geun-Joon ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 10, 2008, Pages 1713~1719
A high temperature superconducting power cable (HTS power cable) was applied large current capacity by no resistance in normal state. Fault state was risen out of over-current but, it was limited to resistance. This study was modeling equivalence, and unbalanced state analyzed operating characteristic of HTS power cable. The equivalence model was composed superconductor, shield, and former part. This model simulation was appeared conductor and shield current in normal state, but unbalanced state was appeared former current as rise current by resistance. So it need to sufficiently influenced the quench characteristic when the former design.
A Fault Effect to Induced Voltage of Gas Pipeline in Transmission Systems
Kim, Hyun-Soo ; Rhee, Sang-Bong ; Kim, Chul-Hwan ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 10, 2008, Pages 1720~1725
Because of the continuous increasing of energy consumption, metallic pipelines are widely used to supply services to customers such as gas, oil, water, etc. Most common metallic pipelines are underground and are now frequently being installed in nearby electric power lines. In recent years, buried gas pipeline close to power lines can be subjected to hazardous induction effects, especially during single line to ground faults. because it can cause corrosion and it poses a threat to the safety of workers responsible for maintenance. Accordingly, it is necessary to take into consideration for analysis of induced voltage on gas pipelines in transmission lines. This paper analyzed the induced voltage on the gas pipelines due to the 154kV transmission lines in normal case and in different faulty case conditions using EMTP (Electro-Magnetic Transients Program).
Development of Cooperated Control System for Multiple FACTS in KEPCO Power Systems
Chang, Byung-Hoon ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 10, 2008, Pages 1726~1730
In this paper, the application schemes for coordinated control system of multiple FACTS were presented to enhance the voltage stability around the metropolitan areas. In order to coordinated control of FACTS devices, f-V analysis method which is one of the indices for voltage stability was performed with real time network data which is transferred from SCADA/EMS system. If the system is unstable after contingencies, the new operation set-point of FACTS would be determined using bus sensitivity from tangent vector at voltage instability point. Otherwise, we would determine the new operation set-point of FACTS for considering economical operation, like as active power loss minimization using Optimal Power Flow algorithm. In simulation, the SCADA/EMS 2007's data are used for studying the coordinated control algorithm of multiple FACTS devices that is installed or will be installed in KOREA power system
A Study on Dielectric Strength and Insulation Property of High Voltage Switchgear Applied Dry Air Gas
Jeong, D.H. ; Chung, Y.H. ; Seo, K.B. ; Kim, T.H. ; Kim, J.B. ; Lee, H.S. ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 10, 2008, Pages 1731~1737
This paper present the fundamental insulation characteristics of Dry Air gas and insulation coating in high voltage power apparatus. It is known that the dielectric strength. of Dry Air is approximately one-third that of SF6 gas. we attempt that the insulation coating and dry air gas have replaced the SF6 gas as insulation of the switchgear. We proposed the dry air insulated switchgear(DAIS) for High Voltage apparatus. To acquire technology of insulation characteristic improvement made standards for complex insulation structure and conducted simulations and experiments
Economic Feasibility of MicroGrid on the Environmental Cost and Operation Type
Park, Jung-Sung ; Shin, Hye-Kyeong ; Lee, Duck-Su ; Choi, In-Sun ; Choi, Young-Jun ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 10, 2008, Pages 1738~1743
Environmental issue is one of the key factors to industry area using fossil fuels, because it accelerates the global warming. So it is supposed to reduce greenhouse gases around the developed nations of the world at times go. This issue is especially for the power industry. Under this background, MicroGrid system that consists of Distributed Energy Resources (DER) system, such as natural power system (wind, solar) and fuel-cell, co-generation, also known as CHP (Combined heat and power), has been developed greatly during the last 10 years. This paper adopts optimal model using GAMS to develop methods for conducting an integrated assessment of MicroGrid system.
Development of Monitor Positioning Algorithm considering Power System Topology and Distributed Generation
Moon, Dae-Seong ; Kim, Yun-Seong ; Won, Dong-Jun ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 10, 2008, Pages 1744~1751
This paper presents a monitor positioning algorithm to identify the power quality event source in the distribution system with distributed generations. This algorithm determines the appropriate number of monitors and their locations considering power system topology together with distributed generation. This paper summarizes the guidelines of monitor positioning into five principles and defines the weighting factors according to the principles. To evaluate the adequacy of monitor positioning results, ambiguity indices considering monitor location and system topology are proposed. The optimal number and locations of monitors are determined from optimization routine using the weighting factors and the monitor positioning results are evaluated in terms of ambiguity indices. The algorithm is applied to IEEE 13 bus test feeder and suggests the optimal number and locations of power quality monitors. The proposed approach can realize the expert's knowledge on monitor positioning into a sophisticated automatic computing algorithm.
Heat Treatment of Stator Core in Permanent Magnet Type Motor for Reduction of Friction Torque and Analysis of Their Cause
Ha, Kyung-Ho ; Lim, Yang-Su ; Kwon, Oh-Yeoul ; Kim, Ji-Hyun ; Kim, Jae-Kwan ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 10, 2008, Pages 1752~1758
This paper deals with the reduction of friction torque in permanent magnet motors by using the heat treatment of stator core. The stator core is made of electrical steel sheared by the punching die. From the punching process, large mechanical stress acting on the edge of stator tooth induces significant plastic and elastic deformation and then cause the change of magnetization properties. Then, the mechanical and magnetic unbalance in the sheared region of stator tooth produced by material cutting has influence on the friction torque. This paper investigated the effect of the punching process on the magnetization process and the mechanical deformation, and then proposed the stress relief annealing method for the reduction of friction torque among one of motor characteristics.
A Study on the Tank Noise Reduction Techniques of Power Transformers
Kweon, Dong-Jin ; Koo, Kyo-Sun ; Kim, Jung-Chan ; Kim, Yoo-Hyun ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 10, 2008, Pages 1759~1766
According to the increase of power demand and expansion of downtown, it is necessary to install transformers additionally in operating substations and construct substations in residential area. But the public complaint has been increased due to the transformer noise of the substation. KEPCO has used a vibration preventing pad, various soundproof walls and an encloser to transformers in outdoor substations, and a soundproof door, shutter and wind-path soundproof equipment in indoor substations to block the sound propagation from the transformers. But these noise reduction methods are not satisfied. It should be considered to reduce transformer noise itself. In this paper, we investigated tank noise reduction techniques to develope a low noise transformer. According to the mode analysis of transformer tank, we found out characteristics and locations of noise on the tank, and it's nature vibration was also analysed. On the basis of these analysis, reinforcement equipment was installed around transformer tank, and ellipse shape tank was changed to round shape tank. The effect of noise reduction was evaluated using noise generation source.
Status of Advanced Tecnhologies and Domestic Researches for Development of Korean Next Generation Maglev
Cho, Han-Wook ; Bang, Je-Sung ; Han, Hyung-Seok ; Sung, Ho-Kyung ; Kim, Dong-Sung ; Kim, Byung-Hyun ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 10, 2008, Pages 1767~1776
This paper presents the status of advanced technologies and domestic researches for development of Korean next generation maglev. Generally, two specific configurations such as the EMS (Electromagnetic Suspension) with LSM (Linear Synchronous Motor) and EDS (Electrodynamic Suspension) with LSM can be employed as a propulsion and levitation device of high-speed maglev. Worldwide high-speed maglev developments refer to projects such as the German Transrapid with EMS, the Japanese MLX with EDS, and the U.S. Inductrack with PM (Permanent Magnet) EDS maglev system. In this paper, the propulsion and levitation systems of these world wide high-speed maglev have been reviewed and analysed.
Optimum Design Criteria for Maximum Torque Density & Minimum Torque Ripple of SynRM according to the Rated Wattage using Response Surface Methodology
Choi, Yun-Chul ; Lee, Jung-Ho ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 10, 2008, Pages 1777~1781
This paper deals with optimum design criteria for maximum torque density & minimum torque ripple of Synchronous Reluctance Motor (SynRM) according to the rated wattage using response surface methodology (RSM). The RSM has been achieved to use the experimental design method in combination with Finite Element Method and well adapted to make analytical model for a complex problem considering of a number of interaction of design variables. The proposed procedure allows the definition of the rotor shape according to flux barrier number, starting from an existing motor or a preliminary design.
The Design of Acoustic Resonance Free and Dimmable Electronic Ballast for 1kW MHL
Lee, Bong-Jin ; Park, Chong-Yun ; Kim, Ki-Nam ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 10, 2008, Pages 1782~1789
This paper presents the design of acoustic resonance(AR) free and dimmable electronic ballast for 1kW Metal-Halide Lamp(MHL). The proposed Ballast consists of a Full-Bridge(FB) rectifier, a passive power factor correction(PFC) circuit, a full-bridge inverter, an ignitor using LC resonance and a control circuit for frequency modulation and dimming control. Whereas a passive PFC provides advantages in terms of high reliability and low cost for constructing the circuit, it is difficult to supply a stable voltage because of the output voltage ripple that occurs with a period of 120Hz. Although the ballast can be designed with a small size and a light weight if it is driven at a switching frequency between 1 and 100 kHz, AR will occur if the eigenvalue frequency of the lamp coincides with the inverter's operation frequency. The operation frequency was modulated in real time according to the output voltage ripple to compensate for the variation in power supplied to the lamp and eliminate AR. For dimming, the method, which modulated drive frequency of FB inverter using the control of DC level by microprocessor, was used. The Dimming ranged at least from 600W to 1kw as rated power of the lamp with 4 stages. Performance of the proposed technique was validated through numerical analysis, computer simulation using Pspice and by applying it to an electronic ballast for a prototype 1kW MHL.
Circuit Component Requirements for Energy Scavenging System
Kang, Sung-Muk ; Park, Kyung-Jin ; Kim, Ho-Seong ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 10, 2008, Pages 1790~1795
Energy scavenging is a technique that converts ambient energy, for example, vibration and light, to electrical energy in order to supply power to low power electronic devices such as ubiquitous sensors. In this paper, we propose an optimal operation condition of power delivery circuit and design strategy for energy scavenging system in which the generated power is order of microwatt and, consequently, efficient handling of power is critical. We also propose that high data transmission rate is more realistic optimal design objective rather than high energy efficiency. It is shown that disconnection of load from the storage capacitor right after data transmission reduces energy wasting and that optimal value of storage capacitor can be determined at this condition. The feasibility of our propose is proved by experiments and we believe that the proposed design strategy will promote the application of piezoelectric micropower generator to the ubiquitous sensor networks.
Design and implementation of 3 kW Photovoltaic Power Conditioning System using a Current based Maximum Power Point Tracking
Cha, Han-Ju ; Lee, Sang-Hoey ; Kim, Jae-Eon ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 10, 2008, Pages 1796~1801
In this paper, a new current based maximum power point tracking (CMPPT) method is proposed for a single phase photovoltaic power conditioning system and the current based MPPT modifies incremental conductance method. The current based MPPT method makes the entire control structure of the power conditioning system simple and uses an inherent current source characteristic of solar cell array. In addition, digital phase locked loop using an all pass filter is introduced to detect phase of grid voltage as well as peak voltage. Controllers about dc/dc boost converter, dc-link voltage, dc/ac inverter is designed for a coordinated operation. Furthermore, PI current control using a pseudo synchronous d-q transformation is employed for grid current control with unity power factor. 3kW prototype photovoltaic power conditioning system is built and its experimental results are given to verify the effectiveness of the proposed control schemes.
A Study on the Improvement of the Efficiency of Dye-sensitized Solar Cell using the Laser Scribing and the Grid Electrode
Seo, Hyun-Woong ; Son, Min-Kyu ; Lee, Kyung-Jun ; Kim, Jeong-Hoon ; Hong, Ji-Tae ; Kim, Hee-Je ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 10, 2008, Pages 1802~1806
Dye-sensitized solar cell (DSC) based on some advantages such as transparency, cheap materials and anti-sensibility for an anlge of incidence has been expected to capture most of solar cell market in the near future. To practical use of DSC, researches on high efficiency as well as upscaling are necessary. In this study, we tried to insert the grid electrode in DSC and scribe transparent conducting oxide (TCO) using Nd:YAG laser. The grid electrode makes the electron movement improved and diffusional movement minimized. Consequently, the efficiency of DSC was increased by reducing electron loss and the surface resistance of TCO. The grid electrode was made using Ag target by radio frequency sputtering. And the scribed surface was confirmed by taking a scanning electron microscopy photos. As the result, grid cell had improved photocurrent and fill factor as compared with the conventional cell. And the efficiency was increased about 1% by enhanced photocurrent and fill factor.
Electrohydrodynamic Drop Formation Processes of a Needle-Centered Nozzle Electrode
Moon, Jae-Duk ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 10, 2008, Pages 1807~1811
In this paper, the meniscus formation/deformation processes and conduction characteristics of the needle-centered ceramic nozzle electrode as an effective electrohydrodynamic (EHD) flow driving mechanisms for de-ionized water and silicone oil have been investigated. Results showed that the applied high voltage affected significantly on the processes, such as the drop formation mode, the deformation mode, the dripping mode, the jet mode, and the atomization mode. There was the EHD atomization mode for the de-ionized water while it was not occurred for the silicone oil, which, however, might be due to the lower electric conductivity and dielectric property of the oil than that of the water.
Electrohydrodynamic Pumping Characteristics of the Needle-Centered Nozzle Electrode
Jung, Hoi-Won ; Moon, Jae-Duk ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 10, 2008, Pages 1812~1817
A cooling system for microelectronics is becoming more important as its surface heat density is projected to reach that of the sun surface. The existing technologies using natural and forced convection are limited to solve the problems. Recently, an electrohydrodynamic driven flow is studied as one of the means to cope with this problems. A new method, utilizing a needle-centered nozzle electrode, has been proposed and investigated. The I-V characteristics of the nozzle electrode for deionized water and silicone oil were significantly different from that of without liquid, which might be due to the liquid drop covered on the nozzle tip by the EHD force acting near the needle tip. Results showed that the liquid pumping rate and flow efficiency of the nozzle electrode were very high, especially for the silicone oil. Theoretical analysis also showed the effectiveness of the needle electrode centered in the ceramic nozzle, which, however, can be a means as a liquid pump.
Assessment of Rotor Winding Insulation Condition for Gas Turbine Generators
Kim, Hee-Dong ; Kim, Byeong-Rae ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 10, 2008, Pages 1818~1821
Several off-line diagnostic tests which include the insulation resistance(IR), polarization index(PI), low-voltage AC, and recurrent surge oscillograph(RSO) tests were performed to assess the condition of generator rotor windings. The low-voltage AC and the RSO tests were performed on the gas turbine generator rotor winding to detect shorted turns. Before intentionally applying artificial shorted faults, it was confirmed by the low voltage AC and the RSO tests that the winding was in sound condition. For simulated shorted rotor winding turns, the RSO test detected the fault in the winding. The RSO test was capable of identifying the number and pole location of the shorted turns for a number of simulated shorted coils.
Design Circuit Parameter Estimation of Impulse Generator and its application to 10/350
Lightning Impulse Current Generator
Lee, Jae-Bok ; Shenderey, S. V. ; Chang, Sug-Hun ; Myung, Sung-Ho ; Cho, Yuen-Gue ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 10, 2008, Pages 1822~1828
This paper presents design parameter calculation methodology and its realization to construction for the 10/350
lightning impulse current generator(ICG) modelled as double exponential function waveform with characteristic parameters
. Matlab internal function, "fzero" was applied to find
which is solution of nonlinear equation linearly related with two wave parameter
. The calculation results for 10/350
lightning impulse current show very good accuracy with error less 0.03%. Two type of 10/350
ICGs based on the calculated design circuit parameters were fabricated by considering the load variation. One is applicable to the MOV based Surge protective device(SPD) for less 15 kA and the other is to test small resistive devices such as spark gap arrester and bonding device with maximum current capability 30 kA. The tested waveforms show error within 10% in comparison with the designed estimation and the waveform tolerance recommended in the IEC 61643-1 and IEC 60060-1.
BPM Design Optimization of Mach-Zehnder Type Tandem Optical Switch and Its Operational Characteristics
Choi, Young-Kyu ; Kim, Gi-Rae ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 10, 2008, Pages 1829~1834
An optical switch/modulator is designed and the light propagating characteristics is analyzed by the simplified BPM. The distinctive feature of the switch/modulator is that all the waveguide branches are designed to be single-mode. Principle of the device is based on the coupled mode theory in the Y-junction interconnecting waveguide. In spite of all the waveguides are designed to be single-mode, adjusting the interconnecting waveguide length of the device, the same characteristics as existing device up to date is obtainable. Numerical results show that the switching characteristics periodically depends on the interconnecting waveguide length with a spatial of about 150
in the Ti:LiNbO3 step index waveguide. The concept of design would be utilized effectively in fabricating the monolithic high density of optical integrated circuit.
Design of Dual Band Microstrip H-shaped Patch Antenna using Shorting Pin
Chang, Se-Wook ; Ko, Jae-Hyeong ; Kim, Hyeong-Seok ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 10, 2008, Pages 1835~1840
In this paper, a dual band H-shaped microstrip patch antenna is designed for RFID application. Using shorting pin and H shaped for dual resonators and control dual frequency independently. The antenna shows a good performance at the frequency, 912MHz and 2.45GHz for the radiation characteristic and input impedance matching, as well. The reflection is lower than -10dB and a good directivity higher than 3dB is achieved for both frequency.
Fabrication of PDMS Microlens Using Electrohydrodynamic Atomization
Kang, Tae-Ho ; Yang, Sang-Sik ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 10, 2008, Pages 1841~1846
In this paper, we present the fabrication of microlens by electrohydrodynamic atomization(EHDA) of PDMS prepolymer. The diameter and contact angle of PDMS microlens can be altered by changing the applied voltage and substrate temperature at the experimental setup. It is considered that PDMS microlens can be integrated into the Lab-on-a-chip directly without any photolithographic process by EHDA. The property of PDMS microlens is confirmed by transmitting and measuring the Gaussian beam through microlens.
Stochastic Model based Fault Diagnosis System of Induction Motors using Online Probability Density Estimation
Cho, Hyun-Cheol ; Kim, Kwang-Soo ; Lee, Kwon-Soon ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 10, 2008, Pages 1847~1853
This paper presents stochastic methodology based fault detection algorithm for induction motor systems. We measure current of healthy induction motors by means of hall sensor systems and then establish its probability distribution. We propose online probability density estimation which is effective in real-time implementation due to its simplicity and low computational burden. In addition, we accomplish theoretical analysis to demonstrate convergence property of the proposed estimation by using statistical convergence and system stability theory. We apply our fault diagnosis approach to three-phase induction motors and achieve real-time experiment for evaluating its reliability and practicability in industrial fields.
Delay-dependent Robust and Non-fragile Stabilization for Descriptor Systems with Parameter Uncertainties and Time-varying Delays
Kim, Jong-Hae ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 10, 2008, Pages 1854~1860
In this paper, we deal with the problem of delay-dependent robust and non-fragile stabilization for descriptor systems with parameter uncertainties and time-varying delays on the basis of strict LMI(linear matrix inequality) technique. Also, the considering controller is composed of multiplicative uncertainty. The delay-dependent robust and non-fragile stability criterion without semi-definite condition and decomposition of system matrices is obtained. Based on the criterion, the problem is solved via state feedback controller, which guarantees that the resultant closed-loop system is regular, impulse free and stable in spite of all admissible parameter uncertainties, time-varying delays, and controller fragility. Numerical examples are presented to demonstrate the effectiveness of the proposed method.
Implementation of Passive Telemetry RF Sensor System Using Unscented Kalman Filter Algorithm
Kim, Kyung-Yup ; Lee, John-Tark ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 10, 2008, Pages 1861~1868
In this paper, Passive Telemerty RF Sensor System using Unscented Kalman Filter algorithm(UKF) is proposed. General Passive Telemerty RF Sensor System means that it should be "wireless", "implantable" and "batterless". Conventional Passive Telemerty RF Sensor System adopts Integrated Circuit type, but there are defects like complexity of structure and limit of large power consumption in some cases. In order to overcome these kinds of faults, Passive Telemetry RF Sensor System based on inductive coupling principle is proposed in this paper. Because passive components R, L, C have stray parameters in the range of high frequency such as about 200[KHz] used in this paper, Passive Telemetry RF Sensor System considering stray parameters has to be derived for accurate model identification. Proposed Passive Telemetry RF Sensor System is simple because it consists of R, L and C and measures the change of environment like pressure and humidity in the type of capacitive value. This system adopted UKF algorithm for estimation of this capacitive parameter included in nonlinear system like Passive Telemetry RF Sensor System. For the purpose of obtaining learning data pairs for UKF Algorithm, Phase Difference Detector and Amplitude Detector are proposed respectively which make it possible to get amplitude and phase between input and output voltage. Finally, it is verified that capacitive parameter of proposed Passive Telemetry RF Sensor System using UKF algorithm can be estimated in noisy environment efficiently.
Frequency Response Based Multi-Objective Design Toolbox for PID Controller
Jin, Lihua ; Lim, Yeon-Soo ; Kim, Young-Chol ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 10, 2008, Pages 1869~1875
Recently, a direct data-driven synthesis of a proportional integral derivative(PID) controller for a linear time-invariant(LTI) plant was presented in . The authors showed that a complete set of PID controllers achieving robust performance and stability can be calculated directly from frequency response(FR) data without an identified transfer function model. However, it is not convenient to use this method because it requires complicated numerical algorithms to find specific frequencies which are solutions of an identical equation. The method also requires determination of the boundary of the controller's parameters from a finite set of FR data. In this paper, we present the development of a user-friendly Matlab toolbox based on the method in . This toolbox allows us to obtain a complete three-dimensional(3-D) graphical solution of PID controllers that meet multiple design objectives. Several examples are given to demonstrate the use of the toolbox.
Nano Visual Servoing Loop Using SEM Image
Choi, Jin-Ho ; Ahn, Sang-Jung ; Park, Byong-Chon ; Lyou, Joon ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 10, 2008, Pages 1876~1882
Nano manipulator is used to manufacture Carbon NanoTube(CNT) tips. Using nano manipulator, operator attaches a CNT at the apex of Atomic Force Microscope(AFM) tip, which requires a mastery of mechanics and long manufacture time. Nano manipulator is installed inside a Scanning Electron Microscope(SEM) chamber to observe the operation. This paper presents a control scheme for horizontal axes of nano manipulator via processing SEM image. Edges of AFM tip and CNT are first detected, and the position information so obtained is fed to control horizontal axes of nano manipulator. That is, a visual servoing loop is realized to control the axes more precisely in nano scale.
Implementation of the Broadcasting System for Digital Media Contents
Shin, Jae-Heung ; Kim, Hong-Ryul ; Lee, Sang-Cheal ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 10, 2008, Pages 1883~1887
Most of digital media contents are composed with video and audio, picture and animation informations. Sometime, there is some deviation of information recognition quality for the video and audio information according to information receiver's characteristics or the understanding. But visual information using the text provide most clear and accurate ways for information recognition to human being. In this paper, we propose a new broadcasting system(BSDMC) to transmit clear and accurate meaning of the digital media contents. We implement general-purpose components to display the video, picture, text and symbol simultaneously. Only plug-in and call these components with proper parameters on the application developing tool, we can easily develop the multimedia contents broadcasting system. These components are implemented based on the object-oriented framework and modular structure so that increase the reusability and can be develop other applications quick and reliable.
The Gain Enhancement of 1.8V CMOS Self-bias High-speed Differential Amplifier by the Parallel Connection Method
Bang, Jun-Ho ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 10, 2008, Pages 1888~1892
In this paper, a new parallel CMOS self-bias differential amplifier is designed to use in high-speed analog signal processing circuits. The designed parallel CMOS self-bias differential amplifier is developed by using internal biasing circuits and the complement gain stages which are parallel connected. And also, the parallel architecture of the designed parallel CMOS self-bias differential amplifier can improve the gain and gain-bandwidth product of the typical CMOS self-bias differential amplifier. With 1.8V
CMOS process parameter, the results of HSPICE show that the designed parallel CMOS self-bias differential amplifier has a dc gain and a gain-bandwidth product of 64 dB and 49 MHz respectively.
Comparison of the Maximum Moment of Ankle Plantarflexors During Various Isokinetic Contractions in the Elderly Males and Females and Young Males and Females
Kim, Ji-Won ; Kim, Sang-Woo ; Moon, Ki-Wook ; Eom, Gwang-Moon ; Lee, Young-Gyu ; Nam, Jung-Sook ; Park, Kwan-Yong ; Kim, Yo-Han ; Hong, Jeong-Hwa ; Park, Bung-Kyu ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 10, 2008, Pages 1893~1895
In this paper, we investigated the maximum ankle joint plantarflexion moment(MPM) of young and elderly subjects during various modes of isokinetic contractions with special interest in the elderly females who were reported to have higher fall rate than the elderly males. Subjects include the young subjects(14 males:
, 13 females:
) and the elderly subjects(17 males:
, 26 females:
). The MPM was normalized by each subject's body weight. The MPM of elderly females was the weakest among the groups, particularly, at the eccentric contractions. The male-to-female ratio of MPM was greater in the elderly than in the young and the young-to-elderly ratio of MPM was greater in female than in male, both during the eccentric contractions. The result suggests that the decreased muscle force per body weight, especially at the eccentric contraction, may be one reason for the more frequent fall of the elderly female than the elderly male.