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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 58, Issue 12 - Dec 2009
Volume 58, Issue 11 - Nov 2009
Volume 58, Issue 10 - Oct 2009
Volume 58, Issue 9 - Sep 2009
Volume 58, Issue 8 - Aug 2009
Volume 58, Issue 7 - Jul 2009
Volume 58, Issue 6 - Jun 2009
Volume 58, Issue 5 - May 2009
Volume 58, Issue 4 - Apr 2009
Volume 58, Issue 3 - Mar 2009
Volume 58, Issue 2 - Feb 2009
Volume 58, Issue 1 - Jan 2009
Selecting the target year
A Study on Forecasting Method for a Short-Term Demand Forecasting of Customer's Electric Demand
Ko, Jong-Min ; Yang, Il-Kwon ; Song, Jae-Ju ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 1, 2009, Pages 1~6
The traditional demand prediction was based on the technique wherein electric power corporations made monthly or seasonal estimation of electric power consumption for each area and subscription type for the next one or two years to consider both seasonally generated and local consumed amounts. Note, however, that techniques such as pricing, power generation plan, or sales strategy establishment were used by corporations without considering the production, comparison, and analysis techniques of the predicted consumption to enable efficient power consumption on the actual demand side. In this paper, to calculate the predicted value of electric power consumption on a short-term basis (15 minutes) according to the amount of electric power actually consumed for 15 minutes on the demand side, we performed comparison and analysis by applying a 15-minute interval prediction technique to the average and that to the time series analysis to show how they were made and what we obtained from the simulations.
Multi-Agent System and its Applications to the Distribution Automation System
Lim, Il-Hyung ; Choi, Myeon-Song ; Lim, Seong-Il ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 1, 2009, Pages 7~13
This paper presents benefits of multi-agent system approach and its application to the distribution automation system. Special attention is devoted to the description of hardware and communication platform used to upgrade the conventional distribution automation system structure. Service restoration of primary distribution system is selected as an example of the multi-agent system application. Application of the algorithm for multi-agent based service restoration technique is disclosed in detail. Real field test in Gochang test center of KEPCO has been performed to establish the feasibility of proposed technique.
A Study of the 10 kW-Level Wind Turbine System by Controlled Hydraulic Torque Converter
Jang, Mi-Hye ; Kim, Dong-Yong ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 1, 2009, Pages 14~17
In this paper, A generator of existing vertical type wind turbine system is connected to bevel gear. But, the generator of proposed wind turbine system is connected to Hydraulic torque converter. In case of the proposed wind turbine system, is possible to make torque transmission long distance, set up generator somewhere in between the tower or the ground as well as, nacelle weight can be greatly down. Lightweight of nacelle exactly wind direction tracking can be easily also, cost down of established frame structure and generator setting, maintenance, easy and improvement of system stability.
Data Mining Technique Using the Coefficient of Determination in Holiday Load Forecasting
Wi, Young-Min ; Song, Kyung-Bin ; Joo, Sung-Kwan ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 1, 2009, Pages 18~22
Short-term load forecasting (STLF) is an important task in power system planning and operation. Its accuracy affects the reliability and economic operation of power systems. STLF is to be classified into load forecasting for weekdays, weekends, and holidays. Due to the limited historical data available, it is more difficult to accurately forecast load for holidays than to forecast load for weekdays and weekends. It has been recognized that the forecasting errors for holidays are large compared with those for weekdays in Korea. This paper presents a polynomial regression with data mining technique to forecast load for holidays. In statistics, a polynomial is widely used in situations where the response is curvilinear, because even complex nonlinear relationships can be adequately modeled by polynomials over a reasonably small range of the dependent variables. In the paper, the coefficient of determination is proposed as a selection criterion for screening weekday data used in holiday load forecasting. A numerical example is presented to validate the effectiveness of the proposed holiday load forecasting method.
Block Coordinate Descent (BCD)-based Decentralized Method for Joint Dispatch of Regional Electricity Markets
Moon, Guk-Hyun ; Joo, Sung-Kwan ; Huang, Anni ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 1, 2009, Pages 23~27
The joint dispatch of regional electricity markets can improve the overall economic efficiency of interconnected markets by increasing the combined social welfare of the interconnected markets. This paper presents a new decentralized optimization technique based on Augmented Lagrangian Relaxation (ALR) to perform the joint dispatch of interconnected electricity markets. The Block Coordinate Descent (BCD) technique is applied to decompose the inseparable quadratic term of the augmented Lagrangian equation into individual market optimization problems. The Interior Point/Cutting Plane (IP/CP) method is used to update the Lagrangian multiplier in the decomposed market optimization problem. The numerical example is presented to validate the effectiveness of the proposed decentralized method.
A Study for CBL(Customer Baseline Load) utilization in Day Ahead Demand Response operation
Ko, Jong-Min ; Yang, Il-Kwon ; Song, Jae-Ju ; Jin, Sung-Il ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 1, 2009, Pages 28~34
In this study firstly we survey the calculation method and the characteristics of the way of estimating CBL(Customer BaseLine Load) that is important calculation tool for DRP internationally. Also we analyze the power consumption pattern using the 15 minutes load profiles of about 120,000 customers in domestic. Based on this pattern, we provide the CBL calculation method that can be utilized in DRP to save the cost, and analyze the accuracy of the CBL calculation proposed in this paper through the simulation.
Stand-Alone Type Single-Phase Fuel Cells Micro-Source with ac Voltage Compensation Capability
Jung, Young-Gook ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 1, 2009, Pages 35~41
This paper proposes a stand alone type single-phase fuel cells micro-source with a voltage sag compensator for compensating the ac output voltage variations (sag or swell) of micro-source. The proposed micro-source is consist of a PEM(polymer electrolyte membrane) fuel cells simulator, a full bridge de converter, a 60Hz PWM(pulse width modulation) VSI(voltage source inverter), and a voltage sag compensator. Voltage sag compensator is similar to the configuration of hybrid series active power filter, and it is directly connected to micro-source through the injection transformer. Compensation algorithm of a voltage sag compensator adopts a single phase p-q theory. Effectiveness of the proposed the system is verified by the PSIM(power electronics simulation tool) simulation in the steady state and transient state which the proposed system is able to simultaneously compensate the harmonic current and source voltage sag or swell.
EMTP Modeling and Dynamic Analysis of Microturbine Based Microsource for Application to Microgrid
Jyung, Tae-Young ; Baek, Young-Sik ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 1, 2009, Pages 42~48
Microgrid supplies loads with power interconnected grid. And it is defined a independent power system compounded micro sources over two devices which have enough capacity to operate independently, storage devices and loads. The energy sources of micro source have different dynamic characteristics corresponding to classes and application skills. However their transient responses are various from a few seconds to minutes. Therefore it is limitation for understanding operation characteristics of microsource modeling constant voltage source or constant current source. This paper shows that we designed EMTP/RV model of micro source which is microturbine based energy source. And we performed dynamic analysis of micro source corresponding to operation mode of microgrid.
Analysis and Design of the Single-phase Line Start Permanent Magnet Motor Considering Overhang Effect
Kang, Han-Byul ; Kim, Byung-Taek ; Baek, Soo-Whang ; Kim, Hong-Seok ; Kwon, Byung-Il ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 1, 2009, Pages 49~56
This paper shows the characteristic analysis of single-phase line start permanent magnet (LSPM) motors considering the overhang structure. To achieve the low-cost design of an LSPM motor, the overhang structure is adapted for the rotor with a constraint of a fixed magnet volume. To obtain the dynamic and steady performance of the motor, the circuit parameters are extracted using the 3D-static FEM(Finite Element Method) and the d-q equivalent circuit is used. The performance of the model with overhang is compared with the conventional model without overhang on the condition that both models have a fixed volume for the permanent magnet.
Optimum Design of a Shield Plate to minimize Extremely-Law-Frequency Magnetic Fields produced by Bus Bars
Jeung, Gi-Woo ; Choi, Nak-Sun ; Kim, Dong-Hun ; Jang, Nak-Won ; Lee, Dong-Young ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 1, 2009, Pages 57~62
This paper deals with the optimal design of a shield plate in order to minimize Extremely-Low-Frequency(ELF) magnetic fields generated from three-phase bus bars. Combining an evolutionary strategy with a 3D finite element analysis tool, the main dimensions of the shield plate are sought out. The optimization procedure consists of two separated design stages to take into account all foreseen structures of the plate. In the first stage, the basic dimensions of the plate are optimized including the distance between the plate and the bus bars. Then the usefulness of the additional structures such as a slit and fillet is investigated in the second stage. Finally the optimum design of the shield plate is suggested from the viewpoint of the shielding effectiveness and manufacturing cost.
Development of an Real-time Multi-machine Power System Simulator using Personal Computers and Fast Ethernet
Kim, Joong-Moon ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 1, 2009, Pages 63~68
As the complexity of the power system becomes higher, tests of the new devices, such as exciter and PCS(Power Conversion System) of the distributed generation sources, in the real operating condition are more important. However tests of the unverified devices in the real power system may cause hazardous malfunction of the system. In order to avoid this problem, power devices may be tested with the real-time simulators instead of the real power system. This paper presents an real-time multi machine power system simulator using PCs(Personal Computer) and Fast Ethernet. Developed real-time simulator performs the electro-mechanical dynamic simulation of multi-machine power system by the network distributed computing technique. Because the simulator consists of usual PCs and Fast Ethernet, it is possible to make up a simulation system very cheaper than the conventional real-time simulator which consists of dedicated expensive hardware devices. The performance of the developed simulator is tested and verified with the scaled model excitation system. The test which adjust the control parameters of the exciter is performed with the well-known New England 10 generator 39 bus sample power system.
Sensorless Control of High-speed Type PMSM in Wide Speed Range using an Iterative Adaptive Sliding Mode Observer
Kim, Jong-Moo ; Choi, Jeong-Won ; Lee, Suk-Gyu ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 1, 2009, Pages 69~76
This paper describes sensorless high-speed control for 45,000rpm/22kw type PMSM by using iterative adaptive sliding mode observer. The proposed algorithm is based on sensorless vector control by on-line estimating the speed of rotor in the wide speed operating range between the starting operation. In addition, it shows the enhanced performance of the iterative adaptive observer by lessening its chattering and getting stable response in limited PWM period. The simulation and experiment results show the reliable performance of the proposed algorithm through starting to high speed operating range.
A Study on the Parameter Optimization of Inverter for Induction Heating Cooking Appliance
Kang, Byung-Kwan ; Lee, Se-Min ; Park, Jung-Wook ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 1, 2009, Pages 77~85
With the advent of power semiconductor switching devices, power electronics relating to high frequency electromagnetic eddy current based induction heating technology have become more suitable and acceptable. This paper presents high-frequency induction heating cooking appliance circuit based on the zero current switching-PWM single ended push-pull(ZCS-PWM SEPP) resonant inverter added AC-DC converter. This inverter uses pulse-width-modulation(PWM) control method with active auxiliary quasi-resonant lossless inductor snubbers and a switched capacitor. To improved the transient performance, the PI controller is applied for this system. For the systematic parameter optimization of the PI controller, the gradient-based optimization algorithm is applied. The performance of optimized parameters is evaluated using simulation and experimental test. These results show that the proposed systematic optimal tuning method improve the transient performances of this system.
Development of 6kW ZVS Boost Converter by 4-Parallel Operation
Rho, Min-Sik ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 1, 2009, Pages 86~92
This paper presents development of 6kw ZVS(Zero Voltage Switching) boost converter by 4-parallel operation. To realize a high capacity converter with 6 kw, 4-parallel operation of 1.5kW unit module is proposed in this paper. To meet high ratio input to output voltage, isolated type booster converter is designed. To achieve ZVS operation of 4-switches of full bridge and protect a voltage overshoot caused by switch turn-off, simple active-clamp circuit is applied to the primary side. For parallel operation of 4-modules, master-slave control method is proposed to achieve input current sharing of 4-unit converter modules accurately. For performance tests, simulation is carried out. Also, load and experimental tests of the developed booster converter, 230Vdc/6kW, are carried out under various conditions. For field tests, the developed converter is applied for boosting a battery power to high DC_link voltage for a VSI inverter which starts a micro-turbine(MT) installed in vehicle and it's performance is verified through high speed motoring a MT up to tens of thousands of rpm.
Fuel Cell Stack Dynamics Modeling Considering Load Variation
Ko, Jeong-Min ; Kim, Jong-Soo ; Choe, Gyu-Yeong ; Kang, Hyun-Soo ; Lee, Byoung-Kuk ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 1, 2009, Pages 93~99
In this paper, transient voltage response of Polmer Electrolyte Membrane Fuel Cell (PEMFC) stack is analyzed and voltage dynamic characteristic is modeled for optimal design of power conditioning system (PCS). According that the load is changed, the corresponding operating voltage of fuel cell stack is also varied with a certain deep and rising time due to the chemical and mechanical responses. This transient behavior can affect on the operation with respect of PI gain in controller, duty ratio, capacitor of capacitor and so on. So in this paper the detailed theoretical analysis of transient voltage dynamics is explained and the methodology of dynamic modeling is introduced. In addition, the validity and feasibility of the proposed dynamic model is verified by experimental results under various load conditions.
The Deduction of the Optimal Length to Width Ratio of Dye-sensitized Solar Cell and the Fabrication of a Module
Kim, Hee-Je ; Park, Sung-Joon ; Choi, Jin-Young ; Seo, Hyun-Woong ; Kim, Mi-Jeong ; Lee, Kyoung-Jun ; Son, Min-Kyu ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 1, 2009, Pages 100~106
A novel 8 V DC power source with an external series-parallel connection of 50 Dye-sensitized Solar Cells (DSCs) has been proposed. One DSC has the optimized length to width ratio of
and an active area
) which attained a conversion efficiency of 4.02%. From the electrochemical impedance spectroscopic analysis, it was found that the resistance elements related to the Pt electrode and electrolyte interface behave like that of diode and the series resistance corresponds to the sum of the other resistance elements. Surface morphology and sheet resistance of Pt counter electrode did not degrade the performance of the cell. This novel 8V-0.33A DC power source shows stable performance with an energy conversion efficiency of 4.24% under 1 sun illumination (AM 1.5, Pin of
Design and Fabrication of the System in Package for the Digital Broadcasting Receiver
Kim, Jee-Gyun ; Lee, Heon-Yong ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 1, 2009, Pages 107~112
This paper describes design and fabrication issues of the SiP(System in Package) one-chip for a portable digital broadcasting receiver. It includes RF tuner chip, demodulator chip and passive components for the receiver system. When we apply the SiP one-chip technology to the broadcasting receiver, the system board size can be reduced from
. SiP one-chip has an advantage that the area reduces more 81% than separated chips. Also the sensitivity performance advances -1dBm about 36 channels in the RF weak electric field, the power consumption reduces about 2mW and the C/N keeps on the same level.
Measurement and Analysis of Risk Voltages by Various Current Sources in Grounding System
Kil, Gyung-Suk ; Moon, Byoung-Doo ; Kim, Hwang-Kuk ; Park, Dae-Won ; Gil, Hyoung-Jun ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 1, 2009, Pages 113~118
Grounding systems set the reference voltage level of electric circuits and suppress the Ground Potential Rise (GPR) by flowing fault currents to the ground safely. There are several parameters which evaluate the performance of grounding systems as ground resistance, touch voltage and step voltage. The touch and step voltages, which is called "risk voltage", are especially important to ensure the safety of human body. This paper dealt with the influence of current sources with the different frequency components on the touch and the step voltages. Three types of current sources as commercial frequency, square wave, and surge with the fast risetime of
were used to analyze the risk voltages in a grounding system. The risk voltages showed remarkable difference in the same current amplitude depending on the current sources, and increased linearly with the current amplitude in the same current source. From the experimental results, it was confirmed that the risk voltages can be evaluated by a small current application in large-scale grounding systems and the possible largest risk voltage can be calculated by a surge current with the risetime of 200 ns or a current source with the same frequency component as the surge current.
Ionization Behaviors by Types of Soil due to Lightning Impulse Voltages in a Hemishperical Electrode System
Lee, Kyu-Sun ; Park, Geon-Hun ; Kim, Hoe-Gu ; Lee, Bok-Hee ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 1, 2009, Pages 119~125
This paper deals with the characteristics of soil ionization affecting the dynamic performance of grounding systems under lightning impulse voltage. A concentric hemispherical electrode system was employed in order to facilitate the field calculation and analysis of the experimental results. The parameters such as the ionization threshold and breakdown field intensity, the pre-ionization and the post ionization resistances, the time-lag to ionization, the transient impedance, the equivalent ionized radius for various soil media were measured and analyzed. The dynamic characteristics of ionization processes under lightning impulse voltage are strongly dependent on the types of soil and water content. As a result, a soil ionization reduces the ground resistance and there is a little effect of applied impulse polarity on the soil ionization threshold field intensity. Although the ionization threshold field intensity of wet clay with 30% water content is the highest, its ionized zone was found to be the smallest amongst the test samples.
A Study on the Optimization of PD Pattern Recognition using Genetic Algorithm
Kim, Seong-Il ; Lee, Sang-Hwa ; Koo, Ja-Yoon ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 1, 2009, Pages 126~131
This study was carried out for the reliability of PD(Partial Discharge) pattern recognition. For the pattern recognition, the database for PD was established by use of self-designed insulation defects which occur and were mostly critical in GIS(Gas Insulated Switchgear). The acquired database was analyzed to distinguish patterns by means of PRPD(Phase Resolved Partial Discharge) method and stored to the form with to unite the average amplitude of PD pulse and the number of PD pulse as the input data of neural network. In order to prove the performance of genetic algorithm combined with neural network, the neural networks with trial-and-error method and the neural network with genetic algorithm were trained by same training data and compared to the results of their pattern recognition rate. As a result, the recognition success rate of defects was 93.2% and the neural network train process by use of trial-and-error method was very time consuming. The recognition success rate of defects, on the other hand, was 100% by applying the genetic algorithm at neural network and it took a relatively short time to find the best solution of parameters for optimization. Especially, it could be possible that the scrupulous parameters were obtained by genetic algorithm.
The Basic Insulation Characteristics of Solid-Nitrogen for Cryocooling of HTS Systems
Choi, Jae-Hyeong ; Choi, Jin-Wook ; Lee, Hai-Gun ; Song, Jung-Bin ; Kim, Hae-Jong ; Seong, Ki-Chul ; Kim, Sang-Hyun ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 1, 2009, Pages 132~136
Recently, for improvement of the magnetic field of high temperature superconductor (HTS) apparatus, many studies investigating on operating in the range of
with liquid helium or the conducting method using cryocooler are actively reviewed. Also, the cooling method using solid nitrogen as cryogen is being suggested. Since the nitrogen has very large specific heat in solid state, it is expected that it can be operated for a long time without a continuous supply of cooling energy. However, there are still insufficient data on the characteristics of solid nitrogen such as thermodynamic properties and liquid-solid phase change. Especially, there was almost no study done on the electrical insulation properties of solid nitrogen so far. In this study, solid nitrogen to find the electrical characteristics was made by using cryocooler and cryostat, and investigated the flashover discharge and breakdown. The results of this study will be useful as a basic data for electrical insulation design of the HTS system using solid nitrogen as cryogen.
High-Q Micromechanical Digital-to-Analog Variable Capacitors Using Parallel Digital Actuator Array
Han, Won ; Cho, Young-Ho ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 1, 2009, Pages 137~146
We present a micromechanical digital-to-analog (DA) variable capacitor using a parallel digital actuator array, capable of accomplishing high-Q tuning. The present DA variable capacitor uses a parallel interconnection of digital actuators, thus achieving a low resistive structure. Based on the criteria for capacitance range (
pF) and the actuation voltage (25 V), the present parallel DA variable capacitor is estimated to have a quality factor 2.0 times higher than the previous serial-parallel DA variable capacitor. In the experimental study, the parallel DA variable capacitor changes the total capacitance from 2.268 to 3.973 pF (0.5 GHz), 2.384 to 4.197 pF (1.0 GHz), and 2.773 to 4.826 pF (2.5 GHz), thus achieving tuning ratios of 75.2%, 76.1%, and 74.0%, respectively. The capacitance precisions are measured to be
fF (0.5 GHz),
fF (1.0 GHz), and
fF (2.5 GHz). The parallel DA variable capacitor shows the total resistance of
(1.0 GHz), and
(2.5 GHz), resulting in high quality factors which are measured to be
(1.0 GHz), and
(2.5 GHz) for large capacitance values (
pF). We experimentally verify the high-Q tuning capability of the present parallel DA variable capacitor, while achieving high-precision capacitance adjustments.
A Disposable Grating-Integrated Multi-channel SPR Sensor Chip for Detection of Biomolecule
Jin, Young-Hyun ; Cho, Young-Ho ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 1, 2009, Pages 147~154
This paper presents a grating~integrated SPR (Surface Plasmon Resonance) sensor chip for simple and inexpensive biomolecule detection. The grating-integrated SPR sensor chip has two sensing channels having a nano grating for SPR coupling. An external mirror is used for multi channel SPR sensing. The present sensor chip replaces bulky and expensive optical components, such as fiber-optic switches or special shaped prisms, resulting in a simple and inexpensive wavelength modulated multi-channel SPR sensing system. We fabricate a SPR sensor chip integrated with 835 nm-pitch gratings by a micromolding technique to reduce the fabrication cost. In the experimental characterization, the refractive index sensitivity of each sensing channel is measured as
/RI, respectively. 0.5uM of the target biomolecule (streptavidin) was detected by a
shift of the SPR dip in the 10%-biotinylated sample channel, while the SPR dip in the reference channel for environmental perturbation monitoring remained at the same position. From the experimental results, multi-channel biomolecule detection capability of the present grating-integrated SPR sensor chip has been verified. On the basis of the preliminary experiments, we successfully measured the binding reaction rate for the
monoclonal-antibiotin, thus verifying biomolecule concentration detectability of the present SPR sensor chip. The binding reaction rates measured from the present SPR sensor chip agredd well with those from a commercialized SPR sensor.
A Study of Discharge Characteristics in Xe-Ne Gas Mixture for ac PDP with Long Gap Hump Electrode
Heo, Jong-Cheol ; Ok, Jung-Woo ; Lee, Don-Kyu ; Lee, Hae-June ; Lee, Ho-Jun ; Park, Chung-Hoo ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 1, 2009, Pages 155~159
To increase the luminance and luminous efficacy in the discharge for alternating current plasma display panel (ac PDP), the increment of Xe contents and long discharge gap are necessary. However, the driving voltage and the cost of driving circuit increases in the high Xe contents and long discharge path condition. In this paper, a long gap ITO hump electrode (LGH) model for discharge cells of ac PDP is evaluated in the various Xe contents(
). The discharge voltage of LGH structure is lower about 30V than that of ITa reference structure with same main discharge gap. The LGH structure has lower power consumption and higher luminance than those of reference structure, respectively. Also, the luminous efficacy of LGH structure is higher about 20% than that of ITO reference structure in the 20% Xe contents.
Design of Disturbance Observer Using Robust Control Method for SPM-based Data Storage Systems
Moon, Jun ; Lee, Choong-Woo ; Chung, Chung-Choo ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 1, 2009, Pages 160~167
In this paper, we apply the robust disturbance observer (DOB) to a SPM-based data storage (SDS) system. In the SDS system, coupling dynamics and parameter uncertainties are obstacles to the precision tracking control. Although the DOB is known to be an effective method to reject disturbances, there has been no systematic design approach to how to design DOB parameters. In this paper, the robust DOB is formulated based on the robust stabilization of normalized coprime factor plant description and the
loop shaping method. From the simulation and experimental results. the improved robustness and performance are obtained by the proposed robust DOB.
A Comparison of Sliding Mode and Integral Sliding Mode Controls for Robot Manipulators
Yoo, Dong-Sang ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 1, 2009, Pages 168~172
We compare an integral sliding mode control with a typical sliding mode control for robot manipulators through two primitive tasks: set-point regulation and trajectory tracking control. To prove the asymptotic stability of two methods for robot manipulators, we introduce three important properties in the robot dynamics: skew-symmetry, positive-definiteness, and boundedness of robot parameter matrices and we present one unified control structure using a parametric velocity vector. From illustrative examples, we show that two methods effectively control for robot manipulators.
Design of Multiple Model Fuzzy Predictors using Data Preprocessing and its Application
Bang, Young-Keun ; Lee, Chul-Heui ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 1, 2009, Pages 173~180
It is difficult to predict non-stationary or chaotic time series which includes the drift and/or the non-linearity as well as uncertainty. To solve it, we propose an effective prediction method which adopts data preprocessing and multiple model TS fuzzy predictors combined with model selection mechanism. In data preprocessing procedure, the candidates of the optimal difference interval are determined based on the correlation analysis, and corresponding difference data sets are generated in order to use them as predictor input instead of the original ones because the difference data can stabilize the statistical characteristics of those time series and better reveals their implicit properties. Then, TS fuzzy predictors are constructed for multiple model bank, where k-means clustering algorithm is used for fuzzy partition of input space, and the least squares method is applied to parameter identification of fuzzy rules. Among the predictors in the model bank, the one which best minimizes the performance index is selected, and it is used for prediction thereafter. Finally, the error compensation procedure based on correlation analysis is added to improve the prediction accuracy. Some computer simulations are performed to verify the effectiveness of the proposed method.
Delay-dependent Robust Stability of Uncertain Dynamic Systems with Time-varying Delays
Kwon, Oh-Min ; Park, Ju-Hyun ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 1, 2009, Pages 181~186
In this paper, the stability analysis for uncertain dynamic systems with time-varying delays is considered. By constructing a new Lyapunov functional, a novel stability criterion is established in terms of linear matrix inequalities (LMIs). Two numerical examples are carried out to support the effectiveness of the proposed method.
Design of a Disturbance Observer Using a Second-Order System Plus Dead Time Modeling Technique
Jeong, Goo-Jong ; Son, Young-Ik ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 1, 2009, Pages 187~192
This paper presents a method for designing a robust controller that alleviates disturbance effects and compensates performance degradation owing to the time-delay. Disturbance observer(DOB) approach as a tool of robust control has been widely employed in industry. However, since the Pade approximation of time-delay makes the plant non-minimum phase, the classical DOB cannot be applied directly to the system with time-delay. By using a new DOB structure for non-minimum phase systems together with the Smith Predictor, we propose a new controller for reducing the both effects of disturbance and time-delay. Moreover, the closed-loop system can be made robust against uncertain time-delay with the help of a Pill controller tuning method that is based on a second-order plus dead time modeling technique.
Control for Uncertain Discrete-time Descriptor Systems with Interval Time-varying Delays in State and Control Input
Kim, Jong-Hae ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 1, 2009, Pages 193~198
In this paper, we consider the design problem of delay-dependent robust
controller of discrete-time descriptor systems with parameter uncertainties and interval time-varying delays in state and control input by delay-dependent LMI (linear matrix inequality) technique. A new delay-dependent bounded real lemma for discrete-time descriptor systems with time-varying delays is derived. The condition for the existence of robust
controller and the robust
state feedback control law are proposed by LMI approach. A numerical example is demonstrated to show the validity of the design method.
Verification of System using Master-Slave Structure
Kim, In-Soo ; Min, Hyoung-Bok ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 1, 2009, Pages 199~202
Scan design is currently the most widely used structured Design For Testability approach. In scan design, all storage elements are replaced with scan cells, which are then configured as one or more shift registers(also called scan chains) during the shift operation. As a result, all inputs to the combinational logic, including those driven by scan cells, can be controlled and all outputs from the combinational logic, including those driving scan cells, can be observed. The scan inserted design, called scan design, is operated in three modes: normal mode, shift mode, and capture mode. Circuit operations with associated clock cycles conducted in these three modes are referred to as normal operation, shift operation, and capture operation, respectively. In spite of these, scan design methodology has defects. They are power dissipation problem and test time during test application. We propose a new methodology about scan shift clock operation and present low power scan design and short test time.
Development of Joint Angle Measurement System for the Feedback Control in FES Locomotion
Moon, Ki-Wook ; Kim, Chul-Seung ; Kim, Ji-Won ; Lee, Jea-Ho ; Kwon, Yu-Ri ; Kang, Dong-Won ; Khang, Gon ; Kim, Yo-Han ; Eom, Gwang-Moon ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 1, 2009, Pages 203~209
The purpose of this study is to develop a minimally constraint joint angle measurement system for the feedback control of FES (functional electrical stimulation) locomotion. Feedback control is desirable for the efficient FES locomotion, however, the simple on-off control schemes are mainly used in clinic because the currently available angle measurement systems are heavily constraint or cosmetically poor. We designed a new angle measurement system consisting of a magnet and magnetic sensors located below and above the ankle joint, respectively, in the rear side of ipsilateral leg. Two magnetic sensors are arranged so that the sensing axes are perpendicular each other. Multiple positions of sensors attachment on the shank part of the ankle joint model and also human ankle joint were selected and the accuracy of the measured angle at each position was investigated. The reference ankle joint angle was measured by potentiometer and motion capture system. The ankle joint angle was determined from the fitting curve of the reference angle and magnetic flux density relationship. The errors of the measured angle were calculated at each sensor position for the ankle range of motion (ROM)
degrees (dorsiflexion as positive) which covers the ankle ROM of both stroke patients and normal subjects during locomotion. The error was the smallest with the sensor at the position 1 which was the nearest position to the ankle joint. In case of human experiment, the RMS (root mean square) errors were
degrees and the maximum errors were
degrees. The proposed system is less constraint and cosmetically better than the existing angle measurement system because the wires are not needed.
Functional Near-Infrared Spectroscopy Extracts EROS in the Prefrontal Cortex
Kang, Ho-Yul ; Baang, Sung-Keun ; Song, Seong-Ho ; Lee, Un-Joo ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 1, 2009, Pages 210~215
In this study event-related optical signals were extracted from the prefrontal cortexes using functional near infrared spectroscopy while subjects were carrying out 2-back working memory tasks. Four events such as start, yes, no, and error were considered based on the onsets of the stimulus, positive true responses, positive false responses, and negative responses in the 2-back working memory task, respectively. The optical signals recorded were analyzed by peri-event histograms and power spectrum distributions. The results showed specific characteristics of the event-related optical neuronal signals and an opened possibility of an application to control a non-invasive brain-computer interface system or an object of a virtual reality.