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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 60, Issue 12 - Dec 2011
Volume 60, Issue 11 - Nov 2011
Volume 60, Issue 10 - Oct 2011
Volume 60, Issue 9 - Sep 2011
Volume 60, Issue 8 - Aug 2011
Volume 60, Issue 7 - Jul 2011
Volume 60, Issue 6 - Jun 2011
Volume 60, Issue 5 - May 2011
Volume 60, Issue 4 - Apr 2011
Volume 60, Issue 3 - Mar 2011
Volume 60, Issue 2 - Feb 2011
Volume 60, Issue 1 - Jan 2011
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A Study on the Evaluation of Distribution Reliability Considering Reliability Model for a Resistive-Type of Superconducting Fault Current Limiter
Kim, Sung-Yul ; Kim, Wook-Won ; Kim, Jin-O ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 3, 2011, Pages 465~470
DOI : 10.5370/KIEE.2011.60.3.465
Recently fault currents are increasing in a network. It is caused by increase in electric demand and high penetration of distributed generation with renewable energy sources. Moreover, distribution network has become more and more complex as mesh network to improve the distribution system reliability and increase the flexibility and agility of network operation. Accordingly, the fault current will exceed capacity of circuit breakers soon and all the various rational solutions to solve this problem are taken into account. Under these circumstances, superconducting fault current limiter(SFCL) is a new alternative in the viewpoint of technical and economic aspects. This study presents operation processes for a resistive-type of SFCL, and it proposes reliability model for the SFCL. When a SFCL is installed into a network, the contribution of decreased fault currents to failure for distribution equipments can be quantified. As a result, it is expected that a SFCL makes the reliability of adjacent equipments on existing network improve and these changes are analyzed. We propose a methodology to evaluate the reliability in the distribution network where a SFCL is installed considering a reliability model for resistive-type of SFCL and reliability changes for adjacent equipments which are proposed in this paper.
Maximum Power Point Tracking using Double Fuzzy Logic Controller for Grid-connected Photovoltaic System
Kim, Kyu-Han ; Kim, Hyung-Su ; Park, June-Ho ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 3, 2011, Pages 471~478
DOI : 10.5370/KIEE.2011.60.3.471
This paper proposes a method of maximum power point tracking (MPPT) using fuzzy logic control for grid-connected photovoltaic systems (PV). First, for the purpose of comparison, because of its proven and good performances, the incremental conductance (IncCond) technique is briefly introduced. A double fuzzy logic controller (DFLC) based MPPT is then proposed which has shown better performances compared to the IncCond MPPT based approach. Modeling and Simulation in grid-connected PV system results are provided for both controllers under same atmospheric condition based PSCAD/EMTDC. The double fuzzy logic MPPT controller is then simulated and evaluated, which has shown better performances.
Proposition of Improved Neutral Grounding Method and Analytical Evaluation on Practicality in Underground Distribution System
Jeong, Seok-San ; Lee, Jong-Beom ; Jang, Seong-Whan ; Kim, Yong-Kap ; Kwon, Shin-Nam ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 3, 2011, Pages 479~485
DOI : 10.5370/KIEE.2011.60.3.479
In 22.9kV underground distribution system, power cables are provided with multiple-point ground in which each neutral line of the distribution cable(A, B, C phases) and three-wire common grounded at every connecting section. But in such grounding methods, circulating current flows between the neutral wire and grounding wire. And power loss due to circulating current also occurs in all conductors. Therefore it is getting necessary reducing circulating current in underground distribution system. This paper presents improved grounding method to overcome such problems. The proposed grounding method eliminates circulating current in the neutral line effectively and is verified that there is no electrical problem or any ineffectiveness of operating protection systems. These analyses are carried out by EMTP/ATPDraw to compare each grounding methods in steady and transient state. This grounding method suggested in this paper can be applied on real distribution system after field tests considering elimination of circulating current was implemented.
A Study on New Data Format of Electrical Shocks in the Environment of Smart Grids
Kim, Jung-Hoon ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 3, 2011, Pages 486~491
DOI : 10.5370/KIEE.2011.60.3.486
Since Korea has high accident rate for the electrical shock than other advanced countries, it causes very serious problems. In this paper, a new classification method for analyzing electricity accidents is proposed, which is based on the microscopic view while existing methods have been based at the macroscopic view point. Electrical accidents cases can be mainly divided by three cases, which are from live works, incompleteness of the grounding system and imperfectness of the safety education and public relations. New data format of electrical shocks are proposed in the environment of smart grids.
Evaluation of Operation Practicality on Line with Aluminum Conductor in Underground T&D Systems
Jang, Ju-Yeong ; Lee, Jong-Beom ; Kim, Yong-Kap ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 3, 2011, Pages 492~499
DOI : 10.5370/KIEE.2011.60.3.492
This paper describes that the evaluation on operation practicality of Al conductor cable will be used instead of Cu conductor cable. Analysis is divided into two kinds of cases as transmission and distribution. To evaluate that Al conductor line has the insulation strength indeed safely, various analysis and calculation such as single line-to-ground fault current, lightning surge and allowance current were carried. Model was established based on real combined transmission and distribution is being used in utility with EMTP. The analysis results on Al and Cu conductor line were compared each other. It was proved that Al conductor line can be operated instead of Cu conductor line without special insulation problem in transmission and distribution, in electrical view point such as overvoltage and allowance current.
Economic Evaluations of The Alternatives to Increase the Supply Capacity For Large Customers In The Distribution Systems
Park, Yong-Gi ; Roh, Jae-Hyung ; Park, Jong-Bae ; Choi, Myeon-Song ; Kim, Gwang-Won ; Kim, Ju-Seong ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 3, 2011, Pages 500~508
DOI : 10.5370/KIEE.2011.60.3.500
In the distribution systems, the maximum power transportation capacity is restricted within 40MW based on two lines, because of the thermal current limit of a distribution line. Recently it has been continuously required to expand the abilities of the power transportation in distribution systems, as the number of large scale industrial complexes and distributed generations are growing. In this paper, we suggested the five alternatives combining two methods, laying the two bundle lines and adding another voltage between the 22.9kV and 154kV in distribution systems. This paper implemented the economic evaluations of proposed alternatives from national and customer perspectives. And then we compare the results with those of 154kV transmission system.
Multi-Stage Generation Allocation Game Considering Ramp-rate Constraints
Park, Yong-Gi ; Park, Jong-Bae ; Roh, Jae-Hyung ; Kim, Hyeong-Jung ; Shin, Jung-Rin ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 3, 2011, Pages 509~516
DOI : 10.5370/KIEE.2011.60.3.509
This paper studies a novel method to find the profit-maximizing Nash Equilibriums in allocating generation quantities with consideration of ramp-rates under competitive market environment. Each GenCo in a market participates in a game to maximize its profit through competitions and play a game with bidding strategies. In order to find the Nash equilibriums it is necessary to search the feasible combinations of GenCos' strategies which satisfy every participant's profit and no one wants various constraints. During the procedure to find Nash equilibriums, the payoff matrix can be simplified as eliminating the dominated strategies. in each time interval. Because of the ramp-rate, generator's physically or technically limits to increase or decrease outputs in its range, it can restrict the number of bidding strategies of each generator at the next stage. So in this paper, we found the Nash Equilibriums for multi-stage generation allocation game considering the ramp-rate limits of generators. In the case studies, we analyzed the generation allocation game for a 12-hour multi-stage and compared it with the results of dynamic economic dispatch. Both of the two cases were considered generator's ramp-rate effects.
A Study on Determination of Optimal Incentives of DSM Programs by Linear Programming
Lee, Byung-Ha ; Kim, Jung-Hoon ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 3, 2011, Pages 517~523
DOI : 10.5370/KIEE.2011.60.3.517
A lot of DSM (Demand Side Management) programs have been implemented to promote the effective utilization of resources and the rational development of power industry, and various economic analyses and policy-based studies on DSM have been executed to determine effective subsidy budget. In this paper, a new objective function for deciding an optimal incentive allocation among various programs is presented by introducing the maximization of the total saving power of the programs. For simplicity, the objective function and the constraints is linearized to apply LP(Linear Programming) method. LP program based on Simplex Method was developed by MATLAB. An optimal incentive allocation of 4 DSM programs is presented by the use of the developed MATLAB program.
Fault Tolerance Improvement of IPM Type BLDC Motor Considering Winding Configuration under a Stator Inter-Turn Fault Condition
Kim, Hee-Woon ; Yoon, Jin-Gyu ; Hur, Jin ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 3, 2011, Pages 524~530
DOI : 10.5370/KIEE.2011.60.3.524
This paper analyzes fault tolerance under a stator turn fault, according to the winding configuration. Improvement of torque characteristics and fault tolerance can be achieved by winding configuration without additional methods. And, torque characteristics and fault tolerance according to the winding configuration can be usually analyzed by analytical method. But, when the stator turn fault generates, compare to the steady-state, analysis of torque characteristics and fault tolerance using the analytical method is not accurate because it does not reflect influence in mutual inductance and magnetic non-linearity. Therefore, analysis of torque characteristics and fault tolerance has to be performed by using the numerical method under fault condition. This paper develops fault characteristics according to the winding configuration using the FEM-base model considered magnetic non-linearity. And, this paper suggests fault tolerance improvement according to the winding configuration, by the comparison of 8/12 and 10/12 models, under fault condition.
Fault Analysis of IPM type BLDC Motor Using Nonlinear Modeling of Stator Inter Turn Faults
Kim, Kyung-Tae ; Hur, Jin ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 3, 2011, Pages 531~537
DOI : 10.5370/KIEE.2011.60.3.531
This paper proposes a finite element method (FEM)-based model of an interior permanent magnet (IPM) type BLDC motor having stator inter-turn faults. For more realistic simulation studies, the magnetic non-linearity is also considered in proposed model. And the simulation data are verified through experiment. By integrating the developed model with a current-controlled voltage source inverter (CCVSI) model, the characteristics of an inter-turn fault operated by six-switched inverter are investigated considering the speed control. And the circulating current, which is induced by magnetic linkage flux originated from PM, was analyzed from the view point of distortion of air-gap magnetic flux distribution caused deterioration of their torque.
Design and Control of Interleaved Boost converter for Multi-string PV Inverter
Kang, Young-Ju ; Cha, Han-Ju ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 3, 2011, Pages 538~543
DOI : 10.5370/KIEE.2011.60.3.538
In this paper, design and control of an interleaved boost converter for multi-string PV Inverter are discussed. Interleaved Boost converter can reduce current ripples at input and output side by cancelling an each phase of inductor currents. Therefore, it contributes to increase efficiency and downsize the whole system volume, cost. One of the advantages of the multi-string system is easy to expand power capacity by connecting the converter modules in parallel. In order to reduce current ripples, the inductor currents on each phase are controlled independently in the converter module, and communication between the converter modules is required for further ripple current reduction. Current control algorithm for the balance of the each phase ripple currents and synchronization of the converter modules based on communication are proposed and implemented in the DSP programming. 10kW prototype of the multi-string converter module is assembled and experimental results are presented to verify the proposed ripple current reduction methods.
Development of Regenerative Energy Storage System for An Electric Vehicle Using Super-Capacitors
Chung, Dae-Won ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 3, 2011, Pages 544~551
DOI : 10.5370/KIEE.2011.60.3.544
This paper presents the circuit arrangement and effective control method of regenerative energy storage system for an electric vehicle using super-capacitors as the braking energy storage element. A bi-directional controlled current flow of the DC-DC converters with the capacitor bank is connected in parallel with battery, and is controlled so that the whole of the braking energy is effectively absorbed into the capacitors and released back to the electric motor upon acceleration. The converter needs the series-parallel switching circuit for making the best use of the series capacitors and for limiting the step-up ratio of the boost converter. The proposed methods are verified by computer simulation and experimental set-up. They are usefully applied to the electric vehicles such as green cars, electric motorcycles, bike, etc which are power- supplied by the electric batteries.
A Study on the Variation of Magnetic Field Intensity and Short Current by Coating Material of Spray in AF Track Circuits
Kim, Min-Seok ; Oh, Sea-Hwa ; Park, Yong-Gul ; Lee, Jong-Woo ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 3, 2011, Pages 552~559
DOI : 10.5370/KIEE.2011.60.3.552
There is a method for offering continuous information by AF track circuits. Magnetic fields are formed by current through rails in the AF track circuit systems. So, the continuous information is received by the magnetic fields on a on-board antenna. Coating materials of spray on rails are researched to decrease defects such as head check, shelling, corrugation, squats and so on in Germany. Currently, a coating method of rail construction is proposed by using the ceramics in Korea. When deciding physical characteristic of the coating material of spray, researches are required about variation of flux density and resistivity by using the coating material of spray. In case that the flux density is much lower than existing value, the information for train control is not transmitted to the on-board antenna. In this paper, inductance on rails is calculated and a model is presented about variation of the magnetic field intensity and resistivity in the AF track circuit. Standard permeability of the coating material of spray is proposed. Also, standard resistivity of the coating material of spray is presented by analyzing short current.
Design of Micro Energy Harvesting System using Thermoplastic Polyurethane and Buck-boost Converter
Son, Young-Dae ; Kim, Gue-Hyun ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 3, 2011, Pages 560~565
DOI : 10.5370/KIEE.2011.60.3.560
This paper proposes the design of micro energy harvesting system by using thermoplastic polyurethane(TPU), which harvests electric energy from the kinetic energy of pedestrian and drives the desired load, and applied it to the self-generating shoes. Also, we designed the buck-boost converter in discontinuous conduction mode(DCM) which functions as a resistor emulator(RE) such that converter's average input current is proportional to input voltage, and it results in transfer of maximum power to buck-boost converter according to control behavior that converter's input resistance is matched with TPU's internal resistance. Therefore, this paper confirms the validity of proposed control scheme and possibility of application for self-generating shoes, from the obtained characteristic of designed micro energy harvesting system by using a TPU and buck-boost converter in DCM.
A Study on the Power Management Algorithm of Centralized Electric Vehicle Charging System
Do, Quan-Van ; Lee, Seong-Joon ; Lee, Jae-Duck ; Bae, Jeong-Hyo ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 3, 2011, Pages 566~571
DOI : 10.5370/KIEE.2011.60.3.566
As Plug-in Hybrid Vehicle and Electric Vehicle (PHEV/EV) take a greater share in the personal automobile market, their high penetration levels may bring potential challenges to electric utility especially at the distribution level. Thus, there is a need for the flexible charging management strategy to compromise the benefits of both PHEV/EV owners and power grid side. There are many different management methods that depend on the objective function and the constraints caused by the system. In this paper, the schema and dispatching schedule of centralized PHEV/EV charging spot network are analyzed. Also, we proposed and compared three power allocation strategies for centralized charging spot. The first strategy aims to maximize state of vehicles at plug-out time, the rest methods are equalized allocation and prioritized allocation based on vehicles SoC. The simulation results show that each run of the optimized algorithms can produce the satisfactory solutions to response properly the requirement from PHEV/EV customers.
RTDS based Transient Analysis of PMSG Type wind Power Generation System
Hwang, Chul-Sang ; Kim, Gyeong-Hun ; Kim, Nam-Won ; Lee, Hyo-Guen ; Seo, Hyo-Ryong ; Park, Jung-Do ; Yi, Dong-Young ; Lee, Sang-Jin ; Park, Min-Won ; Yu, In-Keun ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 3, 2011, Pages 572~576
DOI : 10.5370/KIEE.2011.60.3.572
The operation of permanent magnet synchronous generator (PMSG) type wind power generation system (WPGS) can be affected by the utility condition. Consequently, transient condition of utility should be analyzed for the safe and reliable operation of WPGS. This paper presents transient analysis results of a PMSG type WPGS using real time digital simulator (RTDS). A fault condition was applied to the transient analysis of PMSG type WPGS as the transient grid condition. The simulation results were analyzed to show the operational characteristic of PMSG type WPGS under the transient phenomenon of utility.
CLHS Driving Method for Reducing Reactive Power Consumption in AC PDP
Shin, Jae-Hwa ; Kim, Gun-Su ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 3, 2011, Pages 577~583
DOI : 10.5370/KIEE.2011.60.3.577
In AC-PDP, it is necessary to achieve high luminance efficiency, high luminance and high definition by adopting technologies such as high xenon concentration and long gap. However, it is very difficult to apply above technologies because they make many problems such as mis-discharge and high driving voltage. Especially, the reactive power of PDP must be reduced for satisfaction in international standard IEC62087. In this paper, we proposed CLHS driving method which is half sustain driver without energy recovery capacitor. In the experimental results, CLHS driving method reduced reactive power consumption about 10%. Also, CLHS driving method improved the luminance efficiency in all discharge loads. Therefor, the more the discharge load decreases, the more the luminance efficiency improves. When the discharge load is 20%, CLHS driving method improved 5.35%.
Efficiency Improvement of Metal-Mesh Electrode Type Photoelectrochemical Cells by Oxides Layer Coatings
Han, Chi-Hwan ; Park, Seon-Hee ; Sung, Youl-Moon ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 3, 2011, Pages 584~587
DOI : 10.5370/KIEE.2011.60.3.584
In this work, the
thin films as blocking layers were coated directly onto the metal-mesh electrode surface to prevent unnecessary inflow of back-transfer electrons from the electrolyte (
) to the metal-mesh electrode. The DSCs were fabricated with working electrode of SUS mesh coated with blocking
layers, dye-attached mesoporous
film, gel electrolyte and counter electrode of Pt-deposited F:
. From the experimental result, it was ascertained that the efficiency of metal electrode coated with
by Dip-coating was superior to that of metal electrode coated with
by Dip-coating and screen printing with the results of experiments. The photo-current conversion efficiency of the cell obtained from optimum fabrication condition was 3% (
, ff=0.64) under AM1.5, 100 mW/
A Diagnostic Technique for Power Distribution Line Facilities by the Corona Detector
Cho, Yong-Sang ; Song, Gyu-So ; Choi, Yu-Seong ; Park, Tae-Seong ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 3, 2011, Pages 588~593
DOI : 10.5370/KIEE.2011.60.3.588
The airpollutant may accelerate degradation of power line facilities, and may reduce the life of the electric facilities. In case of korea, there are a tendency that the density of air pollution may be increased by industrial development. while lack of research activity and establishment of a countermeasure on this issue. Recently the occurrence of electricity failure have been reduced on the power transmission and distribution lines. but the occurrence of electricity failure by insulator itself has been increased. It means that we should have develop more clear technique for detection of the wrong insulator. In this study to provide a method for detection of the insulator failure or effective management of the troubled insulator, we analyze the chemical composition of the insulator which used on power distribution line at the sea side locations. To define the relation between insulation and corona intensity, we design and develop an corona detector. We define the variation of insulation by pollution changes on the insulator and verify quantitative relation between corona and insulations using the corona detector.
Development of novel strain sensor using surface acoustic wave
Oh, Hae-Kwan ; Hwang, U-Jin ; Eun, Kyung-Tae ; Choa, Sung-Hun ; Lee, Kee-Keun ; Yang, Sang-Sik ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 3, 2011, Pages 594~599
DOI : 10.5370/KIEE.2011.60.3.594
A SAW strain sensor based on Shear Horizontal wave with an 92 MHz central frequency was developed. It consists of SAW sensor, PCB substrate and bonding material (Loctite 401). External force applied to PCB substrate bonded to a piezoelectric substrate induces strain at the substrate surface, which causes changes in the elastic constant and density of the substrate and hence the propagation velocity of the SAW. The change in the velocity of the SAW result in a frequency shift of the sensor and by measuring a frequency shift, we can extract the strain induced by the external force. The
was used because it has a Leaky shear horizontal(SH) wave propagation mode and a high electromechanical coupling coefficient (
=17.2%). And to compare with Rayleigh wave mode,
was used. And to make a stable and low insert loss, Split IDT structure was used. The obtained sensitivity and linearity of the SAW strain sensor in the case of Split IDT were measured to be 17.2 kHz / % and 0.99, respectively.
Field Test and Evaluation for a Wireless Vehicle Detector with Two Anisotropic Magneto-Resistive Sensors
Kang, Moon-Ho ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 3, 2011, Pages 600~605
DOI : 10.5370/KIEE.2011.60.3.600
This paper shows field test and evaluation results for a wireless vehicle detector with anisotropic magneto-resistive (AMR) sensors. The detector consists of two AMR sensors and mechanical and electronic apparatuses. The AMR sensor senses disturbance of the earth magnetic field caused by a vehicle moving over the sensor and then produces an output indicative of the moving vehicle. In this paper, vehicle speeds are calculated by using two AMR sensors fixed on a board, with constant distance. To test and evaluate the accuracy of the detector in real traffic situations, the detector was installed on a local highway and vehicle speeds and volumes were measured both in a free running and a highly congested traffic. The measurements from the detector are compared with the reference measurements obtained from a traffic camera with the Mean Absolute Percentage Errors (MAPE), which has proved the usefulness of the detector in the field.
Inclination and Non-horizontal Error Correction of Magnetic Compass by the Law of Gravity
Park, Gye-Do ; Lee, Jang-Myung ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 3, 2011, Pages 606~611
DOI : 10.5370/KIEE.2011.60.3.606
This paper proposes a correction method concerning the inclination error and non-horizontal error of magnetic compass when magnetic compass is vibrated. This system used the 2-axis variable resistance and pendulum. A pendulum hanging from the 2-axis variable resistance of this system is always maintain the horizontal because of gravity. but these data had some intrinsic error. So we used the low pass filter to solve this problem. So this system can get the accurate azimuth of magnetic compass. In conclusion, These results demonstrate convincingly by applied algorithm of experiment.
The Integrated eLoran/GPS Navigation Algorithm for Reduced Calculational Complexity and High Accuracy
Song, Se-Phil ; Shin, Mi-Young ; Son, Seok-Bo ; Kim, Young-Baek ; Lee, Sang-Jeong ; Park, Chan-Sik ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 3, 2011, Pages 612~619
DOI : 10.5370/KIEE.2011.60.3.612
Satellite navigation system such as GPS is becoming more important infrastructure for positioning, navigation and timing. But satellite navigation system is vulnerable to interferences because of the low received power, complementary navigation system such as eLoran is needed. In order to develop eLoran/GPS navigation system, integrated eLoran/GPS navigation algorithm is necessary. In this paper, new integrated eLoran/GPS navigation algorithm is proposed. It combines the position domain integration and the range domain integration to get accurate position with less computational burden. Also an eLoran/GPS evaluation platform is designed and performance evaluation of the proposed algorithm using the evaluation platform is given. The proposed algorithm gives an accuracy of the range domain integration with a computational load of the position domain integration.
A New Augmented Lyapunov Functional Approach to Robust Delay-dependent Stability Analysis for Neutral Time-delay Systems
Kwon, Oh-Min ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 3, 2011, Pages 620~624
DOI : 10.5370/KIEE.2011.60.3.620
This paper propose a new delay-dependent stability criterion of neutral time-delay systems. By employing double-integral terms in augmented states and constructing a new Lyapunov-Krasovskii's functional, a delay-dependent stability criterion is established in terms of Linear Matrix Inequality. Through numerical examples, the validity and improvement results obtained by applying the proposed stability criterion will be shown.
Discrete-Time Output Feedback Algorithm for State Consensus of Multi-Agent Systems
Kim, Jae-Yong ; Lee, Jin-Young ; Kim, Jung-Su ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 3, 2011, Pages 625~631
DOI : 10.5370/KIEE.2011.60.3.625
This paper presents a discrete-time output feedback consensus algorithm for Multi-Agent Systems (MAS). Under the assumption that an agent is aware of the relative state information about its neighbors, a state feedback consensus algorithm is designed based on Linear Matrix Inequality (LMI) method. In general, however, it is possible to obtain its relative output information rather than the relative state information. To reconcile this problem, an Unknown Input Observer (UIO) is employed in this paper. To this end, first it is shown that the relative state information can be estimated using the UIO and the measured relative output information. Then a certainty-equivalence type output feedback consensus algorithm is proposed by combining the LMI-based state feedback consensus algorithm with the UIO. Finally, simulation results are given to illustrate that the proposed method successfully achieves the state consensus.
Nonlinear Controller for the Velocity Tracking and Rejection of Sinusoidal Disturbances in Permanent Magnet Stepper Motors
Kim, Won-Hee ; Gang, Dong-Gyu ; Han, Jonh-Pyo ; Chung, Chung-Choo ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 3, 2011, Pages 632~638
DOI : 10.5370/KIEE.2011.60.3.632
In this paper, a nonlinear controller is proposed to track the desired velocity and to cancel sinusoidal disturbances. The proposed method consists of a velocity tracking controller and internal model principles (IMPs). For the design of the velocity tracking controller, mechanical and electrical dynamic controllers are independently designed. For the mechanical dynamics, the velocity tracking controller generates the desired quadrature current to track the desired velocity. The current tracking controller is designed to guarantee the desired quadrature current and to regulate the direct current. Therefore, the proposed velocity tracking controller has a field-oriented control. Since the controllers of the mechanical and electrical dynamics are independently designed, the stability of the closed-loop system is demonstrated using passivity. Since both the cogging torque and DC current errors act as sinusoidal disturbances in PMSM, we use four add-on type IMPs that preserve the merits and performance of the pre-designed controller without sacrificing the closed-loop stability. The performance of the proposed method is validated via simulations.
Design of Data-centroid Radial Basis Function Neural Network with Extended Polynomial Type and Its Optimization
Oh, Sung-Kwun ; Kim, Young-Hoon ; Park, Ho-Sung ; Kim, Jeong-Tae ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 3, 2011, Pages 639~647
DOI : 10.5370/KIEE.2011.60.3.639
In this paper, we introduce a design methodology of data-centroid Radial Basis Function neural networks with extended polynomial function. The two underlying design mechanisms of such networks involve K-means clustering method and Particle Swarm Optimization(PSO). The proposed algorithm is based on K-means clustering method for efficient processing of data and the optimization of model was carried out using PSO. In this paper, as the connection weight of RBF neural networks, we are able to use four types of polynomials such as simplified, linear, quadratic, and modified quadratic. Using K-means clustering, the center values of Gaussian function as activation function are selected. And the PSO-based RBF neural networks results in a structurally optimized structure and comes with a higher level of flexibility than the one encountered in the conventional RBF neural networks. The PSO-based design procedure being applied at each node of RBF neural networks leads to the selection of preferred parameters with specific local characteristics (such as the number of input variables, a specific set of input variables, and the distribution constant value in activation function) available within the RBF neural networks. To evaluate the performance of the proposed data-centroid RBF neural network with extended polynomial function, the model is experimented with using the nonlinear process data(2-Dimensional synthetic data and Mackey-Glass time series process data) and the Machine Learning dataset(NOx emission process data in gas turbine plant, Automobile Miles per Gallon(MPG) data, and Boston housing data). For the characteristic analysis of the given entire dataset with non-linearity as well as the efficient construction and evaluation of the dynamic network model, the partition of the given entire dataset distinguishes between two cases of Division I(training dataset and testing dataset) and Division II(training dataset, validation dataset, and testing dataset). A comparative analysis shows that the proposed RBF neural networks produces model with higher accuracy as well as more superb predictive capability than other intelligent models presented previously.
Frequency Offset Estimation Technique for MB-OFDM Based UWB Systems
Hwang, Hu-Mor ; Rehman, Razi Ur ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 3, 2011, Pages 648~653
DOI : 10.5370/KIEE.2011.60.3.648
We propose a new frequency offset estimation technique for multiband orthogonal frequency modulation (MB-OFDM) based ultra wideband (UWB) systems. The proposed frequency offset estimation technique is related to the scheme of Schmidl for channel model 1 (4-1Om NLOS, rms. delay =14.3ns.) using more than two symbols and with alternate symbols. Variance of frequency offset estimate obtained from the proposed frequency offset estimation technique approaches very nearing to Cramer Rao Lower Bound (CRLB) in an AWGN channel. BER performance of the proposed technique is also presented.
Development of Electrocardiogram Identification Algorithm using SVM classifier
Lee, Sang-Joon ; Lee, Myoung-Ho ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 3, 2011, Pages 654~661
DOI : 10.5370/KIEE.2011.60.3.654
This paper is about a personal identification algorithm using an ECG that has been studied by a few researchers recently. Previously published algorithm can be classified as two methods. One is the method that analyzes of ECG features and the other is the morphological analysis of ECG. The main characteristic of proposed algorithm can be classified the method of analysis ECG features. Proposed algorithm adopts DSTW(Down Slope Trace Wave) for extracting ECG features, and applies SVM(Support Vector Machine) to training and testing as a classifier algorithm. We choose 18 ECG files from MIT-BIH Normal Sinus Rhythm Database for estimating of algorithm performance. The algorithm extracts 100 heartbeats from each ECG file, and use 40 heartbeats for training and 60 heartbeats for testing. The proposed algorithm shows clearly superior performance in all ECG data, amounting to 93.89% heartbeat recognition rate and 100% ECG recognition rate.
Design of Motor Block Resistor for KTX
Park, Keun-Seok ; Lee, Dae-Dong ; Kim, Young-Dal ; Jeong, Jong-An ; Shim, Jae-Myung ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 3, 2011, Pages 662~668
DOI : 10.5370/KIEE.2011.60.3.662
Domestic rail industry for the development of Korea High Speed Rail paid for high technology, imported to Korea. However, If technology based on conditions that are not equipped with relevant skills is received, there are limits to what it used to. so team of high speed railway began technical development. In this study, through the motor block resistant plan, the current block resistant identifies problems related to it, in order to improve the quality of the parts, secure the standards and guarantee their life span. The localization of the resistant is really possible thanks to the technical skills.
A Study in The Efficiency Improvement of Thermal Plasma Gas Processor Through Fluid Dynamics Analysis of Reaction Zone
SeoMun, Jun ; Chung, Jin-Do ; Koo, Kyung-Wan ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 3, 2011, Pages 669~673
DOI : 10.5370/KIEE.2011.60.3.669
This study explores the numerical analysis method of fluid dynamics in the reaction section to improve the gas processing efficiency in the hazardous gas removal by atmospheric thermal plasma. This study also intends to contribute in technology advance to improve the processing efficiency and make the process more stable. Numerical analysis of temperature distribution in the reaction section dependent on the change in flow velocity of Ar and plasma temperature change, which are major control variables in the cracking process of HFC-23 using arc plasma, was done. The characteristic of incoming oxygen by temperature suggested that when temperature increased to 1600K, 1700K, 1800K respectively, the range of cracking temperature 1500K increased to 75.0%, 83.3%, 90.2% respectively. The temperature change of Ar by velocity change was widest in the area higher than 1500K when the velocity was 2.5m/s; however, since there was no big difference when the velocity was 2m/s, it is believed that 2 m/s would be most proper.
A Study on the Electrical Fire Risk Assessment Methods of LED Lightings for Outdoor
Kim, Hyang-Kon ; Kim, Dong-Ook ; Choi, Hyo-Sang ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 3, 2011, Pages 674~679
DOI : 10.5370/KIEE.2011.60.3.674
In this paper, we experimented and analyzed about electric fire risk assessment methods of LED lightings for outdoor. LED lighting is composed of AC power lines, AC/DC converter, DC power lines and LED lamps. There are some risk factors of electric fire in LED lighting such as short circuit between power lines or power line and ground, dielectric breakdown, leakage current, abnormal voltage inflow, poor contacts(connections), etc. As a result of this study, insulation coverings of wire was ignited due to dielectric breakdown between power lines and molten marks were formed in copper conductor. LED lighting was blown out while short circuit, beside that, electrical disorder did not occur. When abnormal voltage was inflowed, electronic components such as varistor, condenser were damaged. Partial heating was produced and insulation was melted and carbonized by arc and heating while poor contacts were happened. We expect that the results of this study would be helpful for electrical safety of LED lightings for outdoor.
An Analysis on Rise of Rail Potential And A Study on Control Method for It in DC Feeding System
Min, Myung-Hwan ; Jung, Ho-Sung ; Park, Young ; Kim, Hyeng-Chul ; Shin, Myong-Chul ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 3, 2011, Pages 680~685
DOI : 10.5370/KIEE.2011.60.3.680
Nowadays, in metropolitan railroad, DC feeding system is being generally applied. In order to reduce damages of electro-chemical corrosion caused by stray current and leakage current, in DC feeding system, rail is used as negative-polarity return conductor for traction load current. However, it has problem of rail potential increase and there are no adequate measures to prevent it in domestic. In this paper, we presented fundamental theory and related standards about rail potential increase. And then, we analyzed field testing data and simulated a variety of operations by using PSCAD/EMTDC as an analysis program of power system. In addition, voltage control device is suggested to prevent accidents caused by rail potential increase.