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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of Electrical Engineering and Technology
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The Korean Institute of Electrical Engineers
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Volume & Issues
Volume 9, Issue 6 - Nov 2014
Volume 9, Issue 5 - Sep 2014
Volume 9, Issue 4 - Jul 2014
Volume 9, Issue 3 - May 2014
Volume 9, Issue 2 - Mar 2014
Volume 9, Issue 1 - Jan 2014
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Feeder Loop Line Control for the Voltage Stabilization of Distribution Network with Distributed Generators
Jeong, Bong-Sang ; Chun, Yeong-Han ;
Journal of Electrical Engineering and Technology, volume 9, issue 1, 2014, Pages 1~5
DOI : 10.5370/JEET.2014.9.1.001
When renewable sources are connected to the distribution network in the form of a distributed generators(DGs), the effect of intermittent output appears as voltage fluctuation. The surplus power at the consumer ends results in the reverse power flow to the distribution network. This reverse power flow causes several problems to the distribution network such as overvoltage. Application of the reactive power control equipment and power flow control by means of BTB inverter have been suggested as the general solutions to overcome the overvoltage, but they are not economically feasible since they require high cost devices. Herein, we suggest the feeder loop line switch control method to solve the problem.
A New Assessment for the Total Harmonic Contributions at the Point of Common Coupling
Han, Jong-Hoon ; Lee, Kyebyung ; Song, Chong Suk ; Jang, Gilsoo ; Byeon, Gilsung ; Park, Chang-Hyun ;
Journal of Electrical Engineering and Technology, volume 9, issue 1, 2014, Pages 6~14
DOI : 10.5370/JEET.2014.9.1.006
A new method to determine the total harmonic contributions of several customers and the utility at the point of common coupling is presented. The proposed method can quantify the individual harmonic impact of each suspicious harmonic source at the point of common coupling. The individual harmonic impact index is then used to assess the total harmonic contribution of each harmonic source. This index can be calculated by the results processed from instantaneous harmonic voltage and current phasor values. The results demonstrate the performance of the proposed method in terms of steady-state accuracy and response to time-varying operating conditions. The proposed index can be used for billing purposes to control harmonic distortion levels in power systems.
Modified Particle Swarm Optimization with Time Varying Acceleration Coefficients for Economic Load Dispatch with Generator Constraints
Abdullah, M.N. ; Bakar, A.H.A ; Rahim, N.A. ; Mokhlis, H. ; Illias, H.A. ; Jamian, J.J. ;
Journal of Electrical Engineering and Technology, volume 9, issue 1, 2014, Pages 15~26
DOI : 10.5370/JEET.2014.9.1.015
This paper proposes a Modified Particle Swarm Optimization with Time Varying Acceleration Coefficients (MPSO-TVAC) for solving economic load dispatch (ELD) problem. Due to prohibited operating zones (POZ) and ramp rate limits of the practical generators, the ELD problems become nonlinear and nonconvex optimization problem. Furthermore, the ELD problem may be more complicated if transmission losses are considered. Particle swarm optimization (PSO) is one of the famous heuristic methods for solving nonconvex problems. However, this method may suffer to trap at local minima especially for multimodal problem. To improve the solution quality and robustness of PSO algorithm, a new best neighbour particle called 'rbest' is proposed. The rbest provides extra information for each particle that is randomly selected from other best particles in order to diversify the movement of particle and avoid premature convergence. The effectiveness of MPSO-TVAC algorithm is tested on different power systems with POZ, ramp-rate limits and transmission loss constraints. To validate the performances of the proposed algorithm, comparative studies have been carried out in terms of convergence characteristic, solution quality, computation time and robustness. Simulation results found that the proposed MPSO-TVAC algorithm has good solution quality and more robust than other methods reported in previous work.
Damping of Inter-Area Low Frequency Oscillation Using an Adaptive Wide-Area Damping Controller
Yao, Wei ; Jiang, L. ; Fang, Jiakun ; Wen, Jinyu ; Wang, Shaorong ;
Journal of Electrical Engineering and Technology, volume 9, issue 1, 2014, Pages 27~36
DOI : 10.5370/JEET.2014.9.1.027
This paper presents an adaptive wide-area damping controller (WADC) based on generalized predictive control (GPC) and model identification for damping the inter-area low frequency oscillations in large-scale inter-connected power system. A recursive least-squares algorithm (RLSA) with a varying forgetting factor is applied to identify online the reduced-order linearlized model which contains dominant inter-area low frequency oscillations. Based on this linearlized model, the generalized predictive control scheme considering control output constraints is employed to obtain the optimal control signal in each sampling interval. Case studies are undertaken on a two-area four-machine power system and the New England 10-machine 39-bus power system, respectively. Simulation results show that the proposed adaptive WADC not only can damp the inter-area oscillations effectively under a wide range of operation conditions and different disturbances, but also has better robustness against to the time delay existing in the remote signals. The comparison studies with the conventional lead-lag WADC are also provided.
Robust Diagnosis Algorithm for Identifying Broken Rotor Bar Faults in Induction Motors
Hwang, Don-Ha ; Youn, Young-Woo ; Sun, Jong-Ho ; Kim, Yong-Hwa ;
Journal of Electrical Engineering and Technology, volume 9, issue 1, 2014, Pages 37~44
DOI : 10.5370/JEET.2014.9.1.037
This paper proposes a new diagnosis algorithm to detect broken rotor bars (BRBs) faults in induction motors. The proposed algorithm is composed of a frequency signal dimension order (FSDO) estimator and a fault decision module. The FSDO estimator finds a number of fault-related frequencies in the stator current signature. In the fault decision module, the fault diagnostic index from the FSDO estimator is used depending on the load conditions of the induction motors. Experimental results obtained in a 75 kW three-phase squirrel-cage induction motor show that the proposed diagnosis algorithm is capable of detecting BRB faults with an accuracy that is superior to a zoom multiple signal classification (ZMUSIC) and a zoom estimation of signal parameters via rotational invariance techniques (ZESPRIT).
Opposition Based Differential Evolution Algorithm for Capacitor Placement on Radial Distribution System
Muthukumar, R. ; Thanushkodi, K. ;
Journal of Electrical Engineering and Technology, volume 9, issue 1, 2014, Pages 45~51
DOI : 10.5370/JEET.2014.9.1.045
Distribution system is a critical link between customer and utility. The control of power loss is the main factor which decides the performance of the distribution system. There are two methods such as (i) distribution system reconfiguration and (ii) inclusion of capacitor banks, used for controlling the real power loss. Considering the improvement in voltage profile with the power loss reduction, later method produces better performance than former method. This paper presents an advanced evolutionary algorithm for capacitor inclusion for loss reduction. The conventional sensitivity analysis is used to find the optimal location for the capacitors. In order to achieve a better approximation for the current candidate solution, Opposition based Differential Evolution (ODE) is introduced. The effectiveness of the proposed technique is validated through 10, 33, 34 and85-bus radial distribution systems.
Development of AC/DC Hybrid Simulation for Operator Training Simulator in Railway System
Cho, Yoon-Sung ; Lee, Hansang ; Jang, Gilsoo ;
Journal of Electrical Engineering and Technology, volume 9, issue 1, 2014, Pages 52~59
DOI : 10.5370/JEET.2014.9.1.052
Operator training simulator, within a training environment designed to understand the principles and behavior of the railway system with respect to operator's entries and predefined scenario, can provide a very strong benefit in facilitating operators' handling undesired operations. This simulator consists of computer system and applications, and the purpose of applications is to generate the power and voltage and analyze the AC substation and DC railway, respectively. This paper describes a novel approach to the new techniques for AC/DC hybrid simulation for the operator training simulator in the railway system. We first propose the structure the database of railway system. Then, topology processing and power flow using a linked-list method based on the proposed database, full or decoupled newton-rapshon methods are presented. Finally, the interface between the analysis for AC substation using a newton-rapshon method and the analysis for DC railway system using a time-interval power flow method is described. We have verified and tested the developed algorithm through the extensive testing for the proposed test system. To demonstrate the validity of the developed algorithm, comparative simulations between the proposed algorithm and PSS/E for the test system were conducted.
Effects of Wind Generation Uncertainty and Volatility on Power System Small Signal Stability
Shi, Li-Bao ; Kang, Li ; Yao, Liang-Zhong ; Qin, Shi-Yao ; Wang, Rui-Ming ; Zhang, Jin-Ping ;
Journal of Electrical Engineering and Technology, volume 9, issue 1, 2014, Pages 60~70
DOI : 10.5370/JEET.2014.9.1.060
This paper discusses the impacts of large scale grid-connected wind farm equipped with permanent magnet synchronous generator (PMSG) on power system small signal stability (SSS) incorporating wind generation uncertainty and volatility. Firstly, a practical simplified PMSG model with rotor-flux-oriented control strategy applied is derived. In modeling PMSG generator side converter, the generator-voltage-oriented control strategy is utilized to implement the decoupled control of active and reactive power output. In modeling PMSG grid side converter, the grid-voltage-oriented control strategy is applied to realize the control of DC link voltage and the reactive power regulation. Based on the Weibull distribution of wind speed, the Monte Carlo simulation technique based is carried out on the IEEE 16-generator-68-bus test system as benchmark to study the impacts of wind generation uncertainty and volatility on small signal stability. Finally, some preliminary conclusions and comments are given.
Determination of Secondary Reserve Requirement Through Interaction-dependent Clearance Between Ex-ante and Ex-post
Kim, Sun Kyo ; Park, Joon-Hyung ; Yoon, Yong Tae ;
Journal of Electrical Engineering and Technology, volume 9, issue 1, 2014, Pages 71~79
DOI : 10.5370/JEET.2014.9.1.071
This paper discusses a method for the determination of frequency control reserve requirement with consideration of the interaction between ex-ante planning and real-time balancing. In proposed method, we consider the fact that the delivered energy for tertiary control reserve is determined based on required capacity for secondary control reserve and the expected amount of load errors. Uncertain load errors are derived by Brownian motion, an optimization method is suggested using a stochastic programming. In a short, we propose an interactive dependent method for determining secondary control reserve requirement based on the principle that it satisfies to minimize the total cost. As a result, this paper provides will analyze for an example model to demonstrate the capabilities of the method.
A New Solution for Stochastic Optimal Power Flow: Combining Limit Relaxation with Iterative Learning Control
Gong, Jinxia ; Xie, Da ; Jiang, Chuanwen ; Zhang, Yanchi ;
Journal of Electrical Engineering and Technology, volume 9, issue 1, 2014, Pages 80~89
DOI : 10.5370/JEET.2014.9.1.080
A stochastic optimal power flow (S-OPF) model considering uncertainties of load and wind power is developed based on chance constrained programming (CCP). The difficulties in solving the model are the nonlinearity and probabilistic constraints. In this paper, a limit relaxation approach and an iterative learning control (ILC) method are implemented to solve the S-OPF model indirectly. The limit relaxation approach narrows the solution space by introducing regulatory factors, according to the relationship between the constraint equations and the optimization variables. The regulatory factors are designed by ILC method to ensure the optimality of final solution under a predefined confidence level. The optimization algorithm for S-OPF is completed based on the combination of limit relaxation and ILC and tested on the IEEE 14-bus system.
Strategy Equilibrium in Stackelberg Model with Transmission Congestion in Electricity Market
Lee, Kwang-Ho ;
Journal of Electrical Engineering and Technology, volume 9, issue 1, 2014, Pages 90~97
DOI : 10.5370/JEET.2014.9.1.090
Nash Cournot Equilibrium (NCE) has been widely used in a competitive electricity market to analyze generation firms' strategic production quantities. Congestion on a transmission network may lead to a mixed strategy NCE. Mixed strategy is complicated to understand, difficult to compute, and hard to implement in practical market. However, Stackelberg model based equilibrium does not have any mixed strategy, even under congestion in a transmission line. A guide to understanding mixed strategy equilibrium is given by analyzing a cycling phenomenon in the players' best choices. This paper connects the concept of leader-follower in Stackelberg model with relations between generation firms on both sides of the congested line. From the viewpoint of social welfare, the surplus analysis is presented for comparison between the NCE and the Stackelberg equilibrium (SE).
Modeling of Battery for EV using EMTP/ATPDraw
Kim, Jun-Hyeok ; Lee, Soon-Jeong ; Kim, Eung-Sang ; Kim, Seul-Ki ; Kim, Chul-Hwan ; Prikler, Laszlo ;
Journal of Electrical Engineering and Technology, volume 9, issue 1, 2014, Pages 98~105
DOI : 10.5370/JEET.2014.9.1.098
As environmentally friendly energy takes center stage, interests for Electric Vehicles/Plug in Hybrid Electric Vehicles (EVs/PHEVs) are getting increase. With this trend, there is no doubt EVs will take large portion to penetrations of total cars. Therefore, accurate EV modeling is required. Battery is one of the main components with the power system view of aspect. Hence, in this paper, reviews and discussions of some types of batteries for EV are contained by considering energy density and weight of the batteries. In addition, simulations of Li-Ion battery are accomplished with various variables such as temperature, capacity fading and charge/discharge current. It is confirmed that temperature is the main factor of capacity fading. Validation of the modeled battery is also conducted by comparing it with commercialized battery.
Influence of Thermal Expansion on Eccentricity and Critical Speed in Dry Submersible Induction Motors
Lv, Qiang ; Bao, Xiaohua ; He, Yigang ;
Journal of Electrical Engineering and Technology, volume 9, issue 1, 2014, Pages 106~113
DOI : 10.5370/JEET.2014.9.1.106
Rotor eccentricity is one of the major factors that directly influence the security of horizontal electrical machines, and the critical speed of the shaft has a close relationship with vibration. This paper deals with the influence of thermal expansion on the rotor eccentricity and critical speed in large dry submersible motors. The dynamic eccentricity (where the rotor is still turning around the stator bore centre but not its own centre) and critical speed of a three-phase squirrel-cage submersible induction motor are calculated via hybrid analytical/finite element method. Then the influence of thermal expansion is investigated by simulation. It is predicted from the study that the thermal expansion of the rotor and stator gives rise to a significant air-gap length decrement and an inconspicuous slower critical speed. The results show that the thermal expansion should be considered as an impact factor when designing the air gap length.
Multi-physics Analysis for Temperature Rise Prediction of Power Transformer
Ahn, Hyun-Mo ; Kim, Joong-Kyoung ; Oh, Yeon-Ho ; Song, Ki-Dong ; Hahn, Sung-Chin ;
Journal of Electrical Engineering and Technology, volume 9, issue 1, 2014, Pages 114~120
DOI : 10.5370/JEET.2014.9.1.114
In this paper, a method for multi-physics analysis of the temperature-dependent properties of an oil-immersed transformer is discussed. To couple thermal fields with electromagnetic and fluid fields, an algorithm employing a user defined function (UDF) is proposed. Using electromagnetic analysis, electric power loss dependent on temperature rise is calculated; these are used as input data for multi-physics analysis in order to predict the temperature rise. A heat transfer coefficient is applied only at the outermost boundary between transformer and the atmosphere in order to reduce the analysis region. To verify the validity of the proposed method, the predicted temperature rises in high-voltage (HV) and low-voltage (LV) windings and radiators were compared with the experimental values.
The Study of the Stray Load Loss and Mechanical Loss of Three Phase Induction Motor considering Experimental Results
Kim, Dong-Jun ; Choi, Jae-Hak ; Chun, Yon-Do ; Koo, Dae-Hyun ; Han, Pil-Wan ;
Journal of Electrical Engineering and Technology, volume 9, issue 1, 2014, Pages 121~126
DOI : 10.5370/JEET.2014.9.1.121
The accurate determination of induction motor efficiency depends on the estimation of the five losses of stator and rotor copper loss, iron loss, mechanical loss and stray load loss. As the mechanical and stray load losses are not calculated by electro-magnetic analysis, the values of these two losses are very important in induction motor design. In this paper, the values of mechanical loss and stray load loss are proposed through investigating testing data from commercial products of three phase induction motors under 37kW. If the values of this paper are applied to motor design, the accuracy of design and analysis can be improved. The losses of motors are obtained by using load and no-load test results following IEC 60034-2-1 standard.
Advanced Cascade Multilevel Converter with Reduction in Number of Components
Ajami, Ali ; Oskuee, Mohammad Reza Jannati ; Mokhberdoran, Ataollah ; Khosroshahi, Mahdi Toupchi ;
Journal of Electrical Engineering and Technology, volume 9, issue 1, 2014, Pages 127~135
DOI : 10.5370/JEET.2014.9.1.127
In this paper a novel converter structure based on cascade converter family is presented. The suggested multilevel advanced cascade converter has benefits such as reduction in number of switches and power losses. Comparison depict that proposed topology has the least number of IGBTs among all multilevel cascade type converters which have been introduced recently. This characteristic causes low cost and small installation area for suggested converter. The number of on state switches in current path is less than conventional topologies and so the output voltage drop and power losses are decreased. Symmetric and asymmetric modes are analyzed and compared with conventional multilevel cascade converter. Simulation and experimental results are presented to illustrate validity, good performance and effectiveness of the proposed configuration. The suggested converter can be applied in medium/high voltage and PV applications.
Sensitivity Analysis of Geometrical Parameters of a Switched Reluctance Motor with Modified Pole Shapes
Balaji, M. ; Ramkumar, S. ; Kamaraj, V. ;
Journal of Electrical Engineering and Technology, volume 9, issue 1, 2014, Pages 136~142
DOI : 10.5370/JEET.2014.9.1.136
A major problem in Switched Reluctance Motor (SRM) is torque ripple, which causes undesirable acoustic noise and vibration. This work focuses on reducing the undesirable torque ripple in SRM by modifying stator and rotor geometry. This paper presents a comparative study on torque ripple minimization in SRM with modified pole shapes such as stator pole taper, stator pole face with non-uniform air gap and pole shoe attached to rotor pole. Further this paper presents a detailed sensitivity analysis of the effect of different geometrical parameters that alter the pole face shapes on the performance of SRM. The analysis is performed using finite-element method considering average torque and torque ripple as performance parameters. Based on the analysis, a design combining stator pole taper with non-uniform air gap is proposed to improve the torque characteristics of SRM. The dynamic characteristics of the proposed design are simulated and the results show satisfactory reduction in torque ripple.
Design and Implementation of Enhanced Resonant Converter for EV Fast Charger
Ahn, Suk-Ho ; Gong, Ji-Woong ; Jang, Sung-Roc ; Ryoo, Hong-Je ; Kim, Duk-Heon ;
Journal of Electrical Engineering and Technology, volume 9, issue 1, 2014, Pages 143~153
DOI : 10.5370/JEET.2014.9.1.143
This paper presents a novel application of LCC resonant converter for 60kW EV fast charger and describes development of the high efficiency 60kW EV fast charger. The proposed converter has the advantage of improving the system efficiency especially at the rated load condition because it can reduce the conduction loss by improving the resonance current shape as well as the switching loss by increasing lossless snubber capacitance. Additionally, the simple gate driver circuit suitable for proposed topology is designed. Distinctive features of the proposed converter were analyzed depending on the operation modes and detail design procedure of the 10kW EV fast charger converter module using proposed converter topology were described. The proposed converter and the gate driver were identified through PSpice simulation. The 60kW EV fast charger which generates output voltage ranges from 50V to 500V and maximum 150A of output currents using six parallel operated 10kW converter modules were designed and implemented. Using 60kW fast charger, the charging experiments for three types of high-capacity batteries were performed which have a different charging voltage and current. From the simulation and experimental results, it is verified that the proposed converter topology can be effectively used as main converter topology for EV fast charger.
Transformer Winding Modeling based on Multi-Conductor Transmission Line Model for Partial Discharge Study
Hosseini, Seyed Mohammad Hassan ; Baravati, Peyman Rezaei ;
Journal of Electrical Engineering and Technology, volume 9, issue 1, 2014, Pages 154~161
DOI : 10.5370/JEET.2014.9.1.154
To study and locate partial discharge(PD) and analyze the transient state of power transformer, there is a need for a high frequency model of transformer winding and calculation of its parameters. Due to the high frequency nature of partial discharge phenomenon, there is a need for an accurate model for this frequency range. To attain this goal, a Multi-Conductor Transmission Line (MTL) model is used in this paper for modeling this transformer winding. In order that the MTL model can properly simulate the transformer behavior within a frequency range it is required that its parameters be accurately calculated. In this paper, all the basic parameters of this model are calculated by the use of Finite Element Method (FEM) for a 20kV winding of a distribution transformer. The comparison of the results obtained from this model with the obtained shape of the waves by the application of PD pulse to the winding in laboratory environment shows the validity and accuracy of this model.
Analysis of Half-coiled Short-pitch Windings with Different Phase Belt for Multiphase Bearingless Motor
Li, Bingnan ; Huang, Jin ; Kong, Wubin ; Zhao, Lihang ;
Journal of Electrical Engineering and Technology, volume 9, issue 1, 2014, Pages 162~169
DOI : 10.5370/JEET.2014.9.1.162
The analysis and comparation of the half-coiled short-pitch windings with different phase belt are presented in the paper. The half-coiled short-pitch windings can supply the odd and even harmonics simultaneously, which can be applied in multiphase bearingless motor (MBLM). The space harmonic distribution of the half-coiled short-pitch windings with two kinds of phase belt is studied wi th respect to different coil pitch, and the suitable coil pitch can be selected from the analysis results to reduce the additional radial force and torque pulse. The two kinds of half-coiled short-pitch windings are applied to the five- and six-phase bearingless motor, and the comparation from the Finite Element Method (FEM) results shows that the winding with
phase belt is fit for the five phase bearingless motor and the winding with
phase belt is suitable for the six phase bearingless motor. Finally, a five phase surface-mounted permanent magnet (PM) bearingless motor is built and the experimental results are presented to verify the validity and feasibility of the analysis. The results presented in this paper will give useful guidelines for design optimization of the MBLM.
Classification of Induction Machine Faults using Time Frequency Representation and Particle Swarm Optimization
Medoued, A. ; Lebaroud, A. ; Laifa, A. ; Sayad, D. ;
Journal of Electrical Engineering and Technology, volume 9, issue 1, 2014, Pages 170~177
DOI : 10.5370/JEET.2014.9.1.170
This paper presents a new method of classification of the induction machine faults using Time Frequency Representation, Particle Swarm Optimization and artificial neural network. The essence of the feature extraction is to project from faulty machine to a low size signal time-frequency representation (TFR), which is deliberately designed for maximizing the separability between classes, a distinct TFR is designed for each class. The feature vectors size is optimized using Particle Swarm Optimization method (PSO). The classifier is designed using an artificial neural network. This method allows an accurate classification independently of load level. The introduction of the PSO in the classification procedure has given good results using the reduced size of the feature vectors obtained by the optimization process. These results are validated on a 5.5-kW induction motor test bench.
Characteristics Analysis of Single Phase Induction Motor via Equivalent Circuit Method and Considering Saturation Factor
Cho, Su-Yeon ; Kim, Won-Ho ; Jin, Chang-Sung ; Kang, Dong-Woo ; Lee, Ju ;
Journal of Electrical Engineering and Technology, volume 9, issue 1, 2014, Pages 178~183
DOI : 10.5370/JEET.2014.9.1.178
This paper presents a motor characteristics analysis method using an equivalent circuit. Motor characteristics analysis via equivalent circuit is very important for designing a high efficiency single phase induction motor. The accuracy of the motor characteristics depends on the accuracy of the parameters, especially saturation factor, which determines the cyclical relationship in the analysis process. Therefore, using the proposed method, the saturation factor was calculated using the iteration routine and numerical technique. The proposed method was verified by comparing the finite element method results and the dynamo test results of manufactured prototype model.
Multi-Objective Optimal Design of a NEMA Design D Three-phase Induction Machine Utilizing Gaussian-MOPSO Algorithm
Zhang, Dianhai ; Ren, Ziyan ; Koh, Chang-Seop ;
Journal of Electrical Engineering and Technology, volume 9, issue 1, 2014, Pages 184~189
DOI : 10.5370/JEET.2014.9.1.184
This paper presents a multi-objective optimization approach to design rotor slot geometry of three-phase squirrel cage induction machine to achieve NEMA design D torque-speed (T-S) characteristics with high efficiency. The multi-objective Particle Swarm Optimization (MOPSO) algorithm combined with the adaptive response surface method and Latin hypercube sampling strategy is applied to obtain the Pareto optimal designs. In order to demonstrate the validity of the suggested optimal algorithm, an application to rotor slot design of three-phase induction motor is presented.
Comparison of ECT Probes in Diagnosis of Defects
Mun, Ho-Young ; Kim, Chang-Eob ;
Journal of Electrical Engineering and Technology, volume 9, issue 1, 2014, Pages 190~196
DOI : 10.5370/JEET.2014.9.1.190
In this paper, the characteristics of a defective elliptical aluminum plate are analyzed by three different eddy current testing probes; T/R, T/T, and Impedance probes. The analysis was done by 3D finite element method, and the impedance change of real and imaginary voltage values were analyzed.
Analysis, Design and Implementation of an Improved ZVZCS-PWM Forward converter
Soltanzadeh, Karim ; Dehghani, Majid ; Khalilian, Hosein ;
Journal of Electrical Engineering and Technology, volume 9, issue 1, 2014, Pages 197~204
DOI : 10.5370/JEET.2014.9.1.197
In this paper an Improved Zero Voltage Zero Current Pulse Width Modulation Forward converter which employs a simple resonance snubber circuit is introduced. A simple snubber circuit consists of a capacitor, an inductor and two diodes. In proposed converter, switch Q1 operates at ZCS turn-on, and ZVS turn-off conditions and all-passive semiconductor devices operate at ZVZCS turn-on and turn-off state. The proposed converter is analyzed and various operating modes of the ZVZCS-PWM forward converter are discussed. Analysis and design considerations are presented and the prototype experimental results of a 100w (40 V/2.5A) proposed converter operating at 30 KHz switching frequency confirm the validity of theoretical analysis.
High Performance MPPT Based on Variable Speed Generator Driven by Wind Power Generation in Battery Applications
Padmanabhan, Sutha ; Kaliyappan, Kannan ;
Journal of Electrical Engineering and Technology, volume 9, issue 1, 2014, Pages 205~213
DOI : 10.5370/JEET.2014.9.1.205
A wind generator (WG) maximum power point tracking (MPPT) system is presented here. It comprises of a variable-speed wind generator, a high-efficiency boost-type dc/dc converter and a control unit. The advantages of the aimed system are that it does not call for the knowledge of the wind speed or the optimal power characteristics and that it operates at a variable speed, thus providing high efficiency. The WG operates at variable speed and thus suffers lower stress on the shafts and gears compared to constant-speed systems. It results in a better exploitation of the available wind energy, especially in the low wind-speed range of 2.5-4.5 m/s. It does not depend on the WG wind and rotor-speed ratings or the dc/dc converter power rating. Higher reliability, lower complexity and cost, and less mechanical stress of the WG. It can be applied to battery-charging applications.
A New Multimachine Robust Based Anti-skid Control System for High Performance Electric Vehicle
Hartani, Kada ; Draou, Azeddine ;
Journal of Electrical Engineering and Technology, volume 9, issue 1, 2014, Pages 214~230
DOI : 10.5370/JEET.2014.9.1.214
This paper presents a high performance sensor less control four motorized wheels for electric vehicle. Firstly, we applied a sensor less master-slave DTC based control to both the two in wheel motors by using sliding mode observer for its quick response and its high reliability in electric vehicle application. Secondly, to overcome the possible loss of adherence of one of the four wheels which is likely to destabilize the vehicle a solution is proposed in this paper. Thirdly, a Fuzzy logic anti-skid control structure well adapted to the non-linear system is used to overcome the main problem of power train system in the wheel road adhesion characteristic. Various Simulation results have been include in this paper to show that the proposed control strategy can prevent vehicle sliding and show good vehicle stability on a curved path.
Study on Optimal Condition of Adaptive Maximum Torque Per Amp Controlled Induction Motor Drives
Kwon, Chun-Ki ;
Journal of Electrical Engineering and Technology, volume 9, issue 1, 2014, Pages 231~238
DOI : 10.5370/JEET.2014.9.1.231
Adaptive Maximum Torque Per Amp (Adaptive MTPA) control for induction motor drives seeks to achieve a desired torque with the minimum possible stator current regardless of operating points. This is favorable in terms of inverter operation and nearly optimal in terms of motor efficiency. However, the Adaptive MTPA control was validated only from the viewpoint of tracking a desired torque and was not shown that the desired torque is achieved with minimum possible stator current. This work experimentally demonstrates that optimal condition for Adaptive Maximum Torque Per Amp Control Strategy is achieved regardless of rotor resistance variation.
Demonstration of a Modular Electrostatic Precipitator to Control Particulate Emissions from a Small Municipal Waste Incinerator
Intra, Panich ; Yawootti, Artit ; Tippayawong, Nakorn ;
Journal of Electrical Engineering and Technology, volume 9, issue 1, 2014, Pages 239~246
DOI : 10.5370/JEET.2014.9.1.239
Incineration is conceptually sound as a waste treatment technology. There is, however, concern over its emissions when it is improperly designed and operated. An electrostatic precipitator is one of the most commonly used devices to control particulate emissions from boilers, incinerators and some other industrial processes. In this work, a modular electrostatic precipitator with sizing of
was developed for removal of particulate matter from the exhaust gases of a small waste incinerator. Its design was based on a simple wire-and-plate concept. The corona discharge wires were connected to a positive high-voltage pulse generator, while the collection plates were grounded. The high-voltage pulse generator was used to produce the corona discharge field between the individual discharge wire and the collection plate. The particulate-laden exhaust gas flow was directed across the corona discharge field. The charged particles were deflected outward and collected on the plate. The collection efficiency was evaluated as a mass loading ratio between the difference at the inlet and the outlet to the particulate loading at the inlet of the precipitator. The collection efficiency of this modular electrostatic precipitator design was approximately 80 %.
An Analytical Modeling and Simulation of Dual Material Double Gate Tunnel Field Effect Transistor for Low Power Applications
Arun Samuel, T.S. ; Balamurugan, N.B. ;
Journal of Electrical Engineering and Technology, volume 9, issue 1, 2014, Pages 247~253
DOI : 10.5370/JEET.2014.9.1.247
In this paper, a new two dimensional (2D) analytical modeling and simulation for a Dual Material Double Gate tunnel field effect transistor (DMDG TFET) is proposed. The Parabolic approximation technique is used to solve the 2-D Poisson equation with suitable boundary conditions and analytical expressions for surface potential and electric field are derived. This electric field distribution is further used to calculate the tunnelling generation rate and thus we numerically extract the tunnelling current. The results show a significant improvement in on-current characteristics while short channel effects are greatly reduced. Effectiveness of the proposed model has been confirmed by comparing the analytical results with the TCAD simulation results.
Analysis of SLF Interruption Performance of Self-Blast Circuit Breaker by Means of CFD Calculation
Kim, Hong-Kyu ; Chong, Jin-Kyo ; Lee, Se-Hee ;
Journal of Electrical Engineering and Technology, volume 9, issue 1, 2014, Pages 254~258
DOI : 10.5370/JEET.2014.9.1.254
This paper presents the performance analysis results of a short line fault interruption of a gas circuit breaker, particularly a self-blast type breaker. Hot gas flow analysis was carried out using a CFD calculation combined with the arc model and nozzle ablation model. To evaluate the interruption performance, the index function was defined using the pressure in the heating chamber and the density above the arc region. The simulation and test results showed that the gas flow field and suitable choice of an interruption performance index can be used to predict the interruption characteristics and provide guidelines for designing self-blast breakers with a higher interruption capability.
A New Reliable Algorithm for Identifying Types of Partial Discharge Detected through Ultrasonic Emission
Hapeez, Mohammad Shukri ; Hamzah, Ngah Ramzi ; Hashim, Habibah ; Abidin, Ahmad Farid ;
Journal of Electrical Engineering and Technology, volume 9, issue 1, 2014, Pages 259~267
DOI : 10.5370/JEET.2014.9.1.259
This paper presents a simple, consistent and reliable technique to identify detected partial discharges (PD) using an acoustic ultrasonic method. A new reliable algorithm named 'Simple Partial Discharge Identifier' (SPDI) is proposed to perform identification process of the detected ultrasonic signals of PD. Experimental works based on recommended practices were setup and the ultrasonic signals of the PD were recorded. The PD data is then employed as the reference data. The SPDI developed has been tested against commonly used models in Neural Network (NN). Results from the SPDI algorithm shows more reliable results compared to NN models results. Comparison made on the mean square error (MSE) results shows SPDI produces the desired outcome with lower MSE in 97.17% of trials. Low error of SPDI indicates a high reliability to be applied in the identification of PD.
Simple Technique for Measurement of Complex Permittivity and Detection of Small Permittivity Change Using Partially Open Cavity
Park, Sangbok ; Chung, Young-Seek ; Cheon, Changyul ;
Journal of Electrical Engineering and Technology, volume 9, issue 1, 2014, Pages 268~272
DOI : 10.5370/JEET.2014.9.1.268
This letter presents a measurement methodology of the complex permittivity of liquid using a partially open cavity in narrow band. The partially open cavity (POC) can measure dielectric small changes caused by the temperature variation of the liquid inside the cavity as well. Using the resonance frequency and unloaded quality factor of the proposed POC, the complex permittivity is evaluated. The apertures on the walls of the cavity are designed to circulate the liquid inside to outside of the POC and located at the corner area of the cavity to minimize the disturbance of field distribution at the dominant mode. The results measured by the proposed POC were compared with those by the conventional open-ended probe and Cole-Cole equation. The POC showed better performance in measuring small dielectric constant changes than the open-ended probe.
Effects of Magneto-Dielectric Ceramics for Small Antenna Application
Kim, Jae-Sik ; Lee, Young-Hie ; Lee, Byungje ; Lee, Jong-Chul ; Choi, Jin Joo ; Kim, Jin Young ;
Journal of Electrical Engineering and Technology, volume 9, issue 1, 2014, Pages 273~279
DOI : 10.5370/JEET.2014.9.1.273
Hexagonal Ba-ferrites are widely suggested as materials for small antennas. In this paper, the sintering behavior and magneto-electric properties of
) ceramics were investigated for small antenna application. All samples of
ceramics were prepared by the solid-state reaction method and sintered at
. From the XRD patterns of the sintered
ceramics, the Z-type phases were found to be the main phases. The real part of permittivity and permeability of the
ceramics decreased with frequency. On the other hand, loss tangents of permittivity and permeability tended to behave opposite to real part of permittivity and permeability. The real part of permeability was affected by Mn additions. The real part of permittivity, the loss tangent of permittivity and the real part of permeability, the loss tangent of permeability of
ceramics were 19.774, 0.176 and 15.183, 0.073, respectively, at 510 MHz. In order to investigate the effect of magneto-dielectric ceramics on antenna, PIFA (Planar Inverted F Antenna) was simulated with CST (Computer Simulation Technology). The operating frequency of antenna was decreased without considerable change of bandwidth by using the
ceramics as the carrier.
Characteristics of Insulation Diagnosis and Failure in Gas Turbine Generator Stator Windings
Kim, Hee-Dong ;
Journal of Electrical Engineering and Technology, volume 9, issue 1, 2014, Pages 280~285
DOI : 10.5370/JEET.2014.9.1.280
In order to evaluate the insulation deterioration in the stator windings of five gas turbine generators(137 MVA, 13.8 kV) which has been operated for more than 13 years, diagnostic test and AC dielectric breakdown test were performed at phases A, B and C. These tests included measurements of AC current, dissipation factor, partial discharge (PD) magnitude and capacitance.
in all three phases (A, B and C) of No. 1 generator stator windings showed that they were in good condition but PD magnitude indicated marginally serviceable and bad level to the insulation condition. Overall analysis of the results suggested that the generator stator windings were indicated serious insulation deterioration and patterns of the PD in all three phases were analyzed to be internal, slot and spark discharges. After the diagnostic test, an AC overvoltage test was performed by gradually increasing the voltage applied to the generator stator windings until electrical insulation failure occurred, in order to determine the breakdown voltage. The breakdown voltage at phases A, B and C of No. 1 generator stator windings failed at 28.0 kV, 17.9 kV, and 21.3 kV, respectively. The breakdown voltage was lower than that expected for good-quality windings (28.6 kV) in a 13.8kV class generator. In the AC dielectric breakdown and diagnostic tests, there was a strong correlation between the breakdown voltage and the voltage at which charging current increases abruptly (
Parameters Optimization of Impulse Generator Circuit for Generating First Short Stroke Lightning Current Waveform
Eom, Ju-Hong ; Cho, Sung-Chul ; Lee, Tae-Hyung ;
Journal of Electrical Engineering and Technology, volume 9, issue 1, 2014, Pages 286~292
DOI : 10.5370/JEET.2014.9.1.286
This paper presents the parameters optimization technology for generating the first short stroke lightning current waveform(
) which is necessary for the performance tests of components of lightning protection systems, as required under IEC 62305 and the newly amended IEC 62561. The circuit using the crowbar device specified in IEC 62305 was applied to generate the lightning current waveform. To find the proper parameters of the circuit is not easy because the circuit consists of two parts; circuit I, which relates to the front of current waveform, and circuit II, which relates to the tail. A simulation in PSpise was carried out to find main factors related to the front and tail of
. The lightning current generator was developed by utilizing the circuit parameters found in the simulation. In the result of experiments, new parameters of the circuits need to be changed because of the difference between the simulation and the experiment results. Using the iterative method, the optimized parameters of the circuits was determined. Also a multistage-type external coil and a damping resistor were proposed to make the efficiency of generation to enhance. According to the result in this paper, an optimized first short stroke lightning current waveform was obtained.
Partial Discharge Pattern Recognition of Cast Resin Current Transformers Using Radial Basis Function Neural Network
Chang, Wen-Yeau ;
Journal of Electrical Engineering and Technology, volume 9, issue 1, 2014, Pages 293~300
DOI : 10.5370/JEET.2014.9.1.293
This paper proposes a novel pattern recognition approach based on the radial basis function (RBF) neural network for identifying insulation defects of high-voltage electrical apparatus arising from partial discharge (PD). Pattern recognition of PD is used for identifying defects causing the PD, such as internal discharge, external discharge, corona, etc. This information is vital for estimating the harmfulness of the discharge in the insulation. Since an insulation defect, such as one resulting from PD, would have a corresponding particular pattern, pattern recognition of PD is significant means to discriminate insulation conditions of high-voltage electrical apparatus. To verify the proposed approach, experiments were conducted to demonstrate the field-test PD pattern recognition of cast resin current transformer (CRCT) models. These tests used artificial defects created in order to produce the common PD activities of CRCTs by using feature vectors of field-test PD patterns. The significant features are extracted by using nonlinear principal component analysis (NLPCA) method. The experimental data are found to be in close agreement with the recognized data. The test results show that the proposed approach is efficient and reliable.
Metamaterial CRLH Structure-based Balun for Common-Mode Current Indicator
Kahng, Sungtek ; Lee, Jinil ; Kim, Koon-Tae ; Kim, Hyeong-Seok ;
Journal of Electrical Engineering and Technology, volume 9, issue 1, 2014, Pages 301~306
DOI : 10.5370/JEET.2014.9.1.301
We proposed a new PCB-type 'common-mode current(
) and differential-mode current(
) detector' working for fast detection of
from the differential-mode signaling, with miniaturization effect and possibility of cheaper fabrication. In order to realize this device, we suggest a branch-line-coupler balun having a composite right- and left-handed(CRLH) one-layer microstrip phase-shifting line as compact as roughly
. The presented balun obviously is different from the conventional bent-&-folded delay lines or slits on the ground for coupling the lines on the top and bottom dielectrics. As we connect the suggested balun output ports of the differential-mode signal lines via the through-port named U and coupled-port named L,
will appear at port
of the present device, in order. The validity of the design scheme is verified by the circuit-and numerical electromagnetic analyses, and the dispersion curve proving the metamaterial characteristics of the geometry. Besides, the examples of the
indicator are observed as the even and odd modes in differential-mode signal feeding. Also, the proposed device is shown to be very compact, compared with the conventional structure.
FE Analysis of Plasma Discharge and Sheath Characterization in Dry Etching Reactor
Yu, Gwang Jun ; Kim, Young Sun ; Lee, Dong Yoon ; Park, Jae Jun ; Lee, Se Hee ; Park, Il Han ;
Journal of Electrical Engineering and Technology, volume 9, issue 1, 2014, Pages 307~312
DOI : 10.5370/JEET.2014.9.1.307
We present a full finite element analysis for plasma discharge in etching process of semiconductor circuit. The charge transport equations of hydrodynamic diffusion-drift model and the electric field equation were numerically solved in a fully coupled system by using a standard finite element procedure for transient analysis. The proposed method was applied to a real plasma reactor in order to characterize the plasma sheath that is closely related to the yield of the etching process. Throughout the plasma discharge analysis, the base electrode of reactor was tested and modified for improving the uniformity around the wafer edge. The experiment and numerical results were examined along with SEM data of etching quality. The feasibility and usefulness of the proposed method was shown by both numerical and experimental results.
Sensor Fault Detection and Isolation of Uncertain Time-Delay Systems
Jee, Sung Chul ; Lee, Ho Jae ; Kim, Do Wan ;
Journal of Electrical Engineering and Technology, volume 9, issue 1, 2014, Pages 313~323
DOI : 10.5370/JEET.2014.9.1.313
Sensor fault detection and isolation problems subject to H_/
, performance are concerned for linear time-invariant systems with time delay in a state and parametric uncertainties. To that end, a model-based observer bank approach is pursued. The design conditions for both continuous- and discrete-time cases are formulated in terms of matrix inequalities, which are then converted to the problems solvable via an algorithm involving convex optimization.
Physiological Status Assessment of Locomotive Engineer During Train Operation
Song, Yong-Soo ; Baek, Jong-Hyen ; Hwang, Do-Sik ; Lee, Jeong-Whan ; Lee, Young-Jae ; Park, Hee-Jung ; Choi, Ju-Hyeon ; Yang, Heui-Kyung ;
Journal of Electrical Engineering and Technology, volume 9, issue 1, 2014, Pages 324~333
DOI : 10.5370/JEET.2014.9.1.324
In this study, physiological status of locomotive engineers were measured through EEG, ECG, EDA, PPG and respiration signals from 6 subjects to evaluate their arousal status during train operating. Existence of tunnels and mechanical vibration of train using 3-axes acceleration sensors were recorded simultaneously and were correlated with operator's physiological status. As the result of the analyzed subjects' physiological signals, mean SCR was increased in the section where more body movement is required. The RR interval was decreased before and after train stop due to the higher level of mental tension. The intensity of beta wave of EEG was found to be higher before and after train stop and tunnel section due to the increased mental arousal and tension. Therefore, it is expected that the outcomes of the physiological signals explored in this study can be utilized as the quantitative assessment methods for the arousal status to be used for sleepiness prevention system for vehicles operators which can greatly contribute to public transportation system safety.
Improvement of Dynamic Respiration Monitoring Through Sensor Fusion of Accelerometer and Gyro-sensor
Yoon, Ja-Woong ; Noh, Yeon-Sik ; Kwon, Yi-Suk ; Kim, Won-Ki ; Yoon, Hyung-Ro ;
Journal of Electrical Engineering and Technology, volume 9, issue 1, 2014, Pages 334~343
DOI : 10.5370/JEET.2014.9.1.334
In this paper, we suggest a method to improve the fusion of an accelerometer and gyro sensor by using a Kalman filter to produce a more high-quality respiration signal to supplement the weakness of using a single accelerometer. To evaluate our proposed algorithm's performance, we developed a chest belt-type module. We performed experiments consisting of aerobic exercise and muscular exercises with 10 subjects. We compared the derived respiration signal from the accelerometer with that from our algorithm using the standard respiration signal from the piezoelectric sensor in the time and frequency domains during the aerobic and muscular exercises. We also analyzed the time delay to verify the synchronization between the output and standard signals. We confirmed that our algorithm improved the respiratory rate's detection accuracy by 4.6% and 9.54% for the treadmill and leg press, respectively, which are dynamic. We also confirmed a small time delay of about 0.638 s on average. We determined that real-time monitoring of the respiration signal is possible. In conclusion, our suggested algorithm can acquire a more high-quality respiration signal in a dynamic exercise environment away from a limited static environment to provide safer and more effective exercises and improve exercise sustainability.
Modifiable Walking Pattern Generation Handling Infeasible Navigational Commands for Humanoid Robots
Lee, Bum-Joo ; Kim, Kab Il ;
Journal of Electrical Engineering and Technology, volume 9, issue 1, 2014, Pages 344~351
DOI : 10.5370/JEET.2014.9.1.344
In order to accomplish complex navigational commands, humanoid robot should be able to modify its walking period, step length and direction independently. In this paper, a novel walking pattern generation algorithm is proposed to satisfy these requirements. Modification of the walking pattern can be considered as a transition between two periodic walking patterns, which follows each navigational command. By assuming the robot as a linear inverted pendulum, the equations of motion between ZMP(Zero Moment Point) and CM(Center of Mass) state is easily derived and analyzed. After navigational command is translated into the desired CM state, corresponding CM motion is generated to achieve the desired state by using simple ZMP functions. Moreover, when the command is not feasible, feasible command is alternated by using binary search algorithm. Subsequently, corresponding CM motion is generated. The effectiveness of the proposed algorithm is verified by computer simulation.
Online Control of DC Motors Using Fuzzy Logic Controller for Remote Operated Robots
Prema, K. ; Kumar, N. Senthil ; Dash, Subhransu Sekhar ;
Journal of Electrical Engineering and Technology, volume 9, issue 1, 2014, Pages 352~362
DOI : 10.5370/JEET.2014.9.1.352
In this paper, a fuzzy logic controller is designed for a DC motor which can be used for navigation control of mobile robots. These mobile robots can be used for agricultural, defense and assorted social applications. The robots used in these fields can reduce manpower, save human life and can be operated using remote control from a distant place. The developed fuzzy logic controller is used to control navigation speed and steering angle according to the desired reference position. Differential drive is used to control the steering angle and the speed of the robot. Two DC motors are connected with the rear wheels of the robot. They are controlled by a fuzzy logic controller to offer accurate steering angle and the driving speed of the robot. Its location is monitored using GPS (Global Positioning System) on a real time basis. IR sensors in the robot detect obstacles around the robot. The designed fuzzy logic controller has been implemented in a robot, which depicts that the robot could avoid obstacle as well as perform its operation efficiently with remote online control.
Enhanced Multi-Frame Based Super-Resolution Algorithm by Normalizing the Information of Registration
Kwon, Soon-Chan ; Yoo, Jisang ;
Journal of Electrical Engineering and Technology, volume 9, issue 1, 2014, Pages 363~371
DOI : 10.5370/JEET.2014.9.1.363
In this paper, a new super-resolution algorithm is proposed by using successive frames for generating high-resolution frames with better quality than those generated by other conventional interpolation methods. Generally, each frame used for super-resolution must only have global translation and motions of sub-pixel unit to generate good result. However, the newly proposed MSR algorithm in this paper is exempt from such constraints. The proposed algorithm consists of three main processes; motion estimation for image registration, normalization of motion vectors, and pattern analysis of edges. The experimental results show that the proposed algorithm has better performance than other conventional algorithms.
A Study on a Healthcare System Using Smart Clothes
Lim, Chae Young ; Kim, Kyungho ;
Journal of Electrical Engineering and Technology, volume 9, issue 1, 2014, Pages 372~377
DOI : 10.5370/JEET.2014.9.1.372
Being able to monitor the heart will allow the diagnosis of heart diseases for patients during daily activities, and the detection of burden on the heart during strenuous exercise. Furthermore, with the help of U-health technology, immediate medical action can be taken, in the case of abnormal symptoms of the heart in daily life. Therefore, it appears to be necessary to develop the corresponding technology to monitor the condition of the heart daily. In this study, a novel wearable smart system was proposed, to monitor the activity of the heart in daily life, and to further evaluate the rhythm of arrhythmia. The wearable system includes three modified bipolar conductive fiber electrodes in the chest part, which can resolve the reduction problem of the magnitude of the signal, by magnifying the signal and removing the noise, to obtain high affinity and validity for medical-type usage (<0.903%). The biological signal acquisition and data lines, and the signal processing engine and communication consist of a conductive ink, and the pic18 and ANT protocol nRF24AP2, respectively. The proposed algorithm was able to detect a strong ECG, signal and r-point passing over the noise. The confidence intervals were 96 %, which could satisfy the requirement to detect arrhythmia under the unconstrained conditions.