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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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Journal DOI :
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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Study on Application of Superconducting Fault Current Limiter Considering Risk of Circuit Breaker Short-Circuit Capacity in a Loop Network System
Kim, Jin-Seok ; Lim, Sung-Hun ; Kim, Jae-Chul ;
Journal of Electrical Engineering and Technology, volume 9, issue 6, 2014, Pages 1789~1794
DOI : 10.5370/JEET.2014.9.6.1789
This paper suggests an application method for a superconducting fault current limiter (SFCL) using an evaluation index to estimate the risk regarding the short-circuit capacity of the circuit breaker (CB). Recently, power distribution systems have become more complex to ensure that supply continuously keeps pace with the growth of demand. However, the mesh or loop network power systems suffer from a problem in which the fault current exceeds the short-circuit capacity of the CBs when a fault occurs. Most case studies on the application of the SFCL have focused on its development and performance in limiting fault current. In this study, an analysis of the application method of an SFCL considering the risk of the CB's short-circuit capacitor was carried out in situations when a fault occurs in a loop network power system, where each line connected with the fault point carries a different current that is above or below the short-circuit capacitor of the CB. A loop network power system using PSCAD/EMTDC was modeled to investigate the risk ratio of the CB and the effect of the SFCL on the reduction of fault current through various case studies. Through the risk evaluations of the simulation results, the estimation of the risk ratio is adequate to apply the SFCL and demonstrate the fault current limiting effect.
Development of a Novel Charging Algorithm for On-board ESS in DC Train through Weight Modification
Jung, Byungdoo ; Kim, Hyun ; Kang, Heechan ; Lee, Hansang ;
Journal of Electrical Engineering and Technology, volume 9, issue 6, 2014, Pages 1795~1804
DOI : 10.5370/JEET.2014.9.6.1795
Owing to the reduction in the peak power of a DC railway subsystem, many studies on energy storage system (ESS) applications have received attention. Each application focuses on improving the efficiency and addressing regulation issues by utilizing the huge regenerative energy generated by braking-phase vehicles. The ESS applications are widely divided into installation on a vehicle or in a substation, depending on the target system characteristics. As the main purpose of the ESS application is to reduce the peak power of starting-phase vehicles, an optimized ESS utilization can be achieved by the operating at the highest peak power section. However, the weight of an entire vehicle, including those of the passengers, continuously changes during operation; thus, considering the total power consumption and the discharging point is difficult. As a contribution to the various storage device algorithms, this study deals with ESS on board vehicles and introduces an ESS operating plan for peak-power reduction by investigating the weight of a train on a real-time basis. This process is performed using a train-performance simulator, and the simulation accuracy can be increased because the weight in each phase can be adopted in the simulation.
A Novel Algorithm for Reducing Restoration Time in Smart Distribution Systems Utilizing Reclosing Dead Time
Hussain, Akhtar ; Choi, Myeon-Song ; Lee, Seung-Jae ;
Journal of Electrical Engineering and Technology, volume 9, issue 6, 2014, Pages 1805~1811
DOI : 10.5370/JEET.2014.9.6.1805
After an occurrence of a fault in any distribution system, it is desired to limit the effects of the fault to smallest possible area and restore the un-faulty areas as soon as possible. Due the advancements in communication technologies, this task can be achieved in multiple efficient ways. In order to decrease the restoration time in the Smart Grid Distribution Management System (SDMS) a communication based algorithm is proposed in this paper, in which the restoration can be done during reclosing. This paper also analyzes various communication failures with power failures cases including the entire network of communication failures. Results of all these cases have been verified by doing simulations.
Adaptive Wavelet Neural Network Based Wind Speed Forecasting Studies
Chandra, D. Rakesh ; Kumari, Matam Sailaja ; Sydulu, Maheswarapu ; Grimaccia, F. ; Mussetta, M. ;
Journal of Electrical Engineering and Technology, volume 9, issue 6, 2014, Pages 1812~1821
DOI : 10.5370/JEET.2014.9.6.1812
Wind has been a rapidly growing renewable power source for the last twenty years. Since wind behavior is chaotic in nature, its forecasting is not easy. At the same time, developing an accurate forecasting method is essential when wind farms are integrated into the power grid. In fact, wind speed forecasting tools can solve issues related to grid stability and reserve allocation. In this paper 30 hours ahead wind speed profile forecast is proposed using Adaptive Wavelet Neural Network (AWNN). The implemented AWNN uses a Mexican hat mother Wavelet, and Morlet Mother Wavelet for seven, eight and nine levels decompositions. For wind speed forecasting, the time series data on wind speed has been gathered from the National Renewable Energy Laboratory (NREL) website. In this work, hourly averaged 10-min wind speed data sets for the year 2004 in the Midwest ISO region (site number 7263) is taken for analysis. Data sets are normalized in the range of [-1, 1] to improve the training performance of forecasting models. Total 8760 samples were taken for this forecasting analysis. After the forecasting phase, statistical parameters are calculated to evaluate system accuracy, comparing different configurations.
Static Switch Controller Based on Artificial Neural Network in Micro-Grid Systems
Saeedimoghadam, Mojtaba ; Moazzami, Majid ; Nabavi, Seyed. M.H. ; Dehghani, Majid ;
Journal of Electrical Engineering and Technology, volume 9, issue 6, 2014, Pages 1822~1831
DOI : 10.5370/JEET.2014.9.6.1822
Micro-grid is connected to the main power grid through a static switch. One of the critical issues in micro-grids is protection which must disconnect the micro-grid from the network in short-circuit contingencies. Protective methods of micro-grid mainly follow the model of distribution system protection. This protection scheme suffers from improper operation due to the presence of single-phase loads, imbalance of three-phase loads and occurrence of power swings in micro-grid. In this paper, a new method which prevents from improper performance of static micro-grid protection is proposed. This method works based on artificial neural network (ANN) and able to differentiate short circuit from power swings by measuring impedance and the rate of impedance variations in PCC bus. This new technique provides a protective system with higher reliability.
Latin Hypercube Sampling Based Probabilistic Small Signal Stability Analysis Considering Load Correlation
Zuo, Jian ; Li, Yinhong ; Cai, Defu ; Shi, Dongyuan ;
Journal of Electrical Engineering and Technology, volume 9, issue 6, 2014, Pages 1832~1842
DOI : 10.5370/JEET.2014.9.6.1832
A novel probabilistic small signal stability analysis (PSSSA) method considering load correlation is proposed in this paper. The superiority Latin hypercube sampling (LHS) technique combined with Monte Carlo simulation (MCS) is utilized to investigate the probabilistic small signal stability of power system in presence of load correlation. LHS helps to reduce the sampling size, meanwhile guarantees the accuracy and robustness of the solutions. The correlation coefficient matrix is adopted to represent the correlations between loads. Simulation results of the two-area, four-machine system prove that the proposed method is an efficient and robust sampling method. Simulation results of the 16-machine, 68-bus test system indicate that load correlation has a significant impact on the probabilistic analysis result of the critical oscillation mode under a certain degree of load uncertainty.
Group Building Based Power Consumption Scheduling for the Electricity Cost Minimization with Peak Load Reduction
Oh, Eunsung ; Park, Jong-Bae ; Son, Sung-Yong ;
Journal of Electrical Engineering and Technology, volume 9, issue 6, 2014, Pages 1843~1850
DOI : 10.5370/JEET.2014.9.6.1843
In this paper, we investigate a group building based power consumption scheduling to minimize the electricity cost. We consider the demand shift to reduce the peak load and suggest the compensation function reflecting the relationship between the change of the building demand and the occupants' comfort. Using that, the electricity cost minimization problem satisfied the convexity is formulated, and the optimal power consumption scheduling algorithm is proposed based on the iterative method. Extensive simulations show that the proposed algorithm achieves the group management gain compared to the individual building operation by increasing the degree of freedom for the operation.
Electricity Market Design for the Incorporation of Various Demand-Side Resources in the Jeju Smart Grid Test-bed
Park, Man-Guen ; Cho, Seong-Bin ; Chung, Koo-Hyung ; Moon, Kyeong-Seob ; Roh, Jae-Hyung ;
Journal of Electrical Engineering and Technology, volume 9, issue 6, 2014, Pages 1851~1863
DOI : 10.5370/JEET.2014.9.6.1851
Many countries are increasing their investments in smart grid technology to enhance energy efficiency, address climate change, and trigger a green energy revolution. In addition to these goals, Korea also seeks to promote national competitiveness, prepare for the growth of the renewable energy industry, and export industrialization through its strategic promotion of the smart grid. Given its inherent representativeness for Korean implementation of the smart grid and its growth potential, Jeju Island was selected by the Korean government as the site for smart grid testing in June 2009. This paper presents a new design for the electricity market and an operational scheme for testing Smart Electricity Services in the Jeju smart grid demonstration project. The Jeju smart grid test-bed electricity market is constructed on the basis of day-ahead and real-time markets to provide two-way electricity transaction environments. The experience of the test-bed market operation shows that the competitive electricity market can facilitate the smart grid deployment in Korea by allowing various demand side resources to be active market players.
Line Security Evaluation of WANS Considering Protectability of Relays and Vulnerability of Lines
Hussain, Akhtar ; Seok, Chang-Ju ; Choi, Myeon-Song ; Lee, Seung-Jae ; Lim, Seong-Il ;
Journal of Electrical Engineering and Technology, volume 9, issue 6, 2014, Pages 1864~1872
DOI : 10.5370/JEET.2014.9.6.1864
Maloperation of protective relays is one of the major causes for cascading tripping in WANS. Another line trip followed by a previous line trip may occur due to overloading of the line, because of the load redistribution or unwanted trip of a backup relay due to change in the flow of fault current. Evaluation of each line is required by considering both of these effects. A new index named Line Security Index (LSI) is proposed in this paper which combines both Vulnerability Index (VI) and Protectability Index (PI) to completely evaluate the security of individual lines and their importance in the power grid. Computer simulations have been performed on the Korean power grid data to establish the feasibility of the proposed idea.
PSSs and SVC Damping Controllers Design to Mitigate Low Frequency Oscillations Problem in a Multi-machine Power System
Darabian, Mohsen ; Jalilvand, Abolfazl ;
Journal of Electrical Engineering and Technology, volume 9, issue 6, 2014, Pages 1873~1881
DOI : 10.5370/JEET.2014.9.6.1873
This paper deals with the design of multi-machine power system stabilizers (PSSs) and Static var compensator (SVC) using Modified shuffled frog leaping algorithm (MSFLA). The effectiveness of the proposed scheme for optimal setting of the PSSs and SVC controllers has been attended. The PSSs and SVC controllers designing is converted to an optimization problem in which the speed deviations between generators are involved. In order to compare the capability of PSS and SVC, they are designed independently once, and in a coordinated mode once again. The proposed method is applied on a multi-machine power system under different operating conditions and disturbances to confirm the effectiveness of it. The results of tuned PSS controller based on MSFLA (MSFLAPSS) and tuned SVC controller based on MSFLA (MSFLA SVC) are compared with the Strength pareto evolutionary algorithm (SPEA) and Particle swarm optimization (PSO) based optimized PSS and SVC through some performance to reveal its strong performance.
Multi-Objective Short-Term Fixed Head Hydrothermal Scheduling Using Augmented Lagrange Hopfield Network
Nguyen, Thang Trung ; Vo, Dieu Ngoc ;
Journal of Electrical Engineering and Technology, volume 9, issue 6, 2014, Pages 1882~1890
DOI : 10.5370/JEET.2014.9.6.1882
This paper proposes an augmented Lagrange Hopfield network (ALHN) based method for solving multi-objective short term fixed head hydrothermal scheduling problem. The main objective of the problem is to minimize both total power generation cost and emissions of
over a scheduling period of one day while satisfying power balance, hydraulic, and generator operating limits constraints. The ALHN method is a combination of augmented Lagrange relaxation and continuous Hopfield neural network where the augmented Lagrange function is directly used as the energy function of the network. For implementation of the ALHN based method for solving the problem, ALHN is implemented for obtaining non-dominated solutions and fuzzy set theory is applied for obtaining the best compromise solution. The proposed method has been tested on different systems with different analyses and the obtained results have been compared to those from other methods available in the literature. The result comparisons have indicated that the proposed method is very efficient for solving the problem with good optimal solution and fast computational time. Therefore, the proposed ALHN can be a very favorable method for solving the multi-objective short term fixed head hydrothermal scheduling problems.
A Reliability Model of Wind Farm Considering the Complex Terrain and Cable Failure Based on Clustering Algorithm
Liu, Wenxia ; Chen, Qi ; Zhang, Yuying ; Qiu, Guobing ; Lin, Chenghui ;
Journal of Electrical Engineering and Technology, volume 9, issue 6, 2014, Pages 1891~1899
DOI : 10.5370/JEET.2014.9.6.1891
A reliability model of wind farm located in mountainous land with complex terrain, which considers the cable and wind turbine (WT) failures, is proposed in this paper. Simple wake effect has been developed to be applied to the wind farm in mountainous land. The component failures in the wind farm like the cable and WT failures which contribute to the wind farm power output (WFPO) and reliability is investigated. Combing the wind speed distribution and the characteristic of wind turbine power output (WTPO), Monte Carlo simulation (MCS) is used to obtain the WFPO. Based on clustering algorithm the multi-state model of a wind farm is proposed. The accuracy of the model is analyzed and then applied to IEEE-RTS 79 for adequacy assessment.
A Water-Wall Model of Supercritical Once-Through Boilers Using Lumped Parameter Method
Go, Geon ; Moon, Un-Chul ;
Journal of Electrical Engineering and Technology, volume 9, issue 6, 2014, Pages 1900~1908
DOI : 10.5370/JEET.2014.9.6.1900
This paper establishes a compact and practical model for a water-wall system comprising supercritical once-through boilers, which can be used for automatic control or simple analysis of the entire boiler-turbine system. Input and output variables of the water-wall system are defined, and balance equations are applied using a lumped parameter method. For practical purposes, the dynamic equations are developed with respect to pressure and temperature instead of density and internal energy. A comparison with results obtained using APESS, a practical thermal power plant simulator developed by Doosan Heavy Industries and Construction, is presented with respect to steady state and transient responses.
Analysis on Current Limiting Characteristics According to the Influence of the Magnetic Flux for SFCL with Two Magnetic Paths
Ko, Seok-Cheol ; Han, Tae-Hee ; Lim, Sung-Hun ;
Journal of Electrical Engineering and Technology, volume 9, issue 6, 2014, Pages 1909~1913
DOI : 10.5370/JEET.2014.9.6.1909
In this study, a superconducting fault current limiter (SFCL) having two magnetic paths was proposed, and its current limiting characteristics were analyzed. For the SFCL to effectively perform the current limiting operation, it must be designed considering the magnetic saturation of the E-I core. Further, the influence of the magnetic flux on its peak current limiting characteristics was investigated. In addition, the magnetic flux curves of the SFCL obtained from the fault current limiting experiments were analyzed, and the subtractive polarity winding case was observed to not only further reduce the saturation potential of the core but also perform the peak current limiting functions well when compared with the additive polarity winding case.
Analysis on Core Loss of Brushless DC Motor Considering Pulse Width Modulation of Inverter
Kim, Ki-Chan ;
Journal of Electrical Engineering and Technology, volume 9, issue 6, 2014, Pages 1914~1920
DOI : 10.5370/JEET.2014.9.6.1914
In this paper, characteristics of blushless direct current (BLDC) motor including core loss are analyzed considering pulse width modulation (PWM) of inverter. Input voltage of BLDC motor due to PWM is calculated considering duty ratio and carrier frequency of inverter in order to control torque or speed of BLDC motor. For the calculation of core loss, the input current with harmonics due to PWM voltage is calculated by using equivalent circuit model of BLDC motor according to switching pattern and carrier frequency. Next, core loss is analyzed by inputting the currents as a source of BLDC motor for FEM. Characteristics including core loss are compared with ones without PWM waveform according to reference speed.
Magnetic Field Gradient Optimization for Electronic Anti-Fouling Effect in Heat Exchanger
Han, Yong ; Wang, Shu-Tao ;
Journal of Electrical Engineering and Technology, volume 9, issue 6, 2014, Pages 1921~1927
DOI : 10.5370/JEET.2014.9.6.1921
A new method for optimizing the magnetic field gradient in the exciting coil of electronic anti-fouling (EAF) system is presented based on changing exciting coil size. In the proposed method, two optimization expressions are deduced based on biot-savart law. The optimization expressions, which can describe the distribution of the magnetic field gradient in the coil, are the function of coil radius and coil length. These optimization expressions can be used to obtain an accurate coil size if the magnetic field gradient on a certain point on the coil's axis of symmetry is needed to be the maximum value. Comparing with the experimental results and the computation results using Finite Element Method simulation to the magnetic field gradient on the coil's axis of symmetry, the computation results obtained by the optimization expression in this article can fit the experimental results and the Finite Element Method results very well. This new method can optimize the EAF system's anti-fouling performance based on improving the magnetic field gradient distribution in the exciting coil.
LabVIEW Based Laboratory Typed Test Setup for the Determination of Induction Motor Performance Characteristics
Calis, Hakan ; Caki, Eyup ;
Journal of Electrical Engineering and Technology, volume 9, issue 6, 2014, Pages 1928~1934
DOI : 10.5370/JEET.2014.9.6.1928
Induction motors are widely used due to their rugged, robust and easy to care features. Since they are heavily used in industry, testing of three phase induction motors have play a vital role. In order to determine motor equivalent circuit parameters, efficiency of motor, squirrel caged laboratory sized an induction motor test setup is prepared. It is suitable for the induction motor with the frame size of 100 and 112. A virtual Instrumentation typed engineering workbench (called as LabVIEW) software packet, is utilized as a graphical user interface program. Motor input power is measured by measuring the input voltage, current and power factor with the help of hall effect typed voltage and current transformers. Also, the output power is measured by measuring the speed and torque with the help of an encoder and torque sensor. All outputs of the voltage and current transformer, encoder and temperature, torque sensors are given to the Data Acquisition Card (DAQ) which acquires the data for processing and then the equivalent circuit parameters, efficiency, performance and loading characteristics are found out, using LabVIEW based user interface. It is suggested to use this test rig for the quality control of produced motors in industry, and an educational experiment setup in the school laboratories.
Analysis of Harmonic Currents Propagation on the Self-Excited Induction Generator with Nonlinear Loads
Nazir, Refdinal ;
Journal of Electrical Engineering and Technology, volume 9, issue 6, 2014, Pages 1935~1943
DOI : 10.5370/JEET.2014.9.6.1935
In recent years, the induction machines are increasingly being used as self-excited induction generators (SEIG). This generator is especially widely employed for small-scale power plants driven by renewable energy sources. The application of power electronic components in the induction generator control (IGC) and the loading of SEIG using nonlinear loads will generate harmonic currents. This paper analyzes the propogation of harmonic currents on the SEIG with nonlinear loads. Transfer function method in the frequency domain is used to calculate the gain and phase angle of each harmonic current component which are generated by a nonlinear loads. Through the superposition approach, this method has also been used to analyze the propagation of harmonic currents from nonlinear load to the stator windings. The simulation for the propagation of harmonic currents for a 4 pole, 1.5 kW, 50Hz, 3.5A, Y-connected, rotor-cage SEIG with energy-saving lamps, have provided results almost the same with the experiment. It can prove that the validity of the proposed models and methods. The study results showed that the propagation of harmonic currents on the stator windings rejects high order harmonics and attenuates low order harmonics, consequently THDI diminish significantly on the stator windings.
Design and Control Methods of Bidirectional DC-DC Converter for the Optimal DC-Link Voltage of PMSM Drive
Kim, Tae-Hoon ; Lee, Jung-Hyo ; Won, Chung-Yuen ;
Journal of Electrical Engineering and Technology, volume 9, issue 6, 2014, Pages 1944~1953
DOI : 10.5370/JEET.2014.9.6.1944
This paper shows the design and control methods of the bidirectional DC-DC converter to generate the proper DC-link voltage of a PMSM drive. Conventionally, because the controllable power of the PWM based voltage source inverter is limited by its DC-link voltage, the DC-DC converter is used for boosted DC-link voltage if the inverter source cannot generate enough operating voltage for the PMSM drive. In this paper, to obtain more utilization of this DC-DC converter, optimal DC-link voltage control for PMSM drive will be explained. First, the process and current path of the DC-DC converter will be illustrated, and a control method of this converter for variable DC-link voltage will then be explained. Finally, an improvement analysis of the optimal DC-link voltage control method, especially on the deadtime effect, will be explained. The DC-DC converter of the proposed control method is verified by the experiments by comparing with the conventional constant voltage control method.
The Application of Classical Direct Torque and Flux Control (DTFC) for Line-Start Permanent Magnet Synchronous and its Comparison with Permanent Magnet Synchronous Motor
Soreshjani, Mohsen Hosseinzadeh ; Heidari, Reza ; Ghafari, Ahmad ;
Journal of Electrical Engineering and Technology, volume 9, issue 6, 2014, Pages 1954~1959
DOI : 10.5370/JEET.2014.9.6.1954
This paper attempts to design and present a comparison of classical Direct Torque Flux Control (DTFC) for Line-Start Permanent Magnet Synchronous Motor (LSPMSM) and its equal Permanent Magnet Synchronous Motor (PMSM). In order to present an in-depth analysis, both motors for DTFC Voltage Source Inverter (VSI)-fed in the same situations of different conditions are simulated and tested. The advantages of the proposed method for LSPMSM over the PMSM are discussed and analyzed.
Analysis of a Surface-Mounted Permanent-Magnet Machine with Overhang Structure by Using a Novel Equivalent Magnetic Circuit Model
Yeo, Han-Kyeol ; Woo, Dong-Kyun ; Lim, Dong-Kuk ; Ro, Jong-Suk ; Jung, Hyun-Kyo ;
Journal of Electrical Engineering and Technology, volume 9, issue 6, 2014, Pages 1960~1966
DOI : 10.5370/JEET.2014.9.6.1960
The rotor overhang is used to enhance the air-gap flux and improve the power density. Due to the asymmetry in the axial direction caused by the overhang, a time consuming 3D analysis is necessary when designing a motor with overhang. To solve this problem, this paper proposes an equivalent magnetic circuit model (EMCM) which takes account overhang effects without a 3D analysis by using effective air-gap length. The analysis time can be reduced significantly via the proposed EMCM. A reduction in the analysis time is essential for a preliminary design of a motor. In order to verify the proposed model, a 3-D finite-element method (FEM) analysis is adopted. 3-D FEM results confirm the validity of the proposed EMCM.
Robust Safety Circuits for DC Powered Home Appliances in Transient State
Ahn, Jung-Hoon ; Kim, Yun-Sung ; Lee, Byoung-Kuk ;
Journal of Electrical Engineering and Technology, volume 9, issue 6, 2014, Pages 1967~1977
DOI : 10.5370/JEET.2014.9.6.1967
In this paper, for the development of a safe and reliable DC home appliance suitable for DC home power supply system, we classified a number of inherent problems with help of the comparative analysis of existing AC and new DC home appliance. Several new technical problems of DC home appliances are mainly linked to the DC transient state. Among them, this paper concentrates on start-up inrush current problem, uni-polarity problem, and heavy DC load control problem. And to address these problems, we herein present an implementation of robust safety circuits for DC home appliances. Specifically, we investigate several multi-circuit countermeasures and select the best among them through comparative evaluation, based on theoretical, simulational, and experimental results.
Power Tracking Control of Domestic Induction Heating System using Pulse Density Modulation Scheme with the Fuzzy Logic Controller
Nagarajan, Booma ; Sathi, Rama Reddy ; Vishnuram, Pradeep ;
Journal of Electrical Engineering and Technology, volume 9, issue 6, 2014, Pages 1978~1987
DOI : 10.5370/JEET.2014.9.6.1978
Power requirement to the induction heating system varies during the heating process. A closed loop control is required to have a smooth control over the power. In this work, a constant frequency pulse density modulation based power tracking control scheme for domestic induction heating system is developed using the Fuzzy Logic Controller. In the conventional power modulation schemes, the switching losses increase with the change in the load. The proposed pulse density modulation scheme maintains minimum switching losses for the entire load range. This scheme is implemented for the class-D series resonant inverter system. Fuzzy logic controller based power tracking control scheme is developed for domestic induction heating power supply for various power settings. The open loop and closed loop simulation studies are done using the MATLAB/Simulink simulation tool. The control logic is implemented in hardware using the PIC16F877A microcontroller. Fuzzy controller tracks the set power by changing the pulse density of the gate pulses applied to the inverter. The results obtained are used to know the effectiveness of the fuzzy logic controller to achieve the set power.
A Second-order Harmonic Current Reduction with a Fast Dynamic Response for a Two-stage Single-phase Grid-connected Inverter
Jung, Hong-Ju ; Kim, Rae-Young ;
Journal of Electrical Engineering and Technology, volume 9, issue 6, 2014, Pages 1988~1994
DOI : 10.5370/JEET.2014.9.6.1988
In a single-phase grid-connected power system consisting of a DC/DC converter and a DC/AC converter, the current drawn from renewable energy sources has a tendency to be pulsated and contains second-order frequency ripple components, which results in several drawback such as a power harvesting loss and a shortening of the energy source's life. This paper presents a new second-order harmonic current reduction scheme with a fast dc-link voltage loop for two-stage dc-dc-ac grid connected systems. In the frequency domain, an adequate control design is performed based on the small signal transfer function of a two-stage dc-dc-ac converter. To verify the effectiveness of proposed control algorithm, a 1 kW hardware prototype has been built and experimental results are presented.
A Study of Field-Ring Design using a Variety of Analysis Method in Insulated Gate Bipolar Transistor (IGBT)
Jung, Eun Sik ; Kyoung, Sin-Su ; Chung, Hunsuk ; Kang, Ey Goo ;
Journal of Electrical Engineering and Technology, volume 9, issue 6, 2014, Pages 1995~2003
DOI : 10.5370/JEET.2014.9.6.1995
Power semiconductor devices have been the major backbone for high-power electronic devices. One of important parameters in view of power semiconductor devices often characterize with a high breakdown voltage. Therefore, many efforts have been made, since the development of the Insulated Gate Bipolar Transistor (IGBT), toward having higher level of breakdown voltage, whereby the typical design thereof is focused on the structure using the field ring. In this study, in an attempt to make up more optimized field-ring structure, the characteristics of the field ring were investigated with the use of theoretical arithmetic model and methodologically the design of experiments (DOE). In addition, the IGBT having the field-ring structure was designed via simulation based on the finding from the above, the result of which was also analyzed. Lastly, the current study described the trench field-ring structure taking advantages of trench-etching process having the improved field-ring structure, not as simple as the conventional one. As a result of the simulation, it was found that the improved trench field-ring structure leads to more desirable voltage divider than relying on the conventional field-ring structure.
Dynamic Analysis and Controller Design for Standalone Operation of Photovoltaic Power Conditioners with Energy Storage
Park, Sun-Jae ; Shin, Jong-Hyun ; Park, Joung-Hu ; Jeon, Hee-Jong ;
Journal of Electrical Engineering and Technology, volume 9, issue 6, 2014, Pages 2004~2012
DOI : 10.5370/JEET.2014.9.6.2004
Energy storage devices are necessary to obtain stable utilization of renewable energy sources. When black-out occurs, distributed renewable power sources with energy storage devices can operate under standalone mode as uninterruptable power supply. This paper proposes a dynamic response analysis with small-signal modeling for the standalone operation of a photovoltaic power generation system that includes a bidirectional charger/discharger with a battery. Furthermore, it proposes a DC-link voltage controller design of the entire power conditioning system, using the storage current under standalone operation. The purpose of this controller is to guarantee the stable operation of the renewable source and the storage subsystem, with the power conversion of a very efficient bypass-type PCS. This paper presents the operating principle and design guidelines of the proposed scheme, along with performance analysis and simulation. Finally, a hardware prototype of 1-kW power conditioning system with an energy storage device is implemented, for experimental verification of the proposed converter system.
Measurement and Comparison of Iron Loss in Bonded- and Embossed-Type Segmented Stator Cores for IPMSM
Jeong, Kwangyoung ; Zhang, Dianhai ; Kwon, Jaehoon ; Ren, Ziyan ; Koh, Chang-Seop ;
Journal of Electrical Engineering and Technology, volume 9, issue 6, 2014, Pages 2013~2018
DOI : 10.5370/JEET.2014.9.6.2013
According to the manufacturing process of the laminated stator core for an inserted permanent magnet synchronous motor (IPMSM), the iron loss may be different. It is because the mechanical stress imposed to electrical steel sheet is strongly dependent on the manufacturing process. This paper proposes a new iron loss measurement algorithm which utilizes the induced voltage of a search coil and exciting current. The method is effective even when the distribution of magnetic flux density is not uniform along the magnetic flux path as well as uniform. The developed iron loss measurement system is applied to bonded- and embossed-type segmented stator cores of an IPMSM, and the iron losses are quantitatively compared.
Optimal Design of a Planar-Type Antenna with a Reduced Number of Design Parameters Using Taguchi Method and Adaptive Particle Swarm Optimization
Lee, Jeong-Hyeok ; Jang, Dong-Hyeok ; Kim, Hyeong-Seok ;
Journal of Electrical Engineering and Technology, volume 9, issue 6, 2014, Pages 2019~2024
DOI : 10.5370/JEET.2014.9.6.2019
This paper presents a method to optimize the design of a planar-type antenna and reduce the number of design parameters for rapid computation. The electromagnetic characteristics of the structure are analyzed, and Taguchi method is used to identify critical design parameters. Adaptive particle swarm optimization, which has a faster convergence rate than particle swarm optimization, is used to achieve the design goal effectively. A compact dual-band USB dongle antenna is tested to verify the advantage of the proposed method. In this case, we can use only five selected geometrical parameters instead of eighteen to accelerate the optimization of the antenna design. The 10 dB bandwidth for return loss ranges from 2.3 GHz to 2.7 GHz and from 5.1 GHz to 5.9 GHz, covering all the WiBro, Bluetooth, WiMAX, and 802.11 b/g/n WLAN bands in both simulation and measurement. The optimization process enables the antenna design to achieve the required performance with fewer design parameters.
Extending the Read Range of UHF Mobile RFID Readers: Arbitration Methods Based on Interference Estimation
Ahn, Si-Young ; Park, Jun-Seok ; Seong, Yeong Rak ; Oh, Ha-Ryoung ;
Journal of Electrical Engineering and Technology, volume 9, issue 6, 2014, Pages 2025~2035
DOI : 10.5370/JEET.2014.9.6.2025
The read range of UHF mobile readers can be extended by a booster for mobile RFID readers (BoMR). But in an environment where multiple BoMRs are installed, the read success rate may be decreased due to signal interference. This paper proposes three arbitration methods based on interference estimation with the purpose of enhancing the read success rate. A central arbitration server manages global information in centralized arbitration method (CAM) without broadcast/multicast communication facility. In fully distributed arbitration method (FDAM), all the arbitration messages are broadcasted from a BoMR to every BoMR, and each BoMR decides with broadcasted global information. Events in FDAM are serialized naturally with broadcasted messages. Cluster Distributed Arbitration Method (CDAM) forms clusters with multicasted BoMRs and a selected BoMR acts as an arbiter in the cluster. Such effects as lengthened read range, improved the read success rates of readers can be obtained by the proposed methods without any hardware modification. In order to evaluate the arbitration methods, the RFID system is modeled by using the DEVS formalism and simulated by using the DEVSim++.
Experimental and Analytical Study on the Bus Duct System for the Prediction of Temperature Variations Due To the Fluctuation of Load
Thirumurugaveerakumar, S. ; Sakthivel, M. ; Valarmathi, S. ;
Journal of Electrical Engineering and Technology, volume 9, issue 6, 2014, Pages 2036~2041
DOI : 10.5370/JEET.2014.9.6.2036
In this paper, a thermal model is developed for the bus bar system to predict the temperature variation during the transient time period and to calculate both the steady-state and transient electrical current carrying capacity (ampacity) of bus bar. The bus bar system installed in the power house of Kumaraguru College of Technology, Coimbatore has been considered. Temperature variation predicted in the modelling is validated by observing the current and steady state temperatures in different feeders of the bus bar. Magnetic field of the extreme phases R and B induces more current in the middle phase Y. Hence, the steady state temperature in the phase Y is greater than other two phases. The transient capabilities of the bus bar are illustrated by calculating the variations in the bus bar temperature when it is subjected to a step change in current during the peak hours due to increase in hostel utilities and facilities (5.30 pm to 10.30 pm). The physical and geometrical properties of the bus bar and temperature variation in the bus bar are used to estimate the thermal time constants for common bus bar cross-sections. An analytical expression for the time constant of the bus bar is derived.
Aging Analysis and Reconductoring of Overhead Conductors for Radial Distribution Systems Using Genetic Algorithm
Legha, Mahdi Mozaffari ; Mohammadi, Mohammad ;
Journal of Electrical Engineering and Technology, volume 9, issue 6, 2014, Pages 2042~2048
DOI : 10.5370/JEET.2014.9.6.2042
In medium voltage electrical distribution networks, reforming the loss reduction is important, and in line with this, the issue of system engineering and use of proper equipment Expansion of distribution systems results in higher system losses and poor voltage regulation. Therefore, an efficient and effective distribution system has become more important. So, proper selection of conductors in the distribution system is crucial as it determines the current density and the resistance of the line. Evaluation of aging conductors for losses and costs imposed in addition to the careful planning of technical and economic networks can be identified in the network design. In this paper the use of imperialist competitive algorithm; genetic algorithm; is proposed to optimal branch conductor selection and reconstruction in radial distribution systems planning. The objective is to minimize the overall cost of annual energy losses and depreciation on the cost of conductors to improve productivity given the maximum current carrying capacity and acceptable voltage levels. Simulations are carried out on 69-bus radial distribution network using genetic algorithm approaches to show the accuracy as well as the efficiency of the proposed solution technique.
Analysis of Shielded Twisted Pair Cable to External Field Coupling by Expanded Chain Matrix Modeling
Cho, Yong-Sun ; Jung, Hyun-Kyo ; Cheon, Changyul ; Chung, Young-Seek ;
Journal of Electrical Engineering and Technology, volume 9, issue 6, 2014, Pages 2049~2057
DOI : 10.5370/JEET.2014.9.6.2049
In this paper, a numerical method for analyzing coupling between high-altitude electromagnetic pulse (HEMP) as external field and a shielded twisted pair (STP) cable is proposed, which is based on an expanded chain matrix. Load responses of electromagnetic (EM) field excitation in uniform transmission line (TL) are solved by Baum-Liu-Tesche (BLT) equations in frequency domain, however, it is difficult to apply BLT equations to solve load responses of STP cable because the iteratively changing configuration of each twisted pairs are involved in cable. To avoid this problem and decrease memory and CPU time, we proposed the expanded chain matrix modeling method that is calculated using ABCD parameters, and applied multi-conductor transmission line (MTL) theory to consider the EMP coupling effectiveness of each twisted pairs. The results implemented by the proposed method are presented and compared with those obtained by the finite-difference time domain (FDTD) method as a kind of 3D full wave analysis.
Intuitionistic Fuzzy Expert System based Fault Diagnosis using Dissolved Gas Analysis for Power Transformer
Mani, Geetha ; Jerome, Jovitha ;
Journal of Electrical Engineering and Technology, volume 9, issue 6, 2014, Pages 2058~2064
DOI : 10.5370/JEET.2014.9.6.2058
In transformer fault diagnosis, dissolved gas analysis (DGA) is been widely employed for a long period and numerous methods have been innovated to interpret its results. Still in some cases it fails to identify the corresponding faults. Due to the limitation of training data and non-linearity, the estimation of key-gas ratio in the transformer oil becomes more complicated. This paper presents Intuitionistic Fuzzy expert System (IFS) to diagnose several faults in a transformer. This revised approach is well suitable to diagnosis the transformer faults and the corresponding action to be taken. The proposed method is applied to an independent data of different power transformers and various case studies of historic trends of transformer units. It has been proved to be a very advantageous tool for transformer diagnosis and upkeep planning. This method has been successfully used to identify the type of fault developing within a transformer even if there is conflict in the results of AI technique applied to DGA data.
Gamma-Ray Effects on the DAC-7512E 12-Bit Serial Digital to Analog Converter for Space Power Applications
Shin, Goo-Hwan ;
Journal of Electrical Engineering and Technology, volume 9, issue 6, 2014, Pages 2065~2069
DOI : 10.5370/JEET.2014.9.6.2065
The DAC-7512E is a 12-bit digital to analog converter that is low power and a single package with internal buffers. The DAC-7512E takes up minimal PCB area for applications of space power electronics design. The spacecraft mass is a crucial point considering spacecraft launch into space. Therefore, we have performed a TID test for the DAC-7512E 12-bit serial input digital to analog converter to reduce the spacecraft mass by using a low-level Gamma-ray irradiator with
gamma-ray sources. The irradiation with
gamma-rays was carried out at doses from 0 krad to 100 krad to check the error status of the device in terms of current, voltage and bit error status during conversion. The DAC-7512E 12-bit serial digital to analog converter should work properly from 0 krad to 30 krad without any error.
Evaluation of Radio-Frequency Performance of Gate-All-Around Ge/GaAs Heterojunction Tunneling Field-Effect Transistor with Hetero-Gate-Dielectric by Mixed-Mode Simulation
Roh, Hee Bum ; Seo, Jae Hwa ; Yoon, Young Jun ; Bae, Jin-Hyuk ; Cho, Eou-Sik ; Lee, Jung-Hee ; Cho, Seongjae ; Kang, In Man ;
Journal of Electrical Engineering and Technology, volume 9, issue 6, 2014, Pages 2070~2078
DOI : 10.5370/JEET.2014.9.6.2070
In this work, the frequency response of gate-all-around (GAA) Ge/GaAs heterojunction tunneling field-effect transistor (TFET) with hetero-gate-dielectric (HGD) and pnpn channel doping profile has been analysed by technology computer-aided design (TCAD) device-circuit mixed-mode simulations, with comparison studies among ppn, pnpn, and HGD pnpn TFET devices. By recursive tracing of voltage transfer curves (VTCs) of a common-source (CS) amplifier based on the HGD pnpn TFET, the operation point (Q-point) was obtained at
, where the maximum available output swing was acquired without waveform distortion. The slope of VTC of the amplifier was 9.21 V/V (19.4 dB), which mainly resulted from the ponderable direct-current (DC) characteristics of HGD pnpn TFET. Along with the DC performances, frequency response with a small-signal voltage of 10 mV has been closely investigated in terms of voltage gain (
), unit-gain frequency (
), and cut-off frequency (
). The Ge/GaAs HGD pnpn TFET demonstrated
Analytical Threshold Voltage Modeling of Surrounding Gate Silicon Nanowire Transistors with Different Geometries
Pandian, M. Karthigai ; Balamurugan, N.B. ;
Journal of Electrical Engineering and Technology, volume 9, issue 6, 2014, Pages 2079~2088
DOI : 10.5370/JEET.2014.9.6.2079
In this paper, we propose new physically based threshold voltage models for short channel Surrounding Gate Silicon Nanowire Transistor with two different geometries. The model explores the impact of various device parameters like silicon film thickness, film height, film width, gate oxide thickness, and drain bias on the threshold voltage behavior of a cylindrical surrounding gate and rectangular surrounding gate nanowire MOSFET. Threshold voltage roll-off and DIBL characteristics of these devices are also studied. Proposed models are clearly validated by comparing the simulations with the TCAD simulation for a wide range of device geometries.
Negative Corona Onset Characteristic of the UHV Conductors Based on the Corona Cage
Liu, Yun-Peng ; Zhu, Lei ; Lv, Fang-Cheng ; Xie, Xiongjie ;
Journal of Electrical Engineering and Technology, volume 9, issue 6, 2014, Pages 2089~2097
DOI : 10.5370/JEET.2014.9.6.2089
Negative corona onset characteristics of the stranded conductors based on the ultra-high voltage (UHV) corona cage were studied in the paper. Based on the corona self-sustaining criterion in extreme uneven electric fields and the secondary emission process of the photoelectrons, the corona onset calculation model in the UHV corona cage is established and the corona current tests of the single LGJ900-75, 6 bundle LGJ900-75, 8 bundle LGJ400-35 conductors in dry and rain conditions were done in the UHV corona cage, and the rain rates are 2.4 mm/h, 20 mm/h and 30 mm/h. Corona onset electric field strength is gained by E-I tangent method, and the onset electric field strength in dry condition proves that the calculation model can be used to calculate the corona onset characteristics of the bundle conductors in the UHV corona cage. A further analysis proves that: the negative corona onset voltage of the conductor increases with the bundle number and the diameter of the sub conductor, but decreases with the bundle space in the corona cage. The onset electric field strength is influenced little by bundle space and bundle number, but decreases with the increase of the diameter of the sub-conductor. The surface irregularity coefficient decreases with the rain rate.
Polynomial Fuzzy Radial Basis Function Neural Network Classifiers Realized with the Aid of Boundary Area Decision
Roh, Seok-Beom ; Oh, Sung-Kwun ;
Journal of Electrical Engineering and Technology, volume 9, issue 6, 2014, Pages 2098~2106
DOI : 10.5370/JEET.2014.9.6.2098
In the area of clustering, there are numerous approaches to construct clusters in the input space. For regression problem, when forming clusters being a part of the overall model, the relationships between the input space and the output space are essential and have to be taken into consideration. Conditional Fuzzy C-Means (c-FCM) clustering offers an opportunity to analyze the structure in the input space with the mechanism of supervision implied by the distribution of data present in the output space. However, like other clustering methods, c-FCM focuses on the distribution of the data. In this paper, we introduce a new method, which by making use of the ambiguity index focuses on the boundaries of the clusters whose determination is essential to the quality of the ensuing classification procedures. The introduced design is illustrated with the aid of numeric examples that provide a detailed insight into the performance of the fuzzy classifiers and quantify several essentials design aspects.
Performance Degradation Due to Particle Impoverishment in Particle Filtering
Lim, Jaechan ;
Journal of Electrical Engineering and Technology, volume 9, issue 6, 2014, Pages 2107~2113
DOI : 10.5370/JEET.2014.9.6.2107
Particle filtering (PF) has shown its outperforming results compared to that of classical Kalman filtering (KF), particularly for highly nonlinear problems. However, PF may not be universally superior to the extended KF (EKF) although the case (i.e. an example that the EKF outperforms PF) is seldom reported in the literature. Particularly, PF approaches show degraded performance for problems where the state noise is very small or zero. This is because particles become identical within a few iterations, which is so called particle impoverishment (PI) phenomenon; consequently, no matter how many particles are employed, we do not have particle diversity regardless of if the impoverished particle is close to the true state value or not. In this paper, we investigate this PI phenomenon, and show an example problem where a classical KF approach outperforms PF approaches in terms of mean squared error (MSE) criterion. Furthermore, we compare the processing speed of the EKF and PF approaches, and show the better speed performance of classical EKF approaches. Therefore, PF approaches may not be always better option than the classical EKF for nonlinear problems. Specifically, we show the outperforming result of unscented Kalman filter compared to that of PF approaches (which are shown in Fig. 7(c) for processing speed performance, and Fig. 6 for MSE performance in the paper).
Impact of Upper Limb Joint Fluid Variation on Inflammatory Diseases Diagnosis
Hari, Krishnan G. ; Ananda, Natarajan R. ; Nanda, Anima ;
Journal of Electrical Engineering and Technology, volume 9, issue 6, 2014, Pages 2114~2117
DOI : 10.5370/JEET.2014.9.6.2114
Joint pain is generally a common disorder not only for the old aged people but also for the immunocompromised patients. The present proposed study reveals the presence of inflammatory diseases in joint generally diagnosed by removing synovial fluid and changes in the volume and composition are examined for the presence of WBC and crystals. This study implement a non-invasive approach to identify the changes in joint fluid by measuring the changes in electrical property of the synovial tissue under the influence of electrical current signal with frequency range between 100 kHz to 300 kHz. The response of tissue for the current signal was measured in terms of potential drop across the tissue. The hardware system design consists of input and output sections. The input section which applies current signal to upper limb joint region is made of ICL8038 function generator IC with amplifier and voltage to current converter. The output section picks voltage variation using metal surface electrode, amplifier, ADC, PIC microcontroller and LCD interface. 100 patient inclusive of normal and disease affected patients where examined for upper limb synovial fluid variation and inflammatory diseases were identified.
Secured Authentication through Integration of Gait and Footprint for Human Identification
Murukesh, C. ; Thanushkodi, K. ; Padmanabhan, Preethi ; Feroze, Naina Mohamed D. ;
Journal of Electrical Engineering and Technology, volume 9, issue 6, 2014, Pages 2118~2125
DOI : 10.5370/JEET.2014.9.6.2118
Gait Recognition is a new technique to identify the people by the way they walk. Human gait is a spatio-temporal phenomenon that typifies the motion characteristics of an individual. The proposed method makes a simple but efficient attempt to gait recognition. For each video file, spatial silhouettes of a walker are extracted by an improved background subtraction procedure using Gaussian Mixture Model (GMM). Here GMM is used as a parametric probability density function represented as a weighted sum of Gaussian component densities. Then, the relevant features are extracted from the silhouette tracked from the given video file using the Principal Component Analysis (PCA) method. The Fisher Linear Discriminant Analysis (FLDA) classifier is used in the classification of dimensional reduced image derived by the PCA method for gait recognition. Although gait images can be easily acquired, the gait recognition is affected by clothes, shoes, carrying status and specific physical condition of an individual. To overcome this problem, it is combined with footprint as a multimodal biometric system. The minutiae is extracted from the footprint and then fused with silhouette image using the Discrete Stationary Wavelet Transform (DSWT). The experimental result shows that the efficiency of proposed fusion algorithm works well and attains better result while comparing with other fusion schemes.
Fuzzy Based Shadow Removal and Integrated Boundary Detection for Video Surveillance
Niranjil, Kumar A. ; Sureshkumar, C. ;
Journal of Electrical Engineering and Technology, volume 9, issue 6, 2014, Pages 2126~2133
DOI : 10.5370/JEET.2014.9.6.2126
We present a scalable object tracking framework, which is capable of removing shadows and tracking the people. The framework consists of background subtraction, fuzzy based shadow removal and boundary tracking algorithm. This work proposes a general-purpose method that combines statistical assumptions with the object-level knowledge of moving objects, apparent objects, and shadows acquired in the processing of the previous frames. Pixels belonging to moving objects and shadows are processed differently in order to supply an object-based selective update. Experimental results demonstrate that the proposed method is able to track the object boundaries under significant shadows with noise and background clutter.
Smooth Wind Power Fluctuation Based on Battery Energy Storage System for Wind Farm
Wei, Zhang ; Moon, Byung Young ; Joo, Young Hoon ;
Journal of Electrical Engineering and Technology, volume 9, issue 6, 2014, Pages 2134~2141
DOI : 10.5370/JEET.2014.9.6.2134
This paper addresses on a wind power system with BESS(Battery Energy Storage System). The concerned system consists of four parts: the wind speed production model, the wind turbine model, configure capacity of the battery energy storage, battery model and control of the BESS. First of all, we produce wind speed by 4-component composite wind speed model. Secondly, the maximum available wind power is determined by analyzing the produced wind speed and the characteristic curve of wind power. Thirdly, we configure capacity of the BESS according to wind speed and characteristic curve of wind speed-power. Then, we propose a control strategy to track the power reference. Finally, some simulations have been demonstrated to visualize the feasibility of the proposed methodology.
An Evolutionary Optimized Algorithm Approach to Compensate the Non-linearity in Linear Variable Displacement Transducer Characteristics
Murugan, S. ; Umayal, S.P. ;
Journal of Electrical Engineering and Technology, volume 9, issue 6, 2014, Pages 2142~2153
DOI : 10.5370/JEET.2014.9.6.2142
Linearization of transducer characteristic plays a vital role in electronic instrumentation because all transducers have outputs nonlinearly related to the physical variables they sense. If the transducer output is nonlinear, it will produce a whole assortment of problems. Transducers rarely possess a perfectly linear transfer characteristic, but always have some degree of non-linearity over their range of operation. Attempts have been made by many researchers to increase the range of linearity of transducers. This paper presents a method to compensate nonlinearity of Linear Variable Displacement Transducer (LVDT) based on Extreme Learning Machine (ELM) method, Differential Evolution (DE) algorithm and Artificial Neural Network (ANN) trained by Genetic Algorithm (GA). Because of the mechanism structure, LVDT often exhibit inherent nonlinear input-output characteristics. The best approximation capability of optimized ANN technique is beneficial to this. The use of this proposed method is demonstrated through computer simulation with the experimental data of two different LVDTs. The results reveal that the proposed method compensated the presence of nonlinearity in the displacement transducer with very low training time, lowest Mean Square Error (MSE) value and better linearity. This research work involves less computational complexity and it behaves a good performance for nonlinearity compensation for LVDT and has good application prospect.
Weight Estimation of the Sea Cucumber (Stichopus japonicas) using Vision-based Volume Measurement
Lee, Donggil ; Kim, Seonghoon ; Park, Miseon ; Yang, Yongsu ;
Journal of Electrical Engineering and Technology, volume 9, issue 6, 2014, Pages 2154~2161
DOI : 10.5370/JEET.2014.9.6.2154
Growth analysis and selection of sea cucumbers (Stichopus japonicas) is typically performed through length or weight measurements. However, because sea cucumbers continuously change shape depending on the external environment, weight measurement has been the preferred approach. Weight measurements require extensive time and labor, moreover it is often difficult to accurately weigh sea cucumbers because of their wet surface. The present study measured sea cucumber features, including the body length, width, and thickness, by using a vision system and regression analysis to generate
values that were used to develop a weight estimation algorithm. The
value between the actual volume and weight of the sea cucumbers was 0.999, which was relatively high. Evaluation of the performance of this algorithm using cross-validation showed that the root mean square error and worst-case prediction error were 1.434 g and
, respectively. In addition, the present study confirmed that the proposed weight estimation algorithm and single slide rail device for weight measurement can measure weights at approximately 4,500 sea cucumbers per hour.
Automatic Manipulation of Tie Rod using Robot with 3D Sensing System
Ha, Jong-Eun ; Lee, Wang-Heon ;
Journal of Electrical Engineering and Technology, volume 9, issue 6, 2014, Pages 2162~2167
DOI : 10.5370/JEET.2014.9.6.2162
Robots are widely used in various automation processes in industrial applications. Traditionally, it operated under fixed condition by teaching operating positions. Recently, diverse 2D/3D sensors are used together with robot to give more flexibility in operation. In this paper, we deal with automatic manipulation of tie rod in automotive production line. Sensor system consisted of a camera and slit laser is used for the acquisition of 3D information and it is used attached on the robot. Nut runner is used for the manipulation of stop nut and adjust bolt on the tie rod. Detailed procedures for the automatic manipulation of tie rod are presented. In the presented approach, we effectively use 3D information in whole procedure such as computing distance to the tie rod, rotation angle of bolt and nut. Experimental results show the feasibility of the proposed algorithm.
A Generalized Loss Analysis Algorithm of Power Semiconductor Devices in Multilevel NPC Inverters
Alemi, Payam ; Lee, Dong-Choon ;
Journal of Electrical Engineering and Technology, volume 9, issue 6, 2014, Pages 2168~2180
DOI : 10.5370/JEET.2014.9.6.2168
In this paper, a generalized power loss algorithm for multilevel neutral-point clamped (NPC) PWM inverters is presented, which is applicable to any level number of multilevel inverters. In the case of three-level inverters, the conduction loss depends on the MI (modulation index) and the PF (power factor), and the switching loss depends on a switching frequency, turn-on and turn-off energy. However, in the higher level of inverters than the three-level, the loss of semiconductor devices cannot be analyzed by conventional methods. The modulation depth should be considered in addition, to find the different conducting devices depending on the MI. In a case study, the power loss analysis for the three- and five-level NPC inverters has been performed with the proposed algorithm. The validity of the proposed algorithm is verified by simulation for the three-and five-level NPC inverters and experiment for three-level NPC inverter.
The Design of Flux Barrier for Improvement of Demagnetization Endurance in BLDC Motor
Kim, Cheol-Min ; Kim, Dong-Yeong ; Cho, Gyu-Won ; Kim, Gyu-Tak ;
Journal of Electrical Engineering and Technology, volume 9, issue 6, 2014, Pages 2181~2186
DOI : 10.5370/JEET.2014.9.6.2181
Generally, the motor inside vehicle is exposed to highly ambient temperature and large vibration according to repeatedly starting and stopping for very short time. So, in this paper, the rotor shape design was performed to improve demagnetization endurance by considering the starting current of the Brushless DC (BLDC) Motor through the Finite Element Method(FEM). As a result, the partial irreversible demagnetization was occurred by starting current at the end of Permanent Magnets of the basic model. To solve this problem, the flux barrier design was performed and the flux on the rotor core was limited. Accordingly, demagnetization endurance and operating characteristics were improved.
Optimization of Magnetic Flux-path Design for Reduction of Shaft Voltage in IPM-Type BLDC Motor
Kim, Kyung-Tae ; Hur, Jin ;
Journal of Electrical Engineering and Technology, volume 9, issue 6, 2014, Pages 2187~2193
DOI : 10.5370/JEET.2014.9.6.2187
In this paper, we propose a method for suppressing shaft voltage by modifying the rotor shape and the permanent magnets in interior permanent magnet type high voltage motors. The shaft voltage, which adversely affects the bearing by occurring bearing current, is induced by parasitic components and the leakage flux in motor-driven systems as well as inherent linkage flux between main magnetic flux and shaft according to rotor configuration. Thus, shaft voltage should be analyzed and considered under inverter-driven and non-inverter-driven conditions because inherent linkage flux can analyze under non-inverter-driven condition. In this study, we designed re-arrangement magnet and re-structuring rotor to minimize the shaft voltage. In addition, we optimized the proposed models. The shaft voltage suppression effect of the designed model was validated experimentally and by comparative finite element analysis.
Design and Operation Characteristics of Novel 2-Phase 6/5 Switched Reluctance Motor
Hieu, Pham Trung ; Lee, Dong-Hee ; Ahn, Jin-Woo ;
Journal of Electrical Engineering and Technology, volume 9, issue 6, 2014, Pages 2194~2200
DOI : 10.5370/JEET.2014.9.6.2194
This paper presents a design of novel 2-phase 6/5 switched reluctance motor (SRM) for an air-blower application. This type of motor is suitable for the applications that require high speed and only one directional rotation as air-blower. The desired air-blower is unidirectional application, and requires a wide positive torque region without torque dead-zone. In order to get a wide positive torque region without torque dead-zone during phase commutation, asymmetric inductance characteristic with non-uniform air-gap is considered. The proposed motor can be operated at any rotor position. The proposed 6/5 SRM uses short flux path technique that achieved by means of winding configuration and lamination geometry. The purpose of short flux path is to reduce the core loss and the absorption MMF in the stator. The proposed 2-phase 6/5 SRM is verified by finite element method (FEM) analysis and Matlab-Simulink. In order to verify the design, a prototype of the proposed motor was manufactured for practical system.
Phase Advance Control to Reduce Torque Ripple of Brush-less DC Motor According to Winding Connection, Wye and Delta
Lee, Tae-Yong ; Song, Jun-Young ; Kim, Jaehong ; Kim, Yong-Jae ; Jung, Sang-Yong ; Je, Jung-Moon ;
Journal of Electrical Engineering and Technology, volume 9, issue 6, 2014, Pages 2201~2208
DOI : 10.5370/JEET.2014.9.6.2201
In this research, the characteristics of Brush-less DC (BLDC) motor in accordance with winding connection method, both Y-connection and D -connection, has been identified with design methodology simply. BLDC motor has been designed for both winding connections, and their torque analysis has been performed considering ideal current source analysis and voltage source analysis with 6-step control. In addition, to reduce torque ripple of BLDC motor, caused by coil inductance, on voltage source analysis with 6-step control, we have proposed suitable control method which is Phase Advance Control. It is verified that the torque ripple has been decreased by virtue of phase advance control, advancing and widening conduction angle of switching, via performance analysis by Finite Element Analysis.
Design and Analysis of a Permanent-Magnet-Assisted Switched Reluctance Motor
Hwang, Hongsik ; Hur, Jin ; Lee, Cheewoo ;
Journal of Electrical Engineering and Technology, volume 9, issue 6, 2014, Pages 2209~2217
DOI : 10.5370/JEET.2014.9.6.2209
A permanent-magnet-assisted switched reluctance motor (SRM) having small excitation poles, where phase coils are concentrically wound on the poles and thin permanent magnets are inserted inside the poles, is proposed in this paper. The insertion of permanent magnets into the stator excitation poles has a significant influence on positive torque improvement leading to a boost in efficiency. Three key design parameters such as the thickness of permanent magnets, space between two adjacent permanent magnets, and the width of stator excitation poles are determined during a design procedure in terms of the enhancement of positive torque. Step-by-step design modification and a comparison between the proposed permanent-magnet-assisted SRM and no-permanent-magnet SRM have been conducted by means of static torque comparison along with dynamic performance. The first prototype from steel laminations up to its physical assembly has been constructed.
Defect Estimation of a Crack in Underground Pipelines by CMFL Type NDT System
Kim, Hui Min ; Park, Gwan Soo ;
Journal of Electrical Engineering and Technology, volume 9, issue 6, 2014, Pages 2218~2223
DOI : 10.5370/JEET.2014.9.6.2218
A crack which is axially oriented with small size is hard to detect in conventional system. CMFL(Circumferential Magnetic Flux Leakage) type PIG(Pipelines Inspection Gauge) in the NDT(Nondestructive Testing), is operated to detect this defect called axially oriented cracks in the pipe. It is necessary to decompose the size and shapes of cracks for the maintenance of underground pipelines. This article is mainly focused on the decomposing method of the size and shape of the axially oriented cracks by using inspection signal data for defect.
Performance Improvement of Isolated High Voltage Full Bridge Converter Using Voltage Doubler
Lee, Hee-Jun ; Shin, Soo-Cheol ; Hong, Seok-Jin ; Hyun, Seung-Wook ; Lee, Jung-Hyo ; Won, Chung-Yuen ;
Journal of Electrical Engineering and Technology, volume 9, issue 6, 2014, Pages 2224~2236
DOI : 10.5370/JEET.2014.9.6.2224
The performance of an isolated high voltage full bridge converter is improved using a voltage doubler. In a conventional high voltage full bridge converter, the diode of the transformer secondary voltage undergoes a voltage spike due to the leakage inductance of the transformer and the resonance occurring with the parasitic capacitance of the diode. In addition, in the phase shift control, conduction loss largely increases from the freewheeling mode because of the circulating current. The efficiency of the converter is thus reduced. However, in the proposed converter, the high voltage dual converter consists of a voltage doubler because the circulating current of the converter is reduced to increase efficiency. On the other hand, in the proposed converter, an input current is distributed when using parallel input / serial output and the output voltage can be doubled. However, the voltages in the 2 serial DC links might be unbalanced due to line impedance, passive and active components impedance, and sensor error. Considering these problems, DC injection is performed due to the complementary operations of half bridge inverters as well as the disadvantage of the unbalance in the DC link. Therefore, the serial output of the converter needs to control the balance of the algorithm. In this paper, the performance of the conventional converter is improved and a balance control algorithm is proposed for the proposed converter. Also, the system of the 1.5[kW] PCS is verified through an experiment examining the operation and stability.