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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 10, Issue 6 - Nov 2015
Volume 10, Issue 5 - Sep 2015
Volume 10, Issue 4 - Jul 2015
Volume 10, Issue 3 - May 2015
Volume 10, Issue 2 - Mar 2015
Volume 10, Issue 1 - Jan 2015
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Harmonic Distortion Contribution for the Transmission Loss Allocation in Deregulated Energy Market: A New Scheme for Industry Consumer
Nojeng, Syarifuddin ; Hassan, Mohammad Yusri ; Said, Dalila Mat ; Abdullah, Md.Pauzi ; Hussin, Faridah ;
Journal of Electrical Engineering and Technology, volume 10, issue 1, 2015, Pages 1~7
DOI : 10.5370/JEET.2015.10.1.001
The industry has rapidly growth and energy supply technology advanced are become main factor which to contribute of the harmonic losses. This problem is one aspect that may affect the capability of the transmission line and also to the efficiency of electricity. This paper proposes a new scheme to allocate the cost pertaining to transmission loss due to harmonics. The proposed method, called as Generalized Harmonic Distribution Factor, uses the principle of proportional sharing method to allocate the losses among the transmission users especially for industry consumers. The IEEE 14- and 30 bus test system is used to compare the proposed method with existing method. The results showed that the proposed method provided a scheme better in allocating the cost of transmission loss, which could encourage the users to minimize the losses.
Power Flow Control of a Multi-bus/Three-feeder Distribution System Using Generalized Unified Power Quality Conditioner
Mohammed, B.S. ; Ibrahim, R. ; Perumal, N. ; Rao, K.S. Rama ;
Journal of Electrical Engineering and Technology, volume 10, issue 1, 2015, Pages 8~17
DOI : 10.5370/JEET.2015.10.1.008
This paper analyses the power flow of a three-feeder/multi-bus distribution system by a custom Generalized Power Quality Conditioner (GUPQC). The GUPQC has been realized by three voltage source converters (VSCs) coupled back-to-back through a common DC-link capacitor on the DC-side. One feeder was controlled by the shunt compensator, whereas each of the other two feeders was controlled by the proposed novel series compensator. The GUPQC has the capability to simultaneously compensate voltage and current quality problems of a multi-bus/three-feeder distribution system. Besides that, the power can be transferred from one feeder to other feeders to compensate for poor power quality problems. Extensive simulation studies were carried out by using MATLAB/SIMULINK software to establish the ability of the GUPQC to improve power quality of the distribution systems under distorted supply voltage conditions.
A Substation-Oriented Approach to Optimal Phasor Measurement Units Placement
Bao, Wei ; Guo, Rui-Peng ; Han, Zhen-Xiang ; Chen, Li-Yue ; Lu, Min ;
Journal of Electrical Engineering and Technology, volume 10, issue 1, 2015, Pages 18~29
DOI : 10.5370/JEET.2015.10.1.018
State Estimation (SE) is the basis of a variety of advanced applications used in most modern power systems. An SE problem formed with enough phasor measurement units (PMUs) data is simply a linear weighted least squares problem requiring no iterations. Thus, designing a minimum-cost placement of PMUs that guarantees observability of a power system becomes a worthy challenge. This paper proposes an equivalent integer linear programming method for substation-oriented optimal PMU placement (SOOPP). The proposed method uses an exhaustive search to determine a globally optimal solution representing the best PMU placement for that particular power system. To obtain a more comprehensive model, contingencies and the limitation of the number of PMU measurement channels are considered and embodied in the model as changes to the original constraints and as additional constraints. The proposed method is examined for applicability using the IEEE 14-bus, 118-bus and 300-bus test systems. The comparison between SOOPP results and results obtained by other methods reveals the excellence of SOOPP. Furthermore, practical large-scale power systems are also successfully analyzed using SOOPP.
Design of DC Side Voltage and Compensation Analysis of THD for Shunt Power Quality Controller under System Load of Rectifier with R-L Load
Zhao, Guopeng ; Han, Minxiao ;
Journal of Electrical Engineering and Technology, volume 10, issue 1, 2015, Pages 30~40
DOI : 10.5370/JEET.2015.10.1.030
For a shunt power quality controller (SPQC) the DC side voltage value which is closely related to the compensation performance is a significant parameter. Buy so far, very little discussion has been conducted on this in a quantitative manner by previous publications. In this paper, a method to design the DC side voltage of SPQC is presented according to the compensation performance in the single-phase system and the three-phase system respectively. First, for the reactive current and the harmonic current compensation, a required minimal value of the DC side voltage with a zero total harmonic distortion (THD) of the source current and a unit power factor is obtained for a typical load, through the equivalent circuit analysis and the Fourier Transform analytical expressions. Second, when the DC side voltage of SPQC is lower than the above-obtained minimal value, the quantitative relationship between the DC side voltage and the THD after compensation is also elaborated using the curve diagram. Hardware experimental results verify the design method.
Prediction of Wind Power by Chaos and BP Artificial Neural Networks Approach Based on Genetic Algorithm
Huang, Dai-Zheng ; Gong, Ren-Xi ; Gong, Shu ;
Journal of Electrical Engineering and Technology, volume 10, issue 1, 2015, Pages 41~46
DOI : 10.5370/JEET.2015.10.1.041
It is very important to make accurate forecast of wind power because of its indispensable requirement for power system stable operation. The research is to predict wind power by chaos and BP artificial neural networks (CBPANNs) method based on genetic algorithm, and to evaluate feasibility of the method of predicting wind power. A description of the method is performed. Firstly, a calculation of the largest Lyapunov exponent of the time series of wind power and a judgment of whether wind power has chaotic behavior are made. Secondly, phase space of the time series is reconstructed. Finally, the prediction model is constructed based on the best embedding dimension and best delay time to approximate the uncertain function by which the wind power is forecasted. And then an optimization of the weights and thresholds of the model is conducted by genetic algorithm (GA). And a simulation of the method and an evaluation of its effectiveness are performed. The results show that the proposed method has more accuracy than that of BP artificial neural networks (BP-ANNs).
Analyzing Stability of Jeju Island Power System with Modular Multilevel Converter Based HVDC System
Quach, Ngoc-Thinh ; Lee, Do Heon ; Kim, Ho-Chan ; Kim, Eel-Hwan ;
Journal of Electrical Engineering and Technology, volume 10, issue 1, 2015, Pages 47~55
DOI : 10.5370/JEET.2015.10.1.047
This paper proposes the installation of a new modular multilevel converter based high-voltage direct current (MMC-HVDC) system to connect between mainland and Jeju island power systems in Korea in 2020. The purpose is to combine with two old line-commutated converters (LCC)-based HVDC system to achieve a stability of the Jeju island power system. The operation of the overall system will be analyzed in three cases: (i) wind speed is variable, (ii) either one of the LCC-HVDC systems is shutdown because of a fault or overhaul, (iii) a short circuit fault occurs at the mainland side. The effectiveness of the proposed control method is confirmed by the simulation results based on a PSCAD/EMTDC simulation program.
Real Coded Biogeography-Based Optimization for Environmental Constrained Dynamic Optimal Power Flow
Kumar, A. Ramesh ; Premalatha, L. ;
Journal of Electrical Engineering and Technology, volume 10, issue 1, 2015, Pages 56~63
DOI : 10.5370/JEET.2015.10.1.056
The optimization is an important role in wide geographical distribution of electrical power market, finding the optimum solution for the operation and design of power systems has become a necessity with the increasing cost of raw materials, depleting energy resources and the ever growing demand for electrical energy. In this paper, the real coded biogeography based optimization is proposed to minimize the operating cost with optimal setting of equality and inequality constraints of thermal power system. The proposed technique aims to improve the real coded searing ability, unravel the prematurity of solution and enhance the population assortment of the biogeography based optimization algorithm by using adaptive Gaussian mutation. This algorithm is demonstrated on the standard IEEE-30 bus system and the comparative results are made with existing population based methods.
The Consumer Rationality Assumption in Incentive Based Demand Response Program via Reduction Bidding
Babar, Muhammad ; Imthias Ahamed, T.P. ; Alammar, Essam A. ;
Journal of Electrical Engineering and Technology, volume 10, issue 1, 2015, Pages 64~74
DOI : 10.5370/JEET.2015.10.1.064
Because of the burgeoning demand of the energy, the countries are finding sustainable solutions for these emerging challenges. Demand Side Management is playing a significant role in managing the demand with an aim to support the electrical grid during the peak hours. However, advancement in controls and communication technologies, the aggregators are appearing as a third party entity in implementing demand response program. In this paper, a detailed mathematical framework is discussed in which the aggregator acts as an energy service provider between the utility and the consumers, and facilitate the consumers to actively participate in demand side management by introducing the new concept of demand reduction bidding (DRB) under constrained direct load control. Paper also presented an algorithm for the proposed framework and demonstrated the efficacy of the algorithm by considering few case studies and concluded with simulation results and discussions.
Design and Implementation of Solar PV for Power Quality Enhancement in Three-Phase Four-Wire Distribution System
Guna Sekar, T. ; Anita, R. ;
Journal of Electrical Engineering and Technology, volume 10, issue 1, 2015, Pages 75~82
DOI : 10.5370/JEET.2015.10.1.075
This paper presents a new technique for enhancing power quality by reducing harmonics in the neutral conductor. Three-Phase Four-Wire (3P4W) system is commonly used where single and three phase loads are connected to Point of Common Coupling (PCC). Due to unbalance loads, the 3P4W distribution system becomes unbalance and current flows in the neutral conductor. If loads are non-linear, then the harmonic content of current will flow in neutral conductor. The neutral current that may flow towards transformer neutral point is compensated by using a series active filter. In order to reduce the harmonic content, the series active filter is connected in series with the neutral conductor by which neutral and phase current harmonics are reduced significantly. In this paper, solar PV based inverter circuit is proposed for compensating neutral current harmonics. The simulation is carried out in MATLAB/SIMULINK and also an experimental setup is developed to verify the effectiveness of the proposed method.
Preventive and Emergency Control of Power System for Transient Stability Enhancement
Siddiqui, Shahbaz A. ; Verma, Kusum ; Niazi, K.R. ; Fozdar, Manoj ;
Journal of Electrical Engineering and Technology, volume 10, issue 1, 2015, Pages 83~91
DOI : 10.5370/JEET.2015.10.1.083
This paper presents preventive and emergency control measures for on line transient stability (security) enhancement. For insecure operating state, generation rescheduling based on a real power generation shift factor (RPGSF) is proposed as a preventive control measure to bring the system back to secure operating state. For emergency operating state, two emergency control strategies namely generator shedding and load shedding have been developed. The proposed emergency control strategies are based on voltage magnitudes and rotor trajectories data available through Phasor Measurement Units (PMUs) installed in the systems. The effectiveness of the proposed approach has been investigated on IEEE-39 bus test system under different contingency and fault conditions and application results are presented.
Power Quality Warning of High-Speed Rail Based on Multi-Features Similarity
Bai, Jingjing ; Gu, Wei ; Yuan, Xiaodong ; Li, Qun ; Chen, Bing ; Wang, Xuchong ;
Journal of Electrical Engineering and Technology, volume 10, issue 1, 2015, Pages 92~101
DOI : 10.5370/JEET.2015.10.1.092
As one type of power quality (PQ) disturbance sources, high-speed rail (HSR) can have major impacts on the power supply grid. Providing timely and accurate warning information for PQ problems of HSR is important for the safe and stable operation of traction power supply systems and the power supply grid. This study proposes a novel warning approach to identify PQ problems and provide warning prompts based on the monitored data of HSR. To embody the displacement and status change of monitored data, multi-features of different sliding windows are computed. To reflect the relative importance degree of these features in the overall evaluation, an analytic hierarchy process (AHP) is used to analyse the weights of multi-features. Finally, a multi-features similarity algorithm is applied to analyse the difference between monitored data and the reference data of HSR, and PQ warning results based on dynamic thresholds can be analysed to quantify its severity. Cases studies demonstrate that the proposed approach is effective and feasible, and it has now been applied to an actual PQ monitoring platform.
A Study on the Agent (Protective Device)-based Fault Determination and Separation Methodology for Smart Grid Distribution System
Ko, Yun-Seok ;
Journal of Electrical Engineering and Technology, volume 10, issue 1, 2015, Pages 102~108
DOI : 10.5370/JEET.2015.10.1.102
This paper proposes a new fault isolation methodology for a smart protective device which plays an agent role on the smart grid distribution system with the distributed generation. It, by itself, determines accurately whether its protection zone is fault or not, identifies the fault zone and separates the fault zone through the exchange of fault information such as the current information and the voltage information with other protective devices using bi-directional communication capabilities on the smart grid distribution system. The heuristic rules are obtained from the structure and electrical characteristics determined according to the location of the fault and DG (Distributed Generation) when faults such as single-phase ground fault, phase-to-phase short fault and three-phase short fault occur on the smart grid distribution system with DG.
Performance Comparison of Optimal Power Flow Algorithms for LMP Calculations of the Full Scale Korean Power System
Lee, Sungwoo ; Kim, Wook ; Kim, Balho H. ;
Journal of Electrical Engineering and Technology, volume 10, issue 1, 2015, Pages 109~117
DOI : 10.5370/JEET.2015.10.1.109
This paper proposes the comparison results of various optimal power flow algorithms (OPF) to calculate the locational marginal prices (LMP) of the unreduced full scale Korean transmission system. Five different types of optimal power flow models are employed: Full AC OPF, Cubic AC OPF, Quadratic AC OPF, Linear AC OPF and DC OPF. As the results, full AC OPF and cubic AC OPF model provides LMP calculation results very similar to each other while the calculation time of cubic AC OPF model is faster than that of the Full AC OPF. Other simplified OPF models, quadratic AC OPF, linear AC OPF and DC OPF offer erroneous results even though the calculation times are much faster than the Full AC OPF and the Cubic AC OPF. Given the condition that the OPF models sometimes fail to find the optimal solution due to the severe complexity of the Korean transmission power system, the Full AC OPF should be used as the primary OPF model while the Cubic AC OPF can be a promising backup OPF model for the LMP calculations and/or real-time operation.
Torque Ripple Minimization Scheme Using Torque Sharing Function Based Fuzzy Logic Control for a Switched Reluctance Motor
Ro, Hak-Seung ; Lee, Kyoung-Gu ; Lee, June-Seok ; Jeong, Hae-Gwang ; Lee, Kyo-Beum ;
Journal of Electrical Engineering and Technology, volume 10, issue 1, 2015, Pages 118~127
DOI : 10.5370/JEET.2015.10.1.118
This paper presents an advanced torque ripple minimization method of a switched reluctance motor (SRM) using torque sharing function (TSF). Generally, TSF is applied into the torque control. However, the conventional TSF cannot follow the expected torque well because of the nonlinear characteristics of the SRM. Moreover, the tail current that is generated at a high speed motor drive makes unexpected torque ripples. The proposed method combined TSF with fuzzy logic control (FLC). The advantage of this method is that the torque can be controlled unity at any conditions. In addition, the controller can track the torque under the condition of the wrong TSF. The effectiveness of the proposed algorithm is verified by the simulations and experiments.
Analysis of a New Parallel Three-Level Zero-Voltage Switching DC Converter
Lin, Bor-Ren ; Chen, Jeng-Yu ;
Journal of Electrical Engineering and Technology, volume 10, issue 1, 2015, Pages 128~137
DOI : 10.5370/JEET.2015.10.1.128
A novel parallel three-level zero voltage switching (ZVS) DC converter is presented for medium voltage applications. The proposed converter includes three sub-circuits connected in parallel with the same power switches to share load current and reduce the current stress of passive components at the output side. Thus, the size of the output chokes is reduced and the switch counts in the proposed converter are less that in the conventional parallel three-level DC/DC converter. Each sub-circuit combines one half-bridge converter and one three-level converter. The transformer secondary windings of these two converters are connected in series in order to reduce the size of output inductor. Due to the three-level circuit topology, the voltage stress of power switches is equal to
. Based on the resonant behavior by the output capacitance of power switches and the leakage inductance (or external inductance) at the transition interval, each switch can be turned on under ZVS. Finally, experiments based on a 2 kW prototype are provided to verify the performance of the proposed converter.
Advanced Static Over-modulation Scheme using Offset Voltages Injection for Simple Implementation and Less Harmonics
Lee, Dong-Myung ;
Journal of Electrical Engineering and Technology, volume 10, issue 1, 2015, Pages 138~145
DOI : 10.5370/JEET.2015.10.1.138
In this paper, a novel static overmodulation scheme (OVM) for space-vector PWM (SVPWM) is proposed. The proposed static OVM scheme uses the concept of adding offset voltages in linear region as well as overmodulation region to fully utilize DC-link voltage. By employing zero sequence voltage injection, the proposed scheme reduces procedures for achieving SVPWM such as complicated gating time calculation. In addition, this paper proposes a stepwise discontinuous angle movement in high modulation region in order to reduce Total Harmonic Distortion (THD). The validity of the proposed scheme is verified through theoretical analysis and experimental results.
A Supercapacitor Remaining Energy Control Method for Smoothing a Fluctuating Renewable Energy Power
Lee, Wujong ; Cha, Hanju ;
Journal of Electrical Engineering and Technology, volume 10, issue 1, 2015, Pages 146~154
DOI : 10.5370/JEET.2015.10.1.146
This paper proposes a control method for maintaining the energy level for a supercapacitor energy storage system coupled with a wind generator to stabilize wind power output. Although wind power is green and clean energy source, disadvantage of the renewable energy output power is fluctuation. In order to mitigate the fluctuating output power, supercapacitor energy storage system (SCESS) and wind power simulator is developed. A remaining energy supercapacitor (RESC) control is introduced and analyzed to smooth for short-term fluctuating power and maintain the supercapacitor voltage within the designed operating range in the steady as well as transient state. When the average and fluctuating component of power increases instantaneously, the RESC compensates fluctuating power and the variation of fluctuating power is reduced 100% to 30% at 5kW power. Furthermore, supercapacitor voltage is maintained within the operating voltage range and near 50% of total energy. Feasibility of SCESS with RESC control is verified through simulation and experiment.
Comparison of Two Rotor Configurations by Changing the Amount of Magnet and Reluctance Components
Beser, Esra Kandemir ; Camur, Sabri ; Arifoglu, Birol ; Beser, Ersoy ;
Journal of Electrical Engineering and Technology, volume 10, issue 1, 2015, Pages 155~164
DOI : 10.5370/JEET.2015.10.1.155
In this paper, two rotor configurations including different amount of magnet and reluctance parts are presented. The rotors are constituted by means of a flexible hybrid motor structure. Considerable features of the hybrid structure are that the combination of the magnet and reluctance parts can be suitably modified and the mechanical angle (
) between the parts can also be varied. Two hybrid rotor configurations have been considered in this study. First, finite element (FE) simulations were carried out and the torque behaviors of the motors were predicted. The average torque (
) and maximum torque (
) curves were obtained from FE simulations in order to find suitable
. Mathematical model of the motors was formed in terms of a,b,c variables considering the amount of the magnet and reluctance parts on the rotor and simulations were performed. Rotor prototypes, motor drive and drive method were introduced. Torque profiles of the motors were obtained by static torque measurement and loaded tests were also realized. Thus, simulation results were verified by experimental study. There is a good match between predictions and measurements. The proposed motors are operated with electrical
mode as a brushless DC motor (BLDC) and torque versus speed characteristics show a compound DC motor characteristic. The motors can be named as brushless DC compound motors.
Model Predictive Control of Bidirectional AC-DC Converter for Energy Storage System
Akter, Md. Parvez ; Mekhilef, Saad ; Tan, Nadia Mei Lin ; Akagi, Hirofumi ;
Journal of Electrical Engineering and Technology, volume 10, issue 1, 2015, Pages 165~175
DOI : 10.5370/JEET.2015.10.1.165
Energy storage system has been widely applied in power distribution sectors as well as in renewable energy sources to ensure uninterruptible power supply. This paper presents a model predictive algorithm to control a bidirectional AC-DC converter, which is used in an energy storage system for power transferring between the three-phase AC voltage supply and energy storage devices. This model predictive control (MPC) algorithm utilizes the discrete behavior of the converter and predicts the future variables of the system by defining cost functions for all possible switching states. Subsequently, the switching state that corresponds to the minimum cost function is selected for the next sampling period for firing the switches of the AC-DC converter. The proposed model predictive control scheme of the AC-DC converter allows bidirectional power flow with instantaneous mode change capability and fast dynamic response. The performance of the MPC controlled bidirectional AC-DC converter is simulated with MATLAB/Simulink(R) and further verified with 3.0kW experimental prototypes. Both the simulation and experimental results show that, the AC-DC converter is operated with unity power factor, acceptable THD (3.3% during rectifier mode and 3.5% during inverter mode) level of AC current and very low DC voltage ripple. Moreover, an efficiency comparison is performed between the proposed MPC and conventional VOC-based PWM controller of the bidirectional AC-DC converter which ensures the effectiveness of MPC controller.
Multi-field Coupling Simulation and Experimental Study on Transformer Vibration Caused by DC Bias
Wang, Jingang ; Gao, Can ; Duan, Xu ; Mao, Kai ;
Journal of Electrical Engineering and Technology, volume 10, issue 1, 2015, Pages 176~187
DOI : 10.5370/JEET.2015.10.1.176
DC bias will cause abnormal vibration of transformers. Aiming at such a problem, transformer vibration affected by DC bias has been studied combined with transformer core and winding vibration mechanism use multi-physical field simulation software COMSOL in this paper. Furthermore the coupling model of electromagnetic-structural force field has been established, and the variation pattern of inner flux density, distribution of mechanical stress, tension and displacement were analyzed based on the coupling model. Finally, an experiment platform has been built up which was employed to verify the correctness of model.
Data Interpolation and Design Optimisation of Brushless DC Motor Using Generalized Regression Neural Network
Umadevi, N. ; Balaji, M. ; Kamaraj, V. ; Padmanaban, L. Ananda ;
Journal of Electrical Engineering and Technology, volume 10, issue 1, 2015, Pages 188~194
DOI : 10.5370/JEET.2015.10.1.188
This paper proposes a generalized regression neural network (GRNN) based algorithm for data interpolation and design optimization of brushless dc (BLDC) motor. The procedure makes use of magnet length, stator slot opening and air gap length as design variables. Cogging torque and average torque are treated as performance indices. The optimal design necessitates mitigating the cogging torque and maximizing the average torque by varying design variables. The data set for interpolation and ensuing design optimisation using GRNN is obtained by modeling a standard BLDC motor using finite element analysis (FEA) tool MagNet 7.1.1. The performance indices of the standard motor obtained using FEA are validated with an experimental model and an analytical method. The optimal design is authenticated using particle swarm optimization (PSO) algorithm and the performance indices of the optimal design obtained using GRNN is validated using FEA. The results indicate the suitability of GRNN as an interpolation and design optimization tool for a BLDC motor.
Cost-Effective APF/UPS System with Seamless Mode Transfer
Lee, Woo-Cheol ;
Journal of Electrical Engineering and Technology, volume 10, issue 1, 2015, Pages 195~204
DOI : 10.5370/JEET.2015.10.1.195
In this paper, the development of a cost-effective active power filter/uninterruptible power supply (APF/UPS) system with seamless mode transfer is described. The proposed scheme employs a pulse-width-modulation (PWM) voltage-source inverter and has two operational modes. First, when the source voltage is normal, the system operates as an APF, which compensates for the harmonics and power factor while boosting the DC-link voltage to be ready for the disturbance, without an additional DC charging circuit. A simple algorithm to detect the load current harmonics is also proposed. Second, when the source voltage is out of the normal range (owing to sag, swell, or outage), it operates a UPS, which controls the output voltage constantly by discharging the DC-link capacitor. Furthermore, a seamless transfer method for the single-phase inverter between the APF mode and the UPS mode is also proposed, in which an IGBT switch with diodes is used as a static bypass switch. Dissimilar to a conventional SCR switch, the IGBT switch can implement a seamless mode transfer. During the UPS operation, when the source voltage returns to the normal range, the system operates as an APF. The proposed system has good transient and steady-state response characteristics. The APF, charging circuit, and UPS systems are implemented in one inverter system. Finally, the validity of the proposed scheme is investigated with simulated and experimental results for a prototype APF/UPS system rated at 3 kVA.
Common Model EMI Prediction in Motor Drive System for Electric Vehicle Application
Yang, Yong-Ming ; Peng, He-Meng ; Wang, Quan-Di ;
Journal of Electrical Engineering and Technology, volume 10, issue 1, 2015, Pages 205~215
DOI : 10.5370/JEET.2015.10.1.205
Common mode (CM) conducted interference are predicted and compared with experiments in a motor drive system of Electric vehicles in this study. The prediction model considers each part as an equivalent circuit model which is represented by lumped parameters and proposes the parameter extraction method. For the modeling of the inverter, a concentrated and equivalent method is used to process synthetically the CM interference source and the stray capacitance. For the parameter extraction in the power line model, a computation method that combines analytical method and finite element method is used. The modeling of the motor is based on measured date of the impedance and vector fitting technique. It is shown that the parasitic currents and interference voltage in the system can be simulated in the different parts of the prediction model in the conducted frequency range (150 kHz-30 MHz). Experiments have successfully confirmed that the approach is effective.
Control and Design of a Arc Power Supply for KSTAR's the Neutral Beam Injection
Ryu, Dong-Kyun ; Lee, Hee-Jun ; Lee, Jung-Hyo ; Won, Chung-Yuen ;
Journal of Electrical Engineering and Technology, volume 10, issue 1, 2015, Pages 216~226
DOI : 10.5370/JEET.2015.10.1.216
The neutral beam injection generate ultra-high temperature energy in the tokamak of nuclear fusion. The neutral beam injection make up arc power supply, filament power supply and acceleration & deceleration power supply. The arc power supply has characteristics of low voltage and high current. Arc power supply generate arc through constant output of voltage and current. So this paper proposed suitable buck converter for low voltage and high current. The proposed buck converter used parallel switch because it can be increased capacity and decrease conduction loss. When an arc generated, the neutral beam injection chamber occur high voltage. And it will break output capacitor of buck converter. Therefore the output capacitor was removed in the proposed converter. Thus the proposed converter should be designed for the characteristics of low voltage and high current. Also, the arc power supply should be guaranteed for system stability. The proposed parallel buck converter enables the system stability of the divided low output voltage and high current. The proposed converter with constant output be the most important design of the output inductor. In this paper, designed arc power supply verified operation of system and stability through simulation and prototype. After it is applied to the 288[kW] arc power supply for neutral beam injection.
Imposed Weighting Factor Optimization Method for Torque Ripple Reduction of IM Fed by Indirect Matrix Converter with Predictive Control Algorithm
Uddin, Muslem ; Mekhilef, Saad ; Rivera, Marco ; Rodriguez, Jose ;
Journal of Electrical Engineering and Technology, volume 10, issue 1, 2015, Pages 227~242
DOI : 10.5370/JEET.2015.10.1.227
This paper proposes a weighting factor optimization method in predictive control algorithm for torque ripple reduction in an induction motor fed by an indirect matrix converter (IMC). In this paper, the torque ripple behavior is analyzed to validate the proposed weighting factor optimization method in the predictive control platform and shows the effectiveness of the system. Therefore, an optimization method is adopted here to calculate the optimum weighting factor corresponds to minimum torque ripple and is compared with the results of conventional weighting factor based predictive control algorithm. The predictive control algorithm selects the optimum switching state that minimizes a cost function based on optimized weighting factor to actuate the indirect matrix converter. The conventional and introduced weighting factor optimization method in predictive control algorithm are validated through simulations and experimental validation in DS1104 R&D controller platform and show the potential control, tracking of variables with their respective references and consequently reduces the torque ripple.
A Novel Skewed-Type Iron Slot Wedge for Permanent Magnet Synchronous Generators for Improving Output Power and Reducing Cogging Torque
Kang, Sun-Il ; Moon, Jae-Won ; You, Yong-Min ; Lee, Jin-Hee ; Kwon, Byung-Il ;
Journal of Electrical Engineering and Technology, volume 10, issue 1, 2015, Pages 243~250
DOI : 10.5370/JEET.2015.10.1.243
This paper proposes a novel skewed-type iron slot wedge that can improve both the cogging torque and the output power of a permanent magnet synchronous generator (PMSG). Generally the open slot structure is adopted in a PMSG due to its convenient winding work, but the high cogging torque is undesired. Firstly, an iron slot wedge was utilized to reduce the cogging torque of an open slot type PMSG. However, the output power of the machine decreased rapidly with this method. Thus, a proposed skewed type iron slot wedge is presented to improve the output power as well as the cogging torque as compared to the open slot type. Shape optimization of the skewed-type iron slot wedge is performed to simultaneously maximize the output power and reduce the cogging torque. The Kriging model based on the Halton sequence method and a genetic algorithm are used to optimize the design.
A Novel Space Vector modulation Scheme and Direct Torque Control for Four-switch BLDCM Using Flux Observer
Pan, Lei ; Wang, Beibei ; Su, Gang ; Cheng, Baohua ; Peng, Guili ;
Journal of Electrical Engineering and Technology, volume 10, issue 1, 2015, Pages 251~260
DOI : 10.5370/JEET.2015.10.1.251
The main purpose of this paper is to describe a DTC (direct torque control) method for four-switch brushless dc motor (BLDCM) drive. In the method, a novel voltage space vector modulation scheme, an optimal switching table, and a flux observation method are proposed. Eight voltage vectors are summarized, which are selected to control BLDCM in SVPWM pattern, and an optimal switching table is proposed to improve the torque distortion caused by midpoint current of the split capacitors. Unlike conventional flux observers, this observer does not require speed adaptation and is not susceptible to speed estimation errors, especially, at low speed. Global asymptotic stability of the flux observer is guaranteed by the Lyapunov stability analysis. DC-offset effects are mitigated by introducing a PI component in the observer gains. This method alleviates the undesired current and torque distortion which is caused by uncontrollable phase. The correctness and feasibility of the method are proved by simulation and experimental results.
Optimal Harmonic Stepped Waveform Technique for Solar Fed Cascaded Multilevel Inverter
Alexander, S.Albert ; Thathan, Manigandan ;
Journal of Electrical Engineering and Technology, volume 10, issue 1, 2015, Pages 261~270
DOI : 10.5370/JEET.2015.10.1.261
In this paper, the Optimal Harmonic Stepped Waveform (OHSW) method is proposed in order to eliminate the selective harmonic orders available at the output of cascaded multilevel inverter (CMLI) fed by solar photovoltaic (SPV). This technique is used to solve the harmonic elimination equations based on stepped waveform analysis in order to obtain the optimal switching angles which in turn reduce the Total Harmonic Distortion (THD). The OHSW method considers the output voltage waveform as four equal symmetries in each half cycle. In the proposed method, a solar fed fifteen level cascaded multilevel is considered where the magnitude of six numbers of harmonic orders is reduced. A programmable pulse generator is developed to carry the switching angles directly to the semiconductor switches obtained as a result of OHSW analysis. Simulations are carried out in MATLAB/Simulink in which a separate model is developed for solar photovoltaic which serves as the input for cascaded multilevel inverter. A 3kWp solar plant with multilevel inverter system is implemented in hardware to show the effectiveness of the proposed system. Based on the observation the OHSW method provides the reduced THD thereby improving power quality in renewable energy applications.
Buck-Boost Interleaved Inverter Configuration for Multiple-Load Induction Cooking Application
Sharath Kumar, P. ; Vishwanathan, N. ; Bhagwan, K. Murthy ;
Journal of Electrical Engineering and Technology, volume 10, issue 1, 2015, Pages 271~279
DOI : 10.5370/JEET.2015.10.1.271
Induction cooking application with multiple loads need high power inverters and appropriate control techniques. This paper proposes an inverter configuration with buck-boost converter for multiple load induction cooking application with independent control of each load. It uses one half-bridge for each load. For a given dc supply of
, one more
is derived using buck-boost converter giving
as the input to each half-bridge inverter. Series resonant loads are connected between the centre point of
and each half-bridge. The output voltage across each load is like that of a full-bridge inverter. In the proposed configuration, half of the output power is supplied to each load directly from the source and remaining half of the output power is supplied to each load through buck-boost converter. With buck-boost converter, each half-bridge inverter output power is increased to a full-bridge inverter output power level. Each half-bridge is operated with constant and same switching frequency with asymmetrical duty cycle (ADC) control technique. By ADC, output power of each load is independently controlled. This configuration also offers reduced component count. The proposed inverter configuration is simulated and experimentally verified with two loads. Simulation and experimental results are in good agreement. This configuration can be extended to multiple loads.
Current Decoupling Control for the Three-level PWM Rectifier with a Low Switching Frequency
Yuan, Qing-Qing ; Xia, Kun ;
Journal of Electrical Engineering and Technology, volume 10, issue 1, 2015, Pages 280~287
DOI : 10.5370/JEET.2015.10.1.280
Three-level PWM rectifiers applied in medium voltage applications usually operate at low switching frequency to keep the dynamic losses under permitted level. However, low switching frequency brings a heavy cross-coupling between the current components
with a poor dynamic system performance and a harmonic distortion in the grid-connecting current. To overcome these problems, a mathematical model based on complex variables of the three-level voltage source PWM rectifier is firstly established, and the reasons of above issues resulted from low switching frequency have been analyzed using modern control theory. Then, a novel control strategy suitable for the current decoupling control based on the complex variables for
is designed here. The comparisons between this kind of control strategy and the normal PI method have been carried out. MATLAB and experimental results are given in detail.
Optimal Design of High Frequency Transformer for 150W Class Module-Integrated Converter
Yoo, Jin-Hyung ; Jung, Tae-Uk ;
Journal of Electrical Engineering and Technology, volume 10, issue 1, 2015, Pages 288~294
DOI : 10.5370/JEET.2015.10.1.288
Recently, the module-integrated converter has shown an interest in the photovoltaic generation system. In this system, the high frequency transformer should be compact and efficient. The proposed method is based on the correlation characteristic between the copper and core loss to minimize the loss of transformer. By sizing an effective cross-sectional area and window area of core, the amount of loss is minimized. This paper presents the design and analysis of high frequency transformer by using the 3D finite element model coupled with DC-DC converter circuit for more accurate analysis by considering the nonlinear voltage and current waveforms in converter circuit. The current waveform in each winding is realized by using the ideal DC voltage source and switching component. And, the thermal analysis is performed to satisfy the electrical and thermal design criteria.
Fabrication of Ozone Bubble Cleaning System and its Application to Clean Silicon Wafers of a Solar Cell
Yoon, J.K. ; Lee, Sang Heon ;
Journal of Electrical Engineering and Technology, volume 10, issue 1, 2015, Pages 295~298
DOI : 10.5370/JEET.2015.10.1.295
Ozone micro-bubble cleaning system was designed, and made to develop a unique technique to clean wafers by using ozone micro-bubbles. The ozone micro-bubble cleaning system consisted of loading, cleaning, rinsing, drying and un-loading zones, respectively. In case of the cleaning the silicon wafers of a solar cell, more than 99 % of cleaning efficiency was obtained by dipping the wafers at 10 ppm of ozone for 10 minutes. Both of long cleaning time and high ozone concentration in the wet-solution with ozone micro-bubbles reduced cleaning efficiency because of the re-sorption of debris. The cleaning technique by ozone micro-bubbles can be also applied to various wafers for an ingot and LED as an eco-friendly method.
Investigations of Accelerated Aged Polymeric Insulators Using Partial Discharge Signal Measurement and Analysis
Mekala, K. ; Chandrasekar, S. ; Ravindran, R. Samson ;
Journal of Electrical Engineering and Technology, volume 10, issue 1, 2015, Pages 299~307
DOI : 10.5370/JEET.2015.10.1.299
Reduction in pollution performance of polymeric insulators, aged due to water absorption stress and thermal stress, is a major threat to the reliable operation of power transmission and distribution system. Formation of partial discharges on the surface of wet polluted insulator plays a major role in determining the life time and pollution performance of outdoor polymeric insulators. However, reports on partial discharge characteristics of water absorption stress aged and thermal aged polymeric insulators are scanty. This paper discusses the pollution performance characteristics of accelerated aged polymeric insulators using the advanced ultra wide band PD signal measurement and analysis. Laboratory experiments on accelerated aged polymeric insulators were carried out as per IEC 60507 under AC voltage, at different humidity and contamination levels using NaCl as a contaminant. PRPD pattern and Time-Frequency map analysis of PD signals were carried out. From the results, it can be speculated that PD analysis is a well suited technique to understand the pollution performance of aged polymeric insulators.
Inverse Scattering of Two-Dimensional Objects Using Linear Sampling Method and Adjoint Sensitivity Analysis
Eskandari, Ahmadreza ; Eskandari, Mohammad Reza ;
Journal of Electrical Engineering and Technology, volume 10, issue 1, 2015, Pages 308~313
DOI : 10.5370/JEET.2015.10.1.308
This paper describes a technique for complete identification of a two-dimensional scattering object and multiple objects immersed in air using microwaves where the scatterers are assumed to be a homogenous dielectric medium. The employed technique consists of initially retrieving the shape and position of the scattering object using a linear sampling method and then determining the electric permittivity and conductivity of the scatterer using adjoint sensitivity analysis. Incident waves are assumed to be TM (Transverse Magnetic) plane waves. This inversion algorithm results in high computational speed and efficiency, and it can be generalized for any scatterer structure. Also, this method is robust with respect to noise. The numerical results clearly show that this hybrid approach provides accurate reconstructions of various objects.
A Numerically Efficient Full Wave Analysis of Circular Resonators Microbandes Stacked Involving Multimetallisations
Chebbara, F. ; Fortaki, T. ;
Journal of Electrical Engineering and Technology, volume 10, issue 1, 2015, Pages 314~319
DOI : 10.5370/JEET.2015.10.1.314
The conventional geometry of a plate microstrip resonator is made up of a single metallic patch, which is printed on a monolayer dielectric substrate. Its arrangement is simple and easy to make, but it is limited in its functional abilities. Many searches have been realized to improve the bandwidth and the gain of the microstrip resonators. Among the various configurations proposed in the open literature, the stacked geometry seems to be very promising. By appropriate design, it is able to provide the operation in dual frequency mode, wide bandwidth enough and high gain. The theoretical investigations of structures composed of two stacked anti-reflection coatings, enhanced metallic coatings are available in the literature, however, for the stacked configurations involving three metallic coatings or more, not to exact or approximate analysis was conducted due to the complexity of the structure.
Estimation of the Substrate Size with Minimum Mutual Coupling of a Linear Microstrip Patch Antenna Array Positioned Along the H-Plane
Kwak, Eun-Hyuk ; Yoon, Young-Min ; Kim, Boo-Gyoun ;
Journal of Electrical Engineering and Technology, volume 10, issue 1, 2015, Pages 320~324
DOI : 10.5370/JEET.2015.10.1.320
Mutual coupling between antenna elements of a linear microstrip patch antenna array positioned along the H-plane including the effect of edge reflections is investigated. Simple formulas are presented for the estimation of the grounded dielectric substrate size with minimum mutual coupling. The substrate sizes calculated by these formulas are in good agreement with those obtained by the full-wave simulation and experimental measurement. The substrate size with minimum mutual coupling is a function of the effective dielectric constant for surface waves and the distance between the antenna centers. The substrate size with minimum mutual coupling decreases as the effective dielectric constant for surface waves on a finite grounded dielectric substrate increases.
An international Comparison Measurement of Silicon Wafer Sheet Resistance using the Four-point Probe Method
Kang, Jeon-Hong ; Ying, Gao ; Cheng, Yuh-Chuan ; Kim, Chang-Soo ; Lee, Sang-Hwa ; Yu, Kwang-Min ;
Journal of Electrical Engineering and Technology, volume 10, issue 1, 2015, Pages 325~330
DOI : 10.5370/JEET.2015.10.1.325
With approval from the Asia Pacific Metrology Program Working Group on Materials Metrology (APMP WGMM), an international comparison for sheet resistance standards for silicon wafers was firstly conducted among Korea Research Institute of Standards and Science (KRISS) in Korea, CMS/ITRI in Taiwan, and NIM in China, which are national metrology institutes (NMIs), from August 2011 to January 2012. The sheet resistance values of the standards are
; the measurement was conducted in sequence at KRISS, CMS/ITRI, NIM, and KRISS again using the four-point probe method with single and dual configuration techniques. The reference value for the measurement results of the three NMIs was obtained through averaging the values of the three results for each sheet resistance range. The differences between the reference value and the measured values is within 0.22% for
, 0.17% for
, and 0.12% for
. Therefore, the international consistency for conducting sheet resistance measurements is confirmed within 0.22% through the APMP WGMM approved comparison.
An Orthogonally Polarized Negative Resonance CRLH Patch Antenna
Kahng, Sungtek ; Jeon, Jinsu ; Park, Taejoon ;
Journal of Electrical Engineering and Technology, volume 10, issue 1, 2015, Pages 331~337
DOI : 10.5370/JEET.2015.10.1.331
A novel fully-printed microstrip antenna with negative first resonance and dual polarization is proposed. The radiator is printed on the 1-layer substrate instead of multilayers. The -1st resonance results from a composite right- and left-handed(CRLH) structure that has a circumferentially interlocked gap capacitively coupling a patch with a shorted-ring. This compact antenna is provided with a dual-polarization capability by creating two orthogonal linear polarizations in one body with coaxial feeds. The design is carried out by doing full-wave EM field simulation which is compared with the measurement of the fabricated antenna prototype. The measured results give the gain of 5 dBi and the efficiency of 78% at the -1st resonance mode as the center frequency of a downlink channel of the bandwidth over 20 MHz with 29 dB polarization isolation for mobile communication.
Compact Band-notched UWB Antenna Design Based On Transmission Line Model
Zhu, Xiaoming ; Yang, Xiaodong ; Chen, Peng ;
Journal of Electrical Engineering and Technology, volume 10, issue 1, 2015, Pages 338~343
DOI : 10.5370/JEET.2015.10.1.338
In order to avoid the interference from existing narrowband communication systems, this paper proposes a compact band-notched UWB (ultra wideband) antenna with size of
. Transmission line model is applied to analyzing wide impedance matching characteristic of the modified base antenna, which has a gradual stepped impedance feeder structure. The proposed antenna realizes dual band-notched function by combining two biased T-shaped parasitic elements on the rear side with a window aperture on the radiation patch. The simulation current distributions of the antenna reflect resonant suppression validity of the two methods. In addition, the measured radiation characteristics demonstrate the proposed antenna prevents signal interference from WLAN (5.15-5.825GHz) and WiMAX (3.4-3.69GHz) effectively, and the measured patterns show the antenna omnidirectional radiation in working frequencies.
Features Extraction and Mechanism Analysis of Partial Discharge Development under Protrusion Defect
Dong, Yu-Lin ; Tang, Ju ; Zeng, Fu-Ping ; Liu, Min ;
Journal of Electrical Engineering and Technology, volume 10, issue 1, 2015, Pages 344~354
DOI : 10.5370/JEET.2015.10.1.344
In order to study the development of partial discharge (PD) under typical protrusion defects in gas-insulated switchgear, we applied step voltages on the defect and obtained the
spectrograms of ultra-high frequency (UHF) PD signals in various PD stages. Furthermore, we extracted seven kinds of features to characterize the degree of deterioration of insulation and analyzed their values, variation trends, and change rates. These characteristics were inconsistent with the development of PD. Hence, the differences of these features could describe the severity of PD. In addition, these characteristics could provide integrated characteristics regarding PD development and improve the reliability of PD severity assessment because these characteristics were extracted from different angles. To explain the variation laws of these seven kinds of parameters, we analyzed the relevant physical mechanism by considering the microphysical process of PD formation and development as well as the distortion effect generated by the space charges on the initial field. The relevant physical mechanism effectively allocated PD severity among these features for assessment, and the effectiveness and reliability of using these features to assess PD severity were proved by testing a large number of PD samples.
Tracking/Erosion Resistance Analysis of Nano-Al(OH)
Filled Silicone Rubber Insulating Materials for High Voltage DC Applications
Kannan, P. ; Sivakumar, M. ; Mekala, K. ; Chandrasekar, S. ;
Journal of Electrical Engineering and Technology, volume 10, issue 1, 2015, Pages 355~363
DOI : 10.5370/JEET.2015.10.1.355
HVDC technology has become popular as an economic mode of bulk power transmission over very long distances. Polymeric insulators in HVDC power transmission lines are affected by surface tracking and erosion problems due to contamination deposit, which pose a greater challenge in maintaining the reliability of the HVDC system. In addition, polymeric insulators are also naturally affected by aging due to various environmental stresses, which in turn accelerates the surface tracking and erosion problems. Research works towards the improvement of tracking and erosion resistance of polymeric insulators by adding nano-sized fillers in the base material are being carried out worldwide. However, surface tracking and erosion performance of nano-filled aged polymeric insulators for HVDC applications are not well reported. Hence, in the present work, tracking and erosion resistance of the nano
filled silicone rubber insulation material has been evaluated under DC voltages at different filler concentrations and aged conditions, as per IEC 60587 test procedures. Leakage current and contact angle measurements were carried out to understand the surface hydrophobicity. Moving average technique was used to analyze the trend followed by leakage current. Water aged specimen shows less tracking resistance when compared with thermal aged specimen. It is observed that nano-filler concentration of 5% is even sufficient to get better tracking/erosion resistance under DC voltages.
Application of a Textile-based Inductive Sensor for the Vital Sign Monitoring
Gi, Sun Ok ; Lee, Young Jae ; Koo, Hye Ran ; Khang, Seonah ; Kim, Kyung-Nam ; Kang, Seung-Jin ; Lee, Joo Hyeon ; Lee, Jeong-Whan ;
Journal of Electrical Engineering and Technology, volume 10, issue 1, 2015, Pages 364~371
DOI : 10.5370/JEET.2015.10.1.364
In this study, we developed a feasible structure of a textile-based inductive sensor using a machine embroidery method, and applied it to a non-contact type vital sign sensing device based on the principle of magnetic-induced conductivity. The mechanical heart activity signals acquired through the inductive sensor embroidered with conductive textile on fabric were compared with the Lead II ECG signals and with respiration signals, which were simultaneously measured in every case with five subjects. The analysis result showed that the locations of the R-peak in the ECG signal were highly associated with sharp peaks in the signals obtained through the textile-based inductive sensor (r=0.9681). Based on the results, we determined the feasibility of the developed textile-based inductive sensor as a measurement device for the heart rate and respiration characteristics.
Background Subtraction in Dynamic Environment based on Modified Adaptive GMM with TTD for Moving Object Detection
Niranjil, Kumar A. ; Sureshkumar, C. ;
Journal of Electrical Engineering and Technology, volume 10, issue 1, 2015, Pages 372~378
DOI : 10.5370/JEET.2015.10.1.372
Background subtraction is the first processing stage in video surveillance. It is a general term for a process which aims to separate foreground objects from a background. The goal is to construct and maintain a statistical representation of the scene that the camera sees. The output of background subtraction will be an input to a higher-level process. Background subtraction under dynamic environment in the video sequences is one such complex task. It is an important research topic in image analysis and computer vision domains. This work deals background modeling based on modified adaptive Gaussian mixture model (GMM) with three temporal differencing (TTD) method in dynamic environment. The results of background subtraction on several sequences in various testing environments show that the proposed method is efficient and robust for the dynamic environment and achieves good accuracy.
An Efficient Control Strategy Based Multi Converter UPQC using with Fuzzy Logic Controller for Power Quality Problems
Paduchuri, Chandra Babu ; Dash, Subhransu Sekhar ; Subramani, C. ; Kiran, S. Harish ;
Journal of Electrical Engineering and Technology, volume 10, issue 1, 2015, Pages 379~387
DOI : 10.5370/JEET.2015.10.1.379
A custom power device provides an integrated solution to the present problems that are faced by the utilities and power distribution. In this paper, a new controller is designed which is connected to a multiconverter unified power quality conditioner (MC-UPQC) for improving the power quality issues adopted modified synchronous reference frame (MSRF) theory with Fuzzy logic control (FLC) technique. This newly designed controller is connected to a source in order to compensate voltage and current in two feeders. The expanded concept of UPQC is multi converter-UPQC; this system has a two-series voltage source inverter and one shunt voltage source inverter connected back to back. This configuration will helps mitigate any type of voltage / current fluctuations and power factor correction in power distribution network to improve power quality issues. In the proposed system the power can be conveyed from one feeder to another in order to mitigate the voltage sag, swell, interruption and transient response of the system. The control strategies of multi converter- UPQC are designed based on the modified synchronous reference frame theory with fuzzy logic controller. The fast dynamics response of dc link capacitor is achieved with the help of Fuzzy logic controller. Different types of fault conditions are taken and simulated for the analysis and the results are compared with the conventional method. The relevant simulation and compensation performance analysis of the proposed multi converter-UPQC with fuzzy logic controller is performed.
A Novel Hybrid Sequential Start Control System for Large Inductive Loads
Kim, Sang-Kon ; Kim, Tae-Kon ;
Journal of Electrical Engineering and Technology, volume 10, issue 1, 2015, Pages 388~394
DOI : 10.5370/JEET.2015.10.1.388
The inrush current of a large inductive load can be reduced with a soft starter; however, the large inrush current caused by simultaneous bulk starts (SBSs) cannot be effectively reduced. In order to reduce the high inrush current and voltage sag owing to the SBSs of large capacity inductive loads within a power network, a novel hybrid sequential start control system is proposed, implemented on embedded systems, and evaluated with a testbed in this study. From the experimental and simulation results of the proposed control system, the inrush current could be effectively restricted below the maximum current capacity of a power distributing board. Moreover, with the proposed system, power cost typically dictated by the peak power consumption can be fairly reduced, and the quality of the power system connected to the inductive loads can be efficiently increased.
A Note on Relay Feedback Identification Under Static Load Disturbances
Kaya, Ibrahim ;
Journal of Electrical Engineering and Technology, volume 10, issue 1, 2015, Pages 395~400
DOI : 10.5370/JEET.2015.10.1.395
Obtaining the parameters for PID controllers based on limit cycle information for the process in a relay controlled feedback loop has become an accepted practical procedure. If the form of the plant transfer function is known, exact expressions for the limit cycle frequency and amplitude can be derived so that their measurements, assumed error free, can be used to calculate the true parameter value. In the literature, parameter estimation for an assumed form of the plant transfer function has generally been considered for disturbance free cases, except a recently published work of the author. In this paper additional simulation results are reported on exact parameter estimation from relay autotuning under static load disturbances.
Improved Spam Filter via Handling of Text Embedded Image E-mail
Youn, Seongwook ; Cho, Hyun-Chong ;
Journal of Electrical Engineering and Technology, volume 10, issue 1, 2015, Pages 401~407
DOI : 10.5370/JEET.2015.10.1.401
The increase of image spam, a kind of spam in which the text message is embedded into attached image to defeat spam filtering technique, is a major problem of the current e-mail system. For nearly a decade, content based filtering using text classification or machine learning has been a major trend of anti-spam filtering system. Recently, spammers try to defeat anti-spam filter by many techniques. Text embedding into attached image is one of them. We proposed an ontology spam filters. However, the proposed system handles only text e-mail and the percentage of attached images is increasing sharply. The contribution of the paper is that we add image e-mail handling capability into the anti-spam filtering system keeping the advantages of the previous text based spam e-mail filtering system. Also, the proposed system gives a low false negative value, which means that user's valuable e-mail is rarely regarded as a spam e-mail.
PMSM Servo Drive for V-Belt Continuously Variable Transmission System Using Hybrid Recurrent Chebyshev NN Control System
Lin, Chih-Hong ;
Journal of Electrical Engineering and Technology, volume 10, issue 1, 2015, Pages 408~421
DOI : 10.5370/JEET.2015.10.1.408
Because the wheel of V-belt continuously variable transmission (CVT) system driven by permanent magnet synchronous motor (PMSM) has much unknown nonlinear and time-varying characteristics, the better control performance design for the linear control design is a time consuming job. In order to overcome difficulties for design of the linear controllers, a hybrid recurrent Chebyshev neural network (NN) control system is proposed to control for a PMSM servo-driven V-belt CVT system under the occurrence of the lumped nonlinear load disturbances. The hybrid recurrent Chebyshev NN control system consists of an inspector control, a recurrent Chebyshev NN control with adaptive law and a recouped control. Moreover, the online parameters tuning methodology of adaptive law in the recurrent Chebyshev NN can be derived according to the Lyapunov stability theorem and the gradient descent method. Furthermore, the optimal learning rate of the parameters based on discrete-type Lyapunov function is derived to achieve fast convergence. The recurrent Chebyshev NN with fast convergence has the online learning ability to respond to the system's nonlinear and time-varying behaviors. Finally, to show the effectiveness of the proposed control scheme, comparative studies are demonstrated by experimental results.
Reversible Watermarking Based on Compensation
Qu, Xiaochao ; Kim, Suah ; Kim, Hyoung Joong ;
Journal of Electrical Engineering and Technology, volume 10, issue 1, 2015, Pages 422~428
DOI : 10.5370/JEET.2015.10.1.422
This paper proposes a high performance reversible watermarking (RW) scheme based on a novel compensation strategy. RW embeds data into a host image by modifying its pixel values slightly. It is found that certain modified pixels can be compensated to their original values during the proposed embedding procedure. The compensation effect in the RW scheme can improve the marked image quality significantly. By incorporating the pixel selection method, a higher quality image is obtained, which is verified by extensive experiments.
A Design of Prototype 1C2M Railway Vehicle Propulsion Control System Considering Slip Reduction of Traction Motor
Chang, Chin-Young ; Kim, Jae-Moon ; Kim, Yoon-Ho ;
Journal of Electrical Engineering and Technology, volume 10, issue 1, 2015, Pages 429~435
DOI : 10.5370/JEET.2015.10.1.429
This study proposes a re-adhesion algorithm that has stable traction effort for rolling stock slip/slide minimization when deliverable traction decreases by slip. The proposed scheme estimates appropriate reference speed using two encoders for reducing slip and controls traction effort stably and has stable control characteristics for disturbance. The algorithm which uses the maximum adhesive effort by instantaneous estimation of adhesion force stably controls traction effort and gives rolling stock excellent acceleration and deceleration characteristics. And a slip sensing element that can quickly detect slip is used. Load motor and inverter were checked in various slip conditions for creating various line conditions.
Development of a Localization System Based on VLC Technique for an Indoor Environment
Yi, Keon Young ; Kim, Dae Young ; Yi, Kwang Moo ;
Journal of Electrical Engineering and Technology, volume 10, issue 1, 2015, Pages 436~442
DOI : 10.5370/JEET.2015.10.1.436
In this paper, we develop an indoor localization device which embeds localization information into indoor light-emitting-diodes (LED) lighting systems. The key idea of our device is the use of the newly proposed "bit stuffing method". Through the use of stuff bits, our device is able to measure signal strengths even in transient states, which prohibits interference between lighting signals. The stuff bits also scatter the parts of the signal where the LED is turned on, thus provides quality indoor lighting. Additionally, for the indoor localization system based on RSSI and TDM to be practical, we propose methods for the control of LED lamps and compensation of received signals. The effectiveness of the proposed scheme is validated through experiments with a low-cost implementation including an indoor navigation task.