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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of Electrical Engineering and Technology
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The Korean Institute of Electrical Engineers
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Volume & Issues
Volume 9, Issue 6 - Nov 2014
Volume 9, Issue 5 - Sep 2014
Volume 9, Issue 4 - Jul 2014
Volume 9, Issue 3 - May 2014
Volume 9, Issue 2 - Mar 2014
Volume 9, Issue 1 - Jan 2014
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Enhancement of Power System Dynamic Stability by Designing a New Model of the Power System
Fereidouni, Alireza ; Vahidi, Behrooz ;
Journal of Electrical Engineering and Technology, volume 9, issue 2, 2014, Pages 379~389
DOI : 10.5370/JEET.2014.9.2.379
Low frequency oscillations (LFOs) are load angle oscillations that have a frequency between 0.1-2.0 Hz. Power system stabilizers (PSSs) are very effective controllers in improvement of the damping of LFOs. PSSs are designed by linearized models of the power system. This paper presents a new model of the power system that has the advantages of the Single Machine Infinite Bus (SMIB) system and the multi machine power system. This model is named a single machine normal-bus (SMNB). The equations that describe the proposed model have been linearized and a lead PSS has been designed. Then, particle swarm optimization technique (PSO) is employed to search for optimum PSS parameters. To analysis performance of PSS that has been designed based on the proposed model, a few tests have been implemented. The results show that designed PSS has an excellent capability in enhancing extremely the dynamic stability of power systems and also maintain coordination between PSSs.
Dynamic Embedded Optimization Applied to Power System Stabilizers
Sung, Byung Chul ; Baek, Seung-Mook ; Park, Jung-Wook ;
Journal of Electrical Engineering and Technology, volume 9, issue 2, 2014, Pages 390~398
DOI : 10.5370/JEET.2014.9.2.390
The systematic optimal tuning of power system stabilizers (PSSs) using the dynamic embedded optimization (DEO) technique is described in this paper. A hybrid system model which has the differential-algebraic-impulsive-switched (DAIS) structure is used as a tool for the DEO of PSSs. Two numerical optimization methods, which are the steepest descent and Broyden-Fletcher-Goldfarb-Shanno (BFGS) algorithms, are investigated to implement the DEO using the hybrid system model. As well as the gain and time constant of phase lead compensator, the output limits of PSSs with non-smooth nonlinearities are considered as the parameters to be optimized by the DEO. The simulation results show the effectiveness and robustness of the PSSs tuned by the proposed DEO technique on the IEEE 39 bus New England system to mitigate system damping.
Hybrid Secondary Voltage Control combined with Large-Scale Wind Farms and Synchronous Generators
Kim, Jihun ; Lee, Hwanik ; Lee, Byongjun ; Kang, Yong Cheol ;
Journal of Electrical Engineering and Technology, volume 9, issue 2, 2014, Pages 399~405
DOI : 10.5370/JEET.2014.9.2.399
For stable integration of large-scale wind farms, integration standards (Grid codes) have been proposed by the system operator. In particular, voltage control of large-scale wind farms is gradually becoming important because of the increasing size of individual wind farms. Among the various voltage control methods, Secondary Voltage Control (SVC) is a method that can control the reactive power reserve of a control area uniformly. This paper proposes hybrid SVC when a large-scale wind farm is integrated into the power grid. Using SVC, the burden of a wind turbine converter for generating reactive power can be reduced. To prove the effectiveness of the proposed strategy, a simulation study is carried out for the Jeju system. The proposed strategy can improve the voltage conditions and reactive power reserve with this hybrid SVC.
Implementation of Under Voltage Load Shedding for Fault Induced Delayed Voltage Recovery Phenomenon Alleviation
Lee, Yun-Hwan ; Park, Bo-Hyun ; Oh, Seung-Chan ; Lee, Byong-Jun ; Shin, Jeong-Hoon ; Kim, Tae-Kyun ;
Journal of Electrical Engineering and Technology, volume 9, issue 2, 2014, Pages 406~414
DOI : 10.5370/JEET.2014.9.2.406
Significant penetration of induction motor loads into residential neighborhood and commercial regions of local transmission systems at least partially determine a vulnerability to a fault induced delayed voltage recovery (FIDVR) event. Highly concentrated induction motor loads with constant torque could stall in response to low voltages associated with system faults. FIDVR is caused by wide spread stalling of small HVAC units (residential air conditioner) during transmission level faults. An under voltage load shedding scheme (UVLS) can be an effective component in a strategy to manage FIDVR risk and limit the any potential disturbance. Under Voltage Load Shedding take advantage of the plan to recovery the voltage of the system by shedding the load ways to alleviation FIDVR.
EP Based PSO Method for Solving Multi Area Unit Commitment Problem with Import and Export Constraints
Venkatesan, K. ; Selvakumar, G. ; Rajan, C. Christober Asir ;
Journal of Electrical Engineering and Technology, volume 9, issue 2, 2014, Pages 415~422
DOI : 10.5370/JEET.2014.9.2.415
This paper presents a new approach to solve the multi area unit commitment problem (MAUCP) using an evolutionary programming based particle swarm optimization (EPPSO) method. The objective of this paper is to determine the optimal or near optimal commitment schedule for generating units located in multiple areas that are interconnected via tie lines. The evolutionary programming based particle swarm optimization method is used to solve multi area unit commitment problem, allocated generation for each area and find the operating cost of generation for each hour. Joint operation of generation resources can result in significant operational cost savings. Power transfer between the areas through the tie lines depends upon the operating cost of generation at each hour and tie line transfer limits. Case study of four areas with different load pattern each containing 7 units (NTPS) and 26 units connected via tie lines have been taken for analysis. Numerical results showed comparing the operating cost using evolutionary programming-based particle swarm optimization method with conventional dynamic programming (DP), evolutionary programming (EP), and particle swarm optimization (PSO) method. Experimental results show that the application of this evolutionary programming based particle swarm optimization method has the potential to solve multi area unit commitment problem with lesser computation time.
NSGA-II Technique for Multi-objective Generation Dispatch of Thermal Generators with Nonsmooth Fuel Cost Functions
Rajkumar, M. ; Mahadevan, K. ; Kannan, S. ; Baskar, S. ;
Journal of Electrical Engineering and Technology, volume 9, issue 2, 2014, Pages 423~432
DOI : 10.5370/JEET.2014.9.2.423
Non-dominated Sorting Genetic Algorithm-II (NSGA-II) is applied for solving Combined Economic Emission Dispatch (CEED) problem with valve-point loading of thermal generators. This CEED problem with valve-point loading is a nonlinear, constrained multi-objective optimization problem, with power balance and generator capacity constraints. The valve-point loading introduce ripples in the input-output characteristics of generating units and make the CEED problem as a nonsmooth optimization problem. To validate its effectiveness of NSGA-II, two benchmark test systems, IEEE 30-bus and IEEE 118-bus systems are considered. To compare the Pareto-front obtained using NSGA-II, reference Pareto-front is generated using multiple runs of Real Coded Genetic Algorithm (RCGA) with weighted sum of objectives. Comparison with other optimization techniques showed the superiority of the NSGA-II approach and confirmed its potential for solving the CEED problem. Numerical results show that NSGA-II algorithm can provide Pareto-front in a single run with good diversity and convergence. An approach based on Technique for Ordering Preferences by Similarity to Ideal Solution (TOPSIS) is applied on non-dominated solutions obtained to determine Best Compromise Solution (BCS).
Active Distribution System Planning for Low-carbon Objective using Cuckoo Search Algorithm
Zeng, Bo ; Zhang, Jianhua ; Zhang, Yuying ; Yang, Xu ; Dong, Jun ; Liu, Wenxia ;
Journal of Electrical Engineering and Technology, volume 9, issue 2, 2014, Pages 433~440
DOI : 10.5370/JEET.2014.9.2.433
In this study, a method for the low-carbon active distribution system (ADS) planning is proposed. It takes into account the impacts of both network capacity and demand correlation to the renewable energy accommodation, and incorporates demand response (DR) as an available resource in the ADS planning. The problem is formulated as a mixed integer nonlinear programming model, whereby the optimal allocation of renewable energy sources and the design of DR contract (i.e. payment incentives and default penalties) are determined simultaneously, in order to achieve the minimization of total cost and
emissions subjected to the system constraints. The uncertainties that involved are also considered by using the scenario synthesis method with the improved Taguchi's orthogonal array testing for reducing information redundancy. A novel cuckoo search (CS) is applied for the planning optimization. The case study results confirm the effectiveness and superiority of the proposed method.
Multi-objective Capacitor Allocations in Distribution Networks using Artificial Bee Colony Algorithm
El-Fergany, Attia ; Abdelaziz, A.Y. ;
Journal of Electrical Engineering and Technology, volume 9, issue 2, 2014, Pages 441~451
DOI : 10.5370/JEET.2014.9.2.441
This article addresses an efficient heuristic-based approach to assign static shunt capacitors along radial distribution networks using the artificial bee colony algorithm. The objective function is adapted to enhance the overall system static voltage stability index and to achieve maximum net yearly savings. Load variations have been considered to optimally scope the fixed and switched capacitors required. The numerical results are compared with those obtained using recent heuristic methods and show that the proposed approach is capable of generating high-grade solutions and validated viability.
Evaluation of Voltage Sag and Unbalance due to the System Connection of Electric Vehicles on Distribution System
Lee, Soon-Jeong ; Kim, Jun-Hyeok ; Kim, Doo-Ung ; Go, Hyo-Sang ; Kim, Chul-Hwan ; Kim, Eung-Sang ; Kim, Seul-Ki ;
Journal of Electrical Engineering and Technology, volume 9, issue 2, 2014, Pages 452~460
DOI : 10.5370/JEET.2014.9.2.452
Due to increased concerns for rising oil prices and environmental problems, various solutions have been proposed for solving energy problems through tightening environmental regulations such as those regarding
reduction. Among them, Electrical Vehicles (EVs) are evaluated to be the most realistic and effective approach. Accordingly, research and development on EVs and charging infrastructures are mainly proceeding in developed countries. Since EVs operate using electric energy form a battery, they must be connected to the power system to charge the battery. If many EVs are connected during a short time, power quality problems can occur such as voltage sag, voltage unbalance and harmonics which are generated from power electronics devices. Therefore, when EVs are charged, it is necessary to analyze the effect of power quality on the distribution system, because EVs will gradually replace gasoline vehicles, and the number of EVs will be increased. In this paper, a battery for EVs and a PWM converter are modeled using an ElectroMagnetic Transient Program (EMTP). The voltage sag and unbalance are evaluated when EVs are connected to the distribution system of the Korea Electric Power Corporation (KEPCO). The simulation results are compared with IEEE standards.
Probabilistic Power Flow Studies Incorporating Correlations of PV Generation for Distribution Networks
Ren, Zhouyang ; Yan, Wei ; Zhao, Xia ; Zhao, Xueqian ; Yu, Juan ;
Journal of Electrical Engineering and Technology, volume 9, issue 2, 2014, Pages 461~470
DOI : 10.5370/JEET.2014.9.2.461
This paper presents a probabilistic power flow (PPF) analysis method for distribution network incorporating the randomness and correlation of photovoltaic (PV) generation. Based on the multivariate kernel density estimation theory, the probabilistic model of PV generation is proposed without any assumption of theoretical parametric distribution, which can accurately capture not only the randomness but also the correlation of PV resources at adjacent locations. The PPF method is developed by combining the proposed PV model and Monte Carlo technique to evaluate the influence of the randomness and correlation of PV generation on the performance of distribution networks. The historical power output data of three neighboring PV generators in Oregon, USA, and 34-bus/69-bus radial distribution networks are used to demonstrate the correctness, effectiveness, and application of the proposed PV model and PPF method.
Optimal Design of a Novel Permanent Magnetic Actuator using Evolutionary Strategy Algorithm and Kriging Meta-model
Hong, Seung-Ki ; Ro, Jong-Suk ; Jung, Hyun-Kyo ;
Journal of Electrical Engineering and Technology, volume 9, issue 2, 2014, Pages 471~477
DOI : 10.5370/JEET.2014.9.2.471
The novel permanent magnetic actuator (PMA) and its optimal design method were proposed in this paper. The proposed PMA is referred to as the separated permanent magnetic actuator (SPMA) and significantly superior in terms of its cost and performance level over a conventional PMA. The proposed optimal design method uses the evolutionary strategy algorithm (ESA), the kriging meta-model (KMM), and the multi-step optimization. The KMM can compensate the slow convergence of the ESA. The proposed multi-step optimization process, which separates the independent variables, can decrease time and increase the reliability for the optimal design result. Briefly, the optimization time and the poor reliability of the optimum are mitigated by the proposed optimization method.
Minimization of Torque-Ripple in Switched Reluctance Motors Over Wide Speed Range
Dowlatshahi, Milad ; Saghaiannejad, Seyed Morteza ; Ahn, Jin-Woo ; Moallem, Mehdi ;
Journal of Electrical Engineering and Technology, volume 9, issue 2, 2014, Pages 478~488
DOI : 10.5370/JEET.2014.9.2.478
Torque pulsation mechanism and highly nonlinear magnetic characterization of switched reluctance motors(SRM) lead to unfavorable torque ripple and limit the variety of applications in industry. In this paper, a modification method proposed for torque ripple minimization of SRM based on conventional torque sharing functions(TSF) to improve maximum speed of torque ripple-free operation considering converter limitations. Due to increasing phase inductance in outgoing phase during the commutation region, reference current tracking can be deteriorated especially when the speed increased. Moreover, phase torque production in incoming phase may not be reached to the reference value near the turn-on angle in which the incremental inductance would be dramatically decreased. Torque error for outgoing phase can cause increasing the resultant motor torque while it would be negative for incoming phase and yields reducing the motor torque. In this paper, a modification method is proposed in which phase torque tracking error for each phase under the commutation added to the other phase so that the resultant torque remained in constant level. This yields to extend constant torque region and reduce peak phase current when the speed increased. Simulation and experimental results for four phase 4 KW, 8/6 SRM validate the effectiveness of the proposed scheme.
Modified Unipolar Carrier-Based PWM Strategy for Three-Level Neutral-Point-Clamped Voltage Source Inverters
Srirattanawichaikul, Watcharin ; Premrudeepreechacharn, Suttichai ; Kumsuwan, Yuttana ;
Journal of Electrical Engineering and Technology, volume 9, issue 2, 2014, Pages 489~500
DOI : 10.5370/JEET.2014.9.2.489
This paper presents a simple modified unipolar carrier-based pulsewidth modulation (CB-PWM) strategy for the three-level neutral-point-clamped (NPC) voltage source inverter (VSI). Analytical expressions for the relationship between modulation reference signals and output voltages are derived. The proposed modulation technique for the three-level NPC VSI includes the maximum and minimum of the three-phase sinusoidal reference voltages with zero-sequence voltage injection concept. The proposed modified CB-PWM strategy incorporates a novel method that requires only of one triangular carrier wave for generate the gating pulses in three-level NPC VSI. It has the advantages of being simplifying the algorithm with no need of complex two/multi-carrier pulsewidth modulation or space vector modulation (SVM) and it's also simple to implement. The possibility of the proposed CB-PWM technique has been verified though computer simulation and experimental results.
A High Efficiency DC-DC Boost Converter with Passive Regenerative Snubber
Radika, P. ;
Journal of Electrical Engineering and Technology, volume 9, issue 2, 2014, Pages 501~507
DOI : 10.5370/JEET.2014.9.2.501
This paper describes the improvement in converter efficiency by reducing the switching loss and by recovering the snubber stored energy. A capacitive based passive regenerative snubber circuit is modeled for a dc-dc boost converter. The proposed snubber is mainly used to reduce the turn-off loss of the main switch. The energy recovery process and the turn-off loss depends on the size of the snubber capacitance; therefore, the conventional and the proposed converters are designed for high and low input voltage conditions with different sizes of the snubber capacitance. Based on the results obtained, the snubber capacitors are classified as small, normal and large snubbers. The Matlab simulation results obtained are presented.
Induction Motor with Adjustable Windings for High Efficiency Drive in Light Load Operation
Zhang, Y. ;
Journal of Electrical Engineering and Technology, volume 9, issue 2, 2014, Pages 508~513
DOI : 10.5370/JEET.2014.9.2.508
Heavy load start but light load operation is a common case in practical drive applications. When an induction motor is employed for such applications, its rated power is usually chosen according to the heavy load start. Then, during light load operation, its efficiency and power factor are low. To solve this problem, it is proposed to adjust the motor windings from the startup to the normal operation conditions. In this paper, arrangement of the adjustable windings is introduced, air gap field with different windings is investigated, and steady state operation performance under various loads is examined. It can be seen that by using proper winding arrangement both startup and operation performances are satisfactory.
A Novel High Precision Electromagnetic Suspension for Long-Stroke Movement and Its Performance Evaluation
Lee, Ki-Chang ; Moon, Seokhwan ; Ha, Hyunuk ; Park, Byoung-Gun ; Kim, Ji-Won ; Baek, Jun-Young ; Lee, Min-Cheol ;
Journal of Electrical Engineering and Technology, volume 9, issue 2, 2014, Pages 514~522
DOI : 10.5370/JEET.2014.9.2.514
A new type of high precision electromagnetic suspension (EMS) which can support heavy tray along long stroke rail is proposed in this paper. Compared with the conventional EMS, the suggested moving-core typed EMS has the levitation electromagnets (EMs) on the fixed rail. This scheme has high load capability caused by iron-core and enables simple tray structure. Also it does not have precision degradation caused by heat generation from EMs, which is a drawback of conventional EMS. With these merits, the proposed EMS can be an optimal contactless linear bearing in next generation flat panel display (FPD) manufacturing process if the ability of long stroke movement is proved. So a special Section Switching Algorithm (SSA) is derived from the resultant force and moment equations of the levitated tray which enables long stroke movement of the tray. In order to verify the feasibility of the suggested SSA, a simple test-setup of the EMS with 2 Section-changes is made up and servo-controlled in the simulation and experiment. The simulation shows the perfect changeover the EMs, and the experiment shows overall control performance of under
gap deviations. These results reveal that the newly suggested contactless linear bearing can simultaneously achieve high load capability and precision gap control as well as long stroke.
A Novel Control Strategy for HEV Using Brushless Dual-Mechanical-Port Electrical Machine on Cruising Condition
Wang, Ende ; Huang, Shenghua ; Wan, Shanming ; Chen, Xiao ;
Journal of Electrical Engineering and Technology, volume 9, issue 2, 2014, Pages 523~531
DOI : 10.5370/JEET.2014.9.2.523
Brushless Dual-Mechanical-Port Electrical Machine (BLDMPEM) is a new type of motor designed for Hybrid Electric Vehicle (HEV), which contains two mechanical ports and two electric ports. Compared with Dual-Mechanical-Port Electrical Machine (DMPEM), the brushless structure brings higher reliability and easier maintenance. In this paper, the model of BLDMPEM is discussed. In Chapter 2, the energy flow and mathematical model of BLDMPEM are analyzed. Then a novel three-phase half-bridge controlled rectifier topology and its control strategy for cruising mode of HEV based on BLDMPEM are proposed in Chapter 3. Compared with the Field Oriented Control (FOC) strategy of BLDMPEM, the proposed method does not require accurate motor parameters, and it is much simpler and easier to be implemented. At last, simulation and experiment results show the feasibility and validity of the proposed strategy.
Analysis and Compensation of Current Measurement Errors in a Doubly Fed Induction Generator
Son, Yung-Deug ; Im, Won-Sang ; Park, Han-Seok ; Kim, Jang-Mok ;
Journal of Electrical Engineering and Technology, volume 9, issue 2, 2014, Pages 532~540
DOI : 10.5370/JEET.2014.9.2.532
It is necessary to measure the current of rotor for controlling the active and reactive power generated by the stator side of the doubly fed induction generator (DFIG) system. There are offset and scaling errors in the current measurement. The offset and scaling errors cause one and two times current ripples of slip frequency in the synchronous reference frame of vector control, respectively. This paper proposes a compensation method to reduce their ripples. The stator current is variable according to the wind force but the rotor current is almost constant. Therefore input of the rotor current is more useful for a compensation method. The proposed method adopts the synchronous d-axis current of the rotor as the input signal for compensation. The ripples of the measurement errors can be calculated by integrating the synchronous d-axis stator current. The calculated errors are added to the reference current of rotor as input of the current regulator, then the ripples are reduced. Experimental results show the effectiveness of the proposed method.
An Extended Switched-inductor Quasi-Z-source Inverter
Deng, Kai ; Mei, Fei ; Mei, Jun ; Zheng, Jianyong ; Fu, Guangxu ;
Journal of Electrical Engineering and Technology, volume 9, issue 2, 2014, Pages 541~549
DOI : 10.5370/JEET.2014.9.2.541
In this paper, an extended switched-inductor quasi-Z-source inverter (ESL-qZSI) with high boost voltage inversion ability is presented, which combines the SL-qZSI with the traditional boost converter, as well as improves the switched-inductor cell. Compared with the classic qZSI topologies, the proposed topology reduces the voltage stresses of capacitors, power devices and diodes for the same input and output voltage. Furthermore, the conversion efficiency is improved. The operation principle of the proposed topology is analyzed in details, which is followed by the comparison between the three topologies. In addition, the performance of the proposed topology is verified by simulations and experiments.
Modeling and Experimental Verification of ANN Based Online Stator Resistance Estimation in DTC-IM Drive
Reza, C.M.F.S. ; Islam, Didarul ; Mekhilef, Saad ;
Journal of Electrical Engineering and Technology, volume 9, issue 2, 2014, Pages 550~558
DOI : 10.5370/JEET.2014.9.2.550
Direct Torque controlled induction motor (DTC-IM) drives use stator resistance of the motor for stator flux estimation. So, stator resistance estimation properly is very important for a stable and effective operation of the induction motor. Stator resistance variations because of changing in temperature make DTC operation difficult mainly at low speed. A method based on artificial neural network (ANN) to estimate the stator resistance online of IM for DTC drive is modeled and verified in this paper. To train the neural network a back propagation algorithm is used. Weight adjustment of neural network is done by back propagating the error signal between measured and estimated stator current. An extensive simulation has been carried out in MATLAB/SIMULINK to prove the efficacy of the proposed stator resistance estimator. The simulation & experimental result reveals that proposed method is able to obtain precise torque and flux control at low speed.
A New Hybrid "Park's Vector - Time Synchronous Averaging" Approach to the Induction Motor-fault Monitoring and Diagnosis
Ngote, Nabil ; Guedira, Said ; Cherkaoui, Mohamed ; Ouassaid, Mohammed ;
Journal of Electrical Engineering and Technology, volume 9, issue 2, 2014, Pages 559~568
DOI : 10.5370/JEET.2014.9.2.559
Induction motors are critical components in industrial processes since their failure usually lead to an unexpected interruption at the industrial plant. The studies of induction motor behavior during abnormal conditions and the possibility to diagnose different types of faults have been a challenging topic for many electrical machine researchers. In this regard, an efficient and new method to detect the induction motor-fault may be the application of the Time Synchronous Averaging (TSA) to the stator current Park's Vector. The aim of this paper is to present a methodology by which defects in a three-phase wound rotor induction motor can be diagnosed. By exploiting the cyclostationarity characteristics of electrical signals, the TSA method is applied to the stator current Park's Vector, allowing the monitoring of the induction motor operation. Simulation and experimental results are presented in order to show the effectiveness of the proposed method. The obtained results are largely satisfactory, indicating a promising industrial application of the hybrid Park's Vector-TSA approach.
Class E Power Amplifiers using High-Q Inductors for Loosely Coupled Wireless Power Transfer System
Yang, Jong-Ryul ; Kim, Jinwook ; Park, Young-Jin ;
Journal of Electrical Engineering and Technology, volume 9, issue 2, 2014, Pages 569~575
DOI : 10.5370/JEET.2014.9.2.569
A highly efficient class E power amplifier is demonstrated for application to wireless power transfer system. The amplifier is designed with an L-type matching at the output for harmonic rejection and output matching. The power loss and the effect of each component in the amplifier with the matching circuit are analyzed with the current ratio transmitted to the output load. Inductors with a quality factor of more than 120 are used in a dc feed and the matching circuit to improve transmission efficiency. The single-ended amplifier with 20 V supply voltage shows 7.7 W output power and 90.8% power added efficiency at 6.78 MHz. The wireless power transfer (WPT) system with the amplifier shows 5.4 W transmitted power and 82.3% overall efficiency. The analysis and measurements show that high-Q inductors are required for the amplifier design to realize highly efficient WPT system.
Chopper Controller Based DC Voltage Control Strategy for Cascaded Multilevel STATCOM
Xiong, Lian-Song ; Zhuo, Fang ;
Journal of Electrical Engineering and Technology, volume 9, issue 2, 2014, Pages 576~588
DOI : 10.5370/JEET.2014.9.2.576
The superiority of CMI (Cascaded Multilevel Inverter) is unparalleled in high power and high voltage STATCOM (Static Synchronous Compensator). However, the parameters and operating conditions of each individual power unit composing the cascaded STATCOM differ from unit to unit, causing unit voltage disequilibrium on the DC side. This phenomenon seriously impairs the operation performance of STATCOM, and thus maintaining the DC voltage balance and stability becomes critical for cascaded STATCOM. This paper analyzes the case of voltage disequilibrium, combines the operation characteristics of the cascaded STATCOM, and proposes a new DC voltage control scheme with the advantages of good control performance and stability. This hierarchical control method uses software to achieve the total active power control and also uses chopper controllers to enable that the imbalance power can flow among the capacitors in order to keep DC capacitor voltages balance. The operating principle of the chopper controllers is analyzed and the implementation is presented. The major advantages of the proposed control strategy are that the number of PI regulators has been decreased remarkably and accordingly the blindness of system design and debugging also reduces obviously. The simulation reveals that the proposed control scheme can achieve the satisfactory control goals.
ESL-𝚪-Z- Source Inverter
Pan, Lei ; Sun, Hexu ; Wang, Beibei ; Dong, Yan ; Gao, Rui ;
Journal of Electrical Engineering and Technology, volume 9, issue 2, 2014, Pages 589~599
DOI : 10.5370/JEET.2014.9.2.589
On the basis of the traditional ZSI (Z-source inverter), this paper presents a ESL-
-ZSI, which uses a unique
-shaped impedance network and an extended SL network for boosting its output voltage in addition to their usual voltage-buck behavior. The inverter can increase the boost factor through adjusting shoot-through duty ratio and increasing the number of inductors. Capacitor voltage stress of ESL-
-ZSI is a constant when 1>D>0, and ESL-
-ZSI has small inductor current stress. The working principle of ESL-
-ZSI and comparison with the classical ZSI and SL- ZSI are analyzed in detail. The power loss comparison between ESL-
-ZSI and Cuk converter is analyzed detailedly. Simulation and experimental results are given to demonstrate the operation features of the inverter.
On-line Parameter Estimation of Interior Permanent Magnet Synchronous Motor using an Extended Kalman Filter
Sim, Hyun-Woo ; Lee, June-Seok ; Lee, Kyo-Beum ;
Journal of Electrical Engineering and Technology, volume 9, issue 2, 2014, Pages 600~608
DOI : 10.5370/JEET.2014.9.2.600
This paper presents estimation of d-axis and q-axis inductance of an interior permanent magnet synchronous motor (IPMSM) by using an extended Kalman filter (EKF). The EKF is widely used for control applications including the motor sensorless control and parameter estimation. The motor parameters can be changed by temperature and air-gap flux. In particular, the variation of the inductance affects torque characteristics like the maximum torque per ampere (MTPA) control. Therefore, by estimating the parameters, it is possible to improve the torque characteristics of the motor. The performance of the proposed estimator is verified by simulations and experimental results based on an 11kW PMSM drive system.
Effects of an Aluminum Contact on the Carrier Mobility and Threshold Voltage of Zinc Tin Oxide Transparent Thin Film Transistors
Ma, Tae-Young ;
Journal of Electrical Engineering and Technology, volume 9, issue 2, 2014, Pages 609~614
DOI : 10.5370/JEET.2014.9.2.609
We fabricated amorphous zinc tin oxide (ZTO) transparent thin-film transistors (TTFTs). The effects of Al electrode on the mobility and threshold voltage of the ZTO TTFTs were investigated. It was found that the aluminum (Al)-ZTO contact decreased the mobility and increased the threshold voltage. Traps, originating from
, were assumed to be the cause of degradation. An indium tin oxide film was inserted between Al and ZTO as a buffer layer, forming an ohmic contact, which was revealed to improve the performance of ZTO TTFTs.
Improvement in Transformer Diagnosis by DGA using Fuzzy Logic
Dhote, Nitin K. ; Helonde, J.B. ;
Journal of Electrical Engineering and Technology, volume 9, issue 2, 2014, Pages 615~621
DOI : 10.5370/JEET.2014.9.2.615
Power transformer is one of the most important equipments in electrical power system. The detection of certain gases generated in transformer is the first indication of a malfunction that may lead to failure if not detected. Dissolved gas analysis (DGA) of transformer oil has been one of the most reliable techniques to detect the incipient faults. Many conventional DGA methods have been developed to interpret DGA results obtained from gas chromatography. Although these methods are widely used in the world, they sometimes fail to diagnose, especially when DGA results falls outside conventional method codes or when more than one fault exist in transformer. To overcome these limitations, fuzzy inference system (FIS) is proposed. 250 different cases are used to test the accuracy of various DGA methods in interpreting the transformer condition.
A Metamaterial-Based Handset Antenna with the SAR Reduction
Kahng, Sungtek ; Kahng, Kyungseok ; Yang, Inkyu ; Park, Taejoon ;
Journal of Electrical Engineering and Technology, volume 9, issue 2, 2014, Pages 622~627
DOI : 10.5370/JEET.2014.9.2.622
A method to reduce the specific absorption rate(SAR) of the antenna for WiMAX mobile communication is proposed in this paper. The SAR reduction is achieved by miniaturizing the physical size of the antenna for the given resonance frequency by devising a metamaterial-composite right- and left-handed(CRLH) configuration-based radiator much smaller than the quarter-guided wavelength adopted a lot in the conventional planar inverted F antenna(PIFA) or modified monopole antenna. The proposed antenna is placed near the head-phantom and its SAR is evaluated by the full-wave simulations(SEMCAD X), where the metamaterial-inspired antenna is shown to have the lower value than a modified monopole as the reference in terms of the SAR.
A Study on Lightning Overvoltage Characteristics of Grounding Systems in Underground Distribution Power Cables
Jung, Chae-Kyun ; Jung, Yeon-Ha ; Kang, Ji-Won ;
Journal of Electrical Engineering and Technology, volume 9, issue 2, 2014, Pages 628~634
DOI : 10.5370/JEET.2014.9.2.628
This paper investigates the transient characteristics of grounding systems used in under-ground distribution power cables. Recently, two kinds of grounding system are used for underground distribution cables in Korea. The first one is conventional multi-point grounding system, the other is newly proposed non-bundled common grounding system. The non-bundled common grounding system has an advantage the decreasing the power loss due to decrease of the shield circulation current. In this paper, the lightning overvoltage induced in neutral wire (in case of non-bundled common grounding system, overvoltage between opened neural wires and grounding in each phase) of these two kinds of grounding systems are estimated and compared by field tests and EMTP simulations. The EMTP simulation methods are firstly verified by comparison of measurement and simulation. Finally, the insulation level against lightning is expected by EMTP simulation results using verified model.
Space Charge Behavior of Oil-Impregnated Paper Insulation Aging at AC-DC Combined Voltages
Li, Jian ; Wang, Yan ; Bao, Lianwei ;
Journal of Electrical Engineering and Technology, volume 9, issue 2, 2014, Pages 635~642
DOI : 10.5370/JEET.2014.9.2.635
The space charge behaviors of oil-paper insulation affect the stability and security of oil-filled converter transformers of traditional and new energies. This paper presents the results of the electrical aging of oil-impregnated paper under AC-DC combined voltages by the pulsed electro-acoustic technique. Data mining and feature extractions were performed on the influence of electrical aging on charge dynamics based on the experiment results in the first stage. Characteristic parameters such as total charge injection and apparent charge mobility were calculated. The influences of electrical aging on the trap energy distribution of an oil-paper insulation system were analyzed and discussed. Longer electrical aging time would increase the depth and energy density of charge trap, which decelerates the apparent charge mobility and increases the probability of hot electron formation. This mechanism would accelerate damage to the cellulose and the formation of discharge channels, enhance the acceleration of the electric field distortion, and shorten insulation lifetime under AC-DC combined voltages.
A Study on the Properties of CSPE According to Accelerated Thermal Aging Years
Lee, Jung-Hoon ; Kang, Myeong-Kyun ; Jeon, Jun-Soo ; Lee, Seung-Hoon ; Kim, In-Yong ; Park, Hyun-Shin ; Shin, Yong-Deok ;
Journal of Electrical Engineering and Technology, volume 9, issue 2, 2014, Pages 643~648
DOI : 10.5370/JEET.2014.9.2.643
The accelerated thermal aging of CSPE (chlorosulfonated polyethylene) was carried out for 40.41, 121.22, and 202.04 days at
, which are equivalent to 20, 60, and 100years of aging at
, respectively. The volume electrical resistivities of the accelerated thermally aged CSPE samples for 0, 40.41, 121.22, and 202.04 days were
, respectively, at room temperature. The permittivities of the accelerated thermally aged CSPE samples for 0, 40.41, 121.22, and 202.04 days were
F/m, respectively, at room temperature. The EAB (elongation at break) of the accelerated thermally aged CSPE samples for 0, 40.41, 121.22, and 202.04 days were 98.8-101.3, 59.5-60.3, 37.8-39.2, and 41.8-44.3%, respectively, at room temperature. The apparent densities of the accelerated thermally aged CSPE samples for 0, 40.41, 121.22, and 202.04 days were 1.603-1.614, 1.611-1.613, 1.622-1.628, and
, respectively, at room temperature. The measured currents of the accelerated thermally aged CSPE and the standard sample were almost constant after 5 min of applying a 300-V/mm electric field to the CSPE. The V-I slope of the accelerated thermally aged CSPE sample was increased if the applied electric field was increased at room temperature, and the V-I slope of the accelerated thermally aged CSPE was higher than that of standard CSPE.
A Compact Quantum Model for Cylindrical Surrounding Gate MOSFETs using High-k Dielectrics
Vimala, P. ; Balamurugan, N.B. ;
Journal of Electrical Engineering and Technology, volume 9, issue 2, 2014, Pages 649~654
DOI : 10.5370/JEET.2014.9.2.649
In this paper, an analytical model for Surrounding Gate (SG) metal-oxide- semiconductor field effect transistors (MOSFETs) considering quantum effects is presented. To achieve this goal, we have used variational approach for solving the Poission and Schrodinger equations. This model is developed to provide an analytical expression for inversion charge distribution function for all regions of device operation. This expression is used to calculate the other important parameters like inversion charge density, threshold voltage, drain current and gate capacitance. The calculated expressions for the above parameters are simple and accurate. This paper also focuses on the gate tunneling issue associated with high dielectric constant. The validity of this model was checked for the devices with different dimensions and bias voltages. The calculated results are compared with the simulation results and they show good agreement.
Analytical Surface Potential Model with TCAD Simulation Verification for Evaluation of Surrounding Gate TFET
Samuel, T.S. Arun ; Balamurugan, N.B. ; Niranjana, T. ; Samyuktha, B. ;
Journal of Electrical Engineering and Technology, volume 9, issue 2, 2014, Pages 655~661
DOI : 10.5370/JEET.2014.9.2.655
In this paper, a new two dimensional (2D) analytical modeling and simulation for a surrounding gate tunnel field effect transistor (TFET) is proposed. The Parabolic approximation technique is used to solve the 2-D Poisson equation with suitable boundary conditions and analytical expressions for surface potential and electric field are derived. This electric field distribution is further used to calculate the tunneling generation rate and thus we numerically extract the tunneling current. The results show a significant improvement in on-current characteristics while short channel effects are greatly reduced. Effectiveness of the proposed model has been confirmed by comparing the analytical results with the TCAD simulation results.
Suitability of Palm Based Oil as Dielectric Insulating Fluid in Transformers
Azis, Norhafiz ; Jasni, Jasronita ; Kadir, Mohd Zainal Abidin Ab ; Mohtar, Mohd Nazim ;
Journal of Electrical Engineering and Technology, volume 9, issue 2, 2014, Pages 662~669
DOI : 10.5370/JEET.2014.9.2.662
Mineral oil has been widely used as dielectric insulating fluid in transformers due to its excellent performance in-service. However, there are few issues with mineral oil such as it has poor biodegradability and could contaminate the environment if a spillage occurs. With the increasing tight regulation on safety and environment, alternative fluids for mineral oil are currently being investigated and among the suitable candidate is the vegetable oil. There are different types of vegetable oils and one of them is the palm based oil. At the moment, extensive research works are carried out to examine its feasibility to be applied in transformers. This paper will review the previous research works that were carried out to examine the suitability of palm based oil as dielectric insulating fluid in transformers. The physical and chemical properties of palm based oil are studied based on viscosity, acidity, oxidation stability and flash point. Next, the electrical characteristics of palm based oil are examined based on AC breakdown voltage, relative permittivity, dissipation factor and partial discharge.
Partial Discharge Ultrasonic Analysis for Generator Stator Windings
Yang, Yong-Ming ; Chen, Xue-Jun ;
Journal of Electrical Engineering and Technology, volume 9, issue 2, 2014, Pages 670~676
DOI : 10.5370/JEET.2014.9.2.670
The objective of this research is to utilize the ultrasonic method to analyze the property of partial discharge (PD) which is generated by the winding of the insulation stator in the generator. Therefore, a PD measurement system is built based on ultrasonic and virtual instruments. Three types of PD models (internal PD model, surface PD model and slot PD model) have been constructed. With the analysis of these experimental results, this research has identified the ultrasonic signals of the discharges which were produced by three types of PD models. This analysis shows the different features among these PD types. Both the time domain and frequency domain of the ultrasonic signals are obviously different. In addition, an experiment based on a large rotating machine has been done to analyze ultrasonic noises. The result indicates that the ultrasonic noises can be wiped off by the filters and algorithms. The application of this system is convenient for the detection of early signs of insulation failure, which is an effective method for diagnosis of insulation faults.
Generation of Ultrawide Band Electromagnetic Pulse from Blumlein Pulse Forming Line
Jin, Yun Sik ; Kim, Jong Soo ; Cho, Chuhyun ; Roh, Young Su ;
Journal of Electrical Engineering and Technology, volume 9, issue 2, 2014, Pages 677~681
DOI : 10.5370/JEET.2014.9.2.677
A high voltage pulse generator was fabricated to radiate ultrawide band electromagnetic pulse. A coaxial type of Blumlein pulse forming line is employed to produce a pulse of high voltage (>300 kV) and short pulse duration (~5 ns). A helical strip/wire type of air-cored pulse transformer was used to charge the Blumlein pulse forming line up to more than 300 kV. A peaking switch is essential to make the pulse rise time as fast as possible. Typically, the rise time is ~500 ps. The output pulse of the generator is radiated into air through an exponentially tapered TEM horn antenna. The electric field intensity of a radiated pulse was measured as a function of the distance from the transmitting horn as well as the output voltage of the peaking switch. The peak-to-peak value of the electric field intensity at 10 m from the TEM antenna was~100 kV/m.
Design of Window Applicable Blind-type Frequency Selective Surface
Lee, In-Gon ; Hong, Ic-Pyo ;
Journal of Electrical Engineering and Technology, volume 9, issue 2, 2014, Pages 682~685
DOI : 10.5370/JEET.2014.9.2.682
In this paper, we presented the window applicable blind-type frequency selective surface to control the coverage area of wireless communication in secure building or conference room. The proposed frequency selective structure has the reconfigurable frequency range depends on its blind rotation angle. To verify the proposed structure, we fabricated the window blind-type frequency selective surface with four-legged loaded element and ring-type element as a unit cell and performed measurements of the transmission characteristics for different blind rotation angles to prove the feasibility. The measurement results show good agreements with the simulation results. One of the advantages is that the proposed structure does not need to have a bias circuit, so it is very easy to implement at low cost and also can be applied to any planar surface for wireless security applications.
A Study on Characteristic Improvement of IGBT with P-floating Layer
Kyoung, Sinsu ; Jung, Eun Sik ; Kang, Ey Goo ;
Journal of Electrical Engineering and Technology, volume 9, issue 2, 2014, Pages 686~694
DOI : 10.5370/JEET.2014.9.2.686
A power semiconductor device, usually used as a switch or rectifier, is very significant in the modern power industry. The power semiconductor, in terms of its physical properties, requires a high breakdown voltage to turn off, a low on-state resistance to reduce static loss, and a fast switching speed to reduce dynamic loss. Among those parameters, the breakdown voltage and on-state resistance rely on the doping concentration of the drift region in the power semiconductor, this effect can be more important for a higher voltage device. Although the low doping concentration in the drift region increases the breakdown voltage, the on-state resistance that is increased along with it makes the static loss characteristic deteriorate. On the other hand, although the high doping concentration in the drift region reduces on-state resistance, the breakdown voltage is decreased, which limits the scope of its applications. This addresses the fact that breakdown voltage and on-state resistance are in a trade-off relationship with a parameter of the doping concentration in the drift region. Such a trade-off relationship is a hindrance to the development of power semiconductor devices that have idealistic characteristics. In this study, a novel structure is proposed for the Insulated Gate Bipolar Transistor (IGBT) device that uses conductivity modulation, which makes it possible to increase the breakdown voltage without changing the on-state resistance through use of a P-floating layer. More specifically in the proposed IGBT structure, a P-floating layer was inserted into the drift region, which results in an alleviation of the trade-off relationship between the on-state resistance and the breakdown voltage. The increase of breakdown voltage in the proposed IGBT structure has been analyzed both theoretically and through simulations, and it is verified through measurement of actual samples.
Partial Discharge Signal Denoising using Adaptive Translation Invariant Wavelet Transform-Online Measurement
Maheswari, R.V. ; Subburaj, P. ; Vigneshwaran, B. ; Iruthayarajan, M. Willjuice ;
Journal of Electrical Engineering and Technology, volume 9, issue 2, 2014, Pages 695~706
DOI : 10.5370/JEET.2014.9.2.695
Partial discharge (PD) measurements have emerged as a dominant investigative tool for condition monitoring of insulation in high voltage equipment. But the major problem behind them the PD signal is severely polluted by several noises like White noise, Random noise, Discrete Spectral Interferences (DSI) and the challenge lies with removing these noise from the onsite PD data effectively which leads to preserving the signal for feature extraction. Accordingly the paper is mainly classified into two parts. In first part the PD signal is artificially simulated and mixed with white noise. In second part the PD is measured then it is subjected to the proposed denoising techniques namely Translation Invariant Wavelet Transform (TIWT). The proposed TIWT method remains the edge of the original signal efficiently. Additionally TIWT based denoising is used to suppress Pseudo Gibbs phenomenon. In this paper an attempt has been made to review the methodology of denoising the PD signals and shows that the proposed denoising method results are better when compared to other wavelet-based approaches like Fast Fourier Transform (FFT), Discrete Wavelet Transform (DWT), by evaluating five different parameters like, Signal to noise ratio, Cross-correlation coefficient, Pulse amplitude distortion, Mean square error, Reduction in noise level.
A Fast and Accurate Face Tracking Scheme by using Depth Information in Addition to Texture Information
Kim, Dong-Wook ; Kim, Woo-Youl ; Yoo, Jisang ; Seo, Young-Ho ;
Journal of Electrical Engineering and Technology, volume 9, issue 2, 2014, Pages 707~720
DOI : 10.5370/JEET.2014.9.2.707
This paper proposes a face tracking scheme that is a combination of a face detection algorithm and a face tracking algorithm. The proposed face detection algorithm basically uses the Adaboost algorithm, but the amount of search area is dramatically reduced, by using skin color and motion information in the depth map. Also, we propose a face tracking algorithm that uses a template matching method with depth information only. It also includes an early termination scheme, by a spiral search for template matching, which reduces the operation time with small loss in accuracy. It also incorporates an additional simple refinement process to make the loss in accuracy smaller. When the face tracking scheme fails to track the face, it automatically goes back to the face detection scheme, to find a new face to track. The two schemes are experimented with some home-made test sequences, and some in public. The experimental results are compared to show that they outperform the existing methods in accuracy and speed. Also we show some trade-offs between the tracking accuracy and the execution time for broader application.
A Fast Converged Solution for Power Allocation of OFDMA System
Hwang, Sungho ; Cho, Ho-Shin ;
Journal of Electrical Engineering and Technology, volume 9, issue 2, 2014, Pages 721~725
DOI : 10.5370/JEET.2014.9.2.721
In this paper, we propose a fast adaptive power allocation method for an orthogonal frequency division multiple access (OFDMA) system that employs an adaptive modulation and coding (AMC) scheme. The proposed scheme aims to reduce the calculation complexity of greedy adaptive power allocation (APA), which is known as the optimal algorithm for maximizing the utility argument of power. Unlike greedy APA, which starts power allocation from "0", the proposed algorithm initially allocates a certain level of power determined by the water-filling scheme. We theoretically demonstrate that the proposed algorithm has almost the same capability of maximizing the utility argument as the greedy APA while reducing the number of operations by 2M, where M is the number of AMC levels.
Analysis of Induced Voltage on Telecommunication Line in Parallel Distribution System
Kim, Hyun-Soo ; Rhee, Sang-Bong ; Lee, Soon-Jeong ; Kim, Chul-Hwan ; Kim, Yoon Sang ;
Journal of Electrical Engineering and Technology, volume 9, issue 2, 2014, Pages 726~732
DOI : 10.5370/JEET.2014.9.2.726
A current flowing through a distribution conductor produces induced voltage, which is harmful to a telecommunication line. Previous research on induced voltage has been focused on single-circuit lines in the distribution system. However, the double-circuit lines, referred to as parallel distribution lines, are widely used in distribution systems because they have significant economic and environmental advantages over single-circuit lines. Therefore, a study on the induced voltage in double-circuit lines is needed. This paper presents a method of calculating the induced voltage in a parallel distribution system using four-terminal parameters and vector analysis. The calculation method is verified by the Electromagnetic Transient Program (EMTP) simulation.
Faster Detection of Step Initiation for the Lower Limb Exoskeleton with Vertical GRF Events
Cha, Dowan ; Kang, Daewon ; Kim, Kab Il ; Kim, Kyung-Soo ; Lee, Bum-Joo ; Kim, Soohyun ;
Journal of Electrical Engineering and Technology, volume 9, issue 2, 2014, Pages 733~738
DOI : 10.5370/JEET.2014.9.2.733
We propose a new approach called as a peak time approach for faster detection of step initiation for the lower limb exoskeleton. As faster detection of step initiation is an important criterion in evaluating the lower limb exoskeleton, many studies have investigated approaches to detect step initiation faster, including using electromyography, the center of pressure, the heel-off time and the toe-off time. In this study, we will utilize vertical ground reaction force events to detect step initiation, and compare our approach with prior approaches. Additionally, we will predict the first step's heel strike time with vertical ground reaction force events from multiple regression equations to support our approach. The lower limb exoskeleton should assist the operator's movement much faster and more reliably with our approach.
Human Action Recognition Via Multi-modality Information
Gao, Zan ; Song, Jian-Ming ; Zhang, Hua ; Liu, An-An ; Xue, Yan-Bing ; Xu, Guang-Ping ;
Journal of Electrical Engineering and Technology, volume 9, issue 2, 2014, Pages 739~748
DOI : 10.5370/JEET.2014.9.2.739
In this paper, we propose pyramid appearance and global structure action descriptors on both RGB and depth motion history images and a model-free method for human action recognition. In proposed algorithm, we firstly construct motion history image for both RGB and depth channels, at the same time, depth information is employed to filter RGB information, after that, different action descriptors are extracted from depth and RGB MHIs to represent these actions, and then multimodality information collaborative representation and recognition model, in which multi-modality information are put into object function naturally, and information fusion and action recognition also be done together, is proposed to classify human actions. To demonstrate the superiority of the proposed method, we evaluate it on MSR Action3D and DHA datasets, the well-known dataset for human action recognition. Large scale experiment shows our descriptors are robust, stable and efficient, when comparing with the-state-of-the-art algorithms, the performances of our descriptors are better than that of them, further, the performance of combined descriptors is much better than just using sole descriptor. What is more, our proposed model outperforms the state-of-the-art methods on both MSR Action3D and DHA datasets.
Tree-Structure-Aware Genetic Operators in Genetic Programming
Seo, Kisung ; Pang, Chulhyuk ;
Journal of Electrical Engineering and Technology, volume 9, issue 2, 2014, Pages 749~754
DOI : 10.5370/JEET.2014.9.2.749
In this paper, we suggest tree-structure-aware GP (Genetic Programming) operators that heed tree distributions in structure space and their possible structural difficulties. The main idea of the proposed GP operators is to place the generated offspring of crossover and/or mutation in a specified region of tree structure space insofar as possible by biasing the tree structures of the altered subtrees, taking into account the observation that most solutions are found in that region. To demonstrate the effectiveness of the proposed approach, experiments on the binomial-3 regression, multiplexor and even parity problems are performed. The results show that the results using the proposed tree-structure-aware operators are superior to the results of standard GP for all three test problems in both success rate and number of evaluations.
An Effective Method of Sharing Heterogeneous Components of OPRoS and RTM
Salov, Andrey D. ; Park, Hong Seong ; Han, Soohee ; Lee, Dooam ;
Journal of Electrical Engineering and Technology, volume 9, issue 2, 2014, Pages 755~761
DOI : 10.5370/JEET.2014.9.2.755
Heterogeneous components have different component models, which prevents such components from sharing the functionalities of other components based on the different models. As one of methods for linking heterogeneous components, this paper suggests a proxy component to construct a bridge between heterogeneous components of OPRoS (Open Platform for Robotic Service) and RTM (Robot Technology Middleware). The proxy component consists of two types of components called Adaptor and Interceptor, via which the heterogeneous components can exchange data and services easily. The proposed method enables adaptor and interceptor components to directly invoke the services of the latter and the former, respectively, in order to exchange data and services on a real-time basis. The proxy component can be implemented for OPRoS and RT (Robot Technology) component models to connect with RT and OPRoS ones, respectively. It is shown through a simple experiment that the proposed method works well for real-time control.
Tangible Tele-Meeting in Tangible Space Initiative
Lee, Joong-Jae ; Lee, Hyun-Jin ; Jeong, Mun-Ho ; Jeong, SeongWon ; You, Bum-Jae ;
Journal of Electrical Engineering and Technology, volume 9, issue 2, 2014, Pages 762~770
DOI : 10.5370/JEET.2014.9.2.762
Tangible Space Initiative (TSI) is a new framework that can provide a more natural and intuitive Human Computer Interface for users. This is composed of three cooperative components: a Tangible Interface, Responsive Cyber Space, and Tangible Agent. In this paper we present a Tangible Tele-Meeting system in TSI, which allows people to communicate with each other without any spatial limitation. In addition, we introduce a method for registering a Tangible Avatar with a Tangible Agent. The suggested method is based on relative pose estimation between the user and the Tangible Agent. Experimental results show that the user can experience an interaction environment that is more natural and intelligent than that provided by conventional tele-meeting systems.
20 MHz-3 GHz Programmable Chirp Spread Spectrum Generator for a Wideband Radio Jamming Application
Kim, Sun-Ryoul ; Ryu, Hyuk ; Ha, Keum-Won ; Kim, Jeong-Geun ; Baek, Donghyun ;
Journal of Electrical Engineering and Technology, volume 9, issue 2, 2014, Pages 771~776
DOI : 10.5370/JEET.2014.9.2.771
In this paper, an agile programmable chirp spread spectrum generator for wideband frequency-jamming applications from 20 MHz to 3 GHz is proposed. A frequency-mixing architecture using two voltage-controlled oscillators is used to achieve a wideband operating frequency range, and the direct digital synthesizer (DDS)-based chirping method with a two-point modulation technique is employed to provide a programmable and consistent chirp bandwidth. The proposed signal generator provides the various programmable FM signals from 20 MHz to 3 GHz with a modulation bandwidth from 0 to 400 MHz. The prototype successfully demonstrates arbitrary sequential jamming operation with a fast band-to-band hopping time of < 10