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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of Electrical Engineering and Technology
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Journal DOI :
The Korean Institute of Electrical Engineers
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Volume & Issues
Volume 9, Issue 6 - Nov 2014
Volume 9, Issue 5 - Sep 2014
Volume 9, Issue 4 - Jul 2014
Volume 9, Issue 3 - May 2014
Volume 9, Issue 2 - Mar 2014
Volume 9, Issue 1 - Jan 2014
Selecting the target year
Real-Time Maximum Power Point Tracking Method Based on Three Points Approximation by Digital Controller for PV System
Kim, Seung-Tak ; Bang, Tae-Ho ; Lee, Seong-Chan ; Park, Jung-Wook ;
Journal of Electrical Engineering and Technology, volume 9, issue 5, 2014, Pages 1447~1453
DOI : 10.5370/JEET.2014.9.5.1447
This paper proposes the new method based on the availability of three points measurement and convexity of photovoltaic (PV) curve characteristic at the maximum power point (MPP). In general, the MPP tracking (MPPT) function is the important part of all PV systems due to their power-voltage (P-V) characteristics related with weather conditions. Then, the analog-to-digital converter (ADC) and low pass filter (LPF) are required to measure the voltage and current for MPPT by the digital controller, which is used to implement the PV power conditioning system (PCS). The measurement and quantization error due to rounding or truncation in ADC and the delay of LPF might degrade the reliability of MPPT. To overcome this limitation, the proposed method is proposed while improving the performances in both steady-state and dynamic responses based on the detailed investigation of its properties for availability and convexity. The performances of proposed method are evaluated with the several case studies by the PSCAD/EMTDC
simulation. Then, the experimental results are given to verify its feasibility in real-time.
A Simple Power Management Scheme with Enhanced Stability for a Solar PV/Wind/Fuel Cell Fed Standalone Hybrid Power Supply using Embedded and Neural Network Controller
Thangavel, S. ; Saravanan, S. ;
Journal of Electrical Engineering and Technology, volume 9, issue 5, 2014, Pages 1454~1470
DOI : 10.5370/JEET.2014.9.5.1454
This paper propose a new power conditioner topology with intelligent power management controller that integrates multiple renewable energy sources such as solar energy, wind energy and fuel cell energy with battery backup to make best use of their operating characteristics and obtain better reliability than that could be obtained by single renewable energy based power supply. The proposed embedded controller is programmed for maintaining a constant voltage at PCC, maximum power point tracking for solar PV panel and WTG and power flow control by regulating the reference currents of the controller on instantaneous basis based on the power delivered by the sources and load demand. Instantaneous variation in reference currents of the controller enhances the controller response as it accommodates the effect of continuously varying solar insolation and wind speed in the power management. The power conditioner uses a battery bank with embedded controller based online SOC estimation and battery charging system to suitably sink or source the input power based on the load demand. The simulation results of the proposed power management system for a standalone solar/WTG/fuel cell fed hybrid power supply with real time solar radiation and wind velocity data collected from solar centre, KEC for a sporadically varying load demand is presented in this paper and the results are encouraging in reliability and stability perspective.
Power Loss Modeling of Individual IGBT and Advanced Voltage Balancing Scheme for MMC in VSC-HVDC System
Son, Gum Tae ; Lee, Soo Hyoung ; Park, Jung-Wook ;
Journal of Electrical Engineering and Technology, volume 9, issue 5, 2014, Pages 1471~1481
DOI : 10.5370/JEET.2014.9.5.1471
This paper presents the new power dissipation model of individual switching device in a high-level modular multilevel converter (MMC), which can be mostly used in voltage sourced converter (VSC) based high-voltage direct current (HVDC) system and flexible AC transmission system (FACTS). Also, the voltage balancing method based on sorting algorithm is newly proposed to advance the MMC functionalities by effectively adjusting switching variations of the sub-module (SM). The proposed power dissipation model does not fully calculate the average power dissipation for numerous switching devices in an arm module. Instead, it estimates the power dissipation of every switching element based on the inherent operational principle of SM in MMC. In other words, the power dissipation is computed in every single switching event by using the polynomial curve fitting model with minimum computational efforts and high accuracy, which are required to manage the large number of SMs. After estimating the value of power dissipation, the thermal condition of every switching element is considered in the case of external disturbance. Then, the arm modeling for high-level MMC and its control scheme is implemented with the electromagnetic transient simulation program. Finally, the case study for applying to the MMC based HVDC system is carried out to select the appropriate insulated-gate bipolar transistor (IGBT) module in a steady-state, as well as to estimate the proper thermal condition of every switching element in a transient state.
Reliability Evaluation Technique for Electrical Distribution Networks Considering Planned Outages
Hu, Bo ; He, Xiao-Hui ; Cao, Kan ;
Journal of Electrical Engineering and Technology, volume 9, issue 5, 2014, Pages 1482~1488
DOI : 10.5370/JEET.2014.9.5.1482
The reliability evaluation of the electrical distribution networks (EDN) requires sufficient consideration of the effects of planned outages. The planned outages of the EDN can be divided, by outage models and their effects on the reliability into two major categories: by equipment and by feeder. After studying the characteristics of different categories of planned outages, this paper expands the classification of load points by outage time from 4 types to 7 types and defines corresponding reliability parameters for the different types. By using the section algorithm, this paper proposes a reliability evaluation technique of EDN considering equipment random failures and two categories of planned outages. The proposed technique has been applied to the RBTS-BUS6 test system and some practical EDNs in China. The study results demonstrate that the proposed technique is of higher practical value and can be used for evaluating the reliability performance of EDN more efficiently considering the planned outages.
Hardware-in-the-loop Simulation Method for a Wind Farm Controller Using Real Time Digital Simulator
Kim, Gyeong-Hun ; Kim, Jong-Yul ; Jeon, Jin-Hong ; Kim, Seul-Ki ; Kim, Eung-Sang ; Lee, Ju-Han ; Park, Minwon ; Yu, In-Keun ;
Journal of Electrical Engineering and Technology, volume 9, issue 5, 2014, Pages 1489~1494
DOI : 10.5370/JEET.2014.9.5.1489
A hardware-in-the-loop simulation (HILS) method for a wind farm controller using a real time digital simulator (RTDS) is presented, and performance of the wind farm controller is analyzed. A 100 MW wind farm which includes 5 MW wind power generation systems (WPGS) is modeled and analyzed in RSCAD/RTDS. The wind farm controller is implemented by using a computer, which is connected to the RTDS through transmission control protocol/internet protocol (TCP/IP). The HILS results show the active power and power factor of the wind farm, which are controlled by the wind farm controller. The proposed HILS method in this paper can be effectively utilized to validate and test a wind farm controller under the environment in practice without a real wind farm.
Power Interruption Costs to Commercial Customers of Electricity in Korea
Kim, Dong-Sub ; Kim, Kil-Sin ;
Journal of Electrical Engineering and Technology, volume 9, issue 5, 2014, Pages 1495~1500
DOI : 10.5370/JEET.2014.9.5.1495
This paper presents the result of the estimation of the power interruption costs of Korean commercial customers. Commercial customers are usually located in urban areas and considered very important because a power interruption on them can expand to additional damage to related users. Their power interruption costs were calculated through a survey with the process of data selection. Also, the power interruption cost for each customer's business type was calculated and compared with that of foreign cases.
A Techno-Economic Feasibility Analysis on LVDC Distribution System for Rural Electrification in South Korea
Afamefuna, David ; Chung, Il-Yop ; Hur, Don ; Kim, Ju-Yong ; Cho, Jintae ;
Journal of Electrical Engineering and Technology, volume 9, issue 5, 2014, Pages 1501~1510
DOI : 10.5370/JEET.2014.9.5.1501
Low voltage direct current (LVDC) distribution system is a suitable techno-economic candidate which can create an innovative solution for distribution network development with respect to rural electrification. This research focuses on the use of LVDC distribution system to replace some of KEPCO's existing traditional medium voltage alternating current (MVAC) distribution network for rural electrification in South Korea. Considering the technical and economic risks and benefits involved in such project, a comparative techno-economic analysis on the LVDC and the MVAC distribution networks is conducted using economic assessment method such as the net present value (NPV) on a discounted cash flow (DCF) basis as well as the sensitivity analysis technique. Each would play a role in an economic performance indicator and a measure of uncertainty and risk involved in the project. In this work, a simulation model and a computational tool are concurrently developed and employed to aid the techno-economic analysis, evaluation, and estimation of the various systems efficiency and/or performance.
Modeling of a Compressed Air Energy Electrification by Using Induction Generator Based on Field Oriented Control Principle
Vongmanee, Varin ; Monyakul, Veerapol ;
Journal of Electrical Engineering and Technology, volume 9, issue 5, 2014, Pages 1511~1519
DOI : 10.5370/JEET.2014.9.5.1511
The objective of this paper is to propose a modelling of a small compressed air energy storage system, which drives an induction generator based on a field-oriented control (FOC) principle for a renewable power generation. The proposed system is a hybrid technology of energy storage and electrification, which is developed to use as a small scale of renewable energy power plant. The energy will be transferred from the renewable energy resource to the compressed air energy by reciprocating air compressor to be stored in a pressurized vessel. The energy storage system uses a small compressed air energy storage system, developed as a small unit and installed above ground to avoid site limitation as same as the conventional CAES does. Therefore, it is suitable to be placed at any location. The system is operated in low pressure not more than 15 bar, so, it easy to available component in country and inexpensive. The power generation uses a variable speed induction generator (IG). The relationship of pressure and air flow of the compressed air, which varies continuously during the discharge of compressed air to drive the generator, is considered as a control command. As a result, the generator generates power in wide speed range. Unlike the conventional CAES that used gas turbine, this system does not have any combustion units. Thus, the system does not burn fuel and exhaust pollution. This paper expresses the modelling, thermodynamic analysis simulation and experiment to obtain the characteristic and performance of a new concept of a small compressed air energy storage power plant, which can be helpful in system designing of renewable energy electrification. The system was tested under a range of expansion pressure ratios in order to determine its characteristics and performance. The efficiency of expansion air of 49.34% is calculated, while the efficiency of generator of 60.85% is examined. The overall efficiency of system of approximately 30% is also investigated.
Probabilistic Assessment of Total Transfer Capability Using SQP and Weather Effects
Kim, Kyu-Ho ; Park, Jin-Wook ; Rhee, Sang-Bong ; Bae, Sungwoo ; Song, Kyung-Bin ; Cha, Junmin ; Lee, Kwang Y. ;
Journal of Electrical Engineering and Technology, volume 9, issue 5, 2014, Pages 1520~1526
DOI : 10.5370/JEET.2014.9.5.1520
This paper presents a probabilistic method to evaluate the total transfer capability (TTC) by considering the sequential quadratic programming and the uncertainty of weather conditions. After the initial TTC is calculated by sequential quadratic programming (SQP), the transient stability is checked by time simulation. Also because power systems are exposed to a variety of weather conditions the outage probability is increased due to the weather condition. The probabilistic approach is necessary to evaluate the TTC, and the Monte Carlo Simulation (MCS) is used to accomplish the probabilistic calculation of TTC by considering the various weather conditions.
Optimal Excitation Angles of a Switched Reluctance Generator for Maximum Output Power
Thongprasri, Pairote ; Kittiratsatcha, Supat ;
Journal of Electrical Engineering and Technology, volume 9, issue 5, 2014, Pages 1527~1536
DOI : 10.5370/JEET.2014.9.5.1527
This paper investigates the optimal values of turn-on and turn-off angles, and ratio of flux linkage at turn-off angle and peak phase current positions of optimal control for accomplishing maximum output power in an 8/6 Switched Reluctance Generator (8/6 SRG). Phase current waveform is analyzed to determine optimal excitation angles (optimal turn-on and turn-off angles) of the SRG for maximum output power which is applied from a nonlinear magnetization curve in terms of control variables (dc bus voltage, shaft speed, and excitation angles). The optimal excitation angles in single pulse mode of operation are proposed via the analytical model. Simulated and experimental results have verified the accuracy of the analytical model.
Single Input Multi Output DC/DC Converter: An Approach to Voltage Balancing in Multilevel Inverter
Banaei, M.R. ; Nayeri, B. ; Salary, E. ;
Journal of Electrical Engineering and Technology, volume 9, issue 5, 2014, Pages 1537~1543
DOI : 10.5370/JEET.2014.9.5.1537
This paper presents a new DC/AC multilevel converter. This configuration uses single DC sources. The proposed converter has two stages. The first stage is a DC/DC converter that can produce several DC-links in the output. The DC/DC converter is one type of boost converter and uses single inductor. The second stage is a multilevel inverter with several capacitor links. In this paper, one single input multi output DC-DC converter is used in order to voltage balancing on multilevel converter. In addition, as compare to traditional multilevel inverter, presented DC/AC multilevel converter has less on-state voltage drop and conduction losses. Finally, in order to verify the theoretical issues, simulation and experimental results are presented.
An Adaptive Optimization Algorithm Based on Kriging Interpolation with Spherical Model and its Application to Optimal Design of Switched Reluctance Motor
Xia, Bin ; Ren, Ziyan ; Zhang, Yanli ; Koh, Chang-Seop ;
Journal of Electrical Engineering and Technology, volume 9, issue 5, 2014, Pages 1544~1550
DOI : 10.5370/JEET.2014.9.5.1544
In this paper, an adaptive optimization strategy utilizing Kriging model and genetic algorithm is proposed for the optimal design of electromagnetic devices. The ordinary Kriging assisted by the spherical covariance model is used to construct surrogate models. In order to improve the computational efficiency, the adaptive uniform sampling strategy is applied to generate sampling points in design space. Through several iterations and gradual refinement process, the global optimal point can be found by genetic algorithm. The proposed algorithm is validated by application to the optimal design of a switched reluctance motor, where the stator pole face and shape of pole shoe attached to the lateral face of the rotor pole are optimized to reduce the torque ripple.
Time Domain Based Digital Controller for Buck-Boost Converter
Vijayalakshmi, S. ; Sree Renga Raja, T. ;
Journal of Electrical Engineering and Technology, volume 9, issue 5, 2014, Pages 1551~1561
DOI : 10.5370/JEET.2014.9.5.1551
Design, Simulation and experimental analysis of closed loop time domain based Discrete PWM buck-boost converter are described. To improve the transient response and dynamic stability of the proposed converter, Discrete PID controller is the most preferable one. Discrete controller does not require any precise analytical model of the system to be controlled. The control system of the converter is designed using digital PWM technique. The proposed controller improves the dynamic performance of the buck-boost converter by achieving a robust output voltage against load disturbances, input voltage variations and changes in circuit components. The converter is designed through simulation using MATLAB/Simulink and performance parameters are also measured. The discrete controller is implemented, and design goal is achieved and the same is verified against theoretical calculation using LabVIEW.
Control-to-output Transfer Function of the Open-loop Step-up Converter in CCM Operation
Wang, Faqiang ; Ma, Xikui ;
Journal of Electrical Engineering and Technology, volume 9, issue 5, 2014, Pages 1562~1568
DOI : 10.5370/JEET.2014.9.5.1562
Based on the average method and the geometrical technique to calculate the average value, the average model of the open-loop step-up converter in CCM operation is established. The DC equilibrium point and corresponding small signal model is derived. The control-to-output transfer function is presented and analyzed. The theoretical analysis and PSIM simulations shows that the control-to-output transfer function includes not only the DC input voltage and the DC duty cycle, but also the two inductors, the two energy-transferring capacitors, the switching frequency and the load. Finally, the hardware circuit is designed, and the circuit experimental results are given to confirm the effectiveness of theoretical derivations and analysis.
Torque Ripple Minimization in Direct Torque Control of Brushless DC Motor
Li, Zhenguo ; Zhang, Songfa ; Zhou, Shenghai ; Ahn, Jin-Woo ;
Journal of Electrical Engineering and Technology, volume 9, issue 5, 2014, Pages 1569~1576
DOI : 10.5370/JEET.2014.9.5.1569
This paper mainly proposes a direct torque control strategy to minimize torque ripple in brushless DC (BLDC) motor. BLDC motor has large current and torque ripple when one voltage vector applied in one cycle due to its low inductance. Hence, this paper proposed a hysteresis torque control with PWM mode to control the resultant torque. Moreover, when the direct torque control system is operating during the two-phase half-bridge
conduction mode, large torque ripple in commutation area appears every 120 electrical degree. Based on analyzing the root of torque ripple in detail, lookup tables of switching devices states for new half-bridge modulation mode in the positive and negative reference torque put forwarded. Finally, simulations by MATLAB software and experiment results from DSP are presented to verify the feasibility and effectiveness of the proposed strategy operating in four-quadrant operation.
Minimization of Torque Ripple for an IPMSM with a Notched Rotor Using the Particle Swarm Optimization Method
Shin, Pan Seok ; Kim, Ho Youn ; Kim, Yong Bae ;
Journal of Electrical Engineering and Technology, volume 9, issue 5, 2014, Pages 1577~1581
DOI : 10.5370/JEET.2014.9.5.1577
This paper presents a method to minimize torque ripple of a V-type IPMSM using the PSO (Particle Swarm Optimization) method with FEM. The proposed algorithm includes one objective function and three design variables for a notch on the surface of a rotor. The simulation model of the V-type IPMSM has 3-phases, 8-poles and 48 slots with 2 notches on the one-pole rotor surface. The arc-angle, length and width of the notch are optimized to minimize the torque ripple of the motor. The cogging torque of the model is reduced by 55.6% and the torque ripple is decreased by 15.5 %. Also, the efficiency of the motor is increased by 15.5 %.
A Simple Strategy for Sensorless Speed Control for an IPMSM During Startup and Over Wide Speed Range
Sim, Hyun-Woo ; Lee, June-Seok ; Lee, Kyo-Beum ;
Journal of Electrical Engineering and Technology, volume 9, issue 5, 2014, Pages 1582~1591
DOI : 10.5370/JEET.2014.9.5.1582
This paper presents a hybrid sensorless control for an interior permanent magnet synchronous motor (IPMSM) for zero-, low-, and high-speed regions. Many sensorless control methods such as an observer-based estimator have been introduced. However, most of the observer-based estimators have a disadvantage at start-up and in the low-speed region. To solve this problem, a simple strategy of using a hybrid system is proposed by integrating a high-frequency (HF) signal injection method and a full-order flux observer. In addition, an HF signal injection method with only a low pass filter (LPF) is proposed to simplify the hybrid system. The hybrid system achieves high-performance drive throughout the entire speed range. The effectiveness of the proposed hybrid technique is verified by experiments using an 11-kW IPMSM drive system.
A Novel Single Phase Soft Switched PFC Converter
Altintas, Nihan ;
Journal of Electrical Engineering and Technology, volume 9, issue 5, 2014, Pages 1592~1601
DOI : 10.5370/JEET.2014.9.5.1592
In this study, a novel single phase soft switched power factor correction (PFC) converter is developed with active snubber cell. The active snubber cell provides boost switch both to turn on with zero voltage transition (ZVT) and to turn off with zero current transition (ZCT). As the switching losses in the proposed converter are too low, L and C size can be reduced by increasing the operating frequency. Also, all the semiconductor devices operate with soft switching. There is no additional voltage stress in the boost switch and diode. The proposed converter has a simple structure, low cost and ease of control as well. It has a simple control loop to achieve near unity power factor with the aid of the UC3854. In this study, detailed steady state analysis of the proposed converter is presented and this theoretical analysis is verified by a prototype of 100 kHz and 500 W converter. The measured power factor and efficiency are 0.99 and 97.9% at full load.
Design and Control of an Optimized Battery Charger for an xEV Based on Photovoltaic Power Systems
Kim, Dong-Hee ; Cheo, Gyu-Yeong ; Lee, Byoung-Kuk ;
Journal of Electrical Engineering and Technology, volume 9, issue 5, 2014, Pages 1602~1613
DOI : 10.5370/JEET.2014.9.5.1602
The continuous growth of electric vehicles has caused electric power shortages in conventional utilities owing to the charging of electric-vehicle batteries. In order to increase the capacity of these utilities, photovoltaic systems may be an appropriate solution because of their benefits. However, a large amount of loss is generated in a conventional charging structure using photovoltaic sources owing to the many power conversion processes. This paper describes a simple integrated battery charger that utilizes a PV generation system. Moreover, the system control algorithm is deduced by analyzing the operation modes in order to control the proposed integrated system. The proposed system and algorithm are verified by a 3.3-kW prototype, resulting in an increase in the efficiency of approximately 7% to 15% compared with the conventional system. And, to examine the feasibility of the proposed system, the simulation for multi-charger with various conditions are progressed.
Flux Sliding-mode Observer Design for Sensorless Control of Dual Three-phase Interior Permanent Magnet Synchronous Motor
Shen, Jian-Qing ; Yuan, Lei ; Chen, Ming-Liang ; Xie, Zhen ;
Journal of Electrical Engineering and Technology, volume 9, issue 5, 2014, Pages 1614~1622
DOI : 10.5370/JEET.2014.9.5.1614
A novel equivalent flux sliding-mode observer (SMO) is proposed for dual three-phase interior permanent magnet synchronous motor (DT-IPMSM) drive system in this paper. The DT-IPMSM has two sets of Y-connected stator three-phase windings spatially shifted by 30 electrical degrees. In this method, the sensorless drive system employs a flux SMO with soft phase-locked loop method for rotor speed and position estimation, not only are low-pass filter and phase compensation module eliminated, but also estimation accuracy is improved. Meanwhile, to get the regulator parameters of current control, the inner current loop is realized using a decoupling and diagonal internal model control algorithm. Experiment results of 2MW-level DT-IPMSM drives system show that the proposed method has good dynamic and static performances.
Inductances Evaluation of a Squirrel-Cage Induction Motor with Curved Dynamic Eccentricity
Lv, Qiang ; Bao, Xiaohua ; He, Yigang ; Fang, Yong ; Cheng, Xiaowei ;
Journal of Electrical Engineering and Technology, volume 9, issue 5, 2014, Pages 1623~1631
DOI : 10.5370/JEET.2014.9.5.1623
Eccentricity faults more or less exist in all rotating electrical machines. This paper establishes a more precise model of dynamic eccentricity (DE) in electrical machines named as curved dynamic eccentricity. It is a kind of axial unequal eccentricity which has not been investigated in detail so far but occurs in large electrical machines. The inductances of a large three-phase squirrel-cage induction machine (SCIM) under different levels of curved DE conditions are evaluated using winding function approach (WFA). These inductances include the stator self and mutual inductances, rotor self and mutual inductances, and mutual inductances between stator phases and rotor loops. A comparison is made between the calculation results under curved DE and the corresponding pure DE conditions. It indicates that the eccentricity condition will be more terrible than the monitored eccentricity based on the conventional pure DE model.
Analysis of an Interleaved Resonant Converter for High Voltage and High Current Applications
Lin, Bor-Ren ; Chen, Chih-Chieh ;
Journal of Electrical Engineering and Technology, volume 9, issue 5, 2014, Pages 1632~1642
DOI : 10.5370/JEET.2014.9.5.1632
This paper presents an interleaved resonant converter to reduce the voltage stress of power MOSFETs and achieve high circuit efficiency. Two half-bridge converters are connected in series at high voltage side to limit MOSFETs at
voltage stress. Flying capacitor is used between two series half-bridge converters to balance two input capacitor voltages in each switching cycle. Variable switching frequency scheme is used to control the output voltage. The resonant circuit is operated at the inductive load. Thus, the input current of the resonant circuit is lagging to the fundamental input voltage. Power MOSFETs can be turn on under zero voltage switching. Two resonant circuits are connected in parallel to reduce the current stress of transformer windings and rectifier diodes at low voltage side. Interleaved pulse-width modulation is adopted to decrease the output ripple current. Finally, experiments are presented to demonstrate the performance of the proposed converter.
Development of LED Street Lighting Controller for Wind-Solar Hybrid Power System
Lee, Yong-Sik ; Gim, Jae-Hyeon ;
Journal of Electrical Engineering and Technology, volume 9, issue 5, 2014, Pages 1643~1653
DOI : 10.5370/JEET.2014.9.5.1643
This paper presents the design and implementation of a wind-solar hybrid power system for LED street lighting and an isolated power system. The proposed system consists of photovoltaic modules, a wind generator, a storage system (battery), LED lighting, and the controller, which can manage the power and system operation. This controller has the functions of maximum power point tracking (MPPT) for the wind and solar power, effective charging/discharging for the storage system, LED dimming control for saving energy, and remote data logging for monitoring the performance and maintenance. The proposed system was analyzed in regard to the operation status of the hybrid input power and the battery voltage using a PSIM simulation. In addition, the characteristics of the proposed system's output were analyzed through experimental verification. A prototype was also developed which uses 300[W] of wind power, 200[W] of solar power, 60[W] LED lighting, and a 24[V]/80[Ah] battery. The control system principles and design scheme of the hardware and software are presented.
Investigation of InAs/InGaAs/InP Heterojunction Tunneling Field-Effect Transistors
Eun, Hye Rim ; Woo, Sung Yun ; Lee, Hwan Gi ; Yoon, Young Jun ; Seo, Jae Hwa ; Lee, Jung-Hee ; Kim, Jungjoon ; Kang, In Man ;
Journal of Electrical Engineering and Technology, volume 9, issue 5, 2014, Pages 1654~1659
DOI : 10.5370/JEET.2014.9.5.1654
Tunneling field-effect transistors (TFETs) are very applicable to low standby-power application by their virtues of low off-current (
) and small subthreshold swing (S). However, low on-current (
) of silicon-based TFETs has been pointed out as a drawback. To improve
of TFET, a gate-all-around (GAA) TFET based on III-V compound semiconductor with InAs/InGaAs/InP multiple-heterojunction structure is proposed and investigated. Its performances have been evaluated with the gallium (Ga) composition (x) for
in the channel region. According to the simulation results for
, S, and on/off current ratio (
), the device adopting
channel showed the optimum direct-current (DC) performance, as a result of controlling the Ga fraction. By introducing an n-type InGaAs thin layer near the source end, improved DC characteristics and radio-frequency (RF) performances were obtained due to boosted band-to-band (BTB) tunneling efficiency.
Investigations on PD Characteristics of Thermal aged Palm and Corn Oil for Power Transformer Insulation Applications
Senthilkumar, S. ; Karthik, B. ; Chandrasekar, S. ;
Journal of Electrical Engineering and Technology, volume 9, issue 5, 2014, Pages 1660~1669
DOI : 10.5370/JEET.2014.9.5.1660
Partial discharge (PD) detection plays a major role in the life time assessment of liquid insulation in power transformers. Many research works are being carried out to replace conventional mineral oil insulation in transformers by vegetable oils. It is necessary to understand the PD characteristics of vegetable oils before recommending them as an alternate for mineral oil. In this paper, the breakdown strength and PD characteristics of palm and corn oil were investigated in both unaged and thermally aged conditions. Laboratory experiments were performed as per IEC test procedures. PD signals were measured using wide band detection system. Phase resolved PD pattern of vegetable oils and mineral oil were compared. Effect of increase in voltage stress on the PD pattern of palm and corn oil were studied. Time and frequency domain analysis of PD pulses at needle-plane electrode configuration was carried out. Statistical analysis of PD pattern i.e. skewness and shape parameter variations with respect to applied thermal stress were also carried out. From the results, it is observed that palm and corn oils have better breakdown strength and PD characteristics even under long-term thermal stress and hence they can be used for power transformer applications.
Analysis of Tunnelling Rate Effect on Single Electron Transistor
Sheela, L. ; Balamurugan, N.B. ; Sudha, S. ; Jasmine, J. ;
Journal of Electrical Engineering and Technology, volume 9, issue 5, 2014, Pages 1670~1676
DOI : 10.5370/JEET.2014.9.5.1670
This paper presents the modeling of Single Electron Transistor (SET) based on Physical model of a device and its equivalent circuit. The physical model is derived from Schrodinger equation. The wave function of the electrode is calculated using Hartree-Fock method and the quantum dot calculation is obtained from WKB approximation. The resulting wave functions are used to compute tunneling rates. From the tunneling rate the current is calculated. The equivalent circuit model discuss about the effect of capacitance on tunneling probability and free energy change. The parameters of equivalent circuit are extracted and optimized using genetic algorithm. The effect of tunneling probability, temperature variation effect on tunneling rate, coulomb blockade effect and current voltage characteristics are discussed.
Prediction of Flashover and Pollution Severity of High Voltage Transmission Line Insulators Using Wavelet Transform and Fuzzy C-Means Approach
Narayanan, V. Jayaprakash ; Sivakumar, M. ; Karpagavani, K. ; Chandrasekar, S. ;
Journal of Electrical Engineering and Technology, volume 9, issue 5, 2014, Pages 1677~1685
DOI : 10.5370/JEET.2014.9.5.1677
Major problem in the high voltage power transmission line is the flashover due to polluted ceramic insulators which leads to failure of equipments, catastrophic fires and power outages. This paper deals with the development of a better diagnostic tool to predict the flashover and pollution severity of power transmission line insulators based on the wavelet transform and fuzzy c-means clustering approach. In this work, laboratory experiments were carried out on power transmission line porcelain insulators under AC voltages at different pollution conditions and corresponding leakage current patterns were measured. Discrete wavelet transform technique is employed to extract important features of leakage current signals. Variation of leakage current magnitude and distortion ratio at different pollution levels were analyzed. Fuzzy c-means algorithm is used to cluster the extracted features of the leakage current data. Test results clearly show that the flashover and pollution severity of power transmission line insulators can be effectively realized through fuzzy clustering technique and it will be useful to carry out preventive maintenance work.
Investigation on Oil-paper Degradation Subjected to Partial Discharge Using Chaos Theory
Gao, Jun ; Wang, Youyuan ; Liao, Ruijin ; Wang, Ke ; Yuan, Lei ; Zhang, Yiyi ;
Journal of Electrical Engineering and Technology, volume 9, issue 5, 2014, Pages 1686~1693
DOI : 10.5370/JEET.2014.9.5.1686
In this paper, oil-paper samples composed of transformer windings were used to investigate the insulation degradation process subjected to partial discharge (PD), with artificial defects inside to simulate the PD induced insulation degradation. To determine appropriate test voltages, the breakdown time obtained through a group of accelerated electrical degradation tests under high voltages was firstly fitted by two-parameter Weibull model to acquire the average breakdown time, which was then applied to establish the inverse power law life model to choose advisable test voltages. During the electrical degradation process, PD signals were synchronously detected by an ultra-high frequency (UHF) sensor from inception to breakdown. For PD analysis, the whole degradation process was divided into ten stages, and chaos theory was introduced to analyze the variation of three chaotic parameters with the development of electrical degradation, namely the largest Lyapunov exponent, correlation dimension and Komogorov entropy of PD amplitude time series. It is shown that deterministic chaos of PD is confirmed during the oil-paper degradation process, and the obtained results provide a new effective tool for the diagnosis of degradation of oil-paper insulation subjected to PD.
On the Lightning Induced Voltage Along Overhead Power Distribution Line
Izadi, Mahdi ; Ab Kadir, Mohd Zainal Abidin ; Hajikhani, Maryam ;
Journal of Electrical Engineering and Technology, volume 9, issue 5, 2014, Pages 1694~1703
DOI : 10.5370/JEET.2014.9.5.1694
Lightning induced voltage is a major factor that causes interruptions on distribution lines. In this paper, analytical expressions are proposed to evaluate a lightning induced voltage on power lines directly in the time domain without the need to apply any extra conversions. The proposed expressions can consider the widely used current functions and models in contrast to the earlier analytical expressions which had a number of limitations related to the simplification of the channel base current and the current along the lightning channel. The results show that the simulated values based on the proposed method are in good agreement with the previous studies and the proposed expressions can be used for optimizing the insulation and protection level of existing and new lines being designed.
Corona generated Radio Interference of the 750 kV AC Bundle Conductors in Sandy and Dusty Weather Condition in the High Altitude Area
Liu, Yun-Peng ; Zhu, Lei ; Lv, Fang-Cheng ; Wan, Bao-Quan ; Pei, Chun-Ming ;
Journal of Electrical Engineering and Technology, volume 9, issue 5, 2014, Pages 1704~1711
DOI : 10.5370/JEET.2014.9.5.1704
Sandy and dusty weather condition often occurs in the high altitude areas of China, which may greatly influence the corona generated radio interference (RI) characteristics of the bundle conductors of 750 kV AC power transmission lines. Corona generated RI of the conductors of the 750 kV AC power transmission lines used in practice is measured by EMI receiver with a coupling circuit and a coupling capacitor connected between the high voltage side and the earth side in fine and sandy and dusty condition. The measuring frequency is 0.5 MHz, and the quasi-peak detection is used. RI excitation function is calculated based on the corona RI current measured by the EMI receiver. Corona generated RI characteristics were analyzed from sand concentration and sand particle size. The test result shows that the corona generated RI excitation function is influenced by the sandy and dusty condition. Corona discharge of the conductors is more serious in sandy and dusty condition with an ultraviolet (UV) detector. Corona generated RI excitation function increases with the increase of sand concentration and also increases with the increase of particle size.
Analysis of the Effects of SD Plasma on Aerodynamic Drag Reduction of a High-speed Train
Lee, Hyung-Woo ; Kwon, Hyeok-Bin ;
Journal of Electrical Engineering and Technology, volume 9, issue 5, 2014, Pages 1712~1718
DOI : 10.5370/JEET.2014.9.5.1712
Experimental analysis according to the plasma actuator design variables was performed in order to verify the effects of sliding discharge plasma on aerodynamic drag reduction of a high-speed train. For the study, sliding discharge plasma actuator and high-frequency, high-voltage power supply were developed and experimented to figure out the best design variables for highest ionic wind velocity which could reduce the drag force. And then, 5% reduced-scale model of a high-speed train was built for wind tunnel test to verify it. From the results, it was confirmed that sliding discharge plasma had contribution to reduce the drag force and it had the potential to be applied to real-scale trains.
The Effects of (Ba
Nano Spheroidization Glass Additives on the Microstructure and Microwave Dielectric Properties of Ba(Zn
Choi, Cheal Soon ; Kim, Ki Soo ; Rhie, Dong Hee ; Yoon, Jung Rag ;
Journal of Electrical Engineering and Technology, volume 9, issue 5, 2014, Pages 1719~1723
DOI : 10.5370/JEET.2014.9.5.1719
In this study, the microwave dielectric properties of nano spheroidization glass powders added
ceramics prepared by solid state reaction have been investigated. Adding
nano spheroidization glass powders could effectively promote the densification even in the case of decreasing the sintering temperature. When the glass frit is 0.3 wt% and sintering is carried out at a temperature of
for 6 hr, a temperature stable microwave dielectric ceramic could be obtained, which has a dielectric constant (
) of 30.2, a quality factor (
) of 124,000 GHz and a temperature coefficient of resonance frequency (
Resistive Grounding Technique of Heat Sink for Reducing Radiation Noise
Ahn, Chang-Hoi ; Oh, JaeHyun ;
Journal of Electrical Engineering and Technology, volume 9, issue 5, 2014, Pages 1724~1728
DOI : 10.5370/JEET.2014.9.5.1724
Heat sink has been used to help an electrical device operate in normal temperature condition. But heat sink radiates unwanted electromagnetic wave, which may cause electromagnetic interference problem. A resistance loaded grounding technique is proposed to reduce electromagnetic wave radiation by a heat sink. Numerical simulations are accomplished to find optimal loading resistance. Also electromagnetic fields radiated by from a heat sink are measured and compared with the simulation results. The test results verify the usefulness of the proposed technique.
Virtual Environment Modeling for Battery Management System
Piao, Chang-Hao ; Yu, Qi-Fan ; Duan, Chong-Xi ; Su, Ling ; Zhang, Yan ;
Journal of Electrical Engineering and Technology, volume 9, issue 5, 2014, Pages 1729~1738
DOI : 10.5370/JEET.2014.9.5.1729
The offline verification of state of charge estimation, power estimation, fault diagnosis and emergency control of battery management system (BMS) is one of the key technologies in the field of electric vehicle battery system. It is difficult to test and verify the battery management system software in the early stage, especially for algorithms such as system state estimation, emergency control and so on. This article carried out the virtual environment modeling for verification of battery management system. According to the input/output parameters of battery management system, virtual environment is determined to run the battery management system. With the integration of the developed BMS model and the external model, the virtual environment model has been established for battery management system in the vehicle's working environment. Through the virtual environment model, the effectiveness of software algorithm of BMS was verified, such as battery state parameters estimation, power estimation, fault diagnosis, charge and discharge management, etc.
Software Fault Prediction at Design Phase
Singh, Pradeep ; Verma, Shrish ; Vyas, O.P. ;
Journal of Electrical Engineering and Technology, volume 9, issue 5, 2014, Pages 1739~1745
DOI : 10.5370/JEET.2014.9.5.1739
Prediction of fault-prone modules continues to attract researcher's interest due to its significant impact on software development cost. The most important goal of such techniques is to correctly identify the modules where faults are most likely to present in early phases of software development lifecycle. Various software metrics related to modules level fault data have been successfully used for prediction of fault-prone modules. Goal of this research is to predict the faulty modules at design phase using design metrics of modules and faults related to modules. We have analyzed the effect of pre-processing and different machine learning schemes on eleven projects from NASA Metrics Data Program which offers design metrics and its related faults. Using seven machine learning and four preprocessing techniques we confirmed that models built from design metrics are surprisingly good at fault proneness prediction. The result shows that we should choose Naïve Bayes or Voting feature intervals with discretization for different data sets as they outperformed out of 28 schemes. Naive Bayes and Voting feature intervals has performed AUC > 0.7 on average of eleven projects. Our proposed framework is effective and can predict an acceptable level of fault at design phases.
An Application of Proportional-Resonant Controller in MMC-HVDC System under Unbalanced Voltage Conditions
Quach, Ngoc-Thinh ; Ko, Ji-Han ; Kim, Dong-Wan ; Kim, Eel-Hwan ;
Journal of Electrical Engineering and Technology, volume 9, issue 5, 2014, Pages 1746~1752
DOI : 10.5370/JEET.2014.9.5.1746
This paper presents an application of proportional-resonant (PR) current controllers in modular multilevel converter-high voltage direct current (MMC-HVDC) system under unbalanced voltage conditions. The ac currents are transformed and controlled in the stationary reference frame (
-frame). Thus, the complex analysis of the positive and negative sequence components in the synchronous rotating reference frame (dq-frame) is not necessary. With this control method, the ac currents are kept balanced and the dc-link voltage is constant under the unbalanced voltage fault conditions. The simulation results based on a detailed PSCAD/EMTDC model confirm the effectiveness of the proposed control method.
Ultrasonic Flaw Detection in Composite Materials Using SSP-MPSD Algorithm
Benammar, Abdessalem ; Drai, Redouane ;
Journal of Electrical Engineering and Technology, volume 9, issue 5, 2014, Pages 1753~1761
DOI : 10.5370/JEET.2014.9.5.1753
Due to the inherent inhomogeneous and anisotropy nature of the composite materials, the detection of internal defects in these materials with non-destructive techniques is an important requirement both for quality checks during the production phase and in service inspection during maintenance operations. The estimation of the time-of-arrival (TOA) and/or time-of-flight (TOF) of the ultrasonic echoes is essential in ultrasonic non-destructive testing (NDT). In this paper, we used split-spectrum processing (SSP) combined with matching pursuit signal decomposition (MPSD) to develop a dedicated ultrasonic detection system. SSP algorithm is used for Signal-to-Noise Ratio (SNR) enhancement, and the MPSD algorithm is used to decompose backscattered signals into a linear expansion of chirplet echoes and estimate the chirplet parameters. Therefore, the combination of SSP and MPSD (SSP-MPSD) presents a powerful technique for ultrasonic NDT. The SSP algorithm is achieved by using Gaussian band pass filters. Then, MPSD algorithm uses the Maximum Likelihood Estimation. The good performance of the proposed method is experimentally verified using ultrasonic traces acquired from three specimens of carbon fibre reinforced polymer multi-layered composite materials (CFRP).
Distributed Coding Scheme for Multi-view Video through Efficient Side Information Generation
Yoo, Jihwan ; Ko, Min Soo ; Kwon, Soon Chul ; Seo, Young-Ho ; Kim, Dong-Wook ; Yoo, Jisang ;
Journal of Electrical Engineering and Technology, volume 9, issue 5, 2014, Pages 1762~1773
DOI : 10.5370/JEET.2014.9.5.1762
In this paper, a distributed image coding scheme for multi-view video through an efficient generation of side information is proposed. A distributed video coding technique corrects the errors in the side information, which is generated with the original image, by using the channel coding technique at the decoder. Therefore, the more correct the generated side information is, the better the performance of distributed video coding. The proposed technique is to apply the distributed video coding schemes to the image coding for multi-view video. It generates side information by selectively and efficiently using both 3-dimensional warping based on the depth map with spatially adjacent frames and motion-compensated temporal interpolation with temporally adjacent frames. In this scheme the difference between the adjacent frames, the sizes of the motion vectors for the adjacent blocks, and the edge information are used as the selection criteria. From the experiments, it was observed that the quality of the side information generated by the proposed technique was improved by the average peak signal-to-noise ratio of 0.97dB than the one by motion-compensated temporal interpolation or 3-dimensional warping. The result from analyzing the rate-distortion curves revealed that the proposed scheme could reduce the bit-rate by 8.01% on average at the same peak signal-to-noise ratio value, compared to previous work.
3-D Inverse Dynamics Analysis of the Effect of Maximum Muscle Force Capacities on a Musculoskeletal System
Han, Kap-Soo ; Kim, Kyungho ;
Journal of Electrical Engineering and Technology, volume 9, issue 5, 2014, Pages 1774~1779
DOI : 10.5370/JEET.2014.9.5.1774
It is known that muscle strength of human body can alter or deteriorate as aging. In this study, we present an inverse dynamics simulation to investigate the effect of muscle strength on performing the daily activities. A 3D musculoskeletal model developed in this study includes several segments of whole body, long and short muscles, ligaments and disc stiffness. Five daily activities such as standing, flexion, finger tip to floor, standing lift close and lifting flexed were simulated with varying the maximum muscle force capacities (MFC) of each muscle fascicles from 30 to
with an increment of
. In the result, no solution can be obtained for finger tip to floor and lifting flexed with
. Even though the solution was available for standing lift close activity in case of
capacity, many of muscle fascicles hit the upper bound of muscle strength which means that it is not physiologically possible to perform the acvities in reality. For lifing flexed, even the case of
capaciy, represents the moderate healthy people, was not able to find the solutions, showing that 18 muscles among 258 muscle fascicles reached 100% of muscle capacity. The estimated results imply that people who have low muscle strength such as elders or rehabilitation patients were required higher muscle work to perform and maintain the same daily activities than healthy one.
Robust Design of Pulse Oximeter Using Dynamic Control and Motion Artifact Detection Algorithms
Cho, Jung Hyun ; Kim, Jong Cheol ; Yoon, Gil Won ;
Journal of Electrical Engineering and Technology, volume 9, issue 5, 2014, Pages 1780~1787
DOI : 10.5370/JEET.2014.9.5.1780
Arterial oxygen saturation (
) monitoring for newborns requires special attention in neonatal intensive care units (NICUs). Newborns have very low photo-plethysmogram (PPG) amplitudes and their body movements are difficult to contain. Hardware design and its associated signal processing algorithms should be robust enough so that faulty measurements can be avoided. In this study, improved designs were implemented to deal with low perfusion, motion artifact, and the influence of ambient light. Dynamic range was increased by using different LED intensities and a feedback system. To minimize the effects of motion artifact and to discard other unqualified data, four additional algorithms were used, which were based on dual-trace detection, continuity of DC level, morphology of PPG, and simultaneity check of
system was tested with newborns with normal respiration in the NICU. Our system provided fast, real-time responses and 100% artifact detection was accomplished under 84% of