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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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The Transactions of The Korean Institute of Electrical Engineers
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The Korean Institute of Electrical Engineers
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Volume & Issues
Volume 65, Issue 11 - Nov 2016
Volume 65, Issue 10 - Oct 2016
Volume 65, Issue 9 - Sep 2016
Volume 65, Issue 8 - Aug 2016
Volume 65, Issue 7 - Jul 2016
Volume 65, Issue 6 - Jun 2016
Volume 65, Issue 5 - May 2016
Volume 65, Issue 4 - Apr 2016
Volume 65, Issue 3 - Mar 2016
Volume 65, Issue 2 - Feb 2016
Volume 65, Issue 1 - Jan 2016
Selecting the target year
Power Smoothing of a Variable-Speed Wind Turbine Generator Based on the Rotor Speed-Dependent Gain
Kim, Yeonhee ; Kang, Yong Cheol ;
The Transactions of The Korean Institute of Electrical Engineers, volume 65, issue 4, 2016, Pages 533~538
DOI : 10.5370/KIEE.2016.65.4.533
In a power grid that has a high penetration of wind power, the highly-fluctuating output power of wind turbine generators (WTGs) adversely impacts the power quality in terms of the system frequency. This paper proposes a power smoothing scheme of a variable-speed WTG that can smooth its fluctuating output power caused by varying wind speeds, thereby improving system frequency regulation. To achieve this, an additional loop relying on the frequency deviation that operates in association with the maximum power point tracking control loop, is proposed; its control gain is modified with the rotor speed. For a low rotor speed, to ensure the stable operation of a WTG, the gain is set to be proportional to the square of the rotor speed. For a high rotor speed, to improve the power smoothing capability, the control gain is set to be proportional to the cube of the rotor speed. The performance of the proposed scheme is investigated under varying wind speeds for the IEEE 14-bus system using an EMTP-RV simulator. The simulation results indicate that the proposed scheme can mitigate the output power fluctuation of WTGs caused by varying wind speeds by adjusting the control gain depending on the rotor speed, thereby supporting system frequency regulation.
A Study on Methodology of Optimal Operation of BESS and Diesel Generators in a Microgrid Considering Efficiency Characteristics According to the Power Ratios of Diesel Generators
Lee, Byung Ha ;
The Transactions of The Korean Institute of Electrical Engineers, volume 65, issue 4, 2016, Pages 539~546
DOI : 10.5370/KIEE.2016.65.4.539
With the growing interest of microgrid systems all over the world, many studies on microgrid operation are being carried out. The battery energy storage system(BESS) and the diesel generator are key equipments in the microgrid. In this paper, we analyze the characteristics of fuel consumption according to the power ratio of the diesel generator. Then, the formula to represent the unit cost of generation according to the power ratio of the diesel generator is derived. A new modeling of battery operation is presented considering the lifetime reduction according to increasing the cycles of charge/discharge operation of the battery. The methodology of determining the optimal operation of the battery and the diesel generator is presented by the use of the formula of fuel consumption of the diesel generator and the new modeling of battery operation. It is shown that this optimization methodology can be applied effectively for economical operation of the BESS and the diesel generator of a microgrid by case studies.
Study on BESS Charging and Discharging Scheduling Using Particle Swarm Optimization
Park, Hyang-A ; Kim, Seul-Ki ; Kim, Eung-Sang ; Yu, Jung-Won ; Kim, Sung-Shin ;
The Transactions of The Korean Institute of Electrical Engineers, volume 65, issue 4, 2016, Pages 547~554
DOI : 10.5370/KIEE.2016.65.4.547
Analyze the customer daily load patterns, be used to determine the optimal charging and discharging schedule which can minimize the electrical charges through the battery energy storage system(BESS) installed in consumers is an object of this paper. BESS, which analyzes the load characteristics of customer and reduce the peak load, is essential for optimal charging and discharging scheduling to save electricity charges. This thesis proposes optimal charging and discharging scheduling method, using particle swarm optimization (PSO) and penalty function method, of BESS for reducing energy charge. Since PSO is a global optimization algorithm, best charging and discharging scheduling can be found effectively. In addition, penalty function method was combined with PSO in order to handle many constraint conditions. After analysing the load patterns of target BESS, PSO based on penalty function method was applied to get optimal charging and discharging schedule.
Optimal Clustering of Energy Storage System for Frequency Regulation Service Considering Life Degradation
Kim, Wook-Won ; Kim, Jin-O ;
The Transactions of The Korean Institute of Electrical Engineers, volume 65, issue 4, 2016, Pages 555~560
DOI : 10.5370/KIEE.2016.65.4.555
Recently, many countries have placed great attention on energy security and climate changes. Governments are promoting the construction of renewable energy projects with regulatory support in Korea. Despite an increasing penetration of renewable resources, however, the photovoltaic and wind power are underutilized due to the endemic problems such as difficulties of output control and intermittent output. The Energy Storage System (ESS) is proposed as a good solution for solving the problems and has been studied in both the private business and the government. However, because of inefficient aspects, the research has been carried out for improving high costs and a small capacity. In addition, the ESS is currently installed for using only one purpose which is frequency regulation or transmission congestion relief such that has an economic limitation. Therefore, methods which are becoming economically justifiable to increase the penetration of the ESS is required. Thus, this paper presents in terms of operation efficiency to improve economic feasibility of the ESS currently used. mainly, there are two aspects for the operation efficiency. Firstly, it is intended to improve the utilization rate through a process that can utilize the ESS for various purposes. It is necessary to be able to use for other purposes by classifying and clustering for increasing the efficiency of availability. The clustering method is proposed to conduct the grouping the ESS. Especially, it is proposed to utilize ESS for frequency regulation service which is the one of ancillary services in the power system. Through case studies, it is confirmed to secure the necessary resources by clustering small size ESS.
A Study on Design of Linear Motor for Maglev for High Efficiency
Kim, Youn-Hyun ; Kim, Ki-Chan ;
The Transactions of The Korean Institute of Electrical Engineers, volume 65, issue 4, 2016, Pages 561~566
DOI : 10.5370/KIEE.2016.65.4.561
In this paper, effective design method of linear induction motor(LIM) for Maglev is proposed in order to maximize system efficiency of Maglev. For the high system efficiency of Maglev, it is important to minimize weight of traction motor. Light weight design by changing materials of core and winding is conducted without changing volume of LIM. For the silicon steel core of primary part for magnetic flux path, iron-cobalt alloy steel with high magnetic saturation characteristic compared to silicon steel is suggested. Moreover, aluminium winding with light weight instead of copper winding is wounded in the widen slot area due to the high magnetic saturation level. For the verification of performance of proposed model, the characteristics are analyzed by using finite element method(FEM).
Voltage Control of Stand-Alone Inverter for Power Quality Improvement Under Unbalanced and Non-linear Load
Lee, Wujong ; Jo, Jongmin ; Cha, Hanju ;
The Transactions of The Korean Institute of Electrical Engineers, volume 65, issue 4, 2016, Pages 567~575
DOI : 10.5370/KIEE.2016.65.4.567
This paper proposed the voltage control of stand-alone inverter for power quality improvement under unbalanced and non-linear load. The 3-phase DC-AC inverter controls CVCF(Constant Voltage Constant Frequency) and selective harmonic eliminate method in stand-alone mode by PR controller, and the stand-lone inverter supplies stable sinusoidal voltage to balanced, unbalanced and non-linear loads. The total harmonic distortion(THD) of line-to-line load voltage(
) is 1.2% in the balanced load. THD of
is reduced from 5.2% to 1.4% and 6.7% to 3.5%, respectively unbalanced and non-linear load. The stand-alone inverter can be supplies sinusoidal balanced voltage to unbalanced load because the voltage unbalanced factor(VUF) of
is reduced from 5.2% to 1.4% in the unbalanced load. Feasibility of control method for a stand-alone inverter will be verified through 30kW stand-alone inverter system.
A Study on New Current Control Method for Square Current Wave in Y Connected 7-Phase BLDC Motor Drive System
Moon, Jong-Joo ; Lee, Won ; Kim, Jang-Mok ;
The Transactions of The Korean Institute of Electrical Engineers, volume 65, issue 4, 2016, Pages 576~585
DOI : 10.5370/KIEE.2016.65.4.576
The current control methods of Y-connected 7 Phase BLDC motor are sine wave current control and square wave control. The sine wave current control method needs dq axis transformation of
matrix for current control and very complex. Also this method is not suitable for multi Phase BLDC motor of trapezoidal back emf wave. Therefore, in Y connected multi phase BLDC motor, the square wave current control methods are required. Generally, in the 3Phase BLDC system, Average current control method is used for current control. The average current is obtained that the summation of absolute value of each phase current magnitude is divided by the number of conduction phase. However, if average current control method is applied to multi-phase system, there is a problem that each phase currents are different. This problem affects unbalance of each phase torque and fluctuation of total torque. This paper proposed each phase current control method of Y connected 7Phase BLDC system. Proposed method is used for PI controller of each phase for each phase current control. This method can perfect square wave current control. Also, configuration of the method is easier than DQ axis transformation. Proposed method is verified through simulation and experiments.
Optimal Hysteresis Control for CCM Driving of a Single-Stage PFC Flyback Converter for LED Lightings
Kim, Choon-Tack ;
The Transactions of The Korean Institute of Electrical Engineers, volume 65, issue 4, 2016, Pages 586~592
DOI : 10.5370/KIEE.2016.65.4.586
The current control of Continuous Conduction Mode(CCM) can be implemented by several methods: peak current control; average current control; and hysteresis control. Among these methods, the hysteresis current control is popularly applied in various converter applications because of its simplicity of implementation, fast current control response and inherent peak current limiting capability. However, a current controller with conventional hysteresis band which multiplies the current reference has the disadvantage that the modulation frequency varies in one cycle of the input voltage and, as a result, generates high switching frequency in the low input voltage section. Also it is complicated to design the input filter due to varying switching frequency. This paper proposed an optimum hysteresis-band current control method where the band is generated by using both multiplication method and sum method to maintain the modulation frequency to be nearly constant. This approach can solve the high switching frequency in the low input voltage section, and achieve easy design of input filter. The performance of the proposed converter is verified with the simulation and the experimental works.
DCM Analysis of Solar Array Regulator for LEO Satellites
Park, Heesung ; Cha, Hanju ;
The Transactions of The Korean Institute of Electrical Engineers, volume 65, issue 4, 2016, Pages 593~600
DOI : 10.5370/KIEE.2016.65.4.593
The solar array regulator for low earth orbit satellites controls a operating point of solar array for suppling electric power to the battery and the other units. Because the control object is reversed, the new approach for large and small signal analysis is needed despite using buck-converter for power stage. In this paper, the steady state analysis of solar array regulator is performed in continuous conduction mode and discontinuous conduction mode, and the border condition for each mode is established. Also, the small signal model of solar array regulator is established in discontinuous conduction mode. Experiments are carried on in worst condition which the solar array regulator can face with discontinuous conduction mode. The results show that the solar array regulator is in stable.
The Study of Ripple Reduction of the PFC CCM Flyback Converter without Electrolytic Capacitor for LED Lightings using LC Resonant Filter
KIm, Choon-Tack ; Kim, Young-Seok ;
The Transactions of The Korean Institute of Electrical Engineers, volume 65, issue 4, 2016, Pages 601~610
DOI : 10.5370/KIEE.2016.65.4.601
The light-emitting diode (LED) has been used in a variety of industrial fields and for general 0lighting purposes on account of its high efficiency, low power consumption and long lifespan. The LED is driven by direct current; therefore, an AC/DC converter is typically required for its use. An electrolytic capacitor is generally used for stabilizing DC voltage during use of the AC/DC converter. However, this capacitor has a short lifespan, which makes it a limiting factor in LED lighting. Furthermore, LED lighting requires a dimmable control to enable energy savings and fulfil a growing consumer demand. In this paper, the dimmable single-stage power factor correction (PFC) continuous conduction mode (CCM) flyback converter that employs no electrolytic capacitor is presented. The LC resonant filter is alternatively applied to reduce the 120[Hz] ripple on the output. And the optimum value of the LC resonant filter parameters considering both efficient and performance is analysed. Simulation and experimental results verify the satisfactory operation of the converter.
Effect of Annealing Temperature on Thermoelectric Properties of Ag
Se Nanoparticle Thin Films
Yang, Seunggen ; Cho, Kyoungah ; Yun, Junggwon ; Choi, Jinyong ; Kim, Sangsig ;
The Transactions of The Korean Institute of Electrical Engineers, volume 65, issue 4, 2016, Pages 611~616
DOI : 10.5370/KIEE.2016.65.4.611
In this study, we synthesized
nanoparticles (NPs) in an aqueous solution and investigated the thermoelectric characteristics of
NPs thin films on plastic substrates. Regardless of thermal annealing treatment, all the
NPs thin films show the negative Seebeck coefficients, indicating the n-type characteristics. As the annealing temperature increases, the electric conductivity increases while the Seebeck coefficient decreases. The electric conductivity of the thin film annealed at
is larger by
times, compared with the as-prepared thin film, And the maximum power density for the thin film annealed at
is calculated to be
The Characteristics of Asymmetric Hybrid Supercapacitor Cells and Modules for Power Quality Stabilization
Lee, Byung-Gwan ; Maeng, Ju-Cheul ; Lee, Joung-Kyu ; Yoon, Jung-Rag ;
The Transactions of The Korean Institute of Electrical Engineers, volume 65, issue 4, 2016, Pages 617~621
DOI : 10.5370/KIEE.2016.65.4.617
In addition to the energy storage facilities based on high power technologies, Electric double layer capacitors(EDLC) are today`s candidate for power quality stabilization. However, its low energy density is often inhibiting factor for application of electric power industry. Hybrid supercapacitor is an promising energy storage device that positioned between conventional EDLC and Li-ion battery. This paper describes the preparation and characteristics of a hybrid supercapacitor and module for power quality stabilization. A cylindrical 3200F hybrid supercapacitor (
) was assembled by using the
electrode as an anode and activated carbon as a cathode. It shows 2.5 times higher energy density than conventional EDLC with the same volume. In order to determine the characteristics of the hybrid supercapacitor Module for uninterruptible power supply (UPS), hybrid supercapacitor cells were connected in series with active balancing circuit. At even the high current density of 14A(10C), Module prepared by 18 cells showed the capacitance of 170F at 30~50V, suggesting the applicability for UPS.
A Portable Potentiostat with Bluetooth Communication for Square wave Voltammetry Measurement
Shim, Wonsik ; Han, Ji-Hoon ; Kim, Suyun ; Kwon, Hyun Jeong ; Pak, Jungho ;
The Transactions of The Korean Institute of Electrical Engineers, volume 65, issue 4, 2016, Pages 622~627
DOI : 10.5370/KIEE.2016.65.4.622
This paper describes the development of a portable potentiostat which can perform square wave voltammetry on electrochemical sensors and wireless transmission of the measured data to a smartphone using Bluetooth. The potentiostat consists of a square wave potential pulse generation circuit for applying the potential pulse to the electrochemical sensor, a reduction/oxidation (or redox) current measurement circuit, and Bluetooth for wireless data transmission to an Android-based smartphone. The measured data are then processed to show the output graph on the smart phone screen in real time. This data transformation into a graph is carried out by developing and installing a simple transformation application software in the Android-based smartphone. This application software also enables the user to set and change the measurement parameters such as the applied voltage range and measured current range at user`s convenience. The square voltammetry output data measured with the developed portable potentiostat were almost same as the data of the commercial potentiostat. The measured oxidation peak current with the commercial potentiostat was
at 0.26 V and the measured oxidation peak current with the developed system was
at 0.25 V. This proves that performance of the developed portable measurement system is comparable to the commercial one.
A Microfluidic Electrochemical Sensor for Detecting the Very Low Concentration Endocrine Disruptor with Self Assembled Monolayer and Preconcentration Technique
Kim, Suyun ; Han, Ji-Hoon ; Pak, James Jungho ;
The Transactions of The Korean Institute of Electrical Engineers, volume 65, issue 4, 2016, Pages 628~634
DOI : 10.5370/KIEE.2016.65.4.628
This paper demonstrates a microfluidic electrochemical sensor for detecting endocrine disruptor such as estradiol at a very low concentration by using preconcentration technique. In addition, self-assembled monolayer(SAM) was also employed on the working electrode of the electrochemical sensor in order to increase the estradiol capture efficiency of the sensor. SAM treatment on the working electrode enhanced the specific binding between the surface of the working electrode and the estradiol antibody. The estradiol antibody was applied on the working electrode at different concentrations(10, 20, 50, 100, 200 pg/ml) for observing the concentration dependency. The measured electrochemical redox current changed with the amount of the bound estradiol on the Au working electrode surface and the sensor can detect all the target material when the immobilized antibody amount is more than the estradiol amount in the water. The elecrochemical estradiol sensor without SAM treatment showed a low current of 7.79 nA, while the sensor treated with SAM resulted in 339 nA at 200 pg/ml, which is more than 40 fold higher output current. When combining the preconcentration technique and the SAM-treated electrode, the measured current became more than 100 fold higher than that of the sensor without neither SAM treatment nor preconcentration technique. The combination of these two techniques can would enable the proposed microfluidic electrochemical sensor to detect a very low concentration endocrine disruptor.
Adaptive PI Controller Design Based on CTRNN for Permanent Magnet Synchronous Motors
Kim, Il-Hwan ;
The Transactions of The Korean Institute of Electrical Engineers, volume 65, issue 4, 2016, Pages 635~641
DOI : 10.5370/KIEE.2016.65.4.635
In many industrial applications that use the electric motors robust controllers are needed. The method using a neural network in order to design a robust controller when a disturbance occurs is studied. Backpropagation algorithm, which is used in a conventional neural network controller is used in many areas, but when the number of neurons in the input layer, hidden layer and output layer of the neural network increases the processing speed of the learning process is slow. In this paper an adaptive PI(Proportional and Integral) controller based on CTRNN(Continuous Time Recurrent Neural Network) for permanent magnet synchronous motors is presented. By varying the load and the speed the validity of the proposed method is verified through simulation and experiments.
Experimental Modeling of Acceleration and Brake Systems for Autonomous Vehicle
Lee, Jong-Eon ; Kim, Young Chol ;
The Transactions of The Korean Institute of Electrical Engineers, volume 65, issue 4, 2016, Pages 642~651
DOI : 10.5370/KIEE.2016.65.4.642
For the acceleration and brake systems of an autonomous vehicle, the dynamic models from acceleration (brake) pedal input to driving(braking) torque at the vehicle wheel are represented by a set of linear transfer functions in this paper. We present an experimental method that can identify these models using a single rectangular pulse response data. Various magnitude of inputs with different running speeds are applied to experimental tests. All the identified models are demonstrated by the measured data. Both acceleration and brake models have been also validated by comparing the velocity of a full vehicle model associated with the proposed models with the measured vehicle velocity.
Design of a Model-Based Low-Order Disturbance Observer to Estimate a Sinusoidal Disturbance with Unknown Constant Offset
Lee, Cho-Won ; Son, Young Ik ;
The Transactions of The Korean Institute of Electrical Engineers, volume 65, issue 4, 2016, Pages 652~658
DOI : 10.5370/KIEE.2016.65.4.652
In practical control systems differences between nominal and real systems arise from internal uncertainties and/or external disturbances. This paper presents a model-based low-order disturbance observer for a sinusoidal disturbance with unknown constant offset. By using the disturbance model of a biased harmonic signal, the proposed method can successfully estimate the biased sinusoidal disturbance with unknown amplitude and phase but known frequency. At the first stage of the observer design, a model-based disturbance observer is designed when all the system states are measurable. Next, a sufficient condition is presented for the proposed observer to estimate the sinusoidal disturbance with a minimal-order additional dynamics using only output measurement. Comparative computer simulations are performed to test the performance of the proposed method. The simulation results show the enhanced performance of the proposed disturbance observer.
Low-end GPS Position Accuracy Enhancement Method by using Map Information
Choe, Tok Son ; Kang, Jung Min ; Kim, Han Sol ; Park, Jin Bae ;
The Transactions of The Korean Institute of Electrical Engineers, volume 65, issue 4, 2016, Pages 659~665
DOI : 10.5370/KIEE.2016.65.4.659
In this paper, we propose a novel position accuracy enhancement method of a low-end GPS using digital map information. The latest digital map has various kinds of information on geographical features. The proposed method uses position information of lane marks among the geographical features. We define the position information of lane marks as the reference points. The position information of a low-end GPS acquired for a period of time is defined as the source points. In the proposed method, rotation and translation matrices between the reference and the source points are calculated by using an Iterative Closest Point(ICP) algorithm. The source points are transformed by the obtained rotation and translation matrices. Finally, the transformed source points are projected on the reference points. Through these processes, the position accuracy of a low-end GPS is ultimately enhanced. To verify the proposed method, the various real experimental results are presented.
Accelerating Fingerprint Enhancement Algorithm on GPGPU using OpenCL
Kim, Daehee ; Park, Neungsoo ;
The Transactions of The Korean Institute of Electrical Engineers, volume 65, issue 4, 2016, Pages 666~672
DOI : 10.5370/KIEE.2016.65.4.666
Recently the fingerprint is widely used as one of biometrics to improve the security of financial mobile applications, because of its user convenience and high recognition rate. However, in order to apply fingerprint algorithms to finance and security applications, the recognition rate and processing speed of the fingerprint algorithms have to be improved further. In this paper, we propose the parallel fingerprint enhancement algorithm on general-purpose computing on graphics processing unit (GPGPU) using OpenCL. We discuss the analysis of the parallelism in the fingerprint algorithm as well as the exploration of optimization parameters of the parallel fingerprint algorithm to improve the performance. The experimental results showed that the execution of parallel fingerprint enhancement algorithm on GPGPUs was accelerated from 29.4 upto 69.2 times compared with the execution of the original one on the host CPUs.
A Study of Human Gait Discrimination Using Multi-pressure Sensor
Choi, Dae-Yeong ; Kim, Kyung-Ho ;
The Transactions of The Korean Institute of Electrical Engineers, volume 65, issue 4, 2016, Pages 673~677
DOI : 10.5370/KIEE.2016.65.4.673
In this study, In order to measure foot pressure, it makes analyzing device using multi-pressure sensor. This device was limited frequency band to 5Hz by using low-pass filter and MCU was detected signal every milliseconds. After wearing the device, the result was confirmed by blue-tooth to measure wirelessly. Also, we propose an algorithm to obtain the walking pattern using a time table in each of the detected peak from the pressure sensor. Using the algorithm, right walking pattern and abnormal pattern was detected. The results can be reflected more individual walking patterns than when using a conventional methods and also, developed device was no restriction on the human activity.
A Comparison of Muscle Activity and Fatigue Between Maximal and Submaximal Repetitions Exercise During the Bench Press
Seo, Sang-Won ; Lee, Ho-Seong ;
The Transactions of The Korean Institute of Electrical Engineers, volume 65, issue 4, 2016, Pages 678~683
DOI : 10.5370/KIEE.2016.65.4.678
The study aim was to investigate a comparison of muscle activity fatigue between maximal and submaximal strength gains during the bench press in men. It was hypothesized that maximal voluntary contraction (%MVC) would similar gains between maximal and submaximal strength gains during the bench press, but median frequency (MDF) would increase in maximal compared with submaximal exercise. Employing a randomized, counterbalanced crossover design, 12 men were asked to perform maximal repetitions and submaximal repetitions (concentric: 1-s, eccentric: 1-s, 2-s/repetition) to failure with a load of 85% of 1RM for the bench press, with a 3-minute recovery between the sets. Each subject was tested for the number of repetitions and sets, total work in bench press. Surface electromyography (EMG) was recorded from the pectoralis major, deltoid anterior, and triceps brachii for %MVC and MDF. Total work was significantly higher in the submaximal repetition exercise than that the maximal repetition exercise (p<.05). Muscle fatigue of pectoralis major, deltoid anterior and triceps brachii were significantly smaller in the submaximnal repetition exercise than that the maximal repetition exercise (p<.05, respectively). However, muscle activity of pectoralis major, deltoid anterior, and triceps brachii were not significantly different between exercises. Our study showed that a smaller muscle fatigue in submaximal repetitions, despite higher in total work and a similar in muscle activity were observed. These results suggest that submaximal repetitions during the bench press would be enhanced intensity and/or volume compared with maximal repetitions exercise.
Characteristics of Wireless Power Transmission Using Superconductor Coil to Improve the Efficiency According to the Shielding Materials
Lee, Yu-Kyeong ; Jeong, In-Sung ; Hwang, Jun-Won ; Choi, Hyo-Sang ;
The Transactions of The Korean Institute of Electrical Engineers, volume 65, issue 4, 2016, Pages 684~688
DOI : 10.5370/KIEE.2016.65.4.684
The magnetic resonance method requires high quality factor(Q-factor) of resonators. Superconductor coils were used in this study to increase the Q-factor of wireless power transfer(WPT) systems in the magnetic resonance method. The results showed better transfer efficiency compared to copper coils. However, as superconducting coils should be cooled below critical temperatures, they require cooling containers. In this viewpoint, shielding materials for the cooling containers were applied for the analysis of the WPT characteristics. The shielding materials were applied at both ends of the transmitter and receiver coils. Iron, aluminum, and plastic were used for shielding. The electric field distribution and S-parameters (S11, S21) of superconducting coils were compared and analyzed according to the shield materials. As a result, plastic shielding showed better transfer efficiency, while iron and aluminum had less efficiency. Also, the maximum magnetic field distribution of the coils according to the shielding materials was analyzed. It was found that plastic shielding had 5 times bigger power transfer rate than iron or aluminum. It is suggested that the reliability of superconducting WPT systems can be secured if plastic is used for the cooling containers of superconducting resonance coils.
A Study on the Development of a Real-time Energy Metering Device for Electric Railway Vehicles
Kim, Yong Ki ; Han, Moon Seob ; Chun, Yoon-Young ; Bae, Chang Han ; Yun, Byeong Ju ;
The Transactions of The Korean Institute of Electrical Engineers, volume 65, issue 4, 2016, Pages 689~694
DOI : 10.5370/KIEE.2016.65.4.689
The objective of this study is to identify the requirements for a energy metering device and develop a real-time energy metering device for measuring energy (electricity) consumption of the electric railway vehicle during its operation. The study also evaluated the performance of the AC voltage sensor, current sensor, and data meter for the device and performed EMC tests such as surge and EFT (Burst). The performance tests showed that the percent errors of the AC voltage sensor and current sensor were
under 10~127V, and 10~250A, respectively. The result of surge and EFT (Burst) tests also indicated that the device had no malfunction in any wave (combination and ring waves) under the treat level with 2kV. The result of the field test also confirmed that the device had no malfunction in data metering.
Implementation of the Measurement Equipment to Measure Return Current and Axle Temperature of High Speed Railway
Lee, Young-Soo ; Lee, Byeong-Gon ; Hwang, In-Kwang ; Han, Seung-Hun ;
The Transactions of The Korean Institute of Electrical Engineers, volume 65, issue 4, 2016, Pages 695~703
DOI : 10.5370/KIEE.2016.65.4.695
The maintenance method for the electrical facility of high speed railway has been evolved from inspection by personnel to the automated way by the detection devices. In particular, the signalling equipment in order to increase the safe and efficient operation of the trains is required to maintain normal operation by periodic maintenance. Because the return current gives the most important effects to the wayside equipment in case of the failures, a method is needed to measure the unbalanced rate of return current on the train at high speed driving. The Hot Box Detector(HBD) device that is installed at track-side has a function to recognize the abnormal axle box by detecting the temperature that occurs in the axle of train passing over its device. In order to implement the measurement equipment for unbalanced rate of return current and axle temperature, the design method is proposed and the experimental test results by test bed are included in the paper.
Pole Position Detection Method by Using Pole and Character Recognition
Choi, Woo-Yong ; Park, Jong-Gook ; Lee, Byeong-Gon ; Joo, Yong-Hwan ; Han, Seung-Hun ;
The Transactions of The Korean Institute of Electrical Engineers, volume 65, issue 4, 2016, Pages 704~710
DOI : 10.5370/KIEE.2016.65.4.704
In this paper, we proposed pole position detection system for providing exact location information to users. The proposed system consists of pole recognition part and pole number recognition part. Above all, exact pole recognition is carried out by PDD(Pole Detection Device). And recognition of pole number is performed by PID(Pole Inspection Device). Acquired image by using line scan camera is judged whether it is free bracket or not through image processing. When it is judged as free bracket, pole number image is acquired by OCR camera and recognized by OCR. By recognizing pole number, exact location information is provided to user.