1999.07a
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The 4-pole LHSM was composed of the figure-of-eight shaped 3-phase armature windings, DC field windings, and the segmented secondary with the transverse bar track. Three dimensional model of LHSM provided the equivalent reluctance and PM model for 2D FEA. From these 2D FEA models, when the motor was fed by DC and 3-phase currents, the magnetic field were calculated and compared with the results of 3D FEA.
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In this paper deals with running test for the UTM(Urban Transit Maglev)-01, that is test and evaluation for the maglev. We will predict about the test value for running maglev vhicle. In this time we tested rms gap fluctuation and peak to peak air gap for levitation system of UTM-01. And then we profit for the upgrade Maglev System.
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A brushless and slotless DC linear motor(LDM)employing a movable set of neodymium-iron-boron type of magnets has high performances in advantages of large thrust per weights and accurate position control. But the Moving Magnet LDM produces thrust ripples owing to mainly end-effects, shape and magnetization of permanent magnets and so on. This paper represents the improvements of thrust ripples using the finite elements methods and phase control topology.
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Recently, the electromagnetic proportional valve has been widely used in order to control pressure and flow in such systems as NC machine and automatic facility. The linear electromagnetic solenoid used for proportional control valve ought to have hysteresis characteristic because of control the thrust force proportionably by input current. Therefore, in this study, we analysis the thrust force characteristics and established design for practical use, which allows Linear Pulse Motor(LPM) to be used as a driving system for electromagnetic proportional control valves.
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A voice-coil-type LOA consists of the NdFeB permanent magnets with high specific energy as the stator, a coil-wrapped nonmagnetic hollow rectangular structure. We have to obtain the back-EMF constant
${\kappa}_E$ from 3D FEA and experiments, precisely. The${\kappa}_E$ and other parameters provide the transfer function, through which is derived the frequency response characteristics. Inverter-fed LOA is examined aiming to compare with results of simulation. -
In the industrial field the necessity of the linear motion is increasing. We selected a moving magnet coreless type LDM, which have the advantages, such as long stoke, brushless, no cogging force. Actually, the design is accomplished using FEM analysis for the basic configuration of a magnetic circuit, and characteristic equations for coil design. In the course of design we have estimated airgap flux density and thrust.
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The alternative precise method for voltage balancing and load compensation using the susceptances control of a STATCOM is discussed. With the control of STATCOM's output current, it is confirmed that the compensation susceptances can be variable. And then the STATCOM's control method about compensation susceptances for load compensation and voltage balancing/regulation is derived. Finally, the effectiveness of load compensation and voltage balancing/regulation is confirmed through computer simulation.
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A new hybrid vehicle Powered by fuel cells is being developed in order to improve the fuel conversion rate and reduce air pollutions. Fuel cell electric vehicle(FCEV) is considered to be the next generation electric vehicle with on board generator. This paper is to determine the current technical status of FCEVs and assess and judge the prospect of the prospects of fuel cell electric engines.
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In this paper HEV's are newly classified and a new breed of HEV's, which is called series-parallel compensated configuration is also presented. In this configuration the engine can be operated on constant-speed and constant-torque mode, while the power converter can be small-sized.
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In this paper, a operating characteristics of the 50 kW grid-connected Photovoltaic(PV) Power system which is by means of initial PV datum analyzing is reported. The development of a 50 kW class photovoltaic power generation system including a DC/AC inverter is suggested to investigate the system performance for grid connection. The results of the demonstration test of a 50 kW class grid-connected PV system show that the system utilization rate is 15.6% and the inverter efficiency is 94% at 80% load.
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2 phase 8 pole HB type LPM(linear pulse motor) has the suitable structure for it's microstep drive. Hence, if this LPM will be drived by this method, the limited(mechanically) step resolution can be increased further and vibration and noise can be decreased considerably. But, It is difficult that this LPM was analyzed in detail because of it's complex magnetic circuits to be composed the LF(longitudinal flux) and TF(transverse flux.) path. If LPM was analyzed by the approximate 2D model, we could not be obtained satisfactory result. Therefore, It is necessary to be analyzed the 3D model in detail for the more satisfactory results. In this paper, we obtain 3D flux distribution of the mover using by 3D FEM(finite element method)
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In this paper, the magnetic fluid linear pump is designed. Inside the small tube, magnetic fluid is shielded with thin rubber protector. The magnetic fluid activated by traveling pulses of magnetic field drags the water inside the pump. The iterative algorithm for the shape of magnetic fluid is presented by using nonlinear finite element method and Navier-Stokes equations. The computed curvature of fluid under the magnetic field and the gravitational force is agreed well with photograph image. The dimension and electric configurations of the magnetic linear pump are optimized and the results are compared with measurements.
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High-speed brushless permanent magnet machines are good for compressor and aerospace applications, etc, since they are conductive to high efficiency, high power density, small size and low weight. This paper describes a diametrically magnetized PM motor with the rating of 4.3kW and 50000 rpm fur high-speed drive applications. To bear strong stress from high speed, rotor was designed cylindrical structure, was magnetized diametrically permanent magnet. The performance characteristic of motor was evaluated by means of FEA(Finite Element Analysis), no-load test And then, in order to find back-EMF constant, used FEA, search coil.
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지금까지 사용된 2차원 유한요소해석은 자계의 프린징(Fringing) 및 누설 자계 등을 무시하기 때문에 정확한 특성을 파악하기 위해서는 3차원 모델을 사용하여야 한다. BLDC 모터의 회전자(자석)의 높이를 고정시킨 상태에서 고정자(Core) 높이의 변화에 따른 코깅(Cogging) 토크의 해석을 통해 높이 비에 대한 2차원과 3차원 유한요소해석 결과 사이에의 상관 오차에 대한 연구를 수행하였다 또한. 정자기의 3차원 형상 설계 민감도 해석 기법을 개발하였다. 개발된 정자기 민감도 프로그램(MAGSEN-magnetic sensitivity)은 유용성과 실용성을 보이기 위하여 BLDC 모터의 코깅토크를 줄이는 형상 최적설계에 적용되었다.
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This paper treated the design and characteristics of high speed motor/generator with ring wound stator for the flywheel energy storage system. The most important advantages of the ring-wound motor is the slotless stator, i.e. no cogging torque, no space harmonic of air-gap flux density, etc. Because of these advantages, ring wound type motor is suitable to operate at the high speed.
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This paper presents an efficient 2D finite element analysis(FEA) for brushless DC motor (BLDCM) taking into account the eddy current and lamination effect of stator. In BLDCM, the dynamic characteristic analysis considering the eddy current and driving circuit is applied for the accurate prediction of motor performance in high speed because the eddy current loss is proportional of square of the driving frequency. According to the variation of lamination number, the characteristics of electro magnetic force, torque, and eddy current loss are analyzed. From the results, it is known that the effect of the lamination of stator on the eddy current loss is verified.
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This paper has proposed various rotor type model to analyze the performance of Reluctance motor. The simulation results show that the proposed models have not revealed performance variation.
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SRM Drives generate large vibration and acoustic noise because it is rotated by step pulse mmf and switching commutation mechanism. The main vibration source of SRM Drive is generated by rapidly variation of radial force when phase winding current is extinguished for commutation action. So the rapidly variation of radial force is repressed firstly to reduce vibrating force of SRM Drive. This paper suggests the vibration reduction method that SRM Drive with unidirect-short compensation winding is excited by a two stage commutation method at commutation period. This reduction effect of vibration is verified with the result obtained in the test of prototype machine.
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This paper presents dynamic performance prediction using Matlab / simulink after parameter estimation of synchronous reluctance motor considering iron loss. Test motor is 3 phase SynRM with the segmental rotor, rating power is 0.175KW. Experiment equipment is consists of testing motor, dynamometer, vector invertor dynamocontroller, and power analyser. The stator iron loss and rotor iron loss are modelled by additional windings on three-phase winding axis. These windings are transformed into d-q axis, and are represented as equivalent eddy current windings. P-Q circle diagram method and single phase standstill method are used to measure motor parameters considering iron loss.
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This paper presents an efficient method for analysis of magnetodynamic system using frequency-dependent parameters. In equivalent electric circuit of linear magnetodynamic system, parameters of inductance and resistance are not constant since they vary with its driving frequency. Once frequency-dependent parameters of equivalent electric circuit for a given system are extracted, they can be used to analyze various characteristics of system. We use the Fourier transform, the high-order sensitivity method and Taylor series in order to efficiently extract the frequency-dependent parameters of magnetodynamic system. The proposed algorithm is applied to an induction heating system to validate its numerical efficiency.
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Switched reluctance motor(SRM) has the advantages of simple structure, low rotor inertia and high efficiency. However, position sensor is essential in SRM in order to synchronize the phase excitation to the rotor position. The position sensors increase the cost of drive system and tend to reduce system reliability. This paper investigates the speed control of sensorless SRM in which the phase current and change rate are utilized in position decision, and the period of dwell angle is variable by compensating the rotor angle. The proposed system consists of position decision, phase locked loop controller, switching angle controller and inverter. The performances in the proposed system are verified through experiments.
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This study deals with the unbalance response of a rotor of Switched Reluctance Motor(SRM) due to unbalanced mass. The method to analyze SRM with rotor-bearing system is based on an extension of the well-known Transfer Matrix Method(TMM). Most of the calculation results present the natural frequencies as a function of the speed of rotation which yields critical speeds and response to unbalanced mass.
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일반적으로 비선형 정자계 문제를 해석하기 위해서 뉴튼-�N슨(Newton -Raphson : NR)법이 이용된다. 하지만 뉴튼-�N슨법의 경우 각 반복계산 때마다 새로운 선형 시스템의 해를 구하기 위해서 LU-decomposition과 같은 과정을 매 반복계산 때마다 시행해야 하므로 절점(node)의 수가 증가할 경우 계산시간이 증가한다는 단점이 있다. 이러한 단점을 보완하기 위해서 최근 TLM (Transmission Line Modeling)법이 새로운 반복계산법으로 비선형 유한 요소 해석에 적용되었으며 뉴튼-�N슨법에 비해 훨씬 우수한 특성을 보여주었다. 하지만 지금까지의 TLM법은 2차원의 정식화만 이루어졌고 3차원에는 적용되지 못한 것이 사실이다. 본 논문에서는 3차원의 비선형 정자계 문제에 TLM법을 적용할 수 있는 수식을 최초로 제안하며 3차원 코어(core)모델에 대해 TLM법을 적용하여 그 타당성을 검증하기로 한다. 또한 3차원 비선형 TLM법을 이용한 해석 결과가 뉴튼-�N슨법에 의한 결과와 완전히 일치하며 수렴 속도에 있어서도 훨씬 향상된 결과를 나타냄을 보이도록 하겠다.
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The time harmonics of an inverter output voltage cause high frequency currents in the rotor bars of a squirrel cage induction motor, so that the harmonic copper loss density increases in the upper lesion of the bars. Such an higher loss density makes an nonuniform thermal source and deforms the bars due to the thermal stress. Therefore, in this paper, the copper loss distribution in the rotor bar of an inverter-fed induction motor, which is the source of the thermal stress, is analyzed by the time-stepping finite element method. As a result, the harmonic copper losses of 11 subregions in a bar are calculated and compared with those of sinusoidally fed induction motor.
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This paper presents Galerkin- and Upwind-finite element analyses solution in the travelling magnetic filed problem. The travelling magnetic field problem is subject to convective- diffusion equation. Therefore, the solution derived from Galerkin-FEM with linear interpolation function may oscillate between the adjacent nodes. A simple model with Derichlet, Noumann and periodic boundary condition respectively, have been analyzed to investigate stabilities of solutions. It is concluded that the solution of Galerkin-FEM may oscillate according to boundary condition and element type, but that of Upwind-FEM is stable regardless boundary condition.
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So far, The methods for identifying the parameters of some region or material have been developed. This paper describes a new method for electric resistivity reconstruction using multi-resolution property of wavelet. The outputs of the potential electrodes are computed using two dimensional FEM in the wave number space by Fourier transforming the governing equation. The resistance distribution in the region of interests, which makes the computed potential distribution coincide with the measured potential, is found by minimizing the objective function using an optimization method. Multi-resolution analysis introduced in this paper will be proved to be the proper method in the viewpoint of effectivity and time-consuming by the numerical results.
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The jumper devices of overhead power transmission lines are getting increased in size with the adoptation of higher voltage and bundled conductors. Increasement of jumper devices' size results in the cost increasement. Therefore, the adoptation of prefabricated jumper device is cost effective method in T/L. This papers are mentioned about selection of proper value of standard deviation for jumper devices by dynamic swing characteristics. And we are analyzed to effects for tower scheme and weight addition.
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An analysis of temperature distribution in transformer is necessary for cooling design. But, it is very difficult to make that analysis because of the complicated structure of transformer. Particulary. if it is asymmetry, 3 dimensional analysis is required. This paper presents the 3-dimensional analysis technique of temperature distribution in transformer using a commercial CFD program FLUENT and the applied results in a simple model.
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The performance of circuit interruption of
$SF_6$ puffer cylinder type gas circuit breaker(GCB) has been evaluated from the results of electrical insulation strength which is depend on material property, such as$SF_6$ gas density in circuit breaker tank. In order to determine circuit breaker dimension in the safety criteria. electrical field analysis has been done by finite element method. Gas density of concerned area in the circuit breaker has been calculated. In order to predict small current break performance, Electrical field analysis result must be calculated based the results of density from cold flow dynamics. The proposed method has been carried out and evaluated for 362kV class high voltage GIS. -
This paper describes the interruption techniques of HVDC circuit breaker which adapts inverse current injection method. A representative circuit configuration of this type of HVDC circuit breaker is presented and its operational mechanism and timing diagrams are investigated.
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It is becoming demand of OPGW required high reliability of the characteristics of earthing and tight transmission. This paper study the mechanical and electrical characteristics of the OPGW stranded stainless tubes lied optical fiber and aluminum alloy wire to grasp their performance and to approach to design suitable for various environment.
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This paper presents very simple driving system for blower of separator. The system be driven by V/F control. The load of the system have hardly variation during steady state, because of fan load. We have studied about the property of the fan load in order to develop driving system for blower of separator. This study can get reduction of energy, high separation rate of a raw of tobacco and high quality.
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This paper presents the design of state feedback controller with state observer(dynamic filter) for Electro-Magnetic Suspension System. Also, the gain scheduling technique using state observer is analyzed in the time domain and frequency domain.
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This paper presents results of FEA and tests on the characteristics of moving coil type LOA due to the static field excitation method. In case the static field is generated by NdFeB permanent magnet, the static thrust is almost 6 times than that by electromagnet. Therefore under the same power, the volume becomes small according to using permanent magnet for the generation of static field.
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In this paper, approximate means of estimating the flux and torque levels in an induction motor is discussed. There exists several method that is used directly by flux meter and flux sensing coils in the airgap. Most of these methods are sensitive to motor parameter value changes. Also, the harmonics in the motor voltage and current due to the nonsinusodial inverter waveform cause errors in the estimated torque. Finally, this result is applicated in arch type linear induction motor for study of noise and vibration.
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This paper deals with the rated output power using grid-connected Doubly-Fed Induction Generator(DFIG) in the supersynchronous speed regions. The rated output power is controlled by both magnitude and frequency of the voltage fed to the rotor. And this rotor voltage is controlled by control of inverter switching frequency and fire angle. A DFIG generating characteristic is analyzed by simulation of steady-state algebraic equation of equivalent circuit using numerical analysis. And it is compared with results of experiment. Consequently, This paper presented to control method for rated output power of DFIG in variable wind speed.
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This paper deals with characteristics of universal motor of which parameters varying by stator turns and propose stator turns that has the highest efficiency. Stator turns variation results difference in current, impedance, power, torque and speed. We try to measure these data. The experimental results show the stator turns which this motor has the highest efficiency.
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This paper describes a new procedure to develop a systems model of a universal motor based on finite element analysis. The purpose of this paper optimized fabrication of Universal Motor for improving its efficiency and performance and driving range. To do this, various design parameters are set such as a number of teeth and stator shape, etc. As results, the optimized model has made good improvement compared with those of the initial.
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The purpose of this paper is to establish a method of design of the Ultrasonic Motor for Driving Robot Hand. This method is based on two models for the ultrasonic motor(a two dimensional elastic contact model. electric equivalent circuit). And analyzed the basic model which installed in the module to match the suitable standard. As varied external diameter, internal diameter and thickness, the proper ultrasonic motor is implemented to find a targeted resonant-frequency and torque near to designed values.
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A transverse flux linear induction motor is studied to assess the feasibility of its application in urban transportation and conveyor and so on. To analyze the TFLIM with E-type, the flux density, thrust and normal force is computed by using an analytical method and 2-D finite element method. TFLIM which the rated thrust is 50[N] is designed and experimented.
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In this paper, we analogized effective thermal conductivity (
$k_{eff}$ ) and effective heat capacity($pc_{p.eff}$ ) of insulators and the air in coil portions of linear pulse motor for CEDM(Control Element Drive Mechanism). The errors of simulated results are under 1.6% when compared with experimental results. And we carried out temperature rise of linear pulse motor for CEDM by the experiment. -
The finite element method (FEM) is suitable for the analysis of a complicated region that includes nonlinear materials, whereas the boundary element method (BEM) is naturally effective for analyzing a very large region with linear characteristics. Therefore, considering the advantages in both methods, a novel algorithm for the alternate application of the FEM and BEM to magnetic field problems with the open boundary is presented. This approach avoids the disadvantages of the typical numerical methods with the open boundary problem such as a great number of unknown values for the FEM and non-symmetric matrix for the Hybrid FE-BE method. The solution of the overall problems is obtained by iterative calculations accompanied with the new acceleration method.
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A simulation method for the direct thrust control of a permanent magnet linear synchronous motor(PMLSM) using the equivalent circuit is presented. The motor self inductance, the initial flux linkage by the permanent magnet is calculated in advance by the finite element analysis, and then the the direct control simulation is carried out. As a result, thrust, flux and speed responses to the commands are examined and the presented simulation method is proved to be very useful.
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Linear Induction Motors (LIMs) with the long secondary conductor often have joints between the segmented secondary, which are specially used for magnetically levitated high-speed vehicle and elevators. In this paper, the dynamic characteristics of the LIM with joints in the secondary are investigated using the time-stepping finite element analysis. It is supposed that both aluminium conductor and back-iron have joint in the active zone during the analysis. As a result, thrust and normal force ripple which have effects on the motor dynamics and vibration are examined.
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This paper presents the design schemes for the improvement of force characteristics in Controlled permanent magnet linear synchronous motor (CPMLSM). The dependence of motor performance on various design schemes, such as the slot shapes, magnetizing patterns of PM and skewing, have been investigated in detail by using FEM and experiment. From this study, it is known that in the various design schemes, skewing is most efficient in the aspects of force characteristic, efficiency and force density.
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This work deals with an application of linear induction motor. In the process of making steel, the molten zinc is required to flow by electromagnetic force. For this purpose, the characteristics of a single sided linear induction motor are analyzed at various conditions.
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A voice type Moving Coil Linear Oscillatory Actuator(MC-LOA) has unbalanced magnetic circuit structure. Its asymmetric magnetic flux distribution along the mover directions causes shifting of displacement center to one side. Therefore, this paper analyzes both thrust and displacement characteristics and settles the unbalanced flux problem by performing shape optimization. The propriety of the improved design model has been verified by dynamic analysis based on the coupling of kinetic and electric equations.
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This paper deals with characteristic analysis of Permanent Magnet Linear Synchronous Motor(PMLSM). Parameters and characteristic variations are evaluated by using Finite Element Method (FEM) and Equivalent Magnetizing Current Method. PMLSM can be classified into the short primary type PMLSM and the short secondary type PMLSM according to their structural features. Especially, the short secondary type PMLSM is focused on because of good control characteristics. And this paper presents the difference of analysis results between the short primary type PMLSM and short secondary type PMLSM and investigates the end effect of two PMLSM's.
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The normal force and vibration characteristic are affected by tooth shapes of linear pulse motor. In this paper, we obtained the normal force according to the position of mover and tooth shapes using the finite element analysis. From the result, we can find the vibration characteristics. Also we predict the characteristics of normal force and vibration.
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A Linear Stepping Motor(LSM) can operate open loop control mode similarly to a rotary stepping motor. The linear motion without any mechanical linkage in the LSM results in several advantages for precise positioning actuators. However, to realize the more stable and higher speed control without hunting, it is necessary to derive an equivalent circuit to explain the steady-state and transisent characteristics in order to find an adequate control rule for high performance control of the LSM. In this paper, magnetic equivalent circuit is obtained, based on the structure of the LSM, and then the electric equivalent circuit of the LSM is derived by solving equations for the magnetic equivalent circuit. The 1-step response characteristic of the LSM is analyzed by the ACSL with the voltage equations, the force equations, the force equations and the kinetic equation.
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We are analyzed the characteristics of maximum thrust and normal force for new model of HB typed LSM by using Finite Element Method and Virtual Work Method. As a result of this paper, it is confirmed that maximum thrust of the enhanced LSM increased 30% without increasing the input energy and the normal force.
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The thrust force of moving magnet-type linear direct current motors(MM-LDM) is analyzed in this study. A moving magnet-type LDM consists of a stator and a carriage. The stator is composed of two stick shaped electro magnetics and the carriage consists of a movable permanent magnet that is located between the two electromagnets. The method for calculating the thrust force of an MM-LDM is to analyze the energy gradient which is determined by the distribution of magnetic flux. And this paper describes the development of the generalized machine theory for d.c. linear motors and its application to determine the motor parameters.
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In this study, dynamic analysis of Linear DC motor has been performed. Dynamic characteristic is carried out from coupling the electrical circuit equation and mechanical kinetic equation. Trust constant and circuit parameters are obtained by FE analysis and static characteristic experiment. From the previous results, dynamic analysis is performed and the appropriateness of analysed result is verified by comparing with experimental result.
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This paper presents the d-q axis inductances calculations method of Interior Permanent Magnet Synchronous Motor(IPMSM) by using Finite Element(FE) analysis. The inductances of d-q axis in IPMSM, which is the function of current magnitude and phase angle are computed by energy dual method. The appropriateness of the proposed FE analysis has been verified by comparing with experimental results.
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This paper deals with modal analysis and displacement of stator in SRM due to electromagnetic forces according to the rotor position. The analysis is performed by using 3 dimensional Finite Element Method(FEM). And, the prediction of resonance speed is achieved from the comparison with current harmonic according to duty ratio of voltage source and the natural frequencies.
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This paper deals with the rotor vibration analysis of Switched Reluctance Motor(SRM) with the 6/4 poles. For this analysis, 3-dimensional mode shapes corresponding to the natural frequency and critical speed map according to rotor speed are presented by using 3D Transfer Matrix Method(TMM). The gyroscopic effect and shear deformation of rotor are considered.
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The Synchronous Reluctance Motor(SynRM) was made and experimented. Salient type SynRM was manufactured by cutting two sides of the three phase squirrel case rotor. So this prototype motor has same stator and capability with the counterparts of the induction motor. The airgap flux density, inductance and torque characteristics was inspected by Finite Element Analysis (FEA). The static torque experiments was accomplished. The paper proposed the effect of rotor bar by comparing two models.
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Sensorless PMSM is much studied for the industrial applications and home appliances because a mechanical sensor reduce reliability and increases cost. Most of sensorless algorithm have poor performances in a low speed range. This paper investigates Performance improvement in a low speed range of PMSM. The proposed control scheme is based on the optimization of ratio between the command and dc-link voltages. The experiment is performed in this study. and the result shows the improved Performance in a low speed range.
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회수에너지를 저장한 콘덴서전압을 이용하여 평활전류 구동방식에서 SRM이 전동기 영역으로 동작할 경우에는 콘덴서에 저장된 에너지 모두를 전동기영역에서 소모할 수 있으나, 발전모드가 장시간 유지되면 콘덴서의 에너지는 더 이상 저장할 수 없는 상태가 되는 치명적인 약점을 갖고 있다. 따라서 본 연구에서는 전동기 영역 및 발전기영역에서 평활전류 모드로 동작할 수 있는 인버터회로를 제안하고, 발전에너지를 효과적으로 사용할 수 있는 스위칭 방식을 돌출하였다.
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SRM의 상 스위칭 제어방식에서 상 스위치의 온, 오프 제어정도는 인코더의 분해능뿐만 아리라 마이크로프로세서의 샘플링 주기에 의해 제약을 받게되며, 전동기의 속도가 고속으로 됨에 따라 상 스위치의 온, 오프 제어정도는 더욱 떨어지게 되어 정상운전상태가 불안전하게 된다. 따라서 본 연구에서는 SRM 구동에 적합한 저가형 인코더를 제안하고, 제안된 인코더의 출력신호를 사용하여 간단한 논리회로에 의해 상 스위치 제어방식을 제안하였다. 제안된 상 스위치 제어방식은 스위치 온, 오프각 지연이 SRM의 운전속도와 관계없게 되어 안정된 고속운전이 가능하게 되었다.
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This paper analyzed the static torque of SRM according to the variation of airgap length using Finite Element Method. The normal and tangential components of flux density are analyzed at uniform airgap field which sap length is 0.3[mm] and nonuniform airgap which gap lengths are 0.2-0.4[mm] and 0.4-0.2[mm]. Also their static torques were simulated by using Virtual Work Principle. We expect that their parameters will help for the design of Switched Reluctance Motor.
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The various advantages of DSPSRM lie in constructional simplicity, robustness and low cost. Also it has a specific characteristic of axial flux machine and radial flux machine simultaneously. In this paper, we designed and manufactured its operating drive and measured the characteristics of torque, efficiency, current to speed.
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This paper verifies that DSPSRM having the rotor pole of "ㅓ" shape has a radial and axial flux distribution, and analyzes the flux density distribution of each direction using 3D FEM.
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There have been great advances in communication and networking in recent times. It is necessary to take advantage of this information infrastructure for the purpose of developing an engineering education system. But the networking system was expensive and hard to develop. The current international netwoking is converging to the use of the World Wide Web system. It has become a new standard for global network communication. But there are not a great number of applications which take full advantage of this environment. In this paper, an interactive virtual electrical machine lab system using the World Wide Web will be presented. This can be used as a supplementary kit for engineering experiment of transformer, induction motor, direct current motor, and synchronous motor. The system is developed using JAVA and can be accessed using Web browsers.
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A method of stochastic finite element analysis is developed for yield a uncertainty of engineering problems. Where, a stochastic finite-element method for shapes modeling is proposed a6 a means to solve the models with the uncertainty and variety. This method is based on the probability and illustrated by a first-Order Second-Moment Method and considering the covariance of random variables. The validity and accuracy of the stochastic finite element method is verified through comparing with those solved by the conventional 2-D finite element method.
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Voltage Source Finite Element Analysis of Electrical Machines Considering Hysteresis CharacteristicsIn this paper, voltage source FEA considering magnetic hysteresis characteristics is presented. Magnetization dependent model is used as a hysteresis model. The unknowns in finite element equation are the magnetic vector potential and current. Core model is analyzed and current waveform is compared with the experimental one. It is found that current can be accurately predicted with the voltage variation.
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A Study on the Insulation Characteristics of Low-Voltage Induction Motor driven by IGBT PWM InverterSince the introduction of IGBT PWM inverters, many low-voltage induction motors have been driven by them. Recently, the stator winding insulation failures have attracted much concern due to high dv/dt of IGBT inverter output. In this paper, presented are the detailed insulation test results of 26 low-voltage induction motors. Six different types of insulation techniques are applied to 26 motors. The tests include PD,
$tan{\delta}$ , and DIV tests. Also, break-down tests by high voltage pulses are performed. -
This paper describes a new method for source current optimization of the electromagnetic devices. In a conventional method of current distribution optimization using design sensitivity based on a finite element method, position and width of coils are generally optimized under condition that shape of those is given. they cannot find the global minimum because the number of coils is pre-determined. To avoid this local minimum, source current region which is discretized uniformly is considered as design parameter. This discretized regions have zero or one current value during the optimization process. The proposed method is applied to magnetic resonance imaging(MRI) magnet.
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This paper discussed an optimal designs of 2 pole fan motors in refrigerator using a Niching Algorithm. We applied a Niching method to multi-objective optimal design of air gap construct. This Niching genetic algorithm is called "Restricted Competition Selection"(RCS) that is suitable for real world problem such as shape or structural optimization of electromagnetic device. The finite element method being used for nonlinear numerical characteristic analysis is provided exact solution in the system. Through this process is reduced the cogging torque ripple in air gap.
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This paper presents a study of 2-dimensional(2-D) eddy current problem using boundary element method(BEM). When compared with finite element method(FEM), there are only a few unknown variables in BEM because it implements numerical analysis only for the surface or boundary of a model. As a result, a lot of computational memory and time can be saved. In order to analyze 2-D eddy current problem, potentials and its derivatives(flux) in a boundary are used as variables. The Mantel function of the second kind of the zero order is used here as a fundamental solution. In order to remove singularity and to solve the integral equations in a boundary, Subtracting Singularity Method and Gauss Quadrature Formula are adopted in this paper.
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This paper presents a numerical analysis of the eddy current testing with cracked pipe using finite element method (FEM).
${\vec{A}},\;{\phi}-{\vec{A}}$ method is adopted for the formulation of 3-dimensional(3-D) FEM with the brick element. The cracks investigated here are the inner and outer surface of axial symmetry, 90 degree circular one. The algorithm of 3-D numerical analysis is employed for the axisymmetric pipe with the cracks. In order to verify the validity of 3-D numerical analysis, the results are compared with those of 2-D analysis with the same type of the model. The differential impedance is obtained by using energy method and its locus are various 8-shaped curves for each cracks. The ICCG method is used for the calculation of a matrix. -
The procedure of optimum design is consist of a system analysis module, an optimum design module and an optimizing method module. In this paper, the method to connect the system analysis module with the optimizing method module using the self script language of OPERA has been provided. Optimum design for a magnet whose central field must be 27 has been carried out with the presented method. OPERA Pre/Post-processor has been used as a system analysis module and mixed decent/gradient method as an optimizing method.
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This paper presents an efficient analysis method using time-stepping finite element method for electric machines driven by pulse width modulation (PWM) inverter. In the method, the value of time-step is changed according to the PWM logic of inverter, and the calculation time can be reduced while maintaining analysis accuracy. Using the method, the dynamic characteristics of a permanent magnet linear synchronous motor (PMLSM) driven by PWM inverter are analyzed.
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For the first time in Korea, a 30kVA superconducting generator has been designed, developed and successfully tested recently. This is the forerunner of a 1MVA superconducting generator which is currently under development. The paper discusses the structure and manufacturing of a superconducting generator. Helium transfer coupling has 3 passages of the recovered Helium gas and a gas flow control system.
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Baik, S.K.;Sohn, M.H.;Kwon, Y..K.;Ko, R.K.;Lee, E.Y.;Ryu, K.S.;Park, D.Y.;Kim, Y.J.;Ahn, J.B.;Kim, K.H. 232
A 30kVA superconducting generator (S.G.) has been designed, developed and successfully tested in KERI before the end of last year. The design is based on 2-dimensional electromagnetic field analysis of cylindrical coordinate. The field winding of rotor has been wound with superconducting wire of Nb-Ti alloy and tested after assembled with other rotor components. The stator has air-gap type armature windings which allow higher terminal voltage and more sinusoidal voltage waveform than conventional iron cored machines. Steady-state open & short-circuit test and lamp load test have been conducted also. The results of tests are given in this paper and compared with design quantities. Moreover the cooling scheme and characteristics of test system is included. -
This paper has proposed a method to estimate effective length of a 30 KVA super-conducting generator using 3-dimensional FEM program. Flux linkage of the stator coil is calculated by the FEM program and the induced voltage is computed using the simple Faraday's law.
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In this paper, the protection resistance determination for the field winding in superconducting generator is suggested. To protect the field winding in a generator, they usually use the external resistance to decrease the field current more rapidly when quench occurs in the winding. Since the field winding is actually separated into four sections (magnets), we have choices to insert 1, 2, and 4 external resistances. For each case, the current decay and the voltages across e winding are calculated, and we can choose the best external resistance.
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This paper describes a series of experiments investigating the operational characteristics of high-Tc superconducting synchronous motor of five to six hundred watts capacity. In this experiment, ac 220V stator phase voltage and DC 4A excitation current are used, and the synchronous speed runs at 1800rpm. Hall Sensors are installed on the pole face and at the side of the Ag/Bi-2223 high-Tc superconducting tape in order to analyze the effect of the time-varying magnetic field on the motor performance when the load changes its value. The experimental observations are compared with the theoretical predictions.
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This paper deals with the design and fabrication of a novel superconducting power supply system, and characteristics have been analyzed through experiments. Superconducting power supply consists of rotating and static parts, and superconducting magnet. In this experiment, the current pumping characteristics have been analyzed with superconducting sheets placed in parallel within the static part of the machine. In addition, in order to observe the rotating flux distribution in the superconducting sheet, several hall-sensors were placed in it. With the flux distribution acquired, the effect of the flux on the superconducting sheet during the process of current pumping have been analyzed. Also, general operational characteristics of the superconducting power supply system have been investigated on the basis of the current and voltage data, and magnetic field values acquired through the experiments.
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This paper presents the design of a small scale High Tc superconducting power transformer. In the design of the transformer, BSCCO-2223 tape was considered as the conductor. Double pan cake winding was adopted in order to easy the construction of the winding and to lessen the leakage reactance of the transformer. Numerical calculation was used to decide the arrangement of the double pan cake winding. Estimation of the AC loss, magnetizing loss and self field loss, in the superconducting winding and the iron loss in the core were given.
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It is certain that the power qualify will be very important at 21 century. Especially instant power shortage or power fault will occur serious problems. Accordingly stable power supplication is very technical problem. There are many way to make stable supplication as auxiliary generator, but this is long time delay complement. To solve this problem the superconducting magnetic energy storage is introduced. High Tc superconductor is more commercial.
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In this paper, a shape optimization algorithm of superconducting magnet using finite element method is presented. Since the superconductor loses its superconductivity over the critical magnetic field and critical current density, this material property should be taken into account in the design process. Trial and error approach of repeating the change of the design variables costs much time and it sometimes does not guarantee an optimal design. This paper presents a systematic and efficient design algorithm for the superconducting magnet. We employ the sensitivity analysis based on finite element formulation. As for optimization algorithm, the inequality constraint for the superconducting state is removed by modifying the objective function and the nonlinear equality constraint of constant volume is satisfied by the gradient projection method. This design algorithm is applied to an optimal design problem of a solenoid air-cored superconducting magnet that has a design objective of the maximum energy storage.
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The quench characteristics of cable consisted of superconducting strand for Tokamak system are observed and analyzed. The superconducting strands chrome-plated are twisted into cable. This cable was wound on bobbin and quench test is carried out by pulse source. At about 2500A the cable quenched.
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In this paper, we investigated the frequency dependences of AC loss and the magnetic properties of a superconductor using magnetization method. We used the YBCO bulk superconductor sample which has a square-shaped cross sectional area of
$6mm{\times}6mm$ . and 43mm-long in axial direction. The applied AC magnetic field was parallel to the direction of sample axis. It is observed that YBCO bulk has the diamagnetic properties. AC loss calculation of YBCO bulk superconductor was performed by evaluating the total area of magnetization traces. We performed two cases of experiments, one for$B_m < B_p$ and the other for$B_m < B_p$ . The experiments showed that the AC loss dependences on frequency were different in each mode, as was indicated in other publications. -
The AC losses of BSCCO-2223 multifilamentary superconducting tapes were measured using magnetization method and compared with the results of theoretically calculated values. In general, AC losses in multifilamentary superconducting tapes could be quantitatively explained by the simple sum of the Hysteresis and Coupling Loss. As a result of experiment, We found that AC losses of multifilamentary superconducting tape increase rapidly in large magnetic field region.
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Bi-2223 테이프의 전력기기 응용을 위해서는 임계전류이하 및 이상에서의 통전특성에 대한 이해가 선행되야 한다. 따라서 본 연구에서는 임계전류이하에서의 특성 중, 중요한 교류 통전손실을 정확히 측정할 수 있는 방법을 제안했으며, 유도전압이 측정의 정밀도에 큰 영향을 준다는 사실과, 측정된 손실은 이론식과 잘 일치하였으며, 마지막으로 통전손실은 주파수에 무관함을 알 수 있었다.
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A dry winding is adopted in
${\mu}$ SMES devices. In these kinds of devices, MPZ and quench propagation velocity are important characteristics in the fabrication of${\mu}$ SMES devices. In this Paper, the influence of disturbance, Cu ratio and external field on MPZ and quench propagation velocity was investigated. -
In this paper 30 kVA Super-Conducting Generator's test and analysis results of OCC and SCC are presented. Also the test and FE analysis results of the generator under 1.2, 2.4, and 3.6[kW] load are described. For FE analysis of the generator's performance, the external circuit is coupled with the FE region. The generator's end winding reactance is obtained based on the design data, actual dimension, preliminary FE analysis, and empirical formulas. The comparison of FE analysis coupled with external circuit to the test results shows a good agreement.
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Transport current is the HTS tape generates the self field loss. To measure the self field loss, rectangular voltage tap has been used. In this paper, self field loss was measured using the spiral voltage tap method. Result of the measurement was compared with that of the theoretical.
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We fabricated a resistive superconducting fault current limiter of two stripe meander type based on a YBCO film, and performed current limitation experiments. In order to disperse the heat generated at hot spots in the YBCO film the film was coated with a gold shunt layer. At
$0^{\circ}$ fault angle the minimum quench current was$9.6 A_{peak}$ (meander line cross section:$5{\times}10^{-6}cm^2$ ) and the fast quench time was 0.63 msec. The resistance of the limiter continued to increase for three cycles due to heat generation in the gold layer and was stabilized afterwards. At$45^{\circ}$ and$90^{\circ}$ the fast quench time were 0.56 msec and 0.26 msec, respectively. The quench time is believed to be reduced because faults occurred when the current was increasing or was at the peak value. With the limiter we could effectively limit the fault current about 1/5 times right after the fault and about 1/8.5 times three cycles after. -
A novel prototype of an inductive superconducting fault current limiter with an iron core and an air sap was fabricated and tested. If its impedance is not high enough to limit the fault current, then destructive damage occurs in the power system. We attained a magnetic saturation under the higher current by introducing an air gap in the three-legged magnetic core. The fault current was successfully limited to two times as much as the nominal current without high fault current within 1/4 cycles at a 60 Hz source having an effective voltage of 70V.
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The 7-dial inductive voltage divider (IVD) which is divided the in put voltage precisely upto 10-7 were fabricated by using the toroidal cores made of super-mumetal strips of 0.025 mm thick and special decade switches. The cores ate of the initial permeability of 200,000 and magnetic flux density of 0.5 T. The in phase and quadrature ratio errors are evaluated to less than
${\pm}4{\times}10^{-7}$ and${\pm}5{\times}10^{-6}$ rad. respectively. The fabrication techniques used are more discussed in this paper. -
This paper proposes mechanism analysis in thermal overload relay. Overload protection performance is closely connected with mechanism of thermal overload relay. In shortage of analytical technique, we have experienced many difficulties in development of thermal overload relay. We applied analytical results to develop optimum thermal overload relay.
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핵연료봉이나 제어봉과 같은 봉구조물의 검사를 위하여 원격장와전류 효과를 낼 수 있는 탐촉자를 설계하고 탐상주파수를 유한요소해석을 통해 설정하였다. 핵연료봉을 대상으로 한 해석에서 exciter coil 주변을 차폐하고 500kHz의 주파수를 사용한 결과 전위계곡과 위상매듭의 존재가 나타나 원격장와전류 효과가 구현되었음을 확인하였다. exciter와 sensor coil로 이루어진 탐촉자를 이동시키면서 예측한 탐상신호에서는 센서를 원격장 의치에 고정시켰을 때, 결함이 센서를 지날 때의 위상신호와 결함이 exciter를 지날 때의 위상신호가 서로 달리 나타났다. 또한, 외부결함과 내부결함이 센서를 지날 때의 위상지연은 작지만 서로 반대의 경향으로 나타났으며, 두 종류의 결함이 exciter를 지날 때는 위상지연이 상대적으로 크게 줄어들고 외부/내부 결함에 상관없이 신호가 비슷하게 나타남을 볼 수 있었다. 이러한 신호형태는 자성체 관의 탐상에서 내, 외부 결함신호가 구별이 안되고, 동일한 위상신호가 항상 쌍으로 나타나는 것과 비교할 때, 신호해석을 훨씬 수월하게 해 줄 수 있을 것이라고 판단된다.
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피 측정물의 변위를 기계적 변화로 감지하여 나타내는 LVDT는 상호인덕턴스 변화를 이용하는 대표적 변위 트랜스듀서이다. 본 연구에서는 LVDT에 대한 상품화를 위한 설계와 제작, 그리고 신호변환장치에 대한 과정을 기술하였으며, 최종 성능 특성을 측정하여 상품화를 위한 신뢰성의 정도와 선형도 등을 평가하였다. 이러한 상품화 과정을 통하여 산업현장에서 자동계측과 제어를 위한 트랜스듀서로 활용할 수 있도록 하고자 한다.
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전압 전류, 유효전력. 무효전력. 피상전력. 역률, 진상. 지상 역률표시. 전력량을 측정할 수 있는 클램프메타의 개발에 관한 내용을 기술하였으며 제품화를 위한 시제품 제작과 그 특성을 시험한 결과 등을 나타내었다. 전류를 측정하는 클램프센서는 홀소자를 이용하였으며 선형도를 개선하기 위하여 홀소자를 2개 사용하였다. 결과에 의하면 현재 상품화되어있는 클램프메타보다 우수하며 전체 소비전력이 10 mA보다 적은 결과를 얻었다.
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비정현전력 품질들을 종합적으로 진단하고 분석할 수 있는 기술을 연구하고 이 기술을 토대로 측정의 신뢰를 보증할 수 있는 전기량 및 고조파, 전압변동 변화를 관찰할 수 있는 모니터링 진단시스템을 개발하였다.
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Voltage sag and swell are the most severe factors affecting power quality in distribution systems. This paper discusses an approach to ensure a high quality power supply to critical loads appling voltage-sag compensator. The proposed system consists of a PWM voltage source inverter, connected in series with the line through a single-phase transformer. The operation Principle and Power circuit configuration of the proposed voltage sag compensator are introduced. And then the transfer function of compensator is derived from simplified single phase power circuit, and simulated so that the benefits of this proposed compensator is confirmed through the open loop response.
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This paper describes the braking performances considering the structures around for the eddy-current brake excited by permanent magnet. As the magnet is excited by permanent magnet, the braking force of this system interferes with the progress of a moving train in normal time. Therefore, it is necessary to determine the reasonable position of eddy current brake from rail. In this paper, the braking force according to the distance from the rail is analyzed by using 2-dimensional finite element method considering the surrounding structure of train.
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A squirrel cage canned induction motor for the main coolant pump of the integral reactor, SMART was designed, manufactured and tested. The motor was first designed using the equivalent circuit theory to determine major dimensions and then finalized through finite element analyses for electromagnetic and thermal characteristics. In order to verify the design methodology, a reduced scale canned induction motor was manufactured and tested. The experimental results have shown a good agreement with the analysis results.
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This paper describes the general formulation for free vibration analysis of rotor by the transfer matrix method. For solving structural dynamics problems, it is used the transfer matrix method. The rotor of the induction motor for main coolant pump is regarded as a distributed mass system.
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This paper presents a method for determining of the equivalent d-q model parameters of three-phase squirrel cage induction motors. The method is based on the use of a finite-element field calculation which enables the precise slot geometry to be modelled accurately, and includes the effects of magnetic saturation of iron core. The proposed method can reduce computational costs compared with the method that needs the iterative field analysis to obtain the impedance. It is verified that the circuit inductances are shown as functions of the current.
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Electric motor transforms electric power into mechanical power. It is important to increase efficiency of motor to save energy and to decrease operating cost. In this paper, some parameters and losses of high-efficiency induction motor and standard induction motor are measured by blocked-rotor test and no-load test. Operational parameters of high-efficiency induction motor that are compared with those of standard motor.
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유도기의 과도 상태를 해석하기 위해 시간 차분 유한요소법 대신 자기 등가 회로법을 적용하기 위한 연구가 있어왔다. 이 방법은 기기의 각 부분을 자기적 회로로 변환하여 해석하는 것으로 계산 시간이 짧고 정화한 장점이 있다. 이 방법으로 해석하기 위해서는 기기의 각 부분을 자기적 요소로 바꾸어야 하고, 에너지 변환이 일어나는 공극을 퍼미언스로 나타내야 한다. 따라서 이 논문에서는 먼저 자기 등가 회로법으로 해석할 수 있도록 공극 퍼미언스로 구성되는 매트릭스를 제시하여, 차후 시스템 매트릭스를 구성할 때 사용코자 한다.
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For induction motors cannot maintain constant speed in various speed conditions, synchronous motors are generally used. But synchronous motor oscillate in shocking load, and it cannot start by itself for the lack of starting torque. In this paper, we analyzed the synchronous induction motor which has both characteristics, and compared the experimental results with FEM analysis.
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본 논문은 3차원 유한요소 프로그램을 이용한 농형 유도전동기의 정자장을 해석한 것이다. 2차원영역에서 해석하기 어려운 누설 인덕턴스를 3차원으로 해석하여 설계 파라미터 선정에 도움을 주고자 하였다. 유도전동기의 공극 자속밀도 분포와 누설 자속밀도 분포를 고찰하고 1[turn]의 coil에 의해 발생하는 자속의 량과 전동기 내부로 통과하는 자속의 량을 비교하여 누설 인덕턴스를 계산할 수 있었다.
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At the present, development of microelectronics technology caused an increase in using of induction motor for variable speed motor drive system instead of do motor. This paper is described the design of induction motor fed by inverter and analyzed 1.5kW motor performance using by finite element method (FEM).
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In this paper, the insulation system of induction motor for subway traction was designed. In order to design the insulation system of induction motor, various types of insulation system were compared, at first, and test method was investigated in order to verify the designed insulation system. The designed insulation system was satisfied economically, technically by experimental test.
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This paper analyzes the torque characteristics with the structure of magnetostatic wobble motor and then compares the torque characteristics of magnetostatic wobble motor with those of electrostatic wobble motor using F.E.M. Through the results, we investigates how design parameters' change affect torque characteristics.
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This paper presents the gear ratio of wobble motor, accounting for finite friction in contact point. The gear ratio of a wobble motor is affected by rotor slip, which is a function of motive torque, excitation angle, and friction torque. The gear ratio of a wobble motor can be expressed as a constant term plus a term that accounts for rotor slip. The ideal gear ratio is constant term and is equal to the rotor radius divided by the distance between the center of the rotor and the center of the stator. The rotor-slip term is shown to be directly proportional to the contact point friction torque and inversely proportional to the square of the excitation voltage.
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This paper presents the analysis of core losses in capacitor-run single phase induction motors using the finite element methods. The double revolving field theory can be used for the analysis to assess the quantitative and qualitative performance of the single-phase induction motor. But it is difficult to evaluate accurately the core losses. It is more difficult to segregate stator and rotor core losses at no-load and load conditions. Numerical analysis such as FEM can be used effectively for the accurate calculation of core losses and motors performances. In this paper, the coupling method of core loss characteristic equation and FEM are proposed for the accurate calculation of core losses in the stator and rotor. The FFT is also used to calculate fundamental and harmonic components in the yoke and teeth parts of motor.
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An arc model based on the N-S equations modified by adding an energy source term to take account of the arc is developed and solved using Taylor-Garlerkin FEM in the present paper. The numerical method is applied to the simulation of the opening procedure of a puffer type GCB. Moving boundary conditions of the arc chamber during operation is taken into account. Numerical predictions of the temperature profiles at different strokes are presented.
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Two of the factors to be considered at the design stage of the extinction chamber have been examined numerically. one is the sectional area of puffer cylinder, another is that of nozzle throat. the variation of the sectional area of puffer cylinder allowed us to find the size optimal at the interrupting performance. it is shown that the sizes of nozzle throat influenced the pressure rise of puffer cylinder strongly.
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In this paper, electric field analysis of 170kV class GCB is carried out. Considering the movement of arcing contacts during circuit interruption, electric field analysis between moving and fixed contacts is performed with changing the stroke length. From analysis results, electric field stresses are high at stationary arcing contact, moving arcing contact and varies at changing nozzle shapes. Specially, the stationary arcing contact shape has an significant effect on the capacitive small current interruption and the reduction of the electric field stress at this area is important. Varying the shape of stationary arcing contact, electric field analysis is carried out and the optimal shpae of the fixed arcing contact where the electric field stress is low is designed.
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Through the Standard of MCCB, the Adjustable Type Instant Trip Unit should NO trip at -20% of each current from
$5{\times}In$ to$10{\times}In$ and trip +20% of those. In this paper, we obtain the attraction force between Fixing Magnet and Moving Armature. So we first made some samples. do experiments of weight, and simulated the modelling by 3D Maxwell S/W. With values of experiment and simulated values, we do design instant trip springs by using the ADAMS S/W of kinematic simulation. Finally we product the 250A Adjustable Instant Trip Unit, and it is very useful to our customers. -
It is necessary for the optimum design of switching devices to calculate repulsion forces acting on the closed electric contacts flowing over-current, e.g. inrush current and overload currents. In this paper, the forces generated by currents and flux densities at the contact point when circuit breakers are in closed position are obtained by using 3D finite element method. According to the analysis, the optimum configuration of wipe springs and arc extinguishing chambers are newly designed and consequently type tests show satisfactory results.
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이 논문은 차단기 시험시 시료가 전류를 차단한 후 변압기의 여자전류가 시료의 회복전압에 미치는 영향을 설명한다. 정확한 영향을 분석하기 위해 변압기의 시험결과 분석을 통한 데이터를 바탕으로 전자기 과도해석 프로그램인 EMTP를 사용하였다. EMTP 해석결과로부터 저압단락시험에 요구되는 한류리액터와 역률조정용 저항의 적절한 위치를 검토하였다.
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800kV GIS(Gas Insulated Switchgear) was first developed by Hyosung Corporation in Korea at Dec. 1998 and is going to be installed first in the Dangjin Thermal Plant. We intoned to verify the structural safety of 800kV GIS under seismic load. The modal analysis of 800kV GIS has been carried out to obtain the natural frequency and mode shape. PATRAN was used for mode)ing exactly 800kV GIS Geometry. 800kV GIS FE(Finite Element) model was constructed of shell elements for the enclosures and beam elements for the conductors and the support insulators NASTRAN was used for analyzing the normal modes of 800kV GIS FE model.
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In this paper, the analysis of the gas flow in the GCB is presented by using the modified FLIC method and the arc model. The modified FLIC method has two step calculation procedure. And it adopts the upwind scheme, which results in the stability.[1] The arc model used in this paper makes arc a heating source in the energy equation. The heating source is composed of ohmic heating and radiation energy transfer. And the type of the GCB in this paper is a auto-expansion type.[2]
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The post-arc current in VCB(Vacuum Circuit Breaker) was calculated from the transient recovery voltage. A differential equation for the post-arc current was derived from the equivalent circuit of the test circuit. And it's results were showed.
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This paper presents an arc(hot-gas flow field) analysis method in GCB. This method includes the Lorentz's force due to magnetic field, turbulent viscous effect and radiation heat transfer which are indispensable to the analysis of hot-gas flow. To verify the applicability of the Proposed method, steady state hot-Eas flow analysis within a simplified interrupter has been carried out. Inlet boundary pressure values were assumed to be 9.0atm and 12.0atm. For each inlet boundary condition, three cases of hot-gas flow field analyses were performed according to the values of arc currents which were assumed to be D.C 0.6kA. 1.0kA and 2.0kA. The results revealed that the arc radius at nozzle throat has been concentrated by increasing the pressure of nozzle upstream and that the maximum temperature of arc core has been decreased along to nozzle exit and the high temperature lesion come to be wide in nozzle downstream. From these results, it is confirmed that the proposed method will be applicable to predict the large current interruption capability of GCB.
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In order to design the current carrying conductor for GIS, it is important to predict temperature-rise when rated current flows. This paper deals with the coupling of Flux2D and analytic method to calculate the heat transfer coefficient. Heat transfer by conduction and convection is considered between the current carrying conductor and
$SF_6$ gas. The result shows reasonable temperature distribution. -
This paper presents a study of the performance of a brushless DC motor (BLDCM) speed control system. Recently, most motor controls are implemented in digital electronics. Digital controllers tend to be more accurate, less susceptible to noise and more flexible in terms of programming. The system used a digital PI controller in order to implement the constant speed of Brushless DC motor. Microprocessor used in this experiment is 80c196kc. The applied motor has been constructed using a 50W, 150V, 3000rpm, four-pole motor.
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Jang, Hong-Min;Kim, Young-Bak;Jeon, Hyoung-Wok;Park, Sang-Hyun;Jun, Hyang-Sig;Choi, Young-Kiu;Kim, Sung-Shin 382
We propose a new method for detecting Backemf of a motor and estimating parameters of a motor using Recursive Least Square Estimator. The motor speed is obtained from the estimated parameters. We experiment the PID speed controller with the estimated speed. -
Brushless DC Motors are widely used because of their high power ratio and easy control. But the brushless DC Motors need rotor Position- and speed- sensor such as encoder, resolver and hall sensor. The position sensor has present several disadvantages from the standpoint of drive cost, machine size and reliability. Hall sensors are used generally because of low cost but their operating temperature is limited up to
$75^{\circ}C$ because of sensitivity of temperature. Now a day many research projects are on the development of sensorless brushless DC motors to correct these disadvantages. In this paper, characteristics such as starting, change of speed and load of a sensorless brushless DC motor are investigated. -
This paper discusses an optimal design of high space factor BLDC motor. Because of high space factor BLDC, Nonliear finite element method considering saturation of outer-rotor is used. For optimal design, a new niching genetic algorithm, namely "Restricted Competitions Selection" is used. This algorithm constructs an objective function using only the most important criteria and provides a designer with a set of solution rather than one solution. To verify its effectiveness, the new niching genetic algorithm is applied to an actual high space factor BLDC motor We show that a new designed high space factor BLDC motor is superior to the actual high space factor BLDC.
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This paper is proposed the design method of Outer Rotor BLDC by the magnetic equivalent method. In order to compute and estimate the performance parameter of Outer type BLDC. The dynamic model and characteristics analysis of BLDC is obtained by Matlab.
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Choi, T.I.;Kong, Y.K.;Kim, H.C.;Kim, C.L.;Song, J.W.;Hong, S.Y.;Kim, B.S.;Jung, Y.B.;Choi, K.H. 394
ADD has developed a special BLDCM(brushless d.c. motor) that has small size and high power density. The model of BLDCM is like that of advanced nation. Design, production and test carried out by ADD and HYOSUNG Corp.. We simulated back EMF of phase, inductance of line and eddy current loss of rotor after we tested the motor at 80 Kw. According to analysis we have established the performance of 100Kw power recently. There are the same results that we designed. -
This paper deals with the torque characteristics of a AFPM motor excited by permanent magnets. According to relative angle difference of two rotor, torque characteristics are studied. According to varied angle of two rotor, torque ripple and, total torque of AFPM motor is different. For minimum torque ripple, angle of two rotor of AFPM motor are investigated. For this study, we used to Maxwell EM 3D program. A prototype AFPM motor have been assembled and driving power supply are made. Characteristics of magnetical and electrical characteristic are investigated.
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We have developed a new type Automatic Vending Machine(AVM) of a small size with simplification of coin mechanisms. The AVM adopts a new type transportation system named thin film-transportation system. Thin films have advantages of safe guide and transportation of various goods which made from various materials and shapes. The AVM has advantages of low price and simple mechanisms. The compact size(
$300{\times}330{\times}630$ , mm)is realized by the use of simple coin mechanisms and thin-transportation system. -
Dissoved oxygen(DO) control by deaerator has a great effect on the integrity of S/G in nuclear power plant. The goal of this study based on the theoretical basis and the extensive surveys is to identify the effect of deaerator in feedwater system on steam generator to clear the need of installation of deaerator. In addition, this paper discusses the review to understand the mechanism of DO formation as well as removal. The conclusion is that the installation of deaerator improve the integrity of S/G and is contributed to the whole nuclear power plant safety.
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캐패시터(capacitor)의 고주파(수십MHz) 전기장에서 유전손실(dielectric loss)에 의한 유리의 용융 및 합성에 관한 이론적 고찰이 수학적 모델에 의하여 이루어졌다. 유전 가열법에 있어서 캐패시터에 놓여진 유전체가 흡수하는 에너지는 용융인자(전압, 주파수)와 피시물(유리)의 전기, 물리적 성질[유전율(
${\epsilon}$ ). power factor($tan{\delta}$ )]에 의존한다. 본 연구에서는 이러한 물성들의 온도 의존성뿐만 아니라 외부로의 열손실 등이 조사되었으며, 특성 분석을 통해 최적의 용융 모델을 설계하였다. -
This paper proposes the circuit of the simple synthetic testing facility using LC resonance circuit. EMTP has been used to analyze the circuit. The obtained results indicate that the simple synthetic testing facility using LC resonance circuit can be easily designed and used very usefully for the research and development for the switchgears.
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통신용전원으로서의 전력저장시스팀(BESS)은 전기요금이 싼 심야시간(또는 필요시간)에 2차전지(축전지)를 이용하여 전력을 저장하고 최대 부하시나 필요한 시기에 전력을 방출하는 시스팀을 말한다. 이 시스팀은 축전지의 충분한 사용과 최대전력제어에 의한 전기요금 절감측면 등에서 상당히 효율적이라 할 수 있다. 본 논문에서는 이러한 전력저장시스팀을 통신용전원으로 활용하기 위한 방법과 실지 적용시 고려사항, 기대효과 및 개략적인 경제성 비교 둥을 통하여 전력저장시스팀의 통신용전원 적용방안을 검토하고자 한다.
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Recently, Reliability of switching devices for transmission & substation system is very important. Therefore, We have investigated fault trend of switching devices from 1982 to 1998 This paper presents fault analysis on Circuit Breakers, Disconnecting Switch, Gas Insulated Switchgear, etc. Thus, this paper will help improve design, manufacture, construction technology and maintenance method.
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Byun, Yeun-Sub;Han, Seong-Ho;Kim, Gil-Dong;Lee, Byung-Song;Han, Young-Jae;Baek, Jong-Hyen;Park, Hyun-Jun 421
The function of the automatic train operation(ATO) system is to regulate the train ride comfort during start, acceleration and deceleration and execute operation of constant speed travelling and fixed point parking. The mathematical model for the train is presented by considering unknown disturbances which consist of start resistance, travelling resistance, slope resistance, curve resistance and so on. The speed control of ATO system is designed by considering the disturbances. The simulation is executed to verify the speed control performance and compare its performance with that of a PID-type ATO control system under the disturbances. Simulation results show that the control performance of gain scheduled control for ATO system is better than that of the conventional PID controller. -
In this paper, the design characteristics, the manufacturing process and the results of performance test on the AC traction motor for urban transit standard E.M.U which is newly developed with applying standardization specification will be introduced. It is reviewed that the design and performance analysis on conventional motors considering system correlation and design constraint and the design optimization through an analysis of electro-magnetic, thermal and dynamic properties. The properties of factory products manufactured by 200 Class VPI process exhibit a excellent performance with a lower noise and vibration, higher efficiency and power factor etc.
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According to the development of power electronic element(GTO. IGBT) and material for electrical machines(permanent magnet. super conductor), the technology for electrical machines is now a day rapidly developing. Here with, a novel electrical machine, based on the new conception of transverse flux configuration leads to a considerable increase in power density and enables simultaneously high efficiency. The transverse flux machine with PM excitation will be applied to gearless direct drives for railway traction system. The designed and measured performance of transverse machine for railway traction system revealed a great potential of system improvements to reduce linear motor mass.
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In this paper, magnetic field inside and outside express railway train is analysed by use of finite element method. We find that high permeability material reduces magnetic field inside train more than thick material. We also know windows in train does not have influence on magnetic field at seat in train.
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전동차의 구동시스템 및 보조 전원장치 등의 제어가 고성능화되고 복잡해지면서 각 기기의 개별 시험이 아닌 조합시험을 통한 신뢰성의 확보가 점점 중요해지고 있다. 특히 구동시스템의 시험을 위해서는 실제 차량부하와 유사한 부하 특성을 조합시험장치가 제공하는 것이 중요하다. 전동차의 부하특성에서 가장 지배적인 역할을 하는 특성은 관성이다. 국내에 운용중인 조합시험장치들은 전동차의 직선 운동에 해당하는 등가 회전관성을 가지는 플라이휠(flywheel)을 이용하여 관성부하를 구현하고 있다. 본 논문에서는 이러한 관성부하를 기계적 질량이 아닌 서보시스템을 이용하여 구현할 경우의 장단점과 특성에 대해 알아보고, 그 적절한 구현방법을 제안하고자 한다. 또한 실험 및 실험 결과를 통해 그 타당성을 검증하고자 한다.
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This paper present a study on the interference levels on the communication lines, which are parallel to the electrified rails. The interference study is carried out using a circuit model approach. First, the self and shunt impedances of all the conductors in the rail system and the mutual impedances between different conductors are computed. Several different scenarios are analyzed, including the load condition and a few fault conditions with different fault locations. The induced potentials on the communication cables are computed. The effect of the buried ground wires is also analyzed by comparing the results with and without the presence of the ground wires. The results presented in the paper can be used as a reference for estimating interference levels in similar rail systems.
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본 연구에서는 전자연동장치의 확장성과 신뢰성 제고를 위해 전자연동장치의 실시간 연동전략으로 활용될 수 있는 연동 지식베이스를 자동 생성, 구축할 수 있는 지능형 연동지식베이스 자동 구축 소프트웨어(IIKBAGS)를 개발한다. IIKBAGS의 추론부는 주어진 역 모델의 동적탐색하에서 휴리스틱 규칙들의 우선순위에 따라 모든 진로를 탐색함은 물론 각 진로들에 대해 진로상 신호설비들간의 연쇄관계를 확인하여 연동패턴들을 자동생성하는 연동지식 자동생성기능을 가진다. 지식베이스는 전자연동장치상의 실시간 전문가 시스템이 직접적으로 활용할 수 있는 구조로 설계됨으로써 연동도표 입력과정에서 발생할 수 있는 오류를 배제, 연동장치의 정확성과 신뢰성을 높인다.
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본 연구에서는 고도의 전문가 수준에서 역구내 상황을 고려하여 실시간 전자연동처리전략을 수립함으로써 열차운행을 안전하고 정확하게 제어 열차충돌이나 탈선 등의 사고를 사전에 방지함으로써 보다 높은 안전도가 보장될 수 있도록 지원하는 전문가 시스템이 제안된다. 전문가 시스템은 열차의 역구내 운행시 신호기, 전철기 궤도회로 등의 입력정보로부터 연동 지식베이스에 근거하여 신호설비들간의 연쇄관계를 확인, 실시간 연동전략을 수립하며, 연동규칙을 정확하고 효과적으로 표시할 수 있도록 규칙기반 시스템으로 구현된다. 특히, 제어실패시 논리적 추론기능과 협조하여 합리적인 진로를 제시함으로써 비상시 역무원이 당황하지 않고 신속하고 안전하게 연동업무를 처리할 수 있도록 한다.
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The forced drainage set up to decrease the cathodic protection in each kind of steel conduit laid under the ground is so proscribed to be maintained less than 60V in its output voltage that insulation coordination is easy to be left out of account, on the basis of 60V of working voltage. When railway or subway break down during the service of a subway, 1,500 voltage approximating to line voltage flows through the load terminal of the drainage (rail and underground conduit) though momentary in the worst case. And so, an accident followed by dielectric breakdown, fire and damage by a fire is expected. Therefore, I suggest that insulation coordination should be considered against such a thing on designing, producing and setting up forced drainage.
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When the traction motor for urban transit E.M.U is driven with VVVF controlled inverter, the insulation degradation factors on the 200 Class insulation system of VPI process are analyzed with considering dielectric, mechanical properties, thermal stability, chemical resistivity and compatibility. A new test method of complex accelerating degradation is proposed to evaluate the insulation reliability and the long-term life including harmonic loss and transient surge stress due to PWM inverter drive.
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In this paper, sample coils for stator form-wound winding of traction motor were made for the accelerative thermal degradation composed of heat, vibration, moisture and overvoltage. In progress of test periods, diagnosis tests such as insulation resistance, dielectric loss and partial discharge were investigated. Reliability and expected life were evaluated on the insulation system for 200 class traction motor considering various environmental stress.
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In this paper, the wearing characteristics of current collecting shoes, interruption phenomena and contact resistances between collecting shoes and conductor rails are established as design parameters for development of the third rail current collector. An experimental analysis for established design parameters is performed as the materials of current collector shoe, contact force, sliding velocity and contact condition(dry/wet condition) between current collectors shoe and conductor rails. As a result of this study, the magnitude of contact force is in proportion to the amount of wear in the collecting shoe, but is in inverse proportion to the interruption and contact resistance between the collecting shoe and the conductor rail. And optimal values of design parameters are pre sented through analyzing the experimental results of the amount of wear, interruption and contact resistance.
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In this paper, the results of FEM electromagnetic analysis performed in the standardization development of traction motor for EMU are reviewed. The selection of optimal design parameter and performance analysis are proven through the complement of the circuit parameters on the basis of Performance test for developed traction motor.
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To improve traction effort performance and stability for the Korean High-Speed Railway Train, practical re-adhesion controller including a novel anti-slip control scheme is proposed. The presented method is verified by train running simulation results based on induction motor vector control with PWM inverter.
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The data transmission system in MAGLEV is required a high quality and high speed for a train safety and reliability driving. In the transmission channel between a vehicle and a ground-site, Gaussian noise is negligible, but impulse noise from the chopper controlled propulsoin unit and the Power supplying device is very severe. The transmission channel must be protected from these noise. In this paper, we propose a DSSS (direct-sequence spread spectrum) modulation as a new data transmission technique in the railway and analyze this data transmission characteristics.
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Using the EMTP(Electro Magnetic Transient Program) for the analysis of lightning direct voltage on the railway system, the shielding effects of overhead grounding wire on the railway were studied quantitatively. Installation of overhead ground wire and sap-type arrester such as s-horn provides a 6.6kV HV distribution line with goof protection effects. Even severe lightning induced voltage were create, 6.6kV HV lines can be withstand.
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Recently, the computer based control systems instead of conventional relays circuitry are widely used to industrial applications, and also those technology is available to railway signaling which are safety-critical systems. However, the safety and reliability of software for those systems are harder to demonstrate than in traditional relays circuitry because the faults or errors can not be analyzed and predicted to those systems. So, the safety problems are crucial more and more in computer based control system. In this paper, the GRAFCET(GRAphe Fonctionnel do Commande Etape/Transition) language is used as a analysis and verification tool for safety-critical interlocking logic. The general description for Grafcet notation are provided and the general modeling for interlocking logic is presented.
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This paper presents the vector control of induction motor for traction drives. Especially, the PWM mode control method is well described to be selected as the change of speed to meet the wide speed range of the traction motor. Asynchronous space vector PWM mode and synchronous one pulse mode are basically used under the full speed range with the overmodulation PWM mode for the soft transfer between them. The validity of this proposed control scheme is verified with the simulation results.
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This paper proposed train operation simulation algorithm, algorithm to determining operational mode and algorithm for train performance program, which play a important role in multi-train operation simulation. Using railway network modelling and signalling systems modelling already developed, these algorithms was presented.
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TCN standard has been applied to international train for provision of interoperability among European countries. In this paper, several TCN analyzers developed by European companies are introduced and the urgent need of TCN project engineering tool is emphasized for Korean High Speed Train.
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Recently, distributed control network system has been widely applied to on-board control system than conventional relay logic with control wire. This paper presents two configuration of driver's desk system using TCN(Train Communication Network). One is configured with TCN, the other is partial adoption of TCN.
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Han, Seong-Ho;Baek, Jong-Hyen;Lee, Su-Gil;Byen, Yun-Sub;An, Tae-Ki;Ohn, Jeung-Geun;Park, Hyun-Jun;Jeon, Young-Jae;Kim, Jae-Chul 486
This paper shows the form of the optimal solution and how to minimize energy of train driving control using SA(simulated annealing). In this paper, we consider the case where a train is to be driven by automatic operation mode along a non-constant gradient, curve and with speed limits. Using the combinational optimal technique, SA, we constructed optimal train driving strategy. -
본 연구에서는 경부고속철도 수익관리시스템 구축방안 연구의 일환으로 철도에 수익관리기법을 도입의 타당성과 그 효과를 검토하기 위하여 현재의 철도에서 사용되고 있는 예약체계, 운임체계 및 좌석할당 방법을 분석하였다. 지금까지 널리 사용되고 있는 여러 가지 수익관리기법을 적용하기 위한 조건을 제시하였으며, 예약실적자료를 사용하여 그 효과를 계산하였다.
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To improve safety operation of urban transit, compatible design of signaling system is most important factor at future train operation and management. Therefore, signaling system should be designed compatible transport demand of target year. In addition, signaling system should be designed improved train safety, based fail-safe principle. Most of all, to solve passenger concentration, high density and to improve efficiency of train operation. Headway improvement of train is most important. Train organization length of new urban transit as light rail is generally shorter than EMU. Therefore, to increase passenger service and operation efficiency, minimum headway of one minute in this system should be important required.
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The TPS accepts as input, vehicle parameters. control parameters. station parameters and right-of-war profile. Outputs of TPS program include velocity elapsed time and power profiles. This paper represents how to develop the TPS program. The TPS program simulates the operation of a single train under the input conditions.