• Proceedings of the KIEE Conference
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• 2005.04a
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• pp.207-209
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• 2005

Recently, the use of IPMSM is coming to be active, in many industrial applications. In sensorless drive of IPMSM, it is important to know the exact information of the initial rotor position, because the wrong estimation of the initial rotor position brings about the decrease of the starting torque, or a temporary reverse revolution, In addition, PMSM is necessary to use the accurate information of the inductance for the precise torque control owing to the reluctance torque. In this paper presents initial rotor position estimation method and, measure method of the each-axis inductance. And to minimize the speed estimations error, the estimated speeds are compensated by using an instantaneous reactive power in synchronously rotating reference frame.

• Journal of Industrial Technology
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• v.30 no.A
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• pp.31-35
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• 2010

In this paper, a speed estimation method at coasting operation in an induction motor speed sensorless control for railway vehicle traction systems is presented. At coasting operation, there is no information obtaining rotor speed since all switches of an inverter are turned off. The inverter frequency should be synchronized with the rotor frequency for repowering at coasting condition. The proposed method injects DC current to the induction motor during a short time, then the flux angle and rotor speed needed for control can be estimated rapidly.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.49 no.11
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• pp.742-748
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• 2000

This paper presents a numerical method to analyze the electromechanical-coupled field in the spindle motor of a computer hard drive and investigates dynamic response due to the electromechanical excitation, i.e. unbalanced magnetic force and centrifugal force for the rotational asymmetric motor. Magnetic field is calculated from Maxwells equation and voltage equation by introducing nonlinear time-dependent finite element analysis. Mechanical motion of rotor is calculated by solving Newton-Euler equation. Electromechanical excitation and dynamic response are characterized by analyzing the free response of a rotating rotor and Fourier analysis of the excitation force and resulting vibration of a rotor. It shows that centrifugal force produces the unbalanced magnetic force even in the rotational symmetric motor. It also shows that resonance produces quite considerable vibration even when the high excitation frequency with small amplitude matches with the natural frequency of the spindle motor.

• Proceedings of the KSR Conference
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• 1998.11a
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• pp.187-193
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• 1998

An inverter-driven induction motor is used as the traction motor for a high speed drive system that required safty, reliability and performance and so on. rotor bar and end ring of the traction motor are the electrical equipments which form the conductive close loop and then induce current by interaction wi th the current of stator. the materials selection of rotor bar and end ring are seriously considered in the aspects of electrical and mechanical specification and Motor slip relation to inverter. Particularly motor slip guarantee the safty and reliability of induction motor. this paper show the material selection and the determining of slip in the design of traction motor for high speed train by analyzing the specifications of material being used currently.

• 제어로봇시스템학회:학술대회논문집
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• 1993.10a
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• pp.26-28
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• 1993

DD motor, with large rotor inertia & wide range of torque, is different from other servo motor in control & drive characteristic. In this paper, for the development of flexible DD robot, we introduced the h/w & s/w technics of DSP to construct the velocity, position & torque control strategies and integrated 2 axes special purpose DD servo dirver into one VME bus.

• The Journal of the Korea institute of electronic communication sciences
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• v.15 no.2
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• pp.259-266
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• 2020

Magnetic gears have the same characteristics as mechanical gears, and each rotor does not come in contact, which is advantageous over mechanical gears in friction noise, heat generation, and maintenance. In addition, when the rotor using the coil-winding is applied, it is possible to control the output of the gear as well as to cut off its own drive in the emergency situation and to change its gear ratio. So the application of the magnetic gear is infinite. However, when the coil-winding rotor is used, cogging torque due to the attraction force between the permanent magnet and the iron core appears, which leads to an increase in the torque ripple component causing the rotor vibration. Therefore, in this paper, various shapes of the coil-winding rotor are analyzed to reduce the torque ripple of the rotor, and the optimum shape for reducing the torque ripple of the magnetic gear is presented.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.2274-2277
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• 2003

A cylindrical permanent magnet inside the four-phase permanent magnet (PM) stepping motor is employed as the rotor. The stator has four teeth around, which its coils are wound. The mode of excitation can be classified into 3 modes: single-phase excitation, two-phase excitation and ministep excitation. The ministep drive is a method to subdivide one step into several small steps by means of electronics. The paper presents the programmable ministep technique drive. This technique decodes the results obtained from the counter to locate the data in Read Only Memory (ROM). The Sinusoidal Pulse Width Modulation (SPWM) is transformed to binary file and saved to the ROM. The experiment is performed with the four-phase PM stepping motor and drives from a two-phase programmable sinusoidal ministep signal, instead of square wave. The results show that the performances of the proposed programmable ministep technique drive have high efficiency, smooth step motion, and high speed response. Moreover, the resolution of sinusoidal ministep signal can be controlled by the input frequency (f command).

• Journal of Electrical Engineering and Technology
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• v.13 no.3
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• pp.1156-1165
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• 2018

This paper presents a detailed realization of direct torque controlled induction motor drive for elevator applications. The drive is controlled according to the well-known space vector modulated direct control scheme (SVM-DTC). As the elevator drives are usually equipped with speed sensors, flux estimation is carried out using a current model where two stator currents are measured and accurate instantaneous rotor speed measurement is used to overcome the need for measuring stator voltages. Speed profiling for a comfortable elevator ride and other supervisory control activities to provide smooth operation are also explained. The drive performance is examined and controllers' parameters are fine-tuned using MATLAB/SIMULINK. The blocks used for flux and torque estimation and control in the offline simulation are compiled for real-time using dSPACE Microlabox. The performance of the drive has been verified experimentally. The results show good performance under transient and steady state conditions.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.03a
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• pp.25-34
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• 2008

In this paper, three-dimensional multiblade row unsteady Navier-Stokes simulations at a hot streak temperature ratio of 2.0 have been performed to reveal the effects of rotor tip clearance on the inlet hot streak migration characteristics in low pressure stage of a Vaneless Counter-Rotating Turbine. The hot streak is circular in shape with a diameter equal to 25% of the high pressure turbine stator span. The hot streak center is located at 50% of the span and the leading edge of the high pressure turbine stator. The tip clearance size studied in this paper is 2.0mm(2.59% high pressure turbine rotor height, and 2.09% low pressure turbine rotor height). The numerical results show that the hot streak is not mixed out by the time it reaches the exit of high pressure turbine rotor. The separation of colder and hotter fluid is observed at the inlet of low pressure turbine rotor. Most of hotter fluid migrates towards the rotor pressure surface, and only little hotter fluid migrates to the rotor suction surface when it convects into the low pressure turbine rotor. And the hotter fluid migrated to the tip region of the high pressure turbine rotor impinges on the leading edge of the low pressure turbine rotor after it goes through the high pressure turbine rotor. The migration of the hotter fluid directly results in very high heat load at the leading edge of the low pressure turbine rotor. The migration characteristics of the hot streak in the low pressure turbine rotor are dominated by the combined effects of secondary flow and leakage flow at the tip clearance. The leakage flow trends to drive the hotter fluid towards the blade tip on the pressure surface and to the hub on the suction surface, even partial hotter fluid near the pressure surface is also driven to the rotor suction surface through the tip clearance. Compared with the case without rotor tip clearance, the heat load of the low pressure turbine rotor is intensified due to the effects of the leakage flow. And the numerical results also indicate that the leakage flow effect trends to increase the low pressure turbine rotor outlet temperature at the tip region.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.55 no.3
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• pp.117-122
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• 2006

The paper is proposed artificial neural network(ANN) sensorless control of induction motor drive with fuzzy learning control-fuzzy neural network(FLC-FNN) controller. The hybrid combination of neural network and fuzzy control will produce a powerful representation flexibility and numerical processing capability. Also this paper is proposed. speed control of induction motor using FLC-FNN and estimation of speed using ANN controller. The back Propagation neural network technique is used to provide a real time adaptive estimation of the motor speed. The error between the desired state variable and the actual one is back-propagated to adjust the rotor speed so that the actual state variable will coincide with the desired one. The proposed control algorithm is applied to induction motor drive system controlled FLC-FNN and ANN controller, Also, this paper is proposed the analysis results to verify the effectiveness of the FLC-FNN and ANN controller.