• Proceedings of the KSR Conference
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• 2002.10a
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• pp.440-445
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• 2002

In this paper, traction system for urban transit maglev system is proposed. Using vector control strategy to control magnitude and frequency of output voltage transiently is general. But in case of traction system for railway vehicle, it is impossible that adapt vector control because there is one-pulse mode in a high speed region. So this paper proposes the control strategy using vector control in a low speed region and slip frequency control in a high speed region. And also proposes overmodulation method that makes to change in one-pulse mode softly. The performance of traction system will be verified by simulation results using ACSL.

• Journal of the Korean Geotechnical Society
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• v.32 no.11
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• pp.97-108
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• 2016

Lunar rover plays an important role in lunar exploration. Especially, performance of rover wheel related to interaction with lunar soil is of great importance when it comes to optimization of rover's configuration. In this study, in order to investigate the motion performance of lunar rover's wheel on Korean Lunar Soil Simulant (KLS-1), a single wheel testbed was developed and used to carry out a series of experiments with two kinds of wheel with grousers and without grousers which were used to perform the experiments. Wheel traction performance was evaluated by using traction parameters such as drawbar pull, torque and sinkage correlated with slip ratio. The results showed that the single wheel testbed was suitable for evaluation of the performance of wheel and rover wheel with grousers which was likely to have higher traction performance than that without grousers in Korean Lunar soil simulant. The experimental results could be utilized in verification of the optimum wheel design and effectiveness of wheel traction for Korean lunar rover.

• The Journal of Korean Physical Therapy
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• v.17 no.4
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• pp.537-557
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• 2005

The purpose of this study was to investigate the effect of pelvic traction and muscle energy technique(MET) for hemiplegic patients on static standing balance. The scale for static standing balance is measured by using mean balance(%), frequence(Hz), sway area($mm^2$), sway path(mm), max sway velocity(mm/s), ant/post sway angle($^{\circ}$), lateral sway angle($^{\circ}$), sway number, change of pelvic height is measured in relation to the height of ASIS and PSIS. The subjects of this study were thirty hemiplegic patients: 15men and 15 women, with an average ages of 50.80 years. The thirty subjects were divided into 3 group of 10 at random ; ten subjects had pelvic traction after bobath therapy (the pelvic traction group), ten subjects had muscle energy technique after bobath therapy (the MET group), and ten subjects had only bobath therapy (the control group). Static standing balance was measured using BPM (balance performance monitor; data print software version 5.3), pelvic height was measured using height measuring with an adjustable horizontal arm. In order to assure the statistical significant of the result, an one-way ANOVA, the paired t-test, and a person's correlation were applied at the.05 level of significance. The results of this study were as follows: 1) The change in pelvic height were statistically significant between the pelvic traction group, the MET group and the control group on pre-treatment and post-treatment(p<.05). 2) The change in affected and non-affected on weight bearing were not statistically significant between the pelvic traction group, the MET group and the control group on pre-treatment and post-treatment(p>.05). 3) The change in frequency were statistically significant between the MET group, the control group and the pelvic traction group on pre-treatment and post-treatment(p<.05). 4) The change in sway area were statistically significant between the MET group, the control group and the pelvic traction group on pre-treatment and post-treatment(p<.05). 5) The change in sway pa1h were statistically significant between the pelvic traction group, the MET group and the control group on pre-treatment and post-treatment(p<.05). 6) The change in max sway velocity were statistically significant between the pelvic traction group, the MET group and the control group on pre-treatment and post-treatment(p<.05). 7) The change in ant/post sway angle were statistically significant between the pelvic traction group, the MET group and the control group on pre-treatment and post-treatment(p<.05). 8) The change in lateral sway angle were statistically significant between the pelvic traction group, the MET group and the control group on pre-treatment and post-treatment(p<.05). 9) The change in sway number were statistically significant between the pelvic traction group, the MET group and the control group on pre-treatment and post-treatment(p<.05). In conclusion, there was a difference between the experimental group and the control group. In the future, we have to study continuously about pelvic traction and muscle energy technique in hemiplegic patients.

• Journal of IKEEE
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• v.26 no.4
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• pp.671-680
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• 2022

In this paper, A 200kW traction motor driver that covers most of the traction motor specification of commercial electric vehicles (EV) is developed. In order to achieve high efficiency and high power density, a next-generation power semiconductors (Silicon carbide, SiC) are applied instead of power semiconductor(IGBT), which is Si based. Through hardware analysis for optimal use of SiC, expected efficiency and heat dissipation characteristics are obtained. A vector control algorithm for an IPMSM (Interior permanent magnet synchronous motor), which is mostly used in EV(Electric vehicle) traction motor, is implemented using DSP (Digital signal processor). In this paper, a prototype traction motor driver based SiC for EV is designed and manufactured, and its performance is verified through experiments.

• Proceedings of the KIPE Conference
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• 1999.07a
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• pp.118-121
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• 1999

In this pager, we studies IGBT VVVF inverter for 1C4M propulsion system of railway traction. This inverter is consisted in inverter stack, DB unit, and control unit. To prove performance of inverter carry out combine test. This test verifies that performance of inverter is excellent.

• Proceedings of the KIEE Conference
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• 2002.11d
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• pp.372-374
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• 2002

In this paper, we studied for performance of traction and braking for on-line test and evaluation of korean high speed rail vehicle. It is composed of 6 DAMs(Data Acquisition Modules), 2 monitoring modules and 1 main computer. The software should set and control the hardware of the measuring system, perform the analysis and calculation of measuring data and interface between users and the measuring system. As a result, It has been shown a good performance of traction and braking for test vehicle.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.55 no.2
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• pp.62-66
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• 2006

This thesis focuses on the design of control schemes for highly efficient BLDC motor drive applications using drives with output capacity of 1Hp. The control system was designed and implemented on a PIC micro-controller and applied to an electric vehicle as a viable replacement to the existing a high phase induction motor that is currently being used for these low cost, small traction drive applications. This paper for the brushless drive research has shown the optimization of the drive system for improved drive design and switching techniques that can improve the entire drive system efficiency for electric vehicle both large and small traction applications using sinusoidal PWM techniques for synthesizing the AC waveforms needed to control these traction drives. In addition, Numerical simulation was conducted to evaluate the performance of designed BLDC Motor using MotorPro simulator.

• Journal of Electrical Engineering and Technology
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• v.12 no.6
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• pp.2411-2418
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• 2017

This study focuses on the effects of using open stator slots in an interior permanent magnet traction motor with a magnetic slot wedge design in order to increase the power density at its base speed. In addition, such a configuration reduces the torque ripple under field-weakening conditions. Five different wedge models were selected, each of which was evaluated using a finite element analysis (FEA). Based on the initial model, we designed magnetic slot wedges for maximum back-EMF and minimum cogging torque. In addition, the d-q axis inductance was slightly altered due to the magnetic slot wedges. Finally, we analyzed the performance of a traction machine under field weakening control. Moreover, we have outlined the requirements for an ideal magnetic slot wedge design.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.21 no.12
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• pp.1124-1129
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• 2008

The object of this paper is to acquire the data related to insulation evaluation of hybrid vehicle traction motors. We made a comparative analysis on Insulation Resistance (IR), Dielectric Absorption Ratio (DAR), and Polarization Index (PI) of the motor stators. The experiment was carried out according to IEEE Std. 43 and IEC 60085-1 for insulation resistance test standard of rotating machinery. Test voltage of 500 V was applied between a phase and the enclosure. The IR and the DAR of used motors were lower than those of new ones. The DAR and the PI were $0.92{\sim}1.02$ and $0.74{\sim}1.1$, respectively and the result did not meet the recommendation basis 2 for insulation level H. From the experimental results, we could prepare parameters and basis for insulation evaluation of the traction motor stator by the comparative analysis of short-time insulation resistance changes, DAR and PI.

• Journal of Power Electronics
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• v.16 no.2
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• pp.572-583
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• 2016

In view of the speed control characteristics of induction traction motors and the problems of direct torque control (DTC) algorithms in current applications, this paper presents a DTC algorithm characterized by a symmetrical polygon flux control and a closed loop power control in the constant-torque base speed region and constant-power field-weakening region of induction traction motors. This algorithm only needs to add a stator flux control algorithm to the traditional DTC structures. This has the benefit of simplicity, while maintaining the features of traditional algorithms such as a rapid dynamic response, uncomplicated control circuit, reduced dependence on motor parameters, etc. In addition, it obtains a smoother flux trajectory that is conducive to improvement of the harmonic elimination capability, the switching frequency utilization as well as the torque and power performance in the field-weakening region. The effectiveness and feasibility of this DTC algorithm are demonstrated by both theoretical analysis and experimental results.