• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.11
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• pp.1919-1924
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• 2016

In general, Diode rectifier has been applied to DC traction power supply system. Diode has some characteristics which is voltage drop in inverse proportion of load because of non-controlled switch, and cannot flow a current in reverse bias. So, voltage drop occurs frequently, and regenerated power cannot use in substation. The PWM rectifier is able to control output voltage constantly to reduce voltage drop and to use regeneration power without additional inverter. This paper proposes analysis algorithm for DC traction power supply system with PWM rectifier.

• Journal of the Korean Society for Precision Engineering
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• v.14 no.3
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• pp.35-40
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• 1997

The traction drive has advantages of having high efficiency and transmitting the power without blacklash. However, when high ratio of speed reduction is desired, excessively large size is required. In this study, a new type of traction drive is invented, designed and manufactured so that stable speed reduction mech- anisms are available by adopting a cross roller type drive. It has a simple structure, but produces high speed reduction ratio. Power loss is observed, and also, driving torque and torque transfer efficiency are calculated. Pre-loads are needed in order that the traction drive transfers power without slipping, and the spacer is enlarged due to the pre-loading. After all, the key point of pre-load mechanism is that the spacer's diameter becomes larger as pre-loads are applied.

• Journal of Drive and Control
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• v.20 no.1
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• pp.16-26
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• 2023

Although the upland field area of Korea is high as 44.8%, the platform optimized for the upland field is insufficient. It is necessary to develop an optimized platform for the upland field because the upland field environment is an irregular environment with many slopes. In addition, due to the characteristic of agricultural operations, the traction power and torque of the platform have to be sufficient. Therefore, in this study, a simulation model that can predict the traction power and driving torque of a crawler-type platform for the upland field was developed and validated using the specifications of the crawler platform. The simulation model was developed using Amesim (19.1, Siemens, Germany). The development of the model was conducted using the specifications of the platform. A measurement system was developed to validate the simulation model. The traction power data of the simulation model was validated with the traction force and vehicle speed. The driving torque data of the simulation model was validated with the torque of the sprocket on the crawler system. As a result of the analysis, the error between measurement and simulation results occurred within 10%, and it was determined that the traction power and driving torque prediction of the crawler platform using this model was possible.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.52 no.11
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• pp.639-646
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• 2003

Nowadays traction motors in the urban rail transit vehicle are controlled by VVVF inverter and have capability of regenerative braking. The algorithms to deal with the regenerating vehicle in simulation for the DC traction power supply is introduced in this paper. Substations have to be separated from the system to represent reverse biased rectifiers in substations. The model of the trains in regenerative braking has to be changed from the ideal current source to the constant voltage source since the train input voltage has to be controlled below the certain train maximum voltage. Some mismatches are unevitable because the constraint of the regenerated power can not be imposed with the constant voltage source. The mismatches represent the unused regenerated power. A computer program is developed to verify the validity of the algorithm. The test run result shows the program behaves as it is expected and proves the algorithm's validity.

• Journal of Electrical Engineering and Technology
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• v.7 no.2
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• pp.200-206
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• 2012

In order to develop a deep-underground great train express (GTX) in South Korea, the specifications decision and development of a traction control system (including an inverter and a traction motor), which considers a variety of route conditions, must be advanced. In this study, we examined the running resistance properties of a high-speed traction system based on a variety of tunnel types and vehicle organization methods. Then, we studied the power requirements necessary for the traction motor to maintain balanced speed in the high-speed traction system. From this, we determined the design criteria for the development of a high-speed traction system for use in the deep-underground GTX. Finally, we designed a linear induction motor (LIM) for a propulsion system, and we used the finite element method (FEM) to analyze its performance as it travelled through deep-underground tunnels.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2007.05a
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• pp.28-32
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• 2007

In this paper, a unified regenerative inverter and control algorithm are proposed in order to perform regenerative action and active power filter action. While the regenerative mode of traction, it works as regenerative inverter to reduce a excessive power of DC bus line and the powering mode of the traction, it works as active power filter to compensate ac current distortion, power factor, and voltage unbalance. In the paper, a regeneration inverter used PWM DC/AC inverter algorithm. And an active power filter used p-q theory. We are carrying out a mode analysis of DC traction system similar to actual system with MG-set and experimenting with prototype model. Through the simulation and experiment, we were proving the regeneration inverter operation which suggested in this paper.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.53 no.10
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• pp.602-609
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• 2004

This paper presents electro-magnetic characteristics of an Interior type Permanent Magnet Synchronous Motor (IPMSM) for traction applications. The importance of instantaneous electric propulsion capability for high torque has been highlighted in the present study and thus parametric analysis is performed by Finite Element Method (FEM). The paper provides analytical & experimental results, which demonstrate a performance of the studied traction motor The goal of this paper is to present a maximum power performance for traction motor which works extension of its own rated power. Experimental results meet well with FEM analysis of traction motor owing to inductance difference.

• Journal of Electrical Engineering and Technology
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• v.8 no.1
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• pp.118-123
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• 2013

This paper presents performance comparison between concentrated winding and distributed winding of IPMSM (Interior Permanent Magnet Synchronous Motors) which is recently used for light-weight railway applications. Motors are designed on various schemes and analyzed by using FEM (Finite Element Method) instead of EMCNM (Equivalent Magnetic Circuit Network Method) in order to take into account saturation and non-linear magnetic property. The overall performance such as torque, torque ripple, losses, demagnetization, efficiency, power density and so on are investigated in detail at the rated and maximum operating speed. The results of the analysis found that both concentrated and distributed winding IPMSMs are promising candidates for high power railway traction motor.

• Proceedings of the KSR Conference
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• 2007.05a
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• pp.804-808
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• 2007

when electric traction system used DC 1500V runs on decline of rail road track and slows down, Dc voltage goes beyond regular voltage. In this case extra power is forcibly wasted by resister because rectifier of substation and electric train including power converter and so on are out of order. This paper described a DC electric railway system, which can generate the excessive DC power form DC bus line to AC source in substation for traction system. The proposed regeneration inverter system for DC traction can be used as both an inverter and an active power filter(APF). As a regeneration inverter mode, it can recycle regenerative energy caused by decelerating tractions and as an active power filter mode, it can compensate for harmonic distortion produced by the rectifier substation. In addition, electric traction system products harmonic current and voltage distortion and reactive power because power converter is used so regeneration inverter normally runs such as active power filter(APF) for improving power quality. From the viewpoint of both power capacity and switching losses, the system is designed on the basis of three phase PWM inverters and composed of parallel inverters, output transformers, and an LCL filter.

• Advances in aircraft and spacecraft science
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• v.4 no.6
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• pp.651-677
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• 2017

For the past ten years' efforts have been made to introduce environmentally-friendly "green" electric-taxi and maneuvering airplane systems. The stated purpose of e-taxi systems is to reduce the taxiing fuel expenses, expedite pushback procedures, reduce gate congestion, reduce ground crew involvement, and reduce noise and air pollution levels at large airports. Airplane-based autonomous traction electric motors receive power from airplane's APU(s) possibly supplemented by onboard batteries. Using additional battery energy storages ads significant inert weight. Systems utilizing nose-gear traction alone are often traction-limited posing serious dispatch problems that could disrupt airport operations. Existing APU capacities are insufficient to deliver power for tractive taxiing while also providing for power off-takes. In order to perform comparative and objective analysis of taxi tractive requirements a "standard" taxiing cycle has been proposed. An analysis of reasonably expected tractive resistances has to account for steepest taxiway and runway slopes, taxiing into strong headwind, minimum required coasting speeds, and minimum acceptable acceleration requirements due to runway incursions issues. A mathematical model of tractive resistances was developed and was tested using six different production airplanes all at the maximum taxi/ramp weights. The model estimates the tractive force, energy, average and peak power requirements. It has been estimated that required maximum net tractive force should be 10% to 15% of the taxi weight for safe and expeditious airport movements. Hence, airplanes can be dispatched to move independently if the operational tractive taxi coefficient is 0.1 or higher.