• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.2203-2206
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• 2005

A load flow and short circuit fault simulation of AC electrified railway distribution systems is presented with DIgSILENT PowerFactory software. Load flow of electrified railways distribution system with concerning multi train lines and dynamic characteristics of train load is studied for different time laps. The dynamic characteristics of train load in starting and braking conditions with different starting and stopping times and its moving positions makes the load flow complicated so there is a great need in studying the effects of electrified railways on load flow. Short circuit fault transients is also studied and simulated for both power system or traction distribution system and their effects on the operation of the train sets is investigated.

• Journal of the Korea Institute of Military Science and Technology
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• v.25 no.5
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• pp.539-544
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• 2022

This research shows the test performance of a 6 kW-scale hybrid electric power system for the high endurance drone. The power system is composed of a two-stroke reciprocal engine, starter-generator and battery, and they are integrated as one power unit. The engine is designed to provide the house for holding the starter-generator at the end of a crankshaft in turn the engine and starter-generator can maintain the same speed during the operational period. In this way, the generated power is readily controlled by just manipulating an engine throttle movement. Moreover, the starter-generator can initiate an engine operation with an aid of battery power until the combustion process becomes stabilized. In consequence, integration mechanism between an engine and generator is simplified, which results in weight reduction achieved. The duty of back-up battery is to provide a starting power to generator via a system controller in addition to covering momentarily power shortage. Therefore, the electric power system is vindicated to provide 6 kW power through a ground test.

• Proceedings of the KIEE Conference
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• 1993.07b
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• pp.575-577
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• 1993

In this study, the reponse characteristic of the time-changing magnetic field measurement system by using the self-integrated magnetic sensor is investigated. The measurement system has the frequency bandwidth of 40[Hz]-50[kHz]. The time-changing magnetic fields generated by the operations of small-size electric machines are investigated. The magnetic field generated by the starting and/or the operation of electric appliances mainly includes the odd harmonics such as the third, the fifth, the seventh, and so on.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.21 no.1
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• pp.189-194
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• 2021

With the recent increase in the proportion of single-person households, starting in 2016, the domestic shared personnel mobility market such as electric kickboards and electric wheels has grown rapidly. Personal transportation means such as electric kickboards are power devices using electricity and are eco-friendly, lightweight, and do not occupy a separate parking space. Above all, it has the advantage of being convenient to travel short and medium distances, so it has been able to obtain a lot of demand from younger users who pursue reasonable consumption, and accordingly, the related market has grown rapidly. However, as absence of the charging station for electric kickboards, electric kickboards are left everywhere on the road, and are emerging as a threat to safety as well as aesthetics. Therefore, this paper aims to research and propose a new IoT management system for efficient recovery of shared electric kickboards. Through this system, it is expected that the high recovery rate of the electric kickboard can be maintained, and in conclusion, the safety of the user and the surrounding environment can be improved.

• 유체기계공업학회:학술대회논문집
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• 1999.12a
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• pp.291-300
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• 1999

Currently under development is an airborne auxiliary power unit with 100 Kw equivalent power, which is composed of a centrifugal compressor, a reverse annular combustor, and a radial turbine. Air-foil bearings are used in this power unit to eliminate the oil supplying system, which can reduce the system complexity and weight. The high speed generator is adopted as an electric power generation and engine starting system, which can also eliminate the reduction gear system. Not only electric power but also pneumatic power is provided by bleeding the compressed air This power unit is aimed for the multi-purpose use such as a primary power unit In the army weapon system, an auxiliary power and environmental control unit in a next-generation tank, and a smoke generating unit.

• Proceedings of the KIPE Conference
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• 2000.07a
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• pp.576-580
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• 2000

This paper describes about the field test of IGBT VVVF inverter for the propulsion system. The 1650kV class IGBT VVVF inverter has been developed. Therefore the field test is performed in SMG 6 Line to confirm its the reliability and performance. The train consists of 4M4T and the electrical equipment for field test are as follows : VVVF inverter 4 sets 16 traction motors and 3 SIVs The propulsion system which have the excellent acceleration/deceleration and the jerk chracteristics as well as starting ability on slope are taken through the field test.

• KEPCO Journal on Electric Power and Energy
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• v.3 no.1
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• pp.41-47
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• 2017

After $SF_6$, which is being used in power equipment as an insulating material, is classified as one of the 6 major greenhouse gases, the maintenance and the refinement of used $SF_6$ started to get attention. In regard to this, KEPCO Research Institute (KEPRI) is developing $SF_6$ recovery and refinement technology starting with establishing a comprehensive $SF_6$ analysis system. With the analysis system, qualitative and quantitative analyses of the purity and the impurities of $SF_6$ before and after recovery, and before and after refinement have been carried out. The analysis system is comprised of GC-DID (Gas Chromatograph -Discharge Ionization Detector) for trace impurities analysis, GC-TCD (Thermal Conductivity Detector) for analyses of $SF_6$ purity and major impurities concentration from several hundred ppm up to percent range, GC-MSD (Mass Selective Detector) for analyses of impurities not included in standard gas, FT-IR (Fourier Transform-Infrared) Spectrometer for analysis of HF and $SO_2$, and moisture analyzer for analysis of moisture below 100 ppm. With this analysis system, complete analysis method of $SF_6$ has been established. This analysis system is being used in the maintenance of power equipment and the development of $SF_6$ recovery and refinement technologies. In this paper, the analysis results of four samples - gas and liquid phase $SF_6$ samples from a $SF_6$ refinement system before and after refinement are presented.

• Proceedings of the KIEE Conference
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• 1995.07a
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• pp.9-11
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• 1995

In order to achieve a essential requirement for the driving system of electric vehicles, that is, starting pick-up ability, a wound-type induction motor with double-rotor structure is proposed. Slip Power Recovery system is adopted to improve the efficiency in the low speed range and to control speed of this system. Theoretical analysis and experimental results from 300[W] prototype motor is presented to verify the improvement of pick-up ability and high-efficiency driving characteristics through the wide speed range, especially under the low speed range.

• Transactions of the Korean Society of Automotive Engineers
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• v.24 no.6
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• pp.649-659
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• 2016

This paper describes control algorithm and control structure of vehicle control unit for range-extended electric vehicle equipped with engine-generator system, and specially presents methods which determine optimal operating points and decreases a vibration or a shock for operating the engine-generating system. The vehicle control algorithm is consisted of several parts which are sequence control, calculation of wheel demand torque, determination of operating points, and management of operating points and so vehicle controller has be made possible to efficiently manage calibration parameters. The control algorithm is evaluated by driving test modes, launching performance and operating engine-generator system and so on. In conclusion, this paper present methods for extending a mileage, improving a launching performance and reducing vibration or shock when the engine-generating system is starting or is stopping.

• Journal of the Korea Convergence Society
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• v.12 no.10
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• pp.211-218
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• 2021

A recent spread of personal mobility devices such as electric kickboards has brought about a rapid increase in accident cases. Such vehicles are susceptible to falling accidents due to their low dynamic stability and lack of outer protection chassis. This paper presents the development of an automatic emergency braking system and a safe starting system as driving assistance devices for electric kickboards. The braking system employed artificial intelligence to detect nearby threaening objects. The starting system was developed to disable powder to the motor until when the driver's boarding is confirmed. This study is meaningful in that it proposes the convergence technology of advanced driver assistance systems specialized for personal mobility devices.