• The Transactions of the Korean Institute of Power Electronics
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• v.8 no.3
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• pp.239-246
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• 2003

Brushless D.C. Motor is widely used for industrial application because of high efficiency and high power density. Especially, in home appliance, BLDCM is very useful due to high control performance and low acoustic noise. In this paper, BLDCM and its controller are designed and developed for tread mill application. With the restricted stator structure, permanent magnet rotor is designed for manufacturing and cost effectiveness using CAD and FEM analysis. A ferrite magnetic material is used as a rotor magnet for the cost and temperature advantages. For a stable operation of tread mill, over current and temperature can be detected and protected. The designed BLDCM and its controller was verified by the experimental results.

• The Transactions of the Korean Institute of Power Electronics
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• v.8 no.6
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• pp.534-542
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• 2003

Small electric motors in an automobile perform various tasks such as engine cooling, pumping, HVAC etc. At present, most of them are DC motors supplied by 12V or 24V batteries. However, DC motors suffer from low efficiency, life cycles and reliability. Therefore, there is a growing interest in substituting DC motors for advanced at motors including switched reluctance motors(SRM). Although there are several other forms SRM convertors, they are either unsatisfactory to the control performance or unsuitable for the 12V battery source. Especially, a conventional asymmetric converter of SRM provides the best flexible and effective control to the current waveform of SRM, but it has the most switches and produces conducting voltage drops across two power switches during SRM operation. For automotive applications with a 12V battery source, this circuit is inadequate. For considering the requirement for effective operation and simple structure of converter in the limited internal circumstance of automobiles, the author inclines toward selecting Modified C-dump converter and Energy efficient c-dump converter.

• KIPS Transactions on Computer and Communication Systems
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• v.8 no.3
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• pp.57-64
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• 2019

In this paper, an efficient prediction-based parallel simulation method using spatially partial simulation strategy is proposed for improving both the performance of the event-driven gate-level timing simulation and the debugging efficiency. The proposed method quickly generates the prediction data on-the-fly, but still accurately for the input values and output values of parallel event-driven local simulations by applying the strategy to the simulation at the higher abstraction level. For those six designs which had used for the performance evaluation of the proposed strategy, our method had shown about 3.7x improvement over the most general sequential event-driven gate-level timing simulation, 9.7x improvement over the commercial multi-core based parallel event-driven gate-level timing simulation, and 2.7x improvement over the best of previous prediction-based parallel simulation results, on average.

• Korean Chemical Engineering Research
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• v.61 no.2
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• pp.202-207
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• 2023

In the case of driving water electrolysis by receiving surplus electricity from solar and wind power generation, operation and stopping must be repeated according to weather fluctuations. When the PEMWE(Polymer Electrolyte Membrane Water Electrolysis) is driven and stopped, the PEM fuel cell is in the same state as the PEM fuel cell due to the residual hydrogen and oxygen, and the high potential of the water electrolysis formed during operation is highly likely to cause degradation of the electrode and membrane even during stopping. In this study, in order to check how much degradation of the electrode and membrane progresses during the repeated driving/shutdown process of PEM water electrolysis, the performance decrease was measured by changing the number of driving/shutdown for 144 hours. Changes in electrode catalyst active area, hydrogen permeability and fluorine emision rate of membranes were analyzed to measure changes in the properties of electrodes and polymer membranes. Overall, the PEMWE performance decreased as the number of stops increased. When stopped 5 times in 144 hours, the IrO_x catalyst activity decreased by more than 30%, and the hydrogen permeability increased by 80%, confirming that both the electrode and the membrane were deteriorated.

• Journal of the Korean Geotechnical Society
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• v.34 no.6
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• pp.49-59
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• 2018

When a tracked vehicle travels off-road, shearing action and ground sinkage occur on the soil-track interface and severely affect tractive performance of the tracked vehicle. Especially, the ground sinkage, which is induced by vehicle's weight (hereinafter referred to as static sinkage) and longitudinal forces in the direction of travel producing slip (hereinafter referred to as slip sinkage), develops soil resistance, directly restricting the tractive performance of an off-road tracked vehicle. Thus, to assess the tractive performance of an off-road tracked vehicle, it is imperative to take both of static sinkage and slip sinkage into consideration. In this research, a series of model track experiments was conducted to investigate the slip sinkage which has not been clarified. Experiment results showed that the slip sinkage increased with increasing the slip ratio, but the increasing rate gradually decreased. Also, the slip sinkage was found to increase as relative density of soil decreased and imposed vertical load increased. From the experiment results, the normalized slip sinkage defined as slip sinkage to static sinkage calculated in the identical condition was investigated, and an empirical equation for the slip sinkage was developed in terms of slip ratio, which allows vehicle operators to predict the slip sinkage in a given soil and operating conditions.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.9
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• pp.24-30
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• 2009

This paper is proposed by fuzzy-based MPPT control of photovoltaic to drive induction motor. Design and prototype implement of a fuzzy logic(FL) controller for maximum power extraction from a stand-alon photovoltaic. Error and the change of error between maximum power and real power are used by input of fuzzy controller. Moreover, it output changing of voltage from control constant. The validity of this paper is proved by comparing maximum power point tracking and performance of motor drive through comparison fuzzy and PI of tradition method.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.34 no.12
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• pp.82-89
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• 2006

This paper describes the development results of electrohydraulic actuation system which performs the attitude and trajectory control of pitch and yaw motion using thrust vector control for high altitude launching vehicle operated in high vacuum environment (altitude higher than 300 km). As compared with electrohydraulic actuation system for low altitude launch vehicle which operated under altitude of stratosphere, the intensified development requirements, newly adopted design and manufacturing technologies, newly developed test equipments and test results are summarized in this paper. The development test and evaluation of actuation system were successfully accomplished. The developed actuation system will be installed on KSLV-I after finishing verification of interface and integration compatibility with related other systems.

• Proceedings of the KIEE Conference
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• 2006.07b
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• pp.1063-1064
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• 2006

본 논문에서는 곡선구간에서도 구동이 가능한 선형 전동기 제어방법을 제안하였다. 곡선구간에 선형 전동기를 적용할 때 전동기의 고정자와 이동자의 기구적인 위치 상호관계에 의해 각 상의 위상관계는 직선구간과 다르게 나타나게 된다. 따라서 직선구간의 제어방법을 그대로 곡선구간에 적용 시 제어성능이 저하되어 전동기의 발생추력은 감소하게 되고, 최악의 경우 곡선구간에서 구동이 불가능한 상태가 된다. 이러한 문제점을 개선하기 위하여 전동기의 역기전력 정보로부터 위상정보를 추출하여 곡선구간의 구동 제어알고리즘에 반영하였고, 제어시스템을 구성하여 곡선구간에서 전동기의 구동성능이 개선됨을 보인다.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.301-301
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• 2013

구동형 부품(Actuated component)중의 하나인 LeadScrew는 이송장치를 구성하는 핵심 부품으로 소재로는 탄소강, 합금강, 스테인레스강 등이 주로 이용된다. 다양한 IT기기의 정밀 이송 및 고속 구동에 사용되며, 제품의 성능을 결정하는 중요 핵심 부품으로 사용되고 있다. IT기기용 구동 요소 부품은 정밀 가공성의 제약으로 내식성이 우수한 스테인레스강 소재보다는 일반적으로 소재비가 저렴하고 가공성이 우수한 탄소강 소재를 사용하게 되며, 위 소재를 사용하면 대기중의 수분등에 의한 부식환경에서 쉽게 부식되어 부식방지를 위한 표면처리 기술개발이 필요하다.또한, 구동형 부품은 부품 상호간의 심한 마찰 등과 같은 가혹한 조건에 노출되어, 부품의 내마모성 및 표면 경도등을 향상시켜 부품의 수명을 연장하고자 한다. 그러기 위해 선 표면경도, 내마모성, 내식성 등의 다양한 기능이 요구되며, 성능을 만족시키기 위해서 열표면처리 공정을 확인하고자 한다.본 연구에서는 냉간압조용 강선인 SWCH계열 표면에 PECVD 장치로 플라즈마 질화공정을 이용하여 동일조건(압력, Gas flow, Power)하에서 $500{\sim}550^{\circ}C$의 온도 범위 내에서 30~300 min의 시간 조건으로 실험을 진행하였다. 위 시험편으로 XRD를 통해 각 플라즈마 질화 공정 조건에 따른 상 변화를 확인하였고, 염수분무테스트를 통해 내식성을 확인하였다. 표면경도 및 단면경도를 통한 실용질화층을 확인하고, 마모테스트를 통하여 마찰계수를 확인하여 표면경도, 내마모성, 내식성을 충족하는 공정에 대한 실험을 진행하였다.

• Proceedings of the KIPE Conference
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• 2011.11a
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• pp.241-242
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• 2011

교통 약자 승객의 편의성 증대, 도심의 매연 감소 및 온실가스 저감 등 대중 교통 선진화를 위해 친환경 초저상 전기버스의 개발이 필요하다. 초저상 전기버스는 초저상 액슬 일체형 휠모터 구동시스템을 탑재한 형태로 구현이 가능하며, 초저상 액슬 일체형 휠모터 구동시스템은 구동 모터를 액슬 허브에 일체화 시킴으로써 기존 구동시스템 대비 무게 및 사이즈가 대폭 줄어들고, 동력 전달 매커니즘을 획기적으로 개선하여 효율 향상 및 차량 연비 개선이 가능하다. 특히 바퀴 중심과 액슬 출력 중심에 단차를 둠으로써 차량의 전방 바닥 뿐만 아니라 후방바닥을 평평하게 유지할 수 있어 실내 공간이 획기적으로 개선되어 교통 약자를 포함한 승객의 편의성을 향상시킬 수 있다. 또한, 액슬 일체형 휠모터 구동시스템은 각 휠의 분산 구동이 가능하므로 동특성 및 구동제어성이 뛰어나고, ESP(Electronic Stability Program), VDC(Vehicle Dynamic Control) 등과 연계하여 통합적인 지능형 시스템을 구현할 수 있다. 액슬 일체형 휠모터 구동시스템은 휠모터와 감속기 및 휠모터제어기 등으로 구성되며, 본 논문에서는 초저상 액슬 일체형 구동시스템용 120kW급 휠모터 및 휠모터제어기의 개발 및 다이나모 환경에서 T-N 특성 및 최대 출력 시험, 효율 시험을 통해 전기버스 등 대형 차량(Heavy Duty Vehicle)에 적용 가능한 전기동력시스템의 성능을 확인하였다.