• 한국전기화학회:학술대회논문집
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• 2002.04a
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• pp.53-53
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• 2002

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.11a
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• pp.269-270
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• 2010

• Proceedings of the IEEK Conference
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• 2002.07a
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• pp.579-582
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• 2002

For train service, safety and reliability is an inevitable performance. Specially, turn-out system of the railway for safety because of actual part. Hence the management is strictly executed over turn-out systems of the railway. Also number of turn-out system need to monitoring systems. In this paper, the data multi-acquisition system for monitoring it is necessary to reduce the cost from the expensive characteristics of multi-monitoring system according to the importance of each data because this system is based on communication of one to several units. We designed the data multi-acquisition system using numbers of micro-controller and the experiment was executed to the actual turn-out system.

• Proceedings of the KIPE Conference
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• 2001.10a
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• pp.36-38
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• 2001

A basic structure of 2500V-4500V reverse-conducting GCT (RC-GCT) is given in this paper. The punch-through type (PT) is adopted for narrow N-base with high resistivity so that the fast turn-off and low on-state voltage can be achieved. The photo mask design was made upon the both turn-off performance and solution of separation between GCT and integrated freewheeling diode (FWD) part. The turn-on and turn-off characteristics for reserve-conducting gate commutated thyristors (RC-GCTs) were investigated by ISE simulation. Additionally, the local carrier lifetime control by proton irradiation was adopted so as not only to obtain the reduction of turn-off losses of GCT but also to reach a soft reverse recovering characteristics of FWD

• Proceedings of the KIPE Conference
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• 2001.10a
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• pp.414-417
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• 2001

SRG (Switched Reluctance Generator) have many advantages such as high efficiency, low cost, high-speed capability and robustness compared with characteristics of other machines. However, the control methods that have been adopted for SRGs are complicated. This paper proposes a simple control method using PID controller that only controls turn-off angles while keeping turn-on angles of SRG constant. The linear characteristics between the generated current and the turn-off angle can be used to control the turn-off angle for load variations. Since the reference current for generation can be produced from an error between the reference and the real voltage, it can be controlled to keep the output voltage constant. The proposed control method enhances the robustness of this system and simplifies the hardware and software by using only the voltage and speed sensors. The proposed method is verified by experimental results.

• Journal of Magnetics
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• v.17 no.1
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• pp.56-60
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• 2012

This paper presents an analysis and experiment of the flat coil actuator with shorted turn. The flat coil actuator is widely used in high precision products because it has no friction between the moving coil and the guide. A shorted turn and a center pole are placed into the flat coil actuator in order to reduce the inductance of the coil and improve the initial response when the actuator is voltage-driven. Enhanced dynamic performance of the flat coil actuator with shorted turn was demonstrated by simulation and experiment.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2004.08a
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• pp.378-382
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• 2004

A study was performed for verification of creation mechanism of turn down mark in thick plate. The roll mark was produced by plate bending when the front of plate was collided with roller table rolls. Various process conditions which are temperatur distribution along the thickness direction of plate, pass line, and reduction ration were investicated. These process conditions affected the amount of plate bending and were a major cause of turn down mark.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.1081-1086
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• 2008

During the manufacturing process of a propeller for a large scale commercial ships, several times of turn-over process should be required. Propeller turn-over is a indispensible process but not easy because of its heavy weight and complicate shape. Recently, we developed a new type of turn-over system for a large scale propeller. The system consists of turning roller devices, sliding transfer system, clamping devices and so on. In this paper, we described the design process which includes mechanical structure design, dynamic analysis and assembly with a laser tracker.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07a
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• pp.327-330
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• 2003

In this work, current-voltage characteristics with time of NPT(Non-PunchThrough) IGBT is proposed during turn-on and turn-off by using analytical method. From the results, power loss at turn-off dominates the total electrical loss with respect to that at turn-on. The results have been compared with those of PSPICE and show the identical trend of power loss with each other.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07a
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• pp.374-377
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• 2003

In this paper, turn on characteristics of (Punch-Through Insulated Gate Bipolar Transistor) PT-IGBT has been studied. Based on the transient power loss, turn on charges first base to collector capacitance. Furthermore we present the charge variation in the base including n+ buffer layer to express the transient turn-on characteristics of the device.