• Proceedings of the KIEE Conference
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• 1997.11a
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• pp.524-526
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• 1997

High speed DC circuit breakers (HSCB) are indispensable for protection of DC electric subway substations from fault current. However, the HSCB has mechanical contact to wear, which requires rather frequent maintenance, we have succeeded in developing and manufacturing a GTO DC circuit breaker using GTOs and ZnO varistors. In this paper, we describes the outline of the system itself, its characteristics and test data.

• Proceedings of the KIEE Conference
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• 1998.07f
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• pp.2169-2171
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• 1998

In order to improved the three phase GTO CSI of high efficiency IM drive with low loss commutation and snubber energy, we studied the energy recovery circuit to recover stored energy in clamping capacitor, dc link inductor and snubber capacitor, used an induction motor as the load of inverter. Specially, we investigated how dc input power is increased or decreased according to size of dc link inductor. The validity of this system is proved through experiment.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.05c
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• pp.57-60
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• 2004

본 논문은 전원단과 부하단사이에 GTO 사이리스터 브리지가 설치된 단상 DC 리액터타입을 적용한 고온초전도 사고전류제한기 동작특성에 대해 분석하였다. GTO 사이리스터 브리지가 설치된 DC 리액터 타입 FCL(Fault Current Limiter)은 평상시에 초전도코일에 전기에너지를 저장한다. 전원단의 사고로 인해 전력 공급이 중단되었을 경우 FCL은 부하에 저장된 에너지를 공급할 수 있을 뿐 아니라 부하단 사고로 인한 사고전류 제한기능을 수행하게 되는데 이와 같은 동작은 GTO 사이리스터를 제어함으로서 가능해진다.

• Proceedings of the KIEE Conference
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• 2004.05b
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• pp.210-212
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• 2004

본 논문은 전원단과 부하단사이에 GTO 사이리스터 브리지가 설치된 단상 DC 리액터타입을 적용한 고온초전도 사고전류제한기 동작특성에 대해 분석하였다. GTO 사이리스터 브리지가 설치된 DC 리액터 타입 FCL(Fault Current Limiter)은 평상시에 초전도코일에 전기에너지를 저장한다. 전원단의 사고로 인해 전력공급이 중단되었을 경우 FCL은 부하에 저장된 에너지를 공급할 수 있을 뿐 아니라 부하단 사고로 인한 사고전류 제한기능을 수행하게 되는데 이와 같은 동작은 GTO 사이리스터를 제어함으로서 가능해진다.

• Proceedings of the KIEE Conference
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• 2001.10a
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• pp.97-99
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• 2001

본 논문은 전원단과 부하단사이에 GTO 사이리스터 브리지가 설치된 단상 DC 리액터타입을 적용한 고온초전도 사고전류제한기 동작특성에 대해 분석하였다. GTO 사이리스터 브리지가 설치된 DC 리액터 타입 FCL(FAULT CURRENT LIMITER)은 평상시에 초전도코일에 전기에너지를 저장한다. 전원단의 사고로 인해 전력공급이 중단되었을 경우 FCL은 부하에 저장된 에너지를 공급할 수 있을 뿐 아니라 부하단 사고로 인한 사고전류 제한기능을 수행하게 되는데 이와 같은 동작은 GTO 사이리스터를 제어함으로서 가능해진다.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.36 no.5
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• pp.328-338
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• 1987

A New CSI which is belived to be much advantageous than ASCI is proposed. The new CSI operates in a much wider frequency range with much lower voltage stresses on the motor terminals and power devices compared with ASCI. Simulation results show that the new CSI is about factor of four times superior to ASCI in operating frequency range or in voltage stress. The exterimental results are shown for a 5HP induction motor.

• Proceedings of the KIEE Conference
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• 1988.07a
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• pp.130-132
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• 1988

A usual line-commutated thyristor inverter with additional onebypass GTO is presented. With the added one bypass GTO, the extended commutating area is investigation and restrictions for the PWM to reduce the high frequency component of line current are shown.

• Proceedings of the KIEE Conference
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• 1997.11a
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• pp.500-504
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• 1997

Current source inverter drives of auto sequentially commutated type are very popular in high power applications, because of simple power circuit configuration with four quadrant operation. But the six-step current output create harmonic problems and the input power factor of such a drive is not always good. In this respect pulse width modulated drives using gate turn off thyristors ( GTO ) are finding application, especially in traction drives. However the switching and snubber loses of a GTO do not permit the inverter switching frequency go beyond a few hundred hertz.This will again introduce low frequency harmonic problems. Multi level inverters of the 3-level and 5-level can be considered as an alternative to overcome the low switching frequency harmonic problem of the 2-level GTO inverters. But with multi level inverters the complexity of the power circuit increases. In this paper a combination of multi level ( 2-level and 3-level ) inverters and multi phase induction motor ( 3-phase and 6-phase) configurations are presented for high power VSI drives for traction applications with reduced inverter switching frequency requirements coupled with reduced voltage rating for the power switch.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.05c
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• pp.213-216
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• 2003

Recently a new high power device GCT (Gate Commutated Turn-off) thyristor has been successfully introduced to high power converting application areas. GCT thyristor has a quite different turn-off mechanism to the GTO thyristor. All main current during turn-off operation is commutated to the gate. Therefore, IGCT thyristor has many superior characteristics compared with GTO thyristor; especially, snubberless tum-off capacibility and higher turn-on capacibility. The basic structure of the GeT thyristor is same as that of the GTO thyristor. This makes the blocking voltage higher and controllable on-state current higher. The turn-off characteristic of the GCT thyristor is influenced by the minority carrier lifetime and the performance of the gate drive unit. In this paper, we present turn-off characteristics of the 2.5kV PT(Punch-Through) type GCT as a function of the minority carrier lifetime and variation of the doping profile shape of p-base region.

• NEWSLETTER 전기공업
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• no.96-11 s.156
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• pp.23-52
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• 1996