• Proceedings of the KIEE Conference
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• 대한전기학회 1994년도 하계학술대회 논문집 A
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• pp.415-418
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• 1994

In this paper, a parallel operation of two single-phase GTO PWM converters is presented. The current ripples on the primary side of the transformer can be much reduced by shifting one modulation period from the other one by a half period. Also, a simple power factor control scheme is presented by which the reactive component of converter input current is controlled. Simulations and experimental results for a laboratory system confirm the validity of the purposed algorithm.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• 제18권5호
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• pp.140-145
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• 2004

In this paper, we analyzed the operational characteristics of the modified DC reactor type SFCL and derived the design condition of superconducting coil to be operated properly as power source as well as fault current limiter. It was confirmed through the simulation for the operation of this SFCL that the modified DC reactor type SFCL could be operated as both the uninterruptible power supply and the fault current limiter by controlling the duty ratio of GTO thyristor bridge.

• Proceedings of the KIEE Conference
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• 대한전기학회 1992년도 하계학술대회 논문집 B
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• pp.1009-1011
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• 1992

This paper discribes a study on the bridge type power converter for laser high power generator with high frequency and high voltage using MOS-GTO. This converter effectively makes the best of the high frequency HV transformer and input-side equivalent parasitic capacitance of high voltage feeding cable in place of DC output smoothing filter. The cicuit configuration and performance are discussed and design criteria are given. The prototype rated of 10 KW, 100 KHz is implemented and experimental results are given.

• The Transactions of The Korean Institute of Electrical Engineers
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• 제56권5호
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• pp.829-833
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• 2007

In this paper, the RCF method is applied to analyze small signal stability of power systems including GTO controlled parallel FACTS equipments such as STATCOM. To apply the RCF method in power system small signal stability problems, state transition equations of generator, controllers and STATCOM are presented. In eigenvalue analysis of power systems, STATCOM is modelled as the equivalents voltage source model and the PWM switching circuit model. As a result of simulation, the RCF method is very powerful to calculate the oscillation modes exactly after the switching operations, and useful to analyze the small signal stability of power systems with periodically operated switching devices such as STATCOM.

• The Transactions of the Korean Institute of Electrical Engineers
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• 제43권2호
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• pp.244-250
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• 1994

This paper presents the design of a new turn-off gate drive circuit for GTO which can accomplish faster turn-off switching. The major disadvantage of the conventional turn-off gate drive technique is that it has a difficulty in realizing high negative diS1GQT/dt because of VS1RGM(maximum reverse gate voltage) and stray inductances of turn-off gate drive circuit[1~2]. The new trun-off gate drive technique can overcome this problem by adding another turn-off gate drive circuit to the conventional turn-off gate drive circuit. Simulation and experimental results of the new turn-off gate drive circuit in conjunction with chopper circuit verify a faster turn-off switching performance.

• Proceedings of the KIEE Conference
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 A
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• pp.230-231
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• 2006

In this paper, the RCF(Resistive Companion Form) analysis method is used to analyze small signal stability of power systems including GTO controlled FACTS equipment such as SSSC. To apply the RCF analysis method in power system small signal stability problems, state transition equations of power system equipments and power systems with SSSC are presented. In eigenvalue analysis of power systems by the RCF analysis method, SSSC is modelled into the equivalents voltage source model and PWM switching circuit model. As a result of simulation, the RCF method is very powerful to calculate the oscillation modes exactly after the switching operations, and useful to analyze the small signal stability of power systems with periodic switching device such as SSSC.

• Proceedings of the KIEE Conference
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• 대한전기학회 1999년도 하계학술대회 논문집 F
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• pp.2628-2631
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• 1999

One of the limitations of conventional ASCI for high-power induction motor drives is the high voltage that is produced in the commutation capacitors during the current commutation from one phase to another. Since the capacitor voltage appears directly on the semiconductor components, it increases their required voltage ratings. Also, the high-voltage spikes generated at the motor terminals may cause damage to the motor insulation. And we investigated how de input power is increased or decreased according to size of de link inductor. In this paper, de link inductor and clamping capacitor in GTO inverter suitable for induction motor drives are propose through experiment.

• Proceedings of the KIEE Conference
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• 대한전기학회 1993년도 정기총회 및 추계학술대회 논문집 학회본부
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• pp.117-120
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• 1993

In this paper, a novel DC link voltage control scheme for a single-phase PWM converter is proposed. The main idea of the control scheme is eliminating the effect of dc link voltage harmonics by using power balance of input side and output side. With the proposed strategy, faster transient response than that of conventional method using low-pass filter can be obtained. In addition, a half period current control, based at equal switching frequency, is proposed. The validity of the proposed scheme is verified by simulation results for GTO PWM converter system.

• Proceedings of the KSR Conference
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• 한국철도학회 2007년도 추계학술대회 논문집
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• pp.1438-1444
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• 2007

Standard Gate Turn Off (GTO) Thyristor drive technology results in inhomogeneous turn-on and turn-off transients which in turn needs costly dv/dt and di/dt snubber circuits. Added to this GTO is bulky in size, needs external cooling, slower switching time etc. The development of high voltage Insulated Gate Bipolar Transistor (IGBT) have given new device advantage in the areas where they compete with conventional GTO technology. Indian Railway has developed first IGBT based traction converter and was commissioned in November 2006. Some of the supremacy of IGBT are smaller in size, no external cooling is required, built in power supply which enhances reliability, lower switching losses which leads to higher efficiency, reduced gate drive, high frequency operation in real time etc. These advantages are highlighted along with IGBT Traction system in operation.

• Proceedings of the KIEE Conference
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• 대한전기학회 1995년도 추계학술대회 논문집 학회본부
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• pp.250-254
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• 1995

The proposed GTO converter system has the better harmonic characteristics, especially, in the distortion factor (55%), than the conventional 12-step converter system. The improved harmonic characteristics was achieved through the unsymmetrical angle control of the each converter. In addition, the proposed system can save the cost (20%), spase (50%) and weigh (8%). The proposed system was studied in simulation and experiment.