• Proceedings of the KIEE Conference
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• 1986.07a
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• pp.574-576
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• 1986

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.10
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• pp.1442-1447
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• 2012

In this paper, direct power control system for three-phase PWM AC/DC converter without the source voltage sensors is proposed. The sinusoidal input current and unity effective power factor are realised based on the estimated flux in the observer. Both active and reactive power calculated using estimated flux. The estimation of flux is performed based on the Reduced-order flux observer using the actual currents and the command control voltage. The source voltage sensors are replaced by a flux estimator. The active and reactive powers estimation are performed based on the estimated flux and Phase anble. The proposed algorithm is verified through simulation and experiment.

• The Transactions of the Korean Institute of Power Electronics
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• v.2 no.3
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• pp.26-36
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• 1997

An single stage AC/DC converter based on half bridge topology suitable for low power level applications is proposed. The proposed converter has high power factor, low harmonic distortion, and tight output regulations. Asymmetrical control and synchronous rectification are adopted to reduce the switching loss and rectification loss, respectively. The modelling employing average modelling method and detailed analysis are performed to derive the design equations. According to these design equations, a prototype converter has been designed and experimented. This prototype meets the IEC 555-2 regulations with near unity power factor and high efficiency.

• Proceedings of the KIEE Conference
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• 1999.07f
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• pp.2653-2655
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• 1999

A technique to suppress the low frequency ripple voltage of the DC output voltage in three-phase buck diode rectifiers is presented. A pulse frequency modulation method is employed to regulate the output voltage of the rectifier and guarantee zero-current switching of the switch over the wide operating range. The pulse frequency control method used in this paper shows generally good performance such as low THD of the input line current and unity power factor. In addition, the pulse frequency method can be effectively used to suppress the low frequency voltage ripple appeared in the dc output voltage. The proposed technique illustrates its validity and effectiveness through the respective simulations and experiments.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.10
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• pp.1467-1472
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• 2014

This paper study on powering characteristic on speed variation of propulsion system of prototype 8200 electric locomotive propulsion system through simulation modeling. For this purpose, it being applied in the field of railway IGBT (Insulated Gate Bipolar Transistor) elements are used. Converter was performed PLL (Phase-Locked Loop) control method that is used to control the phase and output voltage, and the inverter was carried an indirect vector control method to control the speed of traction motor. The results of simulation by modeling and experimental unit, we was confirmed that converter is controlled a unity power factor and output voltage by reference voltage. Also traction motor was controlled by indirect vector control and SVPWM inverter switching method very well.

• Proceedings of the KIEE Conference
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• 1995.11a
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• pp.255-257
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• 1995

Many new electronic products are required to have a unity power factor and a distortion free input current waveform. In this parer, a high performance single phase AC/DC converter with input power factor correction is proposed. And each parameters are determined. Proposed control strategy has many advantages which include two Quadrants operation, simplified control circuit, high performance features and continuous Input current. The experimental results are included to verify the validity of this approach.

• Journal of international Conference on Electrical Machines and Systems
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• v.1 no.4
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• pp.472-476
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• 2012

In this paper, a sensorless control scheme for a three-phase bi-directional voltage-type PWM rectifier in wind power generation system that operates without the input AC voltage sensors (generator side) is described. The basic principles and classification of the PWM rectifier are analyzed, and then the three-phase mathematical model of the input AC voltage sensorless PWM rectifier control system is established. The proposed scheme has been developed in order to lower the cost of the three-phase PWM rectifier but still achieve excellent output voltage regulation, limited current harmonic content, and unity input power factor.

• Proceedings of the KIEE Conference
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• 1997.07f
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• pp.1993-1998
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• 1997

This paper presentes a novel single-phase unity power factor rectifer, which features Critical Conduction Mode and ZVS. The reduced conduction losses are achieved by the employment of a single converter instead of the typical configuration composed of a front end rectifier followed by a boost converter. Theoretical analysis, a design example and experimental results of a 300 converter with $127V_{rms}$ input voltage and 400 VDC output voltage are presented.

• Proceedings of the KIPE Conference
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• 2004.07b
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• pp.670-672
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• 2004

In this paper, single phase boost converter with low current harmonic components and high power factor are proposed. A single-phase half-bridge rectifier based on a neutral point switch clamped scheme is proposed to draw a nearly unity power factor and regulate the DC link voltage. Three power switches are employed in the proposed rectifier. This rectifier is controlled to generate a bipolar or unipolar PWM voltage waveform on the AC side. The proposed converter is implemented by a digital signal processor.

• Proceedings of the KIEE Conference
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• 1997.07a
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• pp.322-325
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• 1997

Concerns for wind energy as alternative energy have been highly increased. In this paper, the mechanism between mechanical wind turbine and power generating system is presented to specify the relationship of the energy transfer. Grid-connected DFIG could achieve unity leading power factor, in addition to variable speed operation at the wide sub-synchronous and super-synchronous shaft speed range and also its independent control of torque and reactive power is possible.