• Proceedings of the KIPE Conference
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• 2005.07a
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• pp.125-127
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• 2005

In this paper, the control algorithm of DC source device for inverter starting is proposed and the control method for compensating unbalance system source on operating time in the voltage type PWM converter with driving and regenerative faculty is suggested. The maintaining way of balancing condition for converter of AC source is used the compensating unbalanced status by current control loop. Because it is possible that the unbalanced System control is used to leakage transformer not equaled reactance by each phase in rectifier system, the proposed H/W and control algorithm of rectifier system is contributed to minimize of device and rising efficiency.

• Proceedings of the KIPE Conference
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• 2019.11a
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• pp.128-129
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• 2019

ITER AC/DC Converter는 플라즈마 운전에서 기능적인 역할과 동작 모드에 따라 PF/CS, TF, CC Plant로 구분되어 동작하며 PF, CS, VS1 컨버터는 플라즈마 전류 발생, 증감, 형상제어, 위치제어를 하며 PCS(Plasma Control System), MRC(Master Controller)에 의해 제어된다. MRC는 상위 제어인 PCS와 LCC(Local Control Cubicle)의 Middle Ware Layer에서 여러 Linux Machine들과 복잡한 통신망으로 연결되어 초전도 코일 전류 Driver에 있어서 Control과 Soft Down을 위한 Real Time 제어 기능을 한다. 본 논문은 이러한 제어를 구현하기 위한 Linux Real Time Control Thread Design의 구성과 결과를 논의하고자 한다.

• Proceedings of the KIPE Conference
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• 2019.11a
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• pp.130-131
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• 2019

국제 핵융합실험로(ITER)를 위해 한국이 제작, 시험, 설치 및 시운전을 하기로 되어 있는 CS(Central Solenoid) 초전도 자석용 전원장치의 시험 및 그 결과에 관하여 논의하고자 한다. 토카막 운전에서 플라즈마 발생 및 제어를 위한 대전류, 고전압, 270 kA 단락 용량 및 4상한 운전 특성을 갖는 45 kA/1050 V의 12펄스 싸이리스터 AC/DC 컨버터 및 제어기를 제작완료하였으며, ITER 부지로 운송하기 전에 공장의 전원 및 부하용량을 고려하여 시험절차서를 개발하였으며, 공장시험(FAT, Factory Acceptance Test)를 진행하였다.

• Proceedings of the KIEE Conference
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• 2000.07b
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• pp.1348-1350
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• 2000

Zero-voltage and zero-current switched single-stage approach with high power factor is presented to reduce the switching losses and to achieve sinusoidal, unity power factor input currents. This single-stage approach, which combines a boost converter used as PFC with a half-bridge converter used as do to do conversion into one power stage, has a simple structure and low cost. At the same time, since the switches of the proposed converter are designed to be turned on at zero-voltage and off at zero-current, the switching losses could be reduced considerably. Detailed analysis and experimental results are presented on the proposed converter, which is operated at constant switching frequency and in discontinuous conduction mode.

• Journal of Industrial Technology
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• v.18
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• pp.323-328
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• 1998

A current controlled VSI-PWM rectifier and inverter with capacitor dc link is regarded as one of the most promising structures for three-phase to three-phase to three-phase power conversion. This type of converter normally requires twelve switches for a rectifier and inverter composed of self turn-off switch such as a bi-polar transistor or IGBT with an anti-parallel diode. In this paper, a new three-phase to three-phase converter for ac motor drives is proposed. The proposed converter employs only eight switches and has the capability of delivering sinusoidal input currents with unity power factor and bidirectional power flow. This paper describes the feasibility and the operational limitations of the proposed structure. A mathematical model of the system is derived using generalized modulation theory and experimental results for steady state and dynamic behavior are presented to verify the developed model.

• Journal of the Korean Society for Railway
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• v.10 no.1 s.38
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• pp.51-56
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• 2007

In this paper, control schemes are developed for a propulsion system(Converter/Inverter) in electrical train. A robust controller for PWM converter is proposed. The converter controller consists of a PI controller for DC output voltage and a current controller using error-space approach for maintaining the sinusoidal current waveform and unity power factor. This proposed method is based on characteristic ratio assignment(CRA) method which has the advantage to design the optimal gain to meet the referenced response and overshoot within the limit range. Inverter system is controlled by vector control and slip frequency control. At low speed region, vector control scheme is applied to control instantaneous torque and slip frequency control is performed under overmodulation region and one pulse mode. Because output voltage of converter contains harmonics ripple at twice input ac line frequency, control scheme is developed to reduce the pulsating torque current. The performance of propulsion system will be verified by simulation and prototype experimental results.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.49 no.8
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• pp.529-535
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• 2000

In this paper, a current control system of a single phase PWM AC/DC converter using a reduced-order Luenberger observer without source voltage sensors is proposed. The sinusoidal input current and unity input power factor are realised based on the estimated source voltage performed by the reduced-order Luenberger observer using actual currents and DC link voltage. The poles of the reduced-order Luenberger observer are placed in the left half plane of s-plane by the pole-placement method in order to acquire the stability of the observer. The magnitude and the phase of the estimated source voltage are used to accomplish the unity power factor. The proposed method is implemented by DSP(Digital Signal Processor). Experimental Results verify that the reduced-order observer estimates the source voltage without the estimation error and the control system accomplishes the unity power factor, and constant DC link voltage.

• Proceedings of the KIEE Conference
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• 2001.10a
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• pp.212-214
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• 2001

This paper proposes a hi-directional current switch with snubber regeneration using Power MOSFETs and to use a loss-less snubber with switching device to perform soft-switching. It results in not only decreasing switching loss in the device drastically, but also improving input ac current waveform distortion. The computer simulation results show that the input current waveform and show the requirements necessary for the elimination of the 3rd harmonic component. We also show the Procedure to design the parameters of the converter.

• KIPE Magazine
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• v.9 no.5
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• pp.40-45
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• 2004

현대식 파워 컨버터 설계는 가격대비 효율적인 파워 솔루션을 위해 간단한 인터페이스를 가진 소형 IGBT 모듈을 필요로 한다. 전반적으로 낮은 높이, 양쪽에 별도로 부착된 AC 및 DC 터미널, 상부의 드라이버 액세스 등은 현대식 파워 모듈에 대한 최근의 시장 요구 사항이다. 이러한 요구에 부응하여 탄생한 것이 바로 SEMiX 모듈 플랫폼이다. 나아가, 이 논문에서는 모듈에 대한 새로운 드라이버 솔루션으로 기본 구동 기능과 보호 기능을 겸비한 간단한 애드온(add-On) 게이트 드라이버인 SKYPER를 선보인다. 이 논문에서, 다양한 모듈에 대한 SKYPER의 적합성은 SEMiX 예를 통해 성공적으로 검증되었다. SEMiX와 SKYPER 모두 IPM과 같이 작동했으나 스위치 특성 제어에 있어 더 많은 유연성을 제공하여 모듈식 인버터 솔루션을 위한 편리한 구축 블록임을 입증하였다.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.45 no.1
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• pp.30-41
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• 1996

Current Source(CS) PWM converter is appropriate for the magnet power supply system which requests high power and high precision current control. Input and output filters should be installed to eliminate the current or voltage harmonics caused by the PWM switching for the CS PWM converter. But the input/output filters limit the output DC current range and may destroy the system with filter resonance, and make the system equation more complicated. In this paper, systematic and simple filter design method which considers not only the harmonic attenuation but also the total system good transfer function characteristics in the dc filter. The simulated and experimental results verify the proposed theory. (author). refs., figs., tabs.