• Proceedings of the KIEE Conference
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• 2000.07b
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• pp.1215-1217
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• 2000

For the application of soft-switching technique to single Phase-full bridge inverter. in this paper ZCT(Zero Current Transition) and ZVT(Zero Voltage Transition) techniques proposed previously are compared and discussed the merit and demerit of both. Both have a excellency that can reduce the number of auxiliary switch and resonant circuit compared to other techniques and achive soft-switching in auxiliary switch itself. Therefore, it has enabled us to have benifits of realizing high efficiency and reliability, low EMI for high switching frequency and reducing the cost as well as size of device.

• Proceedings of the KIPE Conference
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• 2007.07a
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• pp.372-374
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• 2007

본 논문에서는 LCD Backlight를 위한 기존 Phase shift Full bridge 인버터 방식을 검토하여, 이를 바탕으로 기존의 Full bridge Inverter 토폴로지와 전력 시스템은 동일하게 가져가고 좀 더 나은 성능을 위해 독자 기술의 새로운 구동 및 제어 방식을 구현하고자 한다. 인버터 부의 최적 동작을 위해 인버터 구동 신호의 주파수와 시비율을 고정하는 대신 펄스 개수를 제어하는 새로운 Pulse Count Modulation (PCM) 방식을 제안하며 이론적 및 실험적 검증을 통해 제안된 방식의 우수성을 확인한다.

• Proceedings of the KIPE Conference
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• 2007.07a
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• pp.265-267
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• 2007

본 논문은 LCD Backlight 구동을 위한 새로운 방식의 회로를 제안한다. 제안된 회로는 Charge Pump 캐패시터를 이용한 Half-Bridge 타입의 인버터로 Full Bridge 회로와 동등한 성능을 갖는다. 제안 회로는 넓은 입력 범위와 넓은 부하 범위에서 영전압 스위칭(ZVS) 확보가 가능해서 인버터의 고효율 동작이 확보되고, MOSFET의 surge 및 noise를 저감시킨다. 제안된 회로의 동작 원리를 설명하고, 시뮬레이션 및 40" LCD 패널에 실제 적용 실험하여, 회로의 동작을 입증하였다.

• Proceedings of the KIEE Conference
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• 2005.11a
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• pp.214-216
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• 2005

The PAL (Pohang Accelerator Laboratory) is persuading to construct a SASE-XFEL facility (PAL XFEL) that supplies coherent X-rays. The bright and stable electron beam is essential for the PAL XEL. The electron beams has to have an emittance of 1.0 mm-mrad, a peak current of 3 kA, and a low energy spread of 1.0 MeV. In order to provide reasonably stable SASE output, the RF stability of 0.02% rms is required for both RF phase and amplitude. This is a technologically challenging issue for PAL XFEL. An inverter technology is to be applied to charge the PFN of a new modulator. Therefore, a new inverter system should provide very stable charging performances. This paper presents the development of an ultra stable klystron-modulator with an inverter power supply.

• Proceedings of the KIEE Conference
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• 1991.07a
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• pp.466-470
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• 1991

In this paper, full bridge inverter with IGBT is proposed. By Controlling phase angle difference between 2 arms, PWM controlled high frequency link inverter has VVVF capability. For the simplicity, flexibility and compactness of control circuit, 16 bit single chip microcontroller 8797 BH is used and its characteristic is examined through experiment.

• Proceedings of the KIEE Conference
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• 1993.07b
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• pp.721-723
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• 1993

A PWM switching control strategy based on instantaneous integration concept for reducing hamonic components of inverter system with fluctuating input voltage is presented. Applying this strategy to single phase full bridge PWM inverter through bipolor switching method and unipolor switching method, reduction of hamonic components of output voltage and current is demonstrated through simulation. The system operation is examined and confirmed by experiments.

• Journal of Power Electronics
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• v.19 no.2
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• pp.454-462
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• 2019

When compared to traditional bridge-type inverters, the dual-buck inverter has a higher reliability due to the fact that its bridge legs do not have a shoot-through problem. In this paper, the working principle of the dual-buck inverter is analyzed. A comparison of the working modes under full-cycle and half-cycle control is discussed. With half-cycle control, the inverter can realize a higher efficiency. However, this results in current zero-crossing distortion. The corresponding control strategy of the dual-buck inverter is proposed in order to realize both high efficiency and low current harmonic distortion. In addition, the system stability is analyzed. Dead-time is unnecessary due to the advantages of the topology. Thus, the current harmonic distortion can be further reduced. An inverter with the proposed control strategy has the advantages of high reliability, high efficiency and low current harmonic distortion. Finally, simulation and experimental results are given to verify the theoretical analysis.

• Journal of Power Electronics
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• v.18 no.5
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• pp.1315-1324
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• 2018

A novel three-phase four-wire inverter topology is presented in this paper. This topology is equipped with a special capacitor balance grid without magnetic saturation. In response to unbalanced load and unequal split DC-link capacitors problems, a qusi-full-bridge DC/DC topology is applied in the balance grid. By using a high-frequency transformer, the energy transfer within the two split dc-link capacitors is realized. The novel topology makes the voltage across two split dc-link capacitors balanced so that the neutral point voltage ripple is inhibited. Under the condition of a stable neutral point voltage, the three-phase four-wire inverter can be equivalent to three independent single phase inverters. As a result, the three-phase inverter can produce symmetrical voltage waves with an unbalanced load. To avoid forward transformer magnetic saturation, the voltages of the primary and secondary windings are controlled to reverse once during each switching period. Furthermore, an improved mode chosen operating principle for this novel topology is designed and analyzed in detail. The simulated results verified the feasibility of this topology and an experimental inverter has been built to test the power quality produced by this topology. Finally, simulation results verify that the novel topology can effectively improve the inhibition of an inverter with a three-phase unbalanced load while decreasing the value of the split capacitor.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.15 no.4
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• pp.7-13
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• 2001

In this paper, the external-exciting electronic ballast for an 100[W] high pressure sodium lamp using full-bridge inviter is designed. The L-C parallel full-bridge invert circuit for P-SPICE simulation is designed. The values of inductor and capacitor in the proposed equivalent L-C parallel resonant tank circuit are calculated theoretically. Then the ballast for high pressure sodium lamp is implemented using the simulated results. In the experimental results, that is confirmed which the results of implemented ballast are really same with the of simulated one.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.4 no.1
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• pp.283-288
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• 2000

This paper proposes a novel Pulse Width Modulation (PWM) method for microprocessor implementation of full-bridge PWM inverters. In the method, the period of unipolar full-bridge inverters is divided equally into the frequency modulation ratio and the reference fundamental amplitude and the inverter output fundamental amplitude are compared. Using this method, the turn-on time computation of each interval is very favored for the microprocessor implementation. The harmonic analysis shows that the harmonics can be ignored when the modulation ratio is enough large. The simulation and experimental results show the effectiveness of the proposed algorithms.