• 전력전자학회논문지
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• 제25권2호
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• pp.87-93
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• 2020

This study proposes a gate driver that operates semiconductor switches in the bipolar pulsed power modulator. The proposed gate driver was designed to receive isolated power and synchronized signals through the gate transformer. The gate circuit has a separate delay in the on-and-off operation to prevent a short circuit between the top and bottom switches of each leg. On the basis of the proposed gate circuit, a bipolar pulsed power modulator prototype with a 2.5 kV/100 A rating was developed. Finally, the bipolar pulsed power modulator was tested under resistive load and plasma reactor load conditions. It is verified that the proposed gate driver can be applied to a bipolar pulsed power modulator.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2018년도 추계학술대회
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• pp.98-100
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• 2018

This paper describes design of the 40-kV, 300-A solid-state pulsed power modulator for environmental applications. The modulator has been modified based on a solid-state pulsed power modulator with 150-A current capacity. To improve the pulsed power modulator, the discharge IGBT was changed. In addition, the gate driver was tuned according to the characteristics of the switch. Finally, experimental results proved the reliability of the modified solid-state pulsed power modulator.

• 전력전자학회논문지
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• 제26권1호
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• pp.25-31
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• 2021

This paper describes the design of a power cell-based pulsed power modulator with fast rise times. The pulse-generating section of the pulse power modulator is a series stack of power cells. Each power cell is composed of a storage capacitor, a pulse switch, and a bypass diode. When the pulse switches are turned on, the capacitors are connected in series and the sum of voltages is applied to the load. For output pulses with fast rise times, an IGBT with fast turn-on characteristics is adopted as a pulse switch and the optimized gate driving method is used. Pspice simulation is performed to account for the gate driving method. A 10 kV, 12-power cell-based pulsed power modulator is tested under resistive load and plasma reactor load. The rise times of output pulses less than 20 ns are confirmed, showing that the pulsed power modulator can be effectively applied to pulsed power applications with fast rise times.

• Journal of Power Electronics
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• 제11권4호
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• pp.612-619
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• 2011

This paper presents a water treatment system for leachate from sewage-filled ground that uses a pulsed-power modulator developed based on semiconductor switches in order to realize a long life, a high repetition rate, and a fast rising time. The specifications of the developed pulsed-power modulator are the pulsed output voltage, the output current, the pulse repetition rate (PRR), the pulse width, and an average output power of $60\;kV_{max}$, $300\;A_{max}$, 3000, $50\;{\mu}s$, and 15 kW, respectively. The pulsed-power water treatment system was introduced and analyzed using an equivalent electrical circuit model to optimize the output voltage waveform. The experimental results verify that the proposed water treatment system can be effectively used for industrial applications.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2019년도 전력전자학술대회
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• pp.171-173
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• 2019

In this paper, 10kV solid-state pulsed power modulator with high repetition rate is described. The modulator is based on a Marx generator that charges capacitors in parallel and discharges them in series. Twelve IGBTs and capacitors are connected in series to generate output voltages up to 10kV at a repetition rate of 100kHz. The volume of the modulator is 26.1 liters, and its maximum average output power is 10kW. Therefore, the compact design is achieved with a high power density of 380 W/L. Finally, it is confirmed that the pulsed power modulator can operate stably through the experiment results at 10kV 100kHz condition.

• Nuclear Engineering and Technology
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• 제38권8호
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• pp.785-792
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• 2006

The microwave heating system of KSTAR consists of ECH and LHCD. ECH and LHCD offer the benefits ofa reliable operation at the start of plasma formation and a non-inductive current drive durable steady state operation, respectively. LHCD uses a C-band microwave system with a frequency of 5 GHz. A pulsed power modulator with a power of 3.6 MW, $4{\mu}S$, 200 pps is required to drive the high-powered magnetron. The development of a pulse modulator with 1:4 pulse transformers is the focus of the research in this study. The peak power handling capability is 3.6 MW (45 kV, 90 A at load side with a pulse width of $4{\mu}S$). This paper describes the system overview and test results of the pulsed modulator. In particular, a simulated waveform is compared with the tested waveform.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2015년도 전력전자학술대회 논문집
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• pp.193-194
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• 2015

In this paper, the solid state pulsed power modulator developed in KERI, which is based on IGBT technologies are overviewed. During last ten years, several kinds of solid state modulators were developed in KERI such as IGBT stacks with step up transformer, full IGBT stack based marx generator, modified IGBT marx generator and high repetitive solid state modulator. Basic principle of the design is described and each pros and cons are compared. KERI's solid state pulsed power modulators has lot of advantages for industrial pulsed power application focused on everlasting life cycle and high repetitive, and shows superior arching protection ability.

• 전기학회논문지
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• 제56권1호
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• pp.88-99
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• 2007

In this paper, a novel new pulse power generator based on IGBT stacks is proposed for pulse power application. Because it can generate up to 60kV pulse output voltage without any step- up transformer or pulse forming network, it has advantages of fast rising time, easiness of pulse width variation and rectangular pulse shape. Proposed scheme consists of series connected 9 power stages to generate maximum 60kV output pulse and one series resonant power inverter to charge DC capacitor voltage. Each power stages are configured as 8 series connected power cells and each power cell generates up to 850VDC pulse. Finally pulse output voltage is applied using total 72 series connected IGBTs. To reduce component for gate power supply, a simple and robust gate drive circuit is proposed. For gating signal synchronization, full bridge invertor and pulse transformer generates on-off signals of IGBT gating with gate power simultaneously and it has very good characteristics of short circuit protection.

• 한국전자파학회논문지
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• 제22권4호
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• pp.440-446
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• 2011

본 논문에서는 레이더 시스템에 적용이 가능한 50 W 출력을 가지는 X-대역 pulsed SSPA(Solid State Power Amplifier)를 설계 및 제작하였다. SSPA를 펄스 모드로 동작시키는 방법으로 펄스 변조 방법과 전원 스위칭 방법을 혼용한 방법을 제안하였다. SSPA는 구동 증폭기, 고출력 증폭기, 펄스 변조기로 구성되며, 충분한 이득과 출력 크기를 얻기 위해 25 W GaAs FET 4개를 병렬 구조로 구성하였다. 측정 결과 1.12 GHz 대역폭에서 출력 50 W, 이득 44.2 dB의 성능을 가졌다. 또한, pulse droop은 1 dB 이하로 설계 목표를 만족하였으며, 12.45 ns 이하의 상승/하강 시간을 가졌다. 제작된 X-대역 pulsed SSPA 크기는 $150{\times}105{\times}30\;mm^3$로 매우 작은 크기를 가졌다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2012년도 전력전자학술대회 논문집
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• pp.230-231
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• 2012

This paper describes a gate driver that operates numerous semiconductor switch in the solide-state pulsed power modulator. the proposed gate driver is designed to receive both the isolated drive-power and the on/off pulse signals through the transformer. Moreover, the IGBT-switch can be quickly turned off by adding protection circuit. Therefore it protects the IGBT-switch from the arc condition that frequently occurs in high-voltage pulse application. To comprehend operating characteristic of each IGBT-switch in pulse output condition, the device consisting of a high efficiency soft-switching capacitor charger and two series stacking IGBT-switch is developed. Finally, the relability of the proposed gate driver and the device for its test are proved through PSpice simulation and experiments.