• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1410_1411
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• 2009

본 연구에서는 고전압·방전, Laser Beam, Plasma 공학분야 등에 있어서 중요한 현상 중의 하나로 대두되고 있는 Pulse Power 현상과 관련하여 고전압 단 펄스 발생장치(Pulse Width =10 ns, Pulse Height = 3kV) 시스템을 제작 하였다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.05a
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• pp.180-183
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• 2002

The pulsed power system was widely making use good of many industrial and environments. The pulse generator generally required for short pulse duration and high peak value was forced to consider its volume and economy. In this paper, this system is designed and fabricated which has a compact size of pulse generator with switched MOSFET. We have studied the removal of rust material using Arc discharging. It have tested their characteristics by adjusting variable voltage charging and pulse repetition rate. As a result, We can eliminate rust materials with this device.

• Journal of Power Electronics
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• v.18 no.1
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• pp.34-44
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• 2018

This paper presents a pulse-width adjustment (PWA) strategy for a novel bidirectional DC-DC boost converter to improve the performance of the dynamic inductor current response. This novel converter consists of three main components: a full-bridge converter (FBC), a high-frequency isolated transformer with large leakage inductance, and a three-level voltage-doubler rectifier (VDR). A number of scholars have analyzed the principles, such as the soft-switching performance and high-efficiency characteristic, of this converter based on pulse-width modulation plus phase-shift (PPS) control. It turns out that this converter is suitable for energy storage applications and exhibits good performance. However, the dynamic inductor current response processes of control variable adjustment is not analyzed in this converter. In fact, dc component may occur in the inductor current during its dynamic response process, which can influence the stability and reliability of the converter system. The dynamic responses under different operating modes of a conventional feedforward control are discussed in this paper. And a PWA strategy is proposed to enhance the dynamic inductor current response performance of the converter. This paper gives a detailed design and implementation of the PWA strategy. The proposed strategy is verified through a series of simulation and experimental results.

• Proceedings of the KIEE Conference
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• 2005.07c
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• pp.2179-2181
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• 2005

An experimental study on the water plasma characteristics of removal efficiency for organic contaminants in dye waste water has been investigated. In this study, dielectric barrier discharging electrodes with round shape have disposed cross each other in reactor, and pulse power was supplied to between each electrodes. Its output pulse voltage range is from 0[V] to 30[kV] and output frequency range is from 100[Hz] to 2[kHz]. Using proposed system, High frequency discharge is tested in the mixed Tone(air and water) and the space distribution of streamer corona plasma is observed. In spite of the increasement of voltage and frequency, the proposed system have a stable operation characteristics. It is verified by the experimental results.

• Proceedings of the KIPE Conference
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• 2016.07a
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• pp.107-108
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• 2016

Solid State Transformer(SST) has been recently regarded as a good alternative to conventional low frequency transformer. SST is consist of several high voltage power stage, so it is important to select optimal semiconductor switches for specification. This paper presents optimal IGBT switches for low switching losses using analyzing switching characteristics of several high voltage IGBT switches. Double Pulse Tester(DPT) experiment is used to verify characteristics of this IGBT switches.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.7
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• pp.937-942
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• 2013

Equivalent series impedance of high-voltage pulsed power capacitor is one of the important electrical characteristics both for users and for capacitor manufacturers because it may have serious effects on the performance of pulse forming circuits. In this paper, definition of equivalent series impedance and factors which generate equivalent series impedance are reviewed. Theoretical analysis for the calculation of equivalent series impedance based on differential measurement method is described and calculation program has been developed. In order to acquire data which are necessary to calculate equivalent series impedance from discharging current waveform, charging-dischargig controller has been manufactured. Measurement results of equivalent series impedance for high voltage pulsed power capacitor have been given.

• Journal of Power Electronics
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• v.17 no.6
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• pp.1490-1499
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• 2017

The modular multilevel converter (MMC) is generally considered to be a promising topology for medium-voltage and high-voltage applications. However, in order to apply it to high-power applications, a huge number of switching devices is essential. The numerous switching devices lead to considerable switching losses, high cost and a larger heat sink for each of the switching device. In order to reduce the switching losses of a MMC, this paper analyzes the performance of the conventional discontinuous pulse-width modulation (DPWM) method and its efficiency. In addition, it proposes a modified novel DPWM method for advanced switching losses reduction. The novel DPWM scheme includes an additional rotation method for voltage-balancing and power distribution among sub modules (SMs). Simulation and experimental results verify the effectiveness and performance of the proposed modulation method in terms of its switching losses reduction capability.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.54 no.3
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• pp.120-126
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• 2005

The Korean Superconducting Tokamak Advanced Research (KSTAR) tokamak device is being constructed to perform long-pulse, high-beta, advanced tokamak fusion physics experiments. The long-pulse operation requires the non-inductive current drive system such as the Lower-Hybrid Current Drive (LHCD) system. The LHCD system drives the non-inductive plasma current by means of C-band RF with 2-MW CW power and 5-GHz frequency. For the LHCD test experiments, an RF test system is developed. It is composed of a 5-GHz, 1.5-MW pulsed magnetron and a compact pulse modulator with $4\;{\mu}s$ of pulse width. The pulse modulator provides the maximum output voltage of 45 kV and the maximum current of 90 A. It is composed of 7 stages of Pulse Forming Network (PFN), a thyratron tube (E2V, CX1191D), and a pulse transformer with 1:4 step-up ratio. In this paper, the detailed design and the performance test of the pulse modulator are presented.

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.9
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• pp.940-946
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• 2015

In this paper, we study a method that amplifies the output gain of a high voltage pulse using 300 kHz or higher frequency. We conducted a study on a method for amplifying the output gain using the resonance between the capacitance components of the load and the parasitic components of the circuit, instead of the conservative method for amplifying the pulse-amplitude by raising the voltage of the power stage. In particular, the method simplifies the circuit configuration throughout the appliance of flyback-type topology instead of the bridge-type. There are advantages that prevent damage from overload and the heat in the output circuit through the hard switching by amplifying the gain of the output voltage applying to the load as given by the capacitance component of the output electrode to the output pulse waveform. This study proposed a method to enhance the spatial and electrical efficiency of the contact-type heating device through the dielectric heating method applied to the field of medical and industrial heating.

• Proceedings of the KIEE Conference
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• 2000.07b
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• pp.1309-1311
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• 2000

본 논문에서는 입력부, 특고압 발생부 및 고압 정류부, IGBT Pulse Switch로 구성된 Gyro-klystron용 대전력, 고전압, 전류 펄스 전원장치의 설계 및 개발에 대하여 기술하였다. 대전력, 고전압, 전류 펄스 전원장치를 위한 각 구성부분의 제어 및 설계 특징은 다음과 같다. 입력부인 IGBT Inverter는 펄스 전원장치의 전압 제어를 위하여 출력 고전압을 Feedback System 제어에 의해 Pulse 설정 전압을 갖도록 제어하며, 또한 Pulse 출력중에 직류 고전압부의 전압강하, 즉 Pulse 전압의 Drop이 커지는 것을 방지하기 위하여 Fast Dynamics를 갖도록 Feedback System을 구성하였다. 3대의 단상 특고압 승압변압기가 직렬로 구성된 특고압 발생부는 PWM된 전압을 입력받아 특고압으로 승압시킨다. 특고압 변압기는 고압 Pulse성 전압과 매우 높은 dV/dt 전압이 인가되므로 Stray Capacitance가 최소가 되어야 하며 절연파괴로부터 보호될 수 있어야 한다. 고압 정류부는 Inverter와 특고압변압기에 의하여 전원이 공급되므로 교류전압의 교번순간에 매우 높은 전압 변동률을 가지는 Fast Recovery High Voltage Rectifier로 설계, 제작되어졌다. Pulse Switch인 IGBT Switch는 Gate Driver에 의해 구동되어 진다. 주어진 Pulse 사양을 만족시키며 특히 소자의 전압 특성을 고려하여 120KV의 전압값을 갖도록 설계, 제작하였다. 본 논문에서는 고전압 펄스 전원장치 각 부분의 설계에 대하여 기본적인 사항들을 제시하며, 실험결과를 통하여 제안된 방식의 우수한 특성을 입증한다.