• 대한전기학회논문지:전기물성ㆍ응용부문C
• /
• 제49권3호
• /
• pp.177-185
• /
• 2000

In this study, the characteristics of various electricity and high resistivity ash collection were measured at superimposed nanosecond pulse energization. The pulse was generated through the hydrogen thyratron. Superimposed pulse was nanosecond duration pulse that had fast pulse rising time 100[ns], short pulse width 500∼850[ns] and pulse fall time 400∼750[ns]. The results of this study are summarized as followings; Frist, compared with the DC ESP(electrostatic precipitator), superimposed pulse ESP could induce higher peak voltage, and had the about 30[%] reduction of ESP collection area and 50∼80[%] reduction of power consumption. showing the same efficiency. Second, enhancement factor H had 1.9∼3.6 with the increase of migration velocity.

• 대한전기학회논문지:전기물성ㆍ응용부문C
• /
• 제53권8호
• /
• pp.415-419
• /
• 2004

A pulse power supply using IGBTs and MPC (magnetic pulse compression) circuit was developed for a metal vapor laser. The life time of the pulse power supply is expected to be much longer than that of a vacuum tube or thyratron type pulse power supply. A series-connected IGBT array generated a long pulse of its pulse width 2 ${\mu}\textrm{s}$ md then it was compressed to less than 100 ns by a three stage MPC circuit. This pulse power supply was applied to a laser plasma tube of 10 mm inner diameter and 0.5 m discharge length. and successfully operated.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2005년도 제36회 하계학술대회 논문집 C
• /
• pp.2143-2145
• /
• 2005

Power semicondcutor인 IGBT MOSFET, GTO, SI-Thyristor등은 높은 스위치 신뢰성과 life time, 그리고 fast repetition rate 등을 지니고 있기 때문에 medium/High voltage영역에서 스위치 사용이 대두되어 왔으나, Thyratron이나 Trigatron(Gap switch)와 비교하여 낮은 전압/전류를 스위칭하기 때문에 전통적으로 직렬연결을 통해 high voltage 영역의 스위치로 사용되어 왔다. 하지만, 직렬연결되어 있는 각각의 power semiconductor와 gate driving circuit의 on/off synchronization이 맞지 않기 때문에 부하의 급격한 변화에 따른 전압의 balance에 문제가 가장 심각하게 대두되어 왔다. 이러한 문제를 해결하기 위해서 gate driving circuit에서 제어를 해주는 방법과 power semiconductor에서 제어를 해주는 방법이 있으나 두 방식 모두 문제점이 있다. 본 논문에서는 기존의 zener clamping방식에서 벗어나 새로운 active clamping방식의 직렬연결을 제안했으며 시뮬레이션과 실험을 통해 나타난 이 결과들은 on/off transient 시 symmetry를 유지하는데 효과적이라는 것을 보여주고 있다.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2004년도 하계학술대회 논문집 C
• /
• pp.1778-1780
• /
• 2004

Microwave heating system of KSTAR consists of ECH and LHCD. ECH and LHCD offer the reliability of operation in the beginning of plasma formation and non-inductive current drive for long time steady state operation with maintaining MHD stability, respectively. LHCD demands 5 GHz of frequency and consists of c-band waveguide, 4-port circuitor, dry dummy load, dual directional coupler, E-bend, arc detector. Our system is a lineup type pulse modulator that has 45 kV of output pulse voltage, 90 A of pulse current, 4 us of pulse width. 1:4 step-up pulse transformer, 7 stages of PFN and thyratron tube (E2V, CX1191D) are used in this modulator. The purpose of this paper is to show the modulator design and experimental result.

• 한국연소학회:학술대회논문집
• /
• 한국연소학회 1997년도 제15회 KOSCO SYMPOSIUM 논문집
• /
• pp.69-76
• /
• 1997

Industrial-scale pulse corona process to remove $SO_2$ and $NO_x$ simultaneously from combustion flue gas has been studied. The pilot plant built in the present study treats 2,000 $Nm^3$/hr of flue gas from a boiler. The geometry of the pulse corona reactor is similar to that of an electrostatic precipitator commonly used in industry, A thyratron switch and magnetic pulse compressors, which can generate up to 130 kV of peak pulse voltage and up to 30 kW of average pulse power, have been used to produce pulsed corona. The removal efficiencies of $S0_2$ and $NO_x$ with the present process are maximum of 95 % and 85 %, respectively. Electrical power consumption to produce the pulsed corona, which has been one of the major difficulties to apply this process to industry, has been evaluated in the present study. The results showed that the power consumption can be reduced significantly by simultaneous addition of hydrocarbon injection and heterogeneous phase reactions to the process.

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2012년도 제43회 하계 정기 학술대회 초록집
• /
• pp.261-261
• /
• 2012

This paper presents the understandings carried out for the installation of the hydrogen reservoir of the multi-gap pseudospark switch under developing for the accelerator applications. As a cold cold cathode switch, the pseudospark switch could replace the thyratron switch which has hot cathode and being used well currently in the high power field such as laser and accelerator applications. Especially in the klystron modulator, the key component is a switch which mostly defines the jitter and the instability of the modulator system. To get the less jitter and the instability, we need to find proper range of the pressure for the gas discharge inside gas switch. This could be achieved by the understanding of the characteristic of the nonevaporable getter (NEG) which is used as a hydrogen reservoir for the switch. Therefore we verified the characteristics of the NEG (St 172, Saes) and its installation in the switch. Finally we controlled the getter to find best pressure point for the pseudospark switch.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1997년도 하계학술대회 논문집 E
• /
• pp.1779-1781
• /
• 1997

The 2.0 GeV Pohang Light Source (PLS) is consisted of a full energy Linac and a storage ring. Four kicker magnets are installed in the storage ring tunnel to move the stored beam orbit in the storage ring closer to the injected beam from the beam transfer line. The injected beam then falls into the storage ring beam dynamic aperture. A kicker magnet modulator drives all four kicker magnets to maintain field balance and also synchronized kick of the beam. The kicker modulator can handle 2 GeV full energy beam. The kicker magnet modulator is installed in the storage ring tunnel and under stable operation. Specification of the kicker magnet modulator is ${\sim}6.0{\mu}s$ pulse-width, 200 ns flat-top width with ${\pm}0.2%$ regulation, ${\sim}24\;kA$ peak current, and 10 Hz repetition rate. Two thyratron switches (EEV CX-1536AX) are used in the system. In this article, design, and experimental results of the kicker magnet modulator are discussed.

• 대한전기학회논문지:전기물성ㆍ응용부문C
• /
• 제54권3호
• /
• pp.120-126
• /
• 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.

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
• /
• pp.547-547
• /
• 2013

This paper presents the understandings carried out for the installation of the hydrogen reservoir of the multi-gap pseudospark switch under developing for the accelerator applications. As a cold cold cathode switch, the pseudospark switch could replace the thyratron switch which has hot cathode and being used well currently in the high power field such as laser and accelerator applications. Especially in the klystron modulator, the key component is a switch which mostly defines the jitter and the instability of the modulator system. To get the less jitter and the instability, we need to find proper range of the pressure for the gas discharge inside gas switch. This could be achieved by the understanding of the characteristic of the nonevaporable getter (NEG) which is used as a hydrogen reservoir for the switch. Therefore we verified the characteristics of the NEG (St 172, Saes) and its installation in the switch. Finally we controlled the getter to find best pressure point for the pseudospark switch.

• 한국의학물리학회:학술대회논문집
• /
• 한국의학물리학회 2004년도 제29회 추계학술대회 발표논문집
• /
• pp.158-161
• /
• 2004

방사선 치료의 핵심 장비인 선형가속기의 10년간 관리 기록을 분석하여 효율적인 관리 지표로 활용하고자한다. 장비의 장애 요인을 다각적으로 분석하기위해 고장 원인을 치료기 부위별로 세분했고 각각이 미치는 영향을 세 단계로 구분하여 조사했다. 또한 장비 사용량이 고장에 미치는 영향을 분석하기 위해 년도별 치료 환자수와 고장건수, 중요 부속의 평균 수명 등을 분석했다. 10년간 전체 고장건수는 587건 이였으며 이중 조사헤드부의 고장이 20%를 자치해 가장 높게 나타났으며 고장이 미치는 영향에 의한 분석에서는 일시적 장애해 당하는 중간 정도의 고장이 41%를 차지해 가장 높게 나타났다. 장애 영향이 가장 큰 조사 불가능 상태의 고장은 가속부에서 49%로 가장 높게 나타났으며 고장과 관련된 지표는 사용연수 및 치료건수와 밀접한 관계를 나타냈다. 중요 부속의 평균 수명은 클라이스트론과 싸이라트론의 경우 치료건수가 증가함에 따라 교체 주기가 빨라져 각각 제조사 권고치의 42%, 83% 수준이였다. 안정적인 치료서비스 제공을 위해서는 사용 연수가 증가함에 따라 장비 관리의 필요성이 더욱 중요시 되어야하며 10년간 장비 관리기록을 통해 얻은 각종 지표가 향후 효율적 관리의 좋은 지침이 될 것으로 사료된다.