Development of a Pulsed Magnet System

손광효,S. H. KIM,Z. H. JANG,서병진 한국물리학회 2014 새물리 Vol.64 No.6

We report the development of a high-voltage-capacitor-discharge-type pulsed magnet system generating a magnetic field of higher than 30 T. It is composed of a magnet solenoid, a capacitor bank, a high-voltage high-current switching unit, a high-voltage capacitor-charging DC power supply, and a magnet-cooling liquid-nitrogen dewar. The capacitor bank is composed of 10 units of 9 kV 830 μF pulse capacitors. The switching unit is composed of a high-voltage SCR (silicon controlled rectifier) with a surge current capacity of 65 kA and a maximum voltage of 8.5 kV. The maximum output voltage of the high-voltage DC power supply is 10 kV, and the maximum charging current is 0.5 A. From a test with a calibrated induction magnetometer, the maximum field is found to reach ~30 T at a charging voltage of 4 kV. The duration of the pulse is 50 ~ 200 ms, depending on the crowbar's resistance value. The diode circuit can easily be modified to switch between a full-wave mode and a half-wave mode. Results on the training of the magnet is also reported.

Analysis of Output Pulse of High Voltage and Nanosecond Blumlein Pulse Generator

Young-Su Roh,Yun-Sik Jin 대한전기학회 2013 Journal of Electrical Engineering & Technology Vol.8 No.1

A high voltage and nanosecond Blumlein pulse generator has been developed to produce an output pulse whose voltage level is greater than 250 kV and pulse duration 5 ns. The generator consists of various components such as a charging circuit, a pulse transformer, and a spark gap switch. As a heart of the generator, a Blumlein pulse forming line has been constructed in the cylindrical form using three cylindrical aluminum electrodes that are placed concentrically. Unlike the ideal Blumlein line, the output pulse of an actual Blumlein line may be affected by stray inductances and capacitances of switching and charging components, thereby degrading the performance of the generator. In this paper, PSPICE simulations have been performed to examine effects of stray inductances and capacitances on waveforms of output pulses. Simulation results show that the pulse waveform is significantly distorted mainly by the stray inductance of the spark gap switch.

Nanosecond High-Voltage Pulse Generator Using a Spiral Blumlein PFL for Electromagnetic Interference Test

Soo Won Lim,Katsuki, Sunao,Yun Sik Jin,Chuhyun Cho,Young Bae Kim IEEE 2014 IEEE transactions on plasma science Vol.42 No.10

<P>High-power electromagnetic (HPEM) pulse can be delivered to electronic equipment in two ways. One is through the application of radiated fields, and the other is through conduction along cables and wires. In this paper, a high-voltage pulse generator using a spiral Blumlein pulse forming line (PFL) was developed for the test of HPEM effect by radiation and conduction. For the conduction test, a spiral strip Blumlein PFL filled with transformer oil is employed to generate high voltage (>300 kV) and long duration (50 ns) pulse. High-power ultrawideband pulse for the radiation test was generated by combining a TEM horn antenna with the high-voltage generator. The peak-to-peak value of electric field intensity of a radiated pulse is 53.3 kV/m at a distance of 10 m away from the antenna. The pulse generation system was used for the examination of effects of the electric fields and conducted pulses on the operation of electronic devices.</P>

A Study on Optimization of Compact High-voltage Generator Based on Magnetic-core Tesla Transformer

Young-Kyung Jeong,Dong-Gi Youn,Moon-Qee Lee 대한전기학회 2014 Journal of Electrical Engineering & Technology Vol.9 No.4

This paper presents a compact and portable high-voltage generator based on magneticcore Tesla transformer for driving an UWB high power electromagnetic source. In order to optimize the performance of the high-voltage generator, a novel open-loop cylindrical magnetic-core adopting the quad-division lamination structure is proposed and manufactured. The designed high-voltage generator using the proposed magnetic core has a battery-powered operation and compact size of 280 mm × 150 mm in length and diameter, respectively. The high-voltage generator can produce a voltage pulse waveform with peak amplitude of 450 kV, a rise time of 1.5 ns, and pulse duration of 2.5 ns at the 800 V input voltage.

A Study on Optimization of Compact High-voltage Generator Based on Magnetic-core Tesla Transformer

Jeong, Young-Kyung,Youn, Dong-Gi,Lee, Moon-Qee The Korean Institute of Electrical Engineers 2014 Journal of Electrical Engineering & Technology Vol.9 No.4

This paper presents a compact and portable high-voltage generator based on magnetic-core Tesla transformer for driving an UWB high power electromagnetic source. In order to optimize the performance of the high-voltage generator, a novel open-loop cylindrical magnetic-core adopting the quad-division lamination structure is proposed and manufactured. The designed high-voltage generator using the proposed magnetic core has a battery-powered operation and compact size of $280mm{\times}150mm$ in length and diameter, respectively. The high-voltage generator can produce a voltage pulse waveform with peak amplitude of 450 kV, a rise time of 1.5 ns, and pulse duration of 2.5 ns at the 800 V input voltage.

Analysis of Output Pulse of High Voltage and Nanosecond Blumlein Pulse Generator

Roh, Young-Su,Jin, Yun-Sik The Korean Institute of Electrical Engineers 2013 Journal of Electrical Engineering & Technology Vol.8 No.1

A high voltage and nanosecond Blumlein pulse generator has been developed to produce an output pulse whose voltage level is greater than 250 kV and pulse duration 5 ns. The generator consists of various components such as a charging circuit, a pulse transformer, and a spark gap switch. As a heart of the generator, a Blumlein pulse forming line has been constructed in the cylindrical form using three cylindrical aluminum electrodes that are placed concentrically. Unlike the ideal Blumlein line, the output pulse of an actual Blumlein line may be affected by stray inductances and capacitances of switching and charging components, thereby degrading the performance of the generator. In this paper, PSPICE simulations have been performed to examine effects of stray inductances and capacitances on waveforms of output pulses. Simulation results show that the pulse waveform is significantly distorted mainly by the stray inductance of the spark gap switch.

고전압 펄스 발생 장치의 특성에 관한 시뮬레이션 연구

김영주(Young-Ju Kim),신주희(Ju-Hee Shin) 한국조명·전기설비학회 2012 조명·전기설비학회논문지 Vol.26 No.12

The high-voltage pulse generator is consist of transformers of fundamental wave and harmonic waves, and shunt capacitances. The pulse has the fundamental wave and the harmonic waves that have been increased as a series circuit by the transformers to make high voltage pulse. This paper shows the high-voltage pulse generator simulation using a circuit program with experiment data. In the equivalent circuit, magnetized inductances and loss resistances which affect output voltage, have been obtained. The output capacitor circuits have characteristics of band pass. The output voltages of the pulse width 50% and 25%(PWM) were obtained. The output of the high-voltage pulse generator is 2.5kHz, 1.8kV.

트랜스포머를 이용한 고전압 펄스 발생 장치의 설계와 측정평가에 관한 연구

김영주(Young-Ju Kim) 한국조명·전기설비학회 2012 조명·전기설비학회논문지 Vol.26 No.1

High-capacity high-voltage pulse generator that can be used for environmental clean-up was developed using transformers. High-voltage pulse is consists of the primary wave and the harmonic wave which are increased as a series circuit using transformers to make pulses. Each transformer has a band-pass characteristics. The output voltage of the pulse width 50[%] was decided. The output voltage of high-voltage pulse generator device was measured as 1.4[㎸] (Peak-to-Peak)

Formers of High-voltage Subnanosecond Pulses Based on Compression Energy Schemes with Capacitor Storage and Spark Dischargers

Marat Ulmaskulov,V. G. Shpak,S. A. Shunailov,K. A. Sharypov,M. I. Yalandin 한국물리학회 2011 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.59 No.61

Two active formers of high-voltage subnanosecond unidirectional and monocycle pulses based on an energy compression scheme of a nanosecond pulse and two compact designs of passive stubs with oil insulation are presented. The pulse of the RADAN-303 (driver) initial generator with an amplitude of -145 kV and a duration of a ∼4 ns in one case was converted by the active former to a monocycle pulse (one period of sinusoid) with an amplitude drop of ∼350 kV and a period of ∼−1.25 ns. The unidirectional pulse former allowed a maximum amplitude of ∼290 kV to be reached in 0.3 ns (FWHM), and with additional compression energy, the average amplitude amounted to 310 kV. The electrical strength of the compact passive stubs was sufficient to convert an unidirectional pulse with an amplitude of −180 kV and a pulse width of 0.5 ns (FWHM) to a monocycle pulse with a drop of peak-to-peak amplitude of −150 kV and a drop duration of 0.5 ns for repetition rates up to 3 kHz.

고전압 square wave pulse를 이용한 당근 주스의 살균 및 저장 중 품질 변화

신정규(Jung-Kue Shin),하구용(Koo-Yong Ha),변유량(Yu-Ryang Pyun),최문실(Mun-Sil Choi),정명수(Myong-Soo Chung) 한국식품과학회 2007 한국식품과학회지 Vol.39 No.5

비열 살균 기술인 high voltage PEF를 이용하여 당근 주스를 처리하였을 때 당근주스의 살균력과 저장 중 품질 변화를 관찰하였다. 전기장의 세기를 50, 60, 70 kV/cm에서 처리 시간을 달리하여 당근주스를 처리한 결과 전기장의 세기가 증가함에 따라 일반 세균과 효모 및 곰팡이 모두 감소하였다. 효모 및 곰팡이는 65 kV/cm, 200 μs 처리시 모든 균이 사멸되었고 일반세균은 멸균에까지 이르지는 못하였으나 70 kV/cm, 200 μs 처리 후 4 log cycle 정도 감소되었다. 고전압 펄스 전기장 처리에 사용되는 펄스 파형인 square wave pulse와 exponential decay pulse가 살균효과에 미치는 차이를 비교하기 위하여 각각 4.25와 6.25의 pH에서 PEF 처리를 하여 실험하였다. 그 결과 square wave pulse를 이용한 PEF의 살균효과가 exponential decay pulse를 이용하였을 때보다 우수하였으며 처리 시간이 길어질수록, 당근주스의 pH가 낮을수록 두 파형 사이의 살균효과는 더 큰 차이를 나타내었다. 온도 및 pH의 병합처리가 PEF의 살균효과에 미치는 영향을 알아보기 위하여 온도 및 pH를 달리하여 55 kV/cm, 132 μs의 조건에서 PEF 처리한 결과 병합 처리시 살균효과가 눈에 띄게 증가하는 것을 관찰할 수 있었다. PEF 처리한 당근주스의 저장 시품질변화를 관찰한 결과 pH 와 열처리를 PEF와 병합하여 처리한 후 4<suf>o</suf>C 저장한 당근 주스에서만 pH, <suf>o</suf>Brix, 산도, 색도 그리고 α-, β-carotenes 함량에 눈에 띄는 차이를 나타나지 않았으며, 28일 동안 균의 생육을 관찰할 수 없었다. In this study, carrot juice was treated with high voltage pulsed electric fields (PEF) and the changes in its physical and chemical properties during storage at 4oC and 25oC were investigated. The sterility for bacteria, yeast and mold in carrot juice increased with increasing electric field strength and treatment temperature. While yeast and mold were completely inactivated at 65 kV/cm with a treatment time of 200 μs in a continuous PEF treatment system, bacteria were reduced by four log cycles. The results also showed that square wave pulse treatment was more effective for inactivating microorganisms than exponential decay pulse, and this effect was more apparent for carrot juice of lower pH. Although we observed significant changes in physical and chemical properties such as soluble solid content, pH, acidity, color, and carotene retention when the PEF treated samples were stored at the ambient temperature (20oC), no significant physical and chemical changes were found at the cold storage temperature (4oC) during 28 days of storage. The results indicate that the PEF treated carrot juice is appropriate for commercial refrigerated storage.