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다양한 펄스 반복률에서의 NPN BJT (Bipolar Junction Transistor)의 파괴 특성에 관한 연구
방정주,허창수,이종원,Bang, Jeong-Ju,Huh, Chang-Su,Lee, Jong-Won 한국전기전자재료학회 2014 전기전자재료학회논문지 Vol.27 No.3
This paper examines the destruction behavior of NPN BJT (bipolar junction transistor) by repetition pulse. The injected pulse has a rise time of 1 ns and the maximum peak voltage of 2 kV. Pulse was injected into the base of transistor. Transistor was destroyed, current flows even when the base power is turned off. Cause the destruction of the transistor is damaged by heat. Breakdown voltage of the transistor is 975 V at single pulse, and repetition pulse is 525~575 V. Pulse repetition rate increases, the DT (destruction threshold) is reduced. Pulse Repetition rate is high, level of transistor destruction is more serious.
모노폴 안테나에 커플링되는 EMP에 의한 LNA(Low Noise Amplifier)의 민감성 분석
방정주(Jeong-Ju Bang),허창수(Chang-Su Huh) 대한전기학회 2019 전기학회논문지 Vol.68 No.4
In this paper, the output waveform of EMP coupled to 10 MHz monopole antenna analyzed by simulation, and the susceptibility of LNA(Low Noise Amplifier) was evaluated. The waveform of EMP coupled to the monopole antenna is a 10 MHz damped sinusoidal waveform, and the peak voltage is about 22 kV. The susceptibility of LNAs was evaluated using the 10 MHz damped sine wave generator. DFR(Destruction Failure Rate) was measured to investigate the susceptibility of LNA. The susceptibility level of LNA was assessed by voltage of damped sine wave. The voltage of destruction threshold is 71 V and 107.5 V respectively. The coupling voltage is higher than the destruction threshold of LNAs. Therefore, the communication system can be damaged by EMP. It is necessary to apply the protection device to the communication system. Based on these results, susceptibility of LNA can be applied to a basic data for applying the protection device to the communication system against EMP.
방정주(Jeong-Ju Bang),허창수(Chang-Su Huh),장태헌(Tae-Heon Jang) 대한전기학회 2019 전기학회논문지 Vol.68 No.11
This study has examined destruction effect on LNA(Low Noise Amplifier) by damped sine wave. DFR(Destruction Failure Rate) was measured to investigate the diagnostic of LNA test. Three kinds of damped sine wave were injected to input port of LNA module: 1 MHz, 10 MHz, and 100 MHz. The destruction level of LNA was assessed by damped sine wave voltage, and its DFR were observed. The destruction of LNA module has showed the degradation of amplification or loss of amplification function. As the frequency of damped sine wave increased, the destruction threshold voltage increased and destruction threshold energy decreased. Based on these results, the destruction effect of LNA can be used to protect the RF communication equipment from high power electromagnetics.
식물성 절연유의 유속과 BTA에 따른 유동대전 현상 연구
최순호,방정주,허창수,Choi, Sun-Ho,Bang, Jeong-Ju,Huh, Chang-Su 한국전기전자재료학회 2012 전기전자재료학회논문지 Vol.25 No.10
Mineral insulating oils are an important insulating materials in oil-filled transformer. However, the mineral oil is the cause of the environmental problem. The vegetable oils are substitutes for mineral oil because of its biodegradability characteristic. As large size and high rating of the transformer increases, the losses increase at a faster rate. So insulating oil is forced circulation in the oil-filled transformer by using oil pumps. The flow electrification occurs when insulating oil was forced to be circulated. To check the flow electrification, had conducted experiments varying factors. As a result, the streaming electrification could see the changes according to flow velocity, oil temperature and insulation materials.
펄스 반복률에 의한 반도체 소자의 오동작 모드와 고장률에 관한 연구
박기훈,방정주,김륙완,허창수,Park, Ki-Hoon,Bang, Jeong-Ju,Kim, Ruck-Woan,Huh, Chang-Su 한국전기전자재료학회 2015 전기전자재료학회논문지 Vol.28 No.6
Electronic systems based on solid state devices have changed to be more complicated and miniaturized as the electronic systems developed. If the electronic systems are exposed to HPEM (high power electromagnetics), the systems will be destroyed by the coupling effects of electromagnetic waves. Because the HPEM has fast rise time and high voltage of the pulse, the semiconductors are vulnerable to external stress factor such as the coupled electromagnetic pulse. Therefore, we will discuss about malfunction behavior and DFR (destruction failure rate) of the semiconductor caused by amplitude and repetition rate of the pulse. For this experiment, the pulses were injected into the pins of general purpose IC due to the fact that pulse injection test enables the phenomenon after the HPEM is coupled to power cables. These pulses were produced by pulse generator and their characteristics are 2.1 [ns] of pulse width, 1.1 [ns] of pulse rise time and 30, 60, 120 [Hz] of pulse repetition rate. The injected pulses have changed frequency, period and duty ratio of output generated by Timer IC. Also, as the pulse repetition rate increases the breakdown threshold point of the timer IC was reduced.
강호재,허창수,방정주,최진수,박우철,Kang, Ho-Jae,Huh, Chang-Su,Bang, Jeong-Ju,Choi, Jin-Su,Park, Woo-Chul 한국전기전자재료학회 2014 전기전자재료학회논문지 Vol.27 No.4
In modern times, threat of high power electromagnetic wave is increasing. When the electrical grid and communication network are attacked by these high power electromagnetic wave, the whole infrastructure is paralyzed. To protect the infrastructure from these high power electromagnetic wave threat, the shielding facility that can block high power electromagnetic wave is constructed. Also shielding effectiveness evaluation about the constructed facility is important. But, because of space efficiency and saving of construction cost to construct the actual shielding facility, the shielding room wall is generally adjacent to exterior concrete structures. As space between shielding facility wall and concrete structures is very small, arranging the transmitting antenna exterior shielding facility is realistically difficult. Therefore, in this research, The shielding effectiveness measurement plan in the state of exterior narrow space of HEMP shielding facility is presented. And to apply this plan, The influence of shielding effectiveness according to the size of the shielding facility is analyzed.
시뮬레이션을 통한 스파크갭의 SF<sub>6</sub>, N<sub>2</sub> 압력 특성 분석
최순호,이태우,방정주,허창수,Choi, Sun-Ho,Lee, Tae-Woo,Bang, Jeong-Ju,Huh, Chang-Su 한국전기전자재료학회 2014 전기전자재료학회논문지 Vol.27 No.3
Industrial, medical, environment and agriculture application of pulse power technology have been developing rapidly in many field. In order to make use in the form of pulses is applied to the pulse forming technique. At this time, spark gap is generally used for the pulse forming. Spark gap may be possible to simulate the shape of the electrode, to know the uniform or non-uniform electric field of the electrode structure. Further, it can be determined using Paschen's law applied pressure of the insulating gas in accordance with the voltage which is created using the value of the electric field. In this paper, we tried to found using a formula and the simulation process to determine the pressure. The value of the electric field is different according to the shape of the electrode. So, the range of pressure applied also varies. In order to withstand the 100 kV with a gap of 5 mm, the nitrogen gas must be applied to about 7 bar in the electrode structure. On the other hand, in the same conditions, Sulfur hexafluoride gas must be applied to about 2 bar. Consequently, the Sulfur hexafluoride gas has a higher insulation properties than nitrogen gas may be applied to low pressure at the same conditions.
Capacitive Switching Antenna의 최적 에너지 전달에 관한 연구
김진만(Jin-Man Kim),방정주(Jeong-Ju Bang),허창수(Chang-Su Huh) 대한전기학회 2013 전기학회논문지 Vol.62 No.2
In this paper we describe the maximum energy transfer of CSA(Capacitive Switching Antenna). CSA which is radiated antenna system contain energy storage and switch, antenna needs to high voltage source for electrical field radiation experiment. In this experiment we employed Marx generator as a charging source. CSA can radiate electrical field more efficiently by varying antenna capacitance. The electromagnetic generation system which was using CSA has some advantages which are more simple and more effective compared to exist system. We evaluated the performance of electromagnetic wave generating system using CSA. As a result UWB gain of system is 0.47, It is higher level than exist system is 0.3. Radiated electrical field strength at 1m is 70kV/m. It is measured by D-dot sensor and gap distance is 20㎜. Center frequency of CSA is approximately 25MHz. When vary the antenna gap distance from 50㎜ to 20㎜, we can find the radiation field strength is decrease and antenna center frequency is increased. We also simulated the energy transfer efficiency to compare with experiment result. Consequentially, CSA needs to appropriate capacitance which is similar value from marx generator for maximum energy transfer, and gap is less than 1㎜ to increase the CSA capacitance.
배전용 변압기에서의 고온열화와 열 사이클 열화에 따른 식물유와 광유의 특성 분석
안정식(Jung-Sik An),최순호(Sun-Ho Choi),방정주(Jeong-Ju Bang),정중일(Joong-Il Jung),허창수(Chang-Su Huh) 대한전기학회 2011 전기학회논문지 Vol.60 No.6
Most transformers use insulating and cooling fluids derived from petroleum crude oil, but mineral oil has some possibility of environmental pollution and fire with explosion. vegetable oil fluids extracted from seed has superior biodegradation and fire-resistant properties including an exceptionally high fire point enhancing fire safety. In this study, it is aimed at the practicality of substituting natural ester dielectric fluid for mineral oil in liquid insulation system of transformers. As a rise in coil winding temperature has a direct influence on transformer life time, it is important to evaluate the temperature rise of coil winding in vegetable oil in comparison with mineral oil. Four transformers for the test are designed with 10KVA, 13.2㎸, one phase unit. The temperature are directly measured in insulating oil of these transformers with the two sorts of natural ester and mineral oil dielectric fluid respectively. Experiment for aging carry out two means. First means remained 120℃ that transformer of mineral oil were operated at 185% load. Second means is that insulating oils of two natural ester and mineral oil were aged by thermal cycles repeating from 30℃ to 120℃. For the heating, Transformers were operated at 185% load. For the cooling, cooling system was operated in the chamber. Samples were analyzed at 42, 63, 93, 143, 190, 240 300cycles. Analysis contents are dielectric strength, total acid value. Mineral oils compared results of first means with results of second means. And compared two sort natural esters respectively with mineral oil in second means.