• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제49권3호
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• pp.159-164
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• 2000

This paper treats the optimization of rotor construction in the permanent magnet synchronous motor (PMSM) for electric vehicle (EV). While the field system of PMSM has generally one magnet per pole, we replace the magnet into plural sub-magnets. The dimensions of each sub-magnet are determined by the concept of pulse width modulation (PWM). By adopting the proposed rotor construction, we can not only reduce the space harmonics of the air-gap field but also provide space for rotor bars (i.e., damper windings) around the direct-axis. From the investigation by hybrid EE-BE (coupled finite element and boundary element) method coupled with both electric circuit and motion equation, we verify that the construction is effective for practical use.

• 스마트미디어저널
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• 제8권3호
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• pp.47-52
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• 2019

In this paper, we designed HW / SW interfaces for processing the signals of capacitive sensors like Electric Potential Sensor (EPS) to detect the surrounding electric field disturbance as feature signals in motion recognition systems. We implemented a smart light control system with those interfaces. In the system, the on/off switch and brightness adjustment are controlled by hand gestures using the designed and fabricated interface circuits. PWM (Pulse Width Modulation) signals of the controller with a driver IC are used to drive the LED and to control the brightness and on/off operation. Using the hand-gesture signals obtained through EPS sensors and the interface HW/SW, we can not only construct a gesture instructing system but also accomplish the faster recognition speed by developing dedicated interface hardware including control circuitry. Finally, using the proposed hand-gesture recognition and signal processing methods, the light control module was also designed and implemented. The experimental result shows that the smart light control system can control the LED module properly by accurate motion detection and gesture classification.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2020년도 전력전자학술대회
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• pp.230-232
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• 2020

식품을 보다 신선하고 오래 보관하기 위하여 처리 및 보존에 관한 여러 방법들이 연구되고 있다. 특히 열에 민감한 유제품 또는 액체 식품들에 대하여 열을 가하지 않는 비열처리 방식의 기술들이 연구되고 있다. 그 중 식품 내 미생물의 활성화와 고유한 속성의 변화를 최소화하는 방법으로 Pulsed Electric Field 방식에 대한 연구가 활발히 진행되고 있다. 하지만 해당방식은 기존의 열처리 방식에 비해 경제적인 면에서 단점을 가지고 있다. 이에 본 논문에서는 기존 Pulsed Electric Filed 방식의 효율을 높이고 비용을 저감할 수 있는 회로를 제안한다. 전압제어 방식의 DC/DC Power stage 부를 전류제어 방식으로 바꾸어 기존 회로의 Charging resistor를 사용하지 않음으로써 전력손실을 줄이고 비용 및 전기요금을 줄이고자 하였다. 본 논문에서는 시뮬레이션을 통해 제안회로를 검증하였다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1998년도 전력전자학술대회 논문집
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• pp.162-165
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• 1998

The non-thermal pasteurization of foods using High Voltage High Current Pulsed Electric Fields (HVHC-PEF) is a promising technology and a sound complement or replacement to traditional thermal pasteurization. The conventional thermal method also inactivates bacteria and other microorganisms harmful to humans, but degrades natural color, flavor, texture and nutrients. At this point, a nonthermal pasteurization technique, HVPEF is thought to be a new processing technique which is able to produce a good quality foods nutritional as well as sensuous. In this paper, the system for HVHC-PEF pasteurization is presented. It use square wave pulse instead of exponential ones. So, power rating of system is reduced considerably. Design considerations for 20kV 500A class equipment are analyzed and experimental results are discussed.

• KIEE International Transactions on Electrophysics and Applications
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• 제11C권4호
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• pp.120-126
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• 2001

For the past five years, Inha University has been observing the electric fields produced by cloud-to-ground return strokes. This paper presents the summary of most recent results. Statistics on the zero-to-peak rise time, the zero-to-zero crossing time and the amplitude ratio of the second peak in the opposite polarity to the first peak were examined. The radiation electric fields produced by distant cloud-to-ground return strokes were substantially same pattern. The first return stroke field starts with a slowly increasing front and rises abruptly to peak. The rising portions of the electric fields produced by cloud-to-ground return strokes last 1 $mutextrm{s}$ to a few $mutextrm{s}$. The mean values of the zero-to-peak rise times of electric fields were 5.72 $mutextrm{s}$ and 4.12 $mutextrm{s}$ for the positive and the negative cloud-to-ground return strokes, respectively. The mean of the zero-to-zero crossing time for the positive return strokes was 29.48 $mutextrm{s}$ compared with 38.54 $mutextrm{s}$ for the negative return strokes. The depths of the dip after the peak of return stroke electric fields also have the dependence on the polarity of cloud-to-ground return stroke, and the mean values for the positive and negative cloud-to-ground return strokes were 33.55 and 28.19%, respectively.

• 조명전기설비학회논문지
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• 제25권8호
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• pp.39-47
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• 2011

The motion of a conductive spherical particle under uniform electric field is investigated in order to find a suitable method for removing the conducting solid impurities contained in liquid plastic. When the positive dc voltage applied to the upper electrode, the vertical up-and-down motion of a charged particle by electrostatic force is observed by a charge-coupled device (CCD) camera or a high-speed video camera. The experimental data of the static threshold voltage by which the particle starts to move toward the counter electrode in air or silicone oil are in good agreement with theoretical value. When the applied voltage is larger than the static threshold voltage, the particle motion pattern in silicone oil consists of four stages: upward motion, stopping at the upper electrode, downward motion and stopping at the lower electrode. The stopping motion on the electrode is thought to be caused by the liquid flow accompanied by the particle motion. The particle charge calculated by integrating the pulse current, which is generated by the charge exchange between the electrode and the particle, is approximately 0.1~0.25 times of the theoretical value. This study is expected to help understand the electric properties of microparticles in oil circuit breaker (OCB) and oil transformer and improve their performance and longevity.

• 한국자기학회지
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• 제16권4호
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• pp.216-220
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• 2006

10개의 다중 홀(Hall)소자를 이용하여 요골동맥에 놓여진 영구자석의 위치 변화에 따른 전압의 변화를 전기적 신호로 얻었다.전기적 신호는 맥의 파형 신호를 의미하며 이들을 다시 회로의 하드웨어를 통해 신호들을 미분하여 자장의 변화 신호만 얻었다.소프트웨어를 통해 위치 변화에 따른 자장 변화의 크기에 따라 그 형태를 3차원 영상을 얻어 착용형 맥진기로서의 개발 가능성을 보여주었다.

• 동굴
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• 제76호
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• pp.37-42
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• 2006

The Dielectric Barrier Discharge (DBD) is a nonequilibrium gas discharge that is generated in the space between two electrodes, which are separated by an insulating dielectric layer. The dielectric layer can be put on either of the two electrodes or be inserted in the space between two electrodes. If an AC or pulse high voltage is applied to the electrodes that is operated at applied frequency from 50Hz to several MHz and applied voltages from a few to a few tens of kilovolts rms, the breakdown can occur in working gas, resulting in large numbers of micro-discharges across the gap, the gas discharge is the so called DBD. Compared with most other means for nonequilibrium discharges, the main advantage of the DBD is that active species for chemical reaction can be produced at low temperature and atmospheric pressure without the vacuum set up, it also presents many unique physical and chemical process including light, heat, sound and electricity. This has led to a number of important applications such as ozone synthesizing, UV lamp house, CO2 lasers, et al. In recent years, due to its potential applications in plasma chemistry, semiconductor etching, pollution control, nanometer material and large area flat plasma display panels, DBD has received intensive attention from many researchers and is becoming a hot topic in the field of non-thermal plasma.

• 한국전기전자재료학회논문지
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• 제31권1호
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• pp.44-49
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• 2018

This study analyzed the Vulnerability of Network Communication devices when IEMI is coupled with the Network System. An Ultra Wide Band Generator (180 kV, 700 MHz) was used as the IEMI source. The EUTs are the Switch Hub and Workstation, which are used to configure the network system. The network system was monitored through the LAN system configuration, to confirm a malfunction of the network device. The results of the experiment indicate that a malfunction of the network occurs as the electric field increases. The data loss rate increases proportionally with increasing radiating time. In the case of the Switch Hub, the threshold electric field value was 10 kV/m for all conditions used in this experiment. The threshold point causing malfunction was influenced only by the electric field value. The correlation between the threshold point and pulse repetition rate was not found. However, in case of the Workstation, it was found that as the pulse repetition rate increases, the equipment responds weakly and the threshold value decreases. To verify the electrical coupling of the EUT by IEMI, current sensors were used to measure the PCB line inside the EUT and network line coupling current. As a result of the measurement, it can be inferred that when the coupling current due to IEMI exceeds the threshold value, it flows through the internal equipment line, causing a malfunction and subsequent failure. The results of this study can be applied to basic data for equipment protection, and effect analysis of intentional electromagnetic interference.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2004년도 제22회 춘계학술대회논문집
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• pp.271-277
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• 2004

As one of the concepts of the laser/electric hybrid propulsion system, a feasibility study on possibilities of electrostatic acceleration of a laser ablation plasma induced from a solid target was conducted. Energy distributions of accelerated ions were measured by a Faraday cup. A time-of-flight measurement was also conducted for ion velocity measurement. It was found that an average speed of ions from a pure laser ablation in this case was about 20 km/sec for pulse energy of 40 $\mu$J/pulse with pulse width of 250 psec. On the other hand, through an electrostatic field with a + I ,000 V electrode, the speed could be accelerated up to 40 km/sec. It was shown that the electrode with positive potential was more effective than that with negative potential for positive-ion acceleration in laser induced plasma, or pulsed plasma, in which ions were induced with the Coulomb explosion following electrons. In addition, the ion-acceleration or deceleration strongly depended on conditions of pairs of inner diameter and electrodes gap.