• Proceedings of the KIEE Conference
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• 2002.11c
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• pp.290-293
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• 2002

For small capacity rectifier circuits such as these for consumer electronics and appliances, capacitor input type rectifier circuits are generally used. Consequently, various harmonics generated within the power system become a serious problem. Various studies of this effect have been presented previously. However, most of these employ switching devices, such as FETs and the like. The absence of switching devices makes systems more tolerant to over-load, and brings low radio noise benefits. We propose a power factor connection scheme using a LC resonant in commercial frequency without switching devices. In this method, It makes a sinusoidal wave by widening conduction period using the current resonance in commercial frequency, Hence, the harmonic characteristics can be significantly improved, where the lower order harmonics, such as the fifth and seventh orders are much reduced. The result are confirmed by the theoretical and experimental implementations.

• Food Science and Biotechnology
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• v.14 no.5
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• pp.672-675
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• 2005

Two anthocyanins were isolated from 1% HCl-20% methanol extracts of KG 97287 black common bean (Phaseolus vulgaris L.) using semipreparative, high-performance liquid chromatography (HPLC). The anthocyanins were identified using a combination of LC/ES-mass spectrometry (MS) and spectroscopic methods of UV-Vis, $^1H-$ and $^{13}C-$ nuclear magnetic resonance (NMR). The chemical structures of these two anthocyanins were elucidated as delphinidin 3-glucoside and petunidin 3-glucoside and their contents in KG 97287 black common bean seed coats were determined to be $2.614{\pm}0.11$ and $0.167{\pm}0.01\;mg/g$, respectively. These contents were lower than reported internationally and we recommend the introduction into Korea of high anthocyanin varieties of black common bean.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.28 no.11
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• pp.9-16
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• 2014

The electronic ballast for HID lamps needs high ignition voltage which is consisted of high voltage pulse ignitor. However, In the case of street lamp it is far from a lamp to a ballast, the conventional pulsed high voltage ignitor can not turn on the HID lamps because of reduction of ignition voltage. Therefore, it needs to do the research on a resonant ignition to turn on the HID lamps. However, the resonant circuit which is consisted of LC occurs over current, so the capacity of the ignitor increases. The capacity of the ignitor can be reduced by using the transformer. In this case, the capacitor for resonance is installed to the secondary of the transformer, and the capacitor needs high withstanding voltage. Therefore, it needs to do the research on a resonant ignition to reduce the voltage over the resonant capacitor by dividing the secondary of the transformer.

• The Transactions of the Korean Institute of Power Electronics
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• v.21 no.2
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• pp.150-159
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• 2016

This paper presents a study on the design optimization of a 5 kW plasma discharger for driving plasma reactor. The proposed study is composed of a high-frequency inverter based on the full-bridge circuit using soft switching techniques for high-frequency switching. The switching frequency in the operating region is the area of 130-200 kHz. By applying the LC resonance technique and a variable switching frequency, control technique is designed to be stable under changes in the load characteristics of the plasma reactor. This paper presents a quantitative analysis technique for design optimization. Experiments are performed according to load characteristic variations depending on the vacuum of the plasma reactor. This paper has verified the topology and design method for the 5 kW plasma discharger design.

• Journal of Information Display
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• v.2 no.4
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• pp.63-67
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• 2001

The switching power loss due to the panel capacitance during sustain period in AC PDP driving system can be minimized by using the energy recovery circuits. We proposed a new energy recovery circuit, SER1 (Seoul national univ. Energy Recovery circuit 1st). The experimental results of its application to a 42-inch surface discharge type AC PDP showed superior performance of SER1 in energy recovery efficiency and low distortion voltage waveform. Energy recovery efficiency of SER1 was measured up to 92.3 %, and the power dissipation during the sustain period was reduced by 15.2 W in 2000 pulse/frame compared with serial LC resonance energy recovery circuit.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2003.11a
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• pp.403-406
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• 2003

For small capacity rectifier circuits such as these for consumer electronics and appliances, capacitor input type rectifier circuits are generally used. Consequently, various harmonics generated within the power system become a serious problem. Various studies of this effect have been presented previously. However, most of these employ switching devices, such as FET and the like. The absence of switching devices mattes systems more tolerant to over-load and brings low radio noise benefits. We propose a power factor correction scheme using a LC resonant in commercial frequency without switching devices. In this method It makes a sinusoidal wave by widening conduction period using the current resonance in commercial frequency, Hence, the harmonic characteristics can be significantly improved, where the lower order harmonics, such as the fifth and seventh orders are much reduced The result are confirmed by the theoretical and experimental implementations.

• Journal of Power Electronics
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• v.15 no.4
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• pp.987-993
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• 2015

Wireless power transfer technologies typically include inductive coupling, magnetic resonance, and capacitive coupling methods. Among these methods, capacitive coupling wireless power transfer (CCWPT) has been studied to overcome the drawbacks of other approaches. CCWPT has many advantages such as having a simple structure, low standing power loss, reduced electromagnetic interference (EMI) and the ability to transfer power through metal barriers. In this paper, the CCWPT system with 6.78MHz class D inverter is proposed and analyzed. The proposed system consists of a 6.78MHz class D inverter with a LC low pass filter, capacitor between a transmitter and a receiver, and impedance transformers. The system is verified with a prototype for charging mobile devices.

• Proceedings of the KIPE Conference
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• 2015.11a
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• pp.121-122
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• 2015

무선 전력 전송에서 자기장을 이용하는 방식은 인덕티브 커플링 방식과 자기 공진 방식이 있다. 자기 공진 방식은 송수신 코일의 크기를 작게 할 수 있고, 인덕티브 방식보다 전력 수신할 수 있는 범위가 넓다. 본 논문에서는 모바일 기기를 위한 자기 공진 무선 전력 전송의 표준 주파수로 유력한 6.78MHz 시스템을 구성하고, 직렬 공진 송신과 병렬 공진 수신을 제안한다. 전자파 노이즈를 억제하기 위하여 LC Low Pass Filter를 추가한 Half-bridge 인버터 송신 회로를 사용하여, 5.5W급 Smart phone 충전을 위한 Prototype을 제작 및 동작과 특성을 검증하였다.

• Bulletin of the Korean Chemical Society
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• v.32 no.4
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• pp.1170-1178
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• 2011

In the present study, the approach of high accuracy mass measurements for phospholipid identifications was evaluated using a 7 T ESI-FTMS/linear ion trap MS/MS. Experiments were carried out for porcine brain, bovine liver, and soybean total lipid extracts in both positive and negative ion modes. In total, 59, 55, and 18 phospholipid species were characterized in the positive ion mode for porcine brain, bovine liver, and soybean lipid extracts, respectively. Assigned lipid classes were PC, PE, PEt, PS, and SM. In the negative ion mode, PG, PS, PA, PE, and PI classes were observed. In the negative ion mode, for porcine brain, bovine liver, and soybean lipid extracts, 28, 34, and 29 species were characterized, respectively. Comparison of our results with those obtained by other groups using derivatization-LC-APCI MS and nano-RP-LC-MS/MS showed that our approach can characterize PC species as effectively as those methods could. In conclusion, we demonstrated that high accuracy mass measurements of total lipid extracts using a high resolution FTMS, particularly, 7T FTMS, plus ion-trap MS/MS are very useful in profiling lipid compositions in biological samples.

• The Journal of the Korea Contents Association
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• v.18 no.10
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• pp.425-430
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• 2018

The battery system of an electric vehicle suffers from the problem the battery output and the service life decrease at low temperature. A Positive Temperature Coefficient(PTC) heater is used for maintaining room temperature but is heavy due to a complicated insulation structure. The larger the weight is, the lower the fuel economy of the electric vehicle is. On the other hand a induction heater have a simple insulation structure, which is effective in weight reduction and has a rapid temperature rise. The induction heater consists of an LC resonance circuit. The larger the capacitance is, the higher the price and weight is. Therefore, the inductance should be increased to reduce the capacitance. Also, the main heat source of the induction heater is coreloss. So, it is important to optimize inductance and coreloss in terms of electromagnetic field design. In this paper, the inductance and the coreloss according to the change of the induction heater structure were optimized through the Taguchi method and Finite Element Method(FEM) simulation.