• Proceedings of the KIEE Conference
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• 1999.07f
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• pp.2559-2561
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• 1999

The life of a fluorescent lamp is greatly affected by starting scenario and crest factor. This paper will propose a new crest factor control method in electronic ballast for fluorescent lamp using Pulse Frequency Modulation (PFM), which employs a passive Power Factor Correction (PFC) circuit in the input stage. The operation of parellel-loaded circuit, the switching frequency. and the characteristics of electronic ballast with the proposed PFM control scheme are described in detail, and its validity is verified by the simulation results.

• Proceedings of the KIPE Conference
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• 2002.07a
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• pp.746-749
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• 2002

This paper presents a new control method for the high frequency electronic ballast which is operated with raw rectified dc link using diode bridge. For the commercial electronic ballast, proper ac input power factor and crest factor of the lamp current are required. The most ballast, therefore, has a active or passive power factor collection (PFC) circuit. With the proposed method, it can be achieved simultaneously that grater than 0.9 of input power factor and less than 1.85 of lamp current crest factor without any PFC circuit. In this paper, the proposed ballast control scheme and the experimental results for the application to the fluorescent lamp are described.

• Proceedings of the KIEE Conference
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• 1997.07f
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• pp.2072-2074
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• 1997

A new low-cost high power factor correction circuit for electronic ballasts is proposed. The proposed circuit provides good power factor correction, low current harmonic distortion and cost-effectiveness. The prototype meets the IEC555-2 requirements satisfactorily with nearly unity power factor.

• Proceedings of the KIPE Conference
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• 2001.07a
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• pp.268-271
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• 2001

This paper describes the power factor control of doubly fed induction machine using fuzzy logic algorithm in wind power generation system. Under fuzzy logic control, which enables superior dynamic performance, the power factor is independently controllable by decoupled d, q rotor experimental results are presented.

• Smart Media Journal
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• v.6 no.3
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• pp.29-40
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• 2017

Lately weight for smartphone mounted to function for NFC is increasing, rapidly. Because of this, NFC related technology is made by many companies. We developed Gallery-Auction for security enhancements and new services of NFC-based 2 factor electronic payment system. Enhanced security features development of user authentication module through fingerprint recognition to apply FIDO authentication technology and developed electronic contract voice service of Gallery-Auction using TTS(Text to Speech). Therefore we enhanced convenient and simple authentication method and security through NFC mobile electronic payment.

• Journal of Korea Multimedia Society
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• v.22 no.1
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• pp.79-87
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• 2019

Appropriate strategies are needed to ensure long-term preservation of various types of electronic records. For proper preservation of electronic records, it is necessary of decision-making processes for risk assessment, notification and implementation of conservation measures. To do this, the task of assessing various risk factors that impede the long-term preservation and utilization of electronic records should be done first. In this study, since electronic records are mostly stored in file form, risk assessment for electronic records of file type is performed. The risk factors required for the risk assessment of the file format are derived, and the algorithms are developed to devise a calculation method of the weighting factor and the risk factor index for evaluating the risk based on the proposed risk factors. In addition, the proposed methods are applied to the file formats used in Korea and risk assessment is performed and the results are analyzed.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1997.04a
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• pp.245-248
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• 1997

The dielectric resonators(DRs) with dielectric properties are widely used in microwave integrated circuit(MICs) and monolithic microwave integrated circuits(MMICS). The variational method as numerical simulation scheme would be applied to calculate the resonant frequencies(fr) and Q-factors of microwave dielectric resonators. The dielectric resonator with a cylindrical “puck” structure of high dielectric material is modeled in this simulation. The parameters, such as the diameter, the height, and the dielectric constant of dielectric resonator, would determine the resonant frequency and the Q-factor. The relationship between these parameters would effect each other to evaluate the approximate resonant frequency. This simulation method by the variational formula is very effective to calculate fr, and Q-factor. in high frequency microwave dielectric resonator The error rate of the simulation results and the measured results would be considered to design the microwave dielectric resonators.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2001.11a
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• pp.123-127
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• 2001

In this paper, prototype high-power-factor single-stage electronic ballast for fluorescent lamps is designed and implemented. A new low cost single stage high power factor electronic ballast for fluorescent lamps is based on integration of two-boost converter and LC type high frequency resonant converter. A ballast is obtained by simple construction, because full bridge rectifier diode is eliminated and simple control circuit is applied. Using two boost converter operating positive and negative half cycle respectively at line frequency (60Hz), operation in discontinuous conduction mode performs high power factor. The experimental results Show the good performance as PF 0.99, $A_{THD}$ 15.4%, and CF 1.65 at Output 63.5W.W.

• Proceedings of the KIEE Conference
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• 1995.11a
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• pp.242-245
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• 1995

In this paper the multiple three rectifiers for the power factor correction are proposed, analyzed and designed. The multiple three phase rectifiers draw sinusoidal ac currents from the ac voltage sources with nearly unity input power factor and operate with PWM making the control circuit simple and system cost low. Outstandingly it reduces the rated power capacity of devices and the input filter size by reducing input current ripples. Moreover design rules can be obtained from input and output current equations. With the proposed rules, input power factor and output power capacity are determined approximately. Finally these design rules are verified with computer simulations.

• Journal of Power Electronics
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• v.3 no.3
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• pp.175-184
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• 2003

In this paper, a new control scheme of Class-E inverter for reducing the crest factor of electronic ballasts for fluorescent lamps using Pulse-Frequency-Modulation (PFM) is Introduced The lifetime of the lamps is guaranteed by decreasing the lamp crest factor and also voltage stress of the switch is significantly decreased by a new scheme although conventional Class-E Inverter is used In this paper. The proposed PFM control scheme didn't use any auxiliary circuit. The proposed control strategy is executed by feeding back the Input voltage, and the zero-voltage-switching (ZVS) is ensured by maintaining constant turn-off time of the switch Therefore, the control principles of proposed method are explained in detail and its validity is verified through several simulations and experimental results.