• Journal of Power Electronics
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• 제16권5호
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• pp.1861-1868
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• 2016

In this paper, a three-phase AC-DC high step-up converter is developed for application to microscale wind-power generation systems. Such an AC-DC boost converter prossessess the property of the single-switch high step-up DC-DC structure. For power factor correction, the advanced half-stage converter is operated under the discontinuous conduction mode (DCM). Simulatanously, to achieve a high step-up voltage gain, the back half-stage functions in the continuous conduction mode (CCM). A high voltage gain can be obtained by use of an output-capacitor mass and a coupled inductor. Compared to the output voltage, the voltage stress is decreased on the switch. To lessen the conducting losses, a low rated voltage and small conductive resistance MOSFETs are adopted. In addition, the coupled inductor retrieves the leakage-inductor energy. The operation principle and steady-state behavior are analyzed, and a prototype hardware circuit is realized to verify the performance of the proposed converter.

• Journal of Electrical Engineering and Technology
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• 제13권6호
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• pp.2310-2318
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• 2018

Critical conduction mode (CRM) operation is more efficient than continuous conduction mode (CCM) operation at low power levels because of the valley switching of switches and elimination of the reverse recovery losses of boost diodes. When using a sensorless digital control method, an error occurs between the actual and the estimated current. Because of the error, it operates as CCM or discontinuous conduction mode (DCM) during CRM operation and also has an adverse effect on THD of input current. In this paper, a current sensorless technique is presented in an inverter system using a bridgeless boosted power factor correction converter, and a compensation method is proposed to reduce CRM calculation error. The validity of the proposed method is verified by simulation and experiment.

• Journal of Electrical Engineering and information Science
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• 제2권3호
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• pp.88-94
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• 1997

This paper presents the sliding mode observer-model following (SMO-MF) power system stabilizer(PSS) for unmeasurable state variables. This SMO-MF PSS is obtained by combining the sliding mode-model following (SM-MF) including closed-loop feedback(CLF) with the full-order observer(FOO). The control input of the proposed MO-MF PSS is derived by Lyapunov's second method to determine a control input that keeps the system stable for unmeasurable plant state variables. Simulation results show that the proposed SMO-MF PSS including CLF is able to reduce the low frequency oscillation and to achieve asymptotic tracking error between the reference mode state and the estimated plant state at different initial conditions.

• 정보통신설비학회논문지
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• 제9권1호
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• pp.29-34
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• 2010

In this study, we realized the broadband home gateway system of dual mode based upon EDR 2~3Mbps transmission speed and 300Mbps of 802.11n, In broadcasting and telecommunication convergence networks to deliver multimedia services, high-quality home. The bluetooth module is designed to use general low rate data speed service and the 802.11n module also is designed to use high rate speed service at various home network situation. The dual mode home gateway system, bluetooth and 802.l1n module, is well realized for many specification such as emission power, spurious power, impedance matching, frequency channel test.

• 항공우주시스템공학회지
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• 제14권6호
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• pp.79-84
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• 2020

Cooler driver electronics (CDE) for maintaining low temperature of the satellite payload IR sensor consists of a compressor that has a pulsation current load condition when it is operated. This pulsation current produces large voltage fluctuation, which affects both load and regulated bus stability. Thus, CDE power conditioning system consists of a primary bus, infrared power distribution unit for battery charging and protection, reverse current protection diode, and battery, which is used as a buffer. In this study, the operational mode analysis is performed by each part with equivalent impedance modeling verified through system level simulation. From this mode analysis, the safety margin for state of charge and open circuit voltage of the battery is determined for satisfying the minimum operational voltage of the CDE load.

• 전자공학회논문지C
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• 제35C권2호
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• pp.36-47
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• 1998

Low power circuit techniques have been developed to realize the highest possible performance of embedded SRAM at 1V power supply with$0.5\mu\textrm{m}$ single threshold CMOS technology in which the unbalance between NMOS and PMOS threshold voltages is utilized to optimize the low power CMOS IC design. To achieve the best trade-off between the transistor drivability and the subthreshold current increase, the ground potential of memory array is raised to suppressthe subthreshold current. The problems of lower cellstability and bit-line dealy increase due to the enhanced array ground potential are evaluated to be controlled within the allowable range by careful circuit design. 160MHz, 128kb embedded SRAM with 3.4ns access time is demonstrated with the power consumption of 14.8mW in active $21.4{mu}W$ in standby mode at 1V power supply.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 제38회 하계학술대회
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• pp.1560-1561
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• 2007

Electrodeless fluorescent lamp exhibit two modes of operation : a low density mode in which the power is capacitively coupled to the plasma and which is known as the E-mode, and a higher density mode which is an inductive discharge known as the H-mode. The transition between these two(E to H) mode exhibits hysteresis. It is observed that transition currents change at different frequencies and hysteresis exists not only between the starting and minimum maintaining currents of the electromagnetic mode (H mode) discharge but also between the starting and minimum maintaining currents of the electrostatic mode (E mode) discharge. Hysteresis effect can be important role in dimming system.

• 대한전자공학회논문지SD
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• 제45권6호
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• pp.28-36
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• 2008

본 논문에서는 UHF 대역 RFID 태그(tag) 칩을 위한 저전력 CMOS 아날로그 회로를 설계하였다. 설계된 아날로그 front-end 블록은 국제표준인 ISO/EC 18000-6C 표준규격을 따르며, 성능테스트를 위한 메모리 블록을 포함하고 있다. 모든 회로를 1V에서 동작하도록 하여 세부 회로들의 전력소모를 최소화 하였으며, 보다 적은 전류소모로 정확한 복조를 위해 전류 모드 슈미트 트리거를 이용한 ASK 복조기를 제안 하였다. 설계된 회로는 $0.18{\mu}m$ CMOS 공정을 이용하여 칩으로 제작되었으며, 측정결과 최소 $0.25V_{peak}$ 입력으로 동작 가능하였고, 1V 전원전압에서 $2.63{\mu}A$의 전류소모를 갖는다. 칩 면적은 $0.12mm^2$이다.

• Journal of Power Electronics
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• 제13권4호
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• pp.592-599
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• 2013

This paper investigates a new isolated single-phase AC-DC converter, which integrates a modified AC-DC buck-boost converter with a DC-DC forward converter. The front semi-stage is operated in discontinuous conduction mode (DCM) to achieve an almost unity power factor and a low total harmonic distortion of the input current. The rear semi-stage is used for step-down voltage conversion and electrical isolation. The front semi-stage uses a coupled inductor with the same winding-turn in the primary and secondary sides, which is charged in series during the switch-on period and is discharged in parallel during the switch-off period. The discharging time can be shortened. In other words, the duty ratio can be extended. This semi-stage can be operated in a larger duty-ratio range than the conventional AC-DC buck-boost converter for DCM operation. Therefore, the proposed converter is suitable for universal input voltage (90~264 $V_{rms}$) and a wide output-power range. Moreover, the voltage stress on the DC-link capacitor is low. Finally, a prototype circuit is implemented to verify the performance of the proposed converter.

• 한국화재소방학회논문지
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• 제26권1호
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• pp.74-79
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• 2012

본 논문은 2011년 개정된 "감지기 형식승인 및 검정기술기준"에 적합한 단독경보형 감지기 개발에 관한 연구이다. 변경된 내용의 가장 큰 특징은 전원이다. 10년 이상 사용 가능한 단독경보형 감지기를 개발하기 위해 나노전력기술이 사용된 저전력 마이크로컨트롤러를 사용하였다. 마이크로컨트롤러의 슬립모드를 활용하고, 저전력의 전원감시부, 열감지부 및 연기감지부를 제작하여 저전력 단독경보형 감지기를 개발하였다. 특히, 비화재보를 줄이기 위해 단독경보형 감지기는 열연 복합식으로 개발되었다. 사용자는 딥스위치를 이용하여 열감지모드 또는 열 연기감지모드로 동작형태를 선택할 수 있다. 마이크로컨트롤러가 지원하는 RS-485 통신기능을 활용하여 유선으로 단독경보형 감지기 간에 통신이 가능하도록 하였다. 이로써 화재발생시 보다 넓은 지역까지 경보를 알릴 수 있고 비화재보를 줄인 열연 복합식 단독경보형 감지기를 개발하였다.